EJE
Recovery of adrenal function after stopping mitotane in patients with adrenocortical carcinoma
Barbara Altieri,1,1[D Otilia Kimpel, 1,1(D Felix Megerle, 10 Mario Detomas, 10D Irina Chifu, 16 İD
Carmina Teresa Fuss,1 Marcus Quinkler,20D Matthias Kroiss, 1,3 and Martin Fassnacht
1,4,5,* İD
1Division of Endocrinology and Diabetes, Department of Internal Medicine I, University Hospital, University of Würzburg, Oberduerrbacher Strasse 6, 97080 Würzburg, Germany
2Endocrinology in Charlottenburg, Stuttgarter Platz 1, 10627 Berlin, Germany
3Department of Internal Medicine IV, University Hospital, Ludwig-Maximilians-University Munich, Ziemssenstrasse 1, 80336 Munich, Germany AComprehensive Cancer Center Mainfranken, University of Würzburg, Josef-Schneider-Strasse 6, 97080 Würzburg, Germany 5Central Laboratory, University Hospital Würzburg, Oberduerrbacher Strasse 6, 97080 Würzburg, Germany
*Corresponding author: Division of Endocrinology and Diabetes, Department of Internal Medicine I, University Hospital of Würzburg, Oberduerrbacher Str 6, Würzburg 97080, Germany. Email: Fassnacht_M@ukw.de
Abstract
Objective: Mitotane is the standard therapy of adrenocortical carcinoma (ACC) due to its relative selectivity of its cytotoxic effects toward adrenocortical cells. Therefore, it virtually always leads to adrenal insufficiency. Frequency and characteristics of hypothalamic-pituitary- adrenal axis recovery after discontinuation are ill-defined.
Methods: This was a retrospective study of patients with ACC adjuvantly treated with mitotane for ≥12 months who were disease-free at mitotane stop and had a minimum follow-up ≥1 year. Primary endpoint was adrenal recovery. Cox regression analyses were used to identify predictive factors. Moreover, mitotane plasma elimination rate and hormonal changes after mitotane stop were investigated.
Results: Fifty-six patients (36 women) treated with mitotane for a median time of 25 months and an average daily dose of 2.8 g were included. Median time after discontinuation until mitotane levels dropped below 5 and 2 mg/L, and the detection limit was 152 days (interquartile range: 114-202), 280 days (192-370), and 395 days (227-546), respectively. Full adrenal recovery was documented in 32 (57%) patients after a median time of 26 months (95% confidence interval [CI] = 19.6-32.4). In 4 patients (7.1%), adrenal insufficiency persisted >5 years after discontinuation. Mitotane peak ≥ 27 mg/L significantly correlated with longer time to adrenal recovery (hazard ratio [HR] = 0.2, 95% CI = 0.1- 0.8, P =. 03). Twenty-seven of 38 patients (71%) followed in reference centers achieved adrenal recovery compared with only 5/18 (28%) followed up in non-reference centers (HR = 4.51, 95% CI = 1.71-11.89, P =. 002). Other investigated factors were not associated with adrenal function after discontinuation.
Conclusions: Our study demonstrates that adrenal recovery occurs in most patients after stopping mitotane, particularly when followed up in specialized centers, but not in all. Elimination time of mitotane after treatment discontinuation is very long but individually quite variable.
Keywords: mitotane discontinuation, drug exposure, adrenal insufficiency, HPA axis, ACTH
Significance
Mitotane is the first-line medical treatment in patients with adrenocortical carcinoma. It is well known that adrenal function can recover after its discontinuation. However, little is known about the frequency or predictors of adrenal recovery, al- though this is an important information for patients. Here, we demonstrate that adrenal function recovers in most patients, in median after 26 months with a wide range (3-67 months). Mitotane plasma levels (ie, maximum peak ≥ 27 mg/L) signifi- cantly correlate with a longer time to adrenal recovery. The other strong predictor was follow-up at a reference center, sug- gesting that education on glucocorticoid reduction and close monitoring might be the key to adrenal recovery. Mitotane plasma levels decline slowly after its discontinuation and require more than 1 year to become undetectable. This information might be crucial for planning future medical therapies in patients with adrenocortical carcinoma who experience progressive disease under mitotane treatment.
Introduction
Adrenocortical carcinoma (ACC) is a rare malignancy with an incidence of 1 to 2 cases per million persons per year. Even
after complete resection, the rate of recurrence is high and many patients die from metastatic disease. To reduce the risk of recurrence, adjuvant mitotane treatment was intro- duced many decades ago1,2 and more recent studies and guide- lines have further suggested its value.3-9 Although the recent
+ B.A. and O.K. contributed equally.
phase III ADIUVO trials demonstrated that adjuvant mitotane might not be indicated in patients with low-grade ACC (com- plete tumor resection, tumor stages I-III, and Ki67 ≤ 10%),10 adjuvant mitotane is still recommended in patients at high risk of recurrence representing most of ACC cases. 3,4,11
The mechanism of mitotane action on adrenal cortex cells is not fully understood12,13 and involves endoplasmic reticulum stress,14,15 mitochondrial damage, and down- regulation of different mitochondrial enzymes involved in the steroidogenesis,16-18 resulting in a reduction of steroid production.12 In addition, a strong induction of CYP3A4 by mitotane leads to a rapid metabolic clearance of many hormones (including glucocorticoids) and drugs,19-21 ex- plaining a decrease in cortisol bioavailability. Although it is unclear to which extent mitotane is also toxic to normal cells of the adrenal cortex, the above described effects to- gether result in adrenal insufficiency in virtually all treated patients.3,22 Therefore, replacement of glucocorticoids and sometimes mineralocorticoids is an essential part of the man- agement of patients treated with mitotane.3,22 In addition, mitotane might affect the hypothalamic-pituitary-adrenal (HPA) axis at diverse levels, eg, by decreasing the adrenocor- ticotropic hormone (ACTH) levels23 and an inhibitory effect on the pituitary cells.24 Thus, patients under mitotane in addition to the primary adrenal insufficiency may experience a partial inhibition of the pituitary function.
Clinical experience tells that the HPA axis can recover after mitotane discontinuation, and clinicians are often faced with the challenge of trying to predict the likelihood of restoration of normal adrenal function. Until now, there are only 2 small studies that investigated adrenal recovery after mitotane treat- ment in a total of 47 patients with ACC. They reported restor- ation of the adrenal function in 62.5% and 78.3% of patients, respectively.25,26 However, no information about the fre- quency of repeat dynamic testing have been described and no predictive factors for adrenal recovery could be estab- lished.25,26 In addition to that, information about the HPA hormones change after the stop of mitotane is still missing.
Moreover, mitotane comes with multiple pharmacokinetic in- teractions with other drugs due to its capacity as one of the stron- gest inducers of CYP3A4. Its long half-life frequently prevents the successful administration of other anticancer drugs, above all tyrosine kinase inhibitors,20,27-30 in case of disease progres- sion. However, data on the exact half-life or the time until mito- tane is completely eliminated after the drug is stopped are extremely scarce.31 Therefore, contemporary data on the mito- tane plasma disappearance rate after termination are urgently needed to guide clinicians to plan future treatment of a given pa- tients that interfere with mitotane even after discontinuation.
The aim of this study was to retrospectively investigate HPA axis recovery after adjuvant treatment with mitotane in a larger cohort of patients with ACC and to investigate possible factors influencing adrenal recovery that could be helpful for the clini- cians to identify group of patients in whom a normal adrenal function is likely or not to be restored. Moreover, we investi- gated the elimination time of mitotane after its discontinuation as well as the change of ACTH and adrenal hormonal levels.
Subjects and methods
Study population
This retrospective cohort study was part of the European Network for the Study of Adrenal Tumors (ENSAT) registry
study (www.ensat.org/registry) in 3 German reference centers for ACC (Würzburg, Berlin, and Munich). The study was con- ducted in accordance with the principles of the Declaration of Helsinki and approved by the local Ethics Committees of the Universities of Wuerzburg, Charité Berlin, and Munich. All patients provided written informed consent.
Patients with histologically proven ACC and adjuvant mito- tane treatment for a minimum of 12 months were included if they discontinued mitotane at a time when no evidence of dis- ease was present. Patients with lack of relevant information on primary diagnosis or follow-up or with disease recurrence within the first 5 years after mitotane discontinuation before adrenal recovery and who started new medical treatment (in- cluding mitotane) were excluded. Patients with concomitant systemic adjuvant or neo-adjuvant anti-tumor treatment as well as radiotherapy of the tumor bed during mitotane treat- ment were also eligible. We consecutively enrolled all patients who qualified for these selection criteria that were treated with adjuvant mitotane between 2000 and 2020 in one of the refer- ence centers. Follow-up was closed in December 2022. Patients initially treated in our centers who had their follow- up visits after the discontinuation of mitotane in other non- reference centers (including general practitioner or other hospitals treating <25 patients with ACC per year) were also included.
Demographic, clinical, and histological parameters, includ- ing sex, body mass index (BMI), body surface area (BSA), age at mitotane start and discontinuation, evidence of hormonal excess, ENSAT tumor stage,32 as well as comprehensive data (see below) on mitotane and glucocorticoid replacement ther- apy, mineralocorticoid replacement with fludrocortisone, ad- renal function, and gamma-glutamyl transferase (GGT), were retrieved from the ENSAT ACC registry and medical records.
Details on mitotane treatment and glucocorticoid replacement therapy
The following information on mitotane treatment was captured: duration of mitotane treatment, mitotane dose and plasma levels at each available measurement during treatment, as well as plas- ma levels after mitotane discontinuation. Mitotane blood con- centration was centrally measured using the Lysosafe® service provided for free by HRA Pharma for all patients treated with mitotane in Europe (https://lysosafe.clinfile.com). Mitotane ex- posure was expressed as the area under the curve (AUC) of mito- tane plasma levels.33 Cumulative dose of mitotane (g) was estimated as the sum of the reported daily dose of mitotane multi- plied for the number of days on the respective dosage of mitotane during the entire period of treatment. Cumulative mitotane dose was also evaluated adjusted for BSA (g/m2). Mitotane average daily dose (g/d) was calculated as cumulative dose divided by the days of treatment.
Except for 1 patient treated with dexamethasone, all pa- tients received hydrocortisone (HC) as glucocorticoid replace- ment therapy. To permit a comparison of the replacement therapy, HC equivalent (HCeq) dose was calculated for the patient who received dexamethasone as follows: 1 mg dexa- methasone = 30 mg HC.34 HCeq dose before and after mito- tane discontinuation was collected for each available time point. Cumulative HCeq dose (sum of the daily dose multi- plied by the number of days on the respective HCeq dosage during the entire period of treatment, mg) during the time of
mitotane therapy and the HCeq average dose (cumulative dose/days of treatment, mg/d) were evaluated. Both cumula- tive ad average HCeq were adjusted for BSA (mg/m2 and mg/d xm2).
Hormonal assessment
All available morning laboratory values for cortisol, ACTH, dehydroepiandrosterone sulfate (DHEAS), aldosterone, renin, and GGT were collected, as well as the results of all performed corticotropin stimulation test (also known as ACTH 1-24 stimulation test or short Synacthen test).35,36
Serum cortisol, both basal and after corticotropin stimula- tion test, and ACTH plasma levels were analyzed using stand- ard Immunoassays (Immulite 2000 XPi, Siemens Healthcare GmbH, in Würzburg and Berlin, and CLIA, Liaison, DiaSorin, in Munich). For cortisol, ACTH, and corticotropin stimulation test, patients were instructed to interrupt their glucocorticoid supplementation for at least 18 h prior to the analysis. Corticotropin stimulation test was performed be- tween 8 and 12 AM, and serum cortisol was measured before and 60 min after intravenous bolus injection of 250 µg cor- ticotropin.35 The frequency of repeat testing was individually decided by clinicians on a case-by-case basis.
Regarding the other adrenal steroids, serum aldosterone and plasma renin concentrations were measured by Coat-a-Count® RIA (Siemens) and by Renin III Generation RIA (Cisbio), respect- ively, until September 2014, and from October 2014 by an auto- mated chemiluminescence immunoassay (CLIA, iSYS, Immuno Diagnostic Systems). Dehydroepiandrosterone sulfate was meas- ured by chemiluminescence immunoassay (Siemens Immulite 2000 XPi) up to 2017. Since 2017, all the above steroid measure- ments were performed in Würzburg by liquid chromatography tandem mass spectrometry (LC-MS/MS). In Berlin, aldosterone, renin, as well as DHEAS concentrations were measured by im- munoassay (CLIA, Liaison, DiaSorin). In Munich, plasma aldosterone concentration was measured using radioimmuno- assay by Coat-a-Count® RIA (Siemens) until 2014 and was re- placed by the chemiluminescence immunoassay (CLIA, Liaison, DiaSorin). Chemiluminescence immunoassay was used also for the measurement of renin and DHEAS (CLIA, Liaison, DiaSorin).
Outcome assessment
Adrenal recovery and time to adrenal recovery were defined as the primary outcomes for the present analysis. The assessment of adrenal recovery was based on laboratory values and de- tailed clinical information provided in the medical records. Complete adrenal recovery was considered when serum corti- sol concentration after corticotropin stimulation test reached a peak of at least 500 nmol/L (18 µg/dL).35 If no corticotropin stimulation test was performed, recovery of the HPA axis was assumed if the patient had stopped the glucocorticoid replace- ment therapy without any symptoms of adrenal insufficiency for at least 8 weeks and the morning serum cortisol was at least ≥140 nmol/L (5 µg/dL).35 Insufficient adrenal recovery was considered when serum cortisol levels after corticotropin stimulation test were <276 nmol/L (10 µg/dL)37,38 or morning serum cortisol concentration was <140 nmol/L (5 µg/dL)35 or if the patient was under glucocorticoid replacement with HCeq dose more than 10 mg/day. All cases with cortisol levels that do not fit in the criteria of either complete or insufficient adrenal recovery were considered as partial adrenal recovery.
Partial recovery was considered if the patient did not achieve a complete HPA recovery and had serum cortisol levels after corticotropin stimulation test between 276 and 500 nmol/L (10-18 µg/dL) or morning serum cortisol was ≥140 nmol/L (5 µg/dL) and the patient was under HCeq dose ≤ 10 mg/ day. The cutoff of 10 mg/day HCeq dose to differentiate insuf- ficient or partial recovery is what we routinely use in our clin- ical practice.
Time to adrenal recovery was defined as the time elapsed from the first day of mitotane discontinuation to the date the definition of adrenal recovery was met. Patients who did not achieve HPA recovery were censored at the day of the last follow-up.
Statistical analysis
Data were analyzed using SPSS v.26 (IBM SPSS Statistics) and GraphPad Prism (version 9.0, La Jolla, CA, USA). Distribution of the data was evaluated by the Shapiro-Wilk test. Continuous variables were reported as median with lower and upper quartiles (Q1-Q3) if not otherwise specified whereas cat- egorical variables as numbers and percentages. Two-sided t test or Mann-Whitney test and analysis of variance (ANOVA) or Kruskal-Wallis test were used to compare continuous variables, as appropriate, while chi-square (x2) test was used to compare categorical variables. The AUC of mitotane plasma levels during the treatment and the AUC of mitotane dose were calculated us- ing the linear trapezoid method considering all the available con- centrations and doses during the treatment per each patient. Fitted-smoothing curves were used to explore the mitotane plas- ma levels after the discontinuation of the drug.
Time to adrenal recovery was calculated using the Kaplan- Meier method, and comparisons between groups were done by log-rank statistics. We performed Cox proportional haz- ards regression univariate and multivariate analyses of factors that could potentially influence adrenal recovery after mito- tane treatment: sex, BMI, age at mitotane discontinuation, follow-up at our 3 centers (defined as reference centers, where more than 25 patients with ACC per year are treated) or in non-reference centers, duration of mitotane treatment, mito- tane exposure (evaluated as the AUC of mitotane plasma lev- els), AUC of mitotane dose, maximum peak of mitotane concentration, last mitotane concentration prior discontinu- ation, cumulative and average mitotane and HCeq replace- ment dose during the treatment, HCeq replacement dose at mitotane stop and after 6 months of mitotane discontinuation, fludrocortisone therapy, ACTH levels at mitotane stop and after 6 months of mitotane discontinuation, and GGT levels at mitotane discontinuation. For continuous variables, the me- dian value was considered as cutoff for the analysis. In the Cox regressions, partial adrenal recovery and insufficient recovery were considered together as “no recovery.” Hazard ratio (HR) and 95% confidence interval (CI) were evaluated. Only varia- bles with P <. 10 at univariate analysis were included in the multivariate regression.
Changes in serum aldosterone and plasma renin, ACTH, and DHEAS concentrations were analyzed at the time of mito- tane discontinuation and at the time of adrenal recovery or the last follow-up (if not recovery) using Wilcoxon matched-pairs signed rank test only in those patients with available paired measurement at the 2 time points.
All reported P values are 2-sided. P values <. 05 were consid- ered to indicate statistical significance.
Results
Patient characteristics
We identified 77 patients treated adjuvantly with mitotane who were disease-free at the time of treatment discontinu- ation. Of these, a final cohort of 56 patients was included in the study, comprising 38 patients (67.9%) followed up in ref- erence centers and 18 (32.1%) followed up in non-reference centers (Figure 1).
Baseline characteristics of patients were in the expected range for an ACC cohort undergoing adjuvant mitotane ther- apy (Table 1). Details on mitotane treatment and glucocortic- oid replacement are also provided in Table 1.
Mitotane treatment and glucocorticoid replacement
The median duration of adjuvant mitotane treatment slightly exceeded 2 years (25 months, range 23.2-44.7), and the me- dian cumulative mitotane dose was 2670 g (1679-3430), cor- responding to an average daily dose of 2.8 g/d (1.8-3.4) (Table 1). Mitotane plasma levels during treatment were avail- able in 44 patients (78.6%), and the median highest peak of mitotane plasma concentration was 21.0 mg/L (17.7-26.0). Last mitotane plasma concentration was measured 9 days (0-37) before treatment discontinuation reached a median of 13.6 mg/L (10.9-16.5).
Mitotane plasma concentrations were evaluated also after treatment discontinuation in a subgroup of 27 cases (48.2%) with available data and last mitotane plasma levels measured within 1 month before the discontinuation of the treatment. Mitotane plasma levels decreased slowly after discontinuation (Figure 2A), but with a very high variability between individ- ual patients (Figure 2B). For the entire cohort, the median time to mitotane levels below 5, 2, and 1 mg/L (= detection limit) was 152 days (114-202), 280 days (192-370), and 395 days (227-546), respectively (Figure 2A).
Based on the last mitotane level before stopping treatment and using the lower and upper quartiles as cutoff, we divided the pa- tients with at least 4 measurements of mitotane plasma level after its discontinuation (n=22) in 3 subgroups: “low levels” (<11 mg/L, n = 5), “intermediate levels” (≥11 and <16.5 mg/L, n = 12), and “high levels” (≥16.5 mg/L, n =5). As expected, we observed that mitotane plasma levels dropped faster below 5 mg/L (98 days [28-111]), below 2 mg/L (172 days [94-176]), and below detection limit (<1 mg/L) (199 days [125-217]) in pa- tients with “low levels” before the discontinuation compared with those with intermediate and high levels (P < . 03 in all cases) (Figure S1A-C). No significant differences were observed between patients with intermediate mitotane levels and those with high levels before discontinuation.
The average HCeq replacement daily dose during mitotane therapy was in median 49.4 mg/d (41.1-53.5), and the median cumulative HCeq dose reached 44 030 mg (31 935-70 045) (Table 1).
Mineralocorticoid replacement with fludrocortisone was administered in 8 patients (14.3%). At time of mitotane stop, data on antihypertensive medications were available in 47 patients, including 26 cases with drugs interfering with al- dosterone and renin measurements. Considering patients without renin-interfering antihypertensive medication, at time of mitotane discontinuation, median plasma aldosterone and renin levels were 0.1 nmol/L (0.1-0.2) and 0.2 pmol/L (0.1-0.4), respectively, being the renin concentrations below the normal range (0.7-13.5 pmol/L).
Median plasma ACTH levels at the end of the treatment period reached 3.4 pmol/L (1.8-10.9) and were therefore in the lower part of the normal range (0-10.1 pmol/L). Dehydroepiandrosterone sulfate levels were below the lower normal range (0.5-4.1 µmol/L) in all patients at the time of mi- totane discontinuation.
Adrenal recovery
The first laboratory analysis for the evaluation of the HPA axis after mitotane discontinuation was performed in median after 3 months.2-17 A median number of 21-4 corticotropin stimula- tion tests was available in 37 cases (66.1%).
In 42 out 56 patients (75%), complete and partial recovery of the adrenal function was observed (Figure 3A), including 32 cases (57.1%) in whom a complete recovery was documented after a median time of 792 days (95% CI 572-1011) (equiva- lent to 26 months [95% CI 19.6-32.4]) after mitotane discon- tinuation (Figure 3B). Among these, 22 cases (69%) achieved HPA recovery within the first 24 months after mitotane dis- continuation (Figure S2). To note, a complete recovery after more than 67 months did not occur. Interestingly, among the 38 patients followed up in reference centers, the propor- tion of complete adrenal recovery was much higher in com- parison with those followed up in non-reference centers (71% vs 27.8%, respectively, P =. 002).
Partial adrenal recovery was achieved by 10 additional pa- tients (17.9%) after a median time of 84 months (95% CI 65.3-102.7), whereas 14 patients (25%) had insufficient re- covery. Partial adrenal recovery and insufficient recovery were considered together as “no recovery.” In these patients, the median HCeq daily dose/BSA at the last follow-up was 12.5 mg/d xm2 (6.5-15.25). Of note, 13 of 24 patients (54.2%) who did not achieve complete adrenal recovery were not in follow-up in our centers. Furthermore, 5 patients who presented insufficient recovery had a follow-up time <2 years (median 15 months13-20), which was clearly below the median time to adrenal recovery.
An explorative analysis for potential predictive factors in- fluencing time to adrenal recovery has been performed. Table 2 depicts the detailed results for 24 factors including several clinical characteristics and variables on mitotane treat- ment as well as on replacement therapies (Table 2).
Most of the investigated potential predictor factors, includ- ing sex, age, BMI, hormone secretion, duration of mitotane treatment, median cumulative mitotane dose, cumulative and average HCeq dose during the mitotane treatment and after its stop, ACTH and GGT levels after mitotane stop, and fludrocortisone therapy, did not correlate with the dur- ation to adrenal recovery. However, patients followed up in reference centers had a significantly shorter time to achieve ad- renal recovery (median 623 days) in comparison with those followed up in non-reference centers (median not reached, HR =4.51, 95% CI 1.71-11-89, P =. 002; Figure 4A and Table 2). On the contrary, patients having higher mitotane ex- posure (AUC ≥ 11 624 mg × d/L) had a longer median time to HPA recovery compared with those having lower mitotane exposure (771 vs 609 days, HR = 0.49, 95% CI 0.23-1.03, P =. 06; Figure 4B and Table 2). Considering the highest peak of mitotane levels during the treatment, we observed a significant longer time to adrenal recovery for mitotane peak ≥ 27 mg/L (median time not reached vs. 693 days in those with mitotane peak 20-27 mg/L vs. 458 days in case of
77 ACC patients who discontinued mitotane without evidence of disease
Excluded n=21:
· n=12, mitotane therapy < 1 year
· n=3, lost at FU right after the discontinuation
· n=1, FU ≤1 year after mitotane discontinuation
· n=5, recurrence ≤5 years after mitotane discontinuation
Final cohort n=56 ACC patients
FU in reference center n=38
FU in non-reference center n=18
Complete recovery n=27 (71.1%)
Partial recovery n=3 (7.9%)
Insufficient recovery n=8 (21.0%)
Complete recovery n=5 (27.8%)
Partial recovery n=7 (38.9%)
Insufficient recovery n=6 (33.3%)
· n=2, FU ≥ 5 years (potential permanent insufficiency)
· n=2, FU ≥ 5 years (potential permanent insufficiency)
· n=3, FU 2-5 years
· n=2, FU 2-5 years
· n=3, FU< 2 years
· n=2, FU < 2 years
mitotane peak < 20 mg/L, HR =0.24, 95% CI 0.07-0.85. P = . 042; Figure 4C and Table 2). On the other hand, the last mitotane concentration before discontinuation did not have a significant impact on adrenal recovery (Figure 4D and Table 2). However, none of these parameters were signifi- cant at multivariate analysis (Table S1).
Considering cases under fludrocortisone replacement (n= 8), 4 patients achieved adrenal recovery, among which 3 (75%) also stopped fludrocortisone, whereas in 1 patient flu- drocortisone was still ongoing at the last follow-up after stop- ping glucocorticoid replacement therapy. None of the patients failing to achieve adrenal recovery stopped the fludrocorti- sone. All except 1 patient under fludrocortisone were treated with various antihypertensive drug classes interfering with the renin-angiotensin-aldosterone axis. Paired data on aldos- terone and renin plasma levels at mitotane stop and time of re- covery were available in only 9 and 8 patients, respectively, without antihypertensive drugs. No paired aldosterone and re- nin measurements were available for patients without antihy- pertensive medications and who did not achieved the HPA recovery. Median aldosterone levels significantly increased at time of recovery compared with the time of mitotane stopping (0.1 [0.1-0.2] vs 0.2 [0.1-0.4] nmol/L, respectively, P =. 04) (Figure S3A). Renin concentrations did not change at the time of recovery and remained under the reference range in all except 1 patient (Figure S3B). Data on antihypertensive treatment change at the time of mitotane stop and after ad- renal recovery or the last follow-up were available in 21 pa- tients. Although a decrease of doses or number of antihypertensive treatments was slightly higher in patients who achieved the complete adrenal recovery compared with those who did not (42.9% vs 28.6%, respectively), no
significant differences were observed between the 2 groups of patients in terms of changes in antihypertensive medications (x2 = 1.98, P =. 37). We have also found 2 patients who achieved the HPA recovery who increased the doses or number of antihypertensive drugs.
The change in ACTH and DHEAS plasma levels between the time of stopping mitotane and time of recovery or the last follow-up (if not recovered) was also investigated in patients with available data at both time points. At the time of mitotane stop, 5 out 31 patients (16%) had ACTH levels > 2-fold the upper reference limit (median 60.3 pmol/L), indicating poten- tial primary adrenal insufficiency (PAI) according to the Endocrine Society Guidelines,35 whereas most patients (84%) had median ACTH levels of 2.5 pmol/L, presumably suggesting a potential secondary adrenal insufficiency (SAI). However, all patients had been treated with HC, which might contribute to the low ACTH. Interestingly, a lower proportion of patients with potential PAI achieved complete adrenal recov- ery (40%) compared with 77% of those with potential SAI, but this difference was not significant (P = . 13). More in details, in patients who recovered (n = 22), median ACTH levels signifi- cantly increased at the time of adrenal recovery (19.6 pmol/L [6.9-28.7]) compared with the time of mitotane discontinu- ation (2.5 pmol/L [1.5-8.0], P =. 003; median time between the 2 measurement 16.5 months) (Figure S4A). A slightly but not significant increase in median ACTH levels was observed in patients without adrenal recovery (n = 9) at the last follow- up compared with the time of stopping mitotane (24.4 [2.5-177.3] vs 4.3 [2.5-59.5] pmol/L, respectively, P = . 16; me- dian time between the 2 measurement 36 months) (Figure S4B).
Dehydroepiandrosterone sulfate increased very slowly during follow-up and remained below the normal range in most patients
| Variable | Value |
|---|---|
| Sex | |
| Female | 36 (64.3) |
| Male | 20 (35.7) |
| Tumor size, cm | 9.7 (6.6-13.4) |
| Hormone secretion | |
| Glucocorticoid (alone or with other steroids) | 13 (23.2) |
| Androgens | 9 (16.1) |
| Aldosterone | 1 (1.8) |
| Inactive | 18 (32.1) |
| Unknown | 15 (26.8) |
| ENSAT tumor stage | |
| I | 3 (5.4) |
| II | 43 (76.8) |
| III | 10 (17.9) |
| Resection status at primary diagnosis | |
| R0 | 49 (87.5) |
| R1 | 1 (1.8) |
| Unknown | 6 (10.7) |
| Weiss score | 5 (3-6) |
| Ki67% | 10 (5-20) |
| Duration of mitotane treatment, months | 25 (23-45) |
| Age at mitotane discontinuation, years | 52.5 (44-60) |
| Number of patients treated adjuvantly with mitotane after: | |
| First surgery | 46 (82.1) |
| Second surgery | 10 (17.9) |
| Mitotane adjuvant regimen | |
| Alone | 47 (83.9) |
| Associated with radiotherapy of tumor bed | 3 (5.4) |
| Associated with adjuvant or neo-adjuvant cytotoxic chemotherapy | 6 (10.7) |
| Cumulative mitotane dose, g | 2670 (1679-3430) |
| Cumulative mitotane dose/BSA, g/m2 | 1414 (987-2080) |
| Average mitotane daily dose, g/d | 2.8 (1.8-3.4) |
| Cumulative HCeq doseª, mg | 44 030 (31 935-70 045) |
| Cumulative HCeq dose/BSAª, mg/m2 | 26 224 (18 627-38 819) |
| Average HCeq daily doseª, mg/d | 49.4 (41.1-53.5) |
| Average HCeq daily dose/BSAª, mg/d xm2 | 27.9 (22.2-34.3) |
| Fludrocortisone replacement | |
| Yes | 8 (14.3) |
| No | 40 (71.4) |
| Unknown | 8 (14.3) |
| Follow-up in reference center | |
| Yes | 38 (67.9) |
| No | 18 (32.1) |
Continuous variables were reported as median (lower and upper quartiles), whereas categorical variables as numbers (percentages).
Abbreviations: BSA, body surface area; d, days; ENSAT, European Network for the Study of Adrenal Tumors; HCeq, hydrocortisone equivalent; RO, complete tumor resection; R1, microscopically not completely resected tumor. ªDuring mitotane treatment.
(Figure S4C and D). However, in patients with adrenal recovery (n =21), median DHEAS levels significantly increased in few pa- tients (n =7) at the time of recovery (0.03 mol/L [0.03-3.34]) compared with the time of mitotane stopping (always undetect- ed, P =. 002; median time between the 2 measurements: 18 months) (Figure S4C). No patient without adrenal recovery (n = 10) showed normal values for DHEAS during the time of the follow-up (median time 48 months) (Figure S4D).
Discussion
Mitotane therapy causes adrenal insufficiency in virtually all treated patients. However, in clinical experience, adrenal
function recovers in many patients, but the published evidence on HPA recovery after mitotane treatment is very limited and coming from 2 small previous studies including 23 and 24 pa- tients, respectively.25,26 The primary aim of our study was to investigate the frequency of HPA recovery in a larger cohort of patients with ACC after discontinuation of adjuvant mito- tane treatment. In 32 (57.1%) of our patients, a complete ad- renal recovery was documented, which was achieved by the majority of patients (69% of those cases) within the first 2 years after mitotane discontinuation. However, among pa- tients from reference centers, a higher proportion (71%) achieved normal adrenal function, underlining the importance of follow-up in specialized centers even after mitotane discon- tinuation. Our results are in line with 2 previous smaller stud- ies25,26 investigating 23 and 24 ACC patients, which reported complete adrenal recovery in 62.5% and 78.3% of cases, re- spectively. Of note, 16% of our cases (n = 9) had a partial re- covery, with partial normalization of adrenal function but with ongoing glucocorticoid replacement therapy at the last follow-up. Moreover, among patients with insufficient ad- renal recovery (n= 15), 33% of cases had a follow-up time <2 years, which was clearly below the median time to adrenal recovery. Patients with partial or insufficient HPA recovery but short follow-up could still have the possibility to achieve a complete adrenal recovery. In contrast, we identified 4 pa- tients (7.1%) without any adrenal recovery after more than 5 years of mitotane discontinuation making a permanent ad- renal insufficiency very likely.
Until now, no predictive factors of complete adrenal recov- ery have been investigated.25,26 Our analysis reveals potential predictive factors associated with the time to adrenal recovery. First, follow-up in a reference center seems to significantly in- crease the likelihood of adrenal recovery, which was 4.5 times higher in specialized centers. Although we cannot prove any causality, it is tempting to speculate that the required dose ta- pering of HC was probably done more stringent in these cen- ters. Second, mitotane plasma levels also seem to play a role in the recovery of adrenal function. In fact, the highest peak of mitotane levels ≥ 27 mg/L during the treatment was associated with a significant longer time to adrenal recovery and a higher mitotane exposure showed a trend for a longer time to adrenal recovery. Again one could speculate that very high mitotane plasma level might be particularly toxic to adrenocortical cells or other cells in the HPA axis. However, before concluding clinical recommendations, these data that based only on 8 pa- tients need confirmation in an independent series. Several oth- er investigated parameters did not correlate with time to adrenal recovery, including sex, age at stop mitotane, BMI, hormone secretion, duration of mitotane treatment, median cumulative mitotane dose, cumulative and average HCeq dose during the mitotane treatment and levels after its stop, ACTH and GGT levels after mitotane stop, and fludrocorti- sone replacement therapy.
Due to induction of CYP3A4 and pharmacokinetic inter- action with other drugs, mitotane could delay the administra- tion of other therapies, above all tyrosine kinase inhibitors, in case of tumor progression.20,30 Until now, there was no reli- able evidence on the elimination time of mitotane after its dis- continuation. However, this information might be crucial for planning future therapy in a given patient. In our cohort, we observed that mitotane plasma levels sank slowly after discon- tinuation but with a huge variability between individual pa- tients. Not surprisingly, the higher the mitotane level at
Altieri et al.
A
Mitotane plasma levels (mg/L)
20
18
16.
14-
12.
10
8
6
4
2
0
Last levels (n=27)
Discontinuation
14 d (n=3)
30 d (n=16)
60 d (n=14)
B
90 d (n=18)
120 d (n=13)
150 d (n=8)
Mitotane plasma levels (mg/L)
Mitotane levels after discontinuation (n=27)
180 d (n=10)
210 d (n=7)
28
240 d (n=8)
26
270 d (n=5)
24-
300 d (n=7)
22
330 d (n=5)
20
360 d / 1 year (n=10)
18
390 d (n=6)
16
420 d (n=3)
14-
450 d (n=1)
12.
480 d (n=6)
10.
510 d (n=4)
8
540 d (n=1)
6
570 d (n=3)
4
600 d (n=0)
2
630 d (n=3)
0
660 d (n=4)
690 d (n=1)
Last levels (n=27) Discontinuation
720 d / 2 years (n=0)
750 d (n=0)
14 d (n=3)
780 d (n=1)
145
30 d (n=16)
810 d (n=0)
Complete and partial adrenal recovery (%)
Figure 3. Adrenal recovery after mitotane discontinuation. Kaplan-Meier analysis of (A) time to complete and partial adrenal recovery and (B) time to
mitotane discontinuation. The number of patients evaluated at each analyzed time point is reported in brackets.
available mitotane plasma levels measured within 1 month before the discontinuation of the treatment were included. Time is reported in days from the mean ± standard deviation for the cohort of patients with detailed follow-up information (n=27) and (B) per single patient. Only patients with a last
Figure 2. Mitotane plasma levels after its discontinuation. Decrease of the mitotane plasma levels (mg/L) after its discontinuation represented (A) as
Mitotane levels after discontinuation per single patient (n=27)
Days from discontinuation
60 d (n=14)
840 d (n=1)
90 d (n=18)
870 d (n=0)
120 d (n=13)
900 d (n=1)
150 d (n=8)
930 d (n=1)
180 d (n=10)
960 d (n=1)
210 d (n=7)
990 d (n=0)
A
240 d (n=8)
1020 d (n=0)
270 d (n=5)
1050 d (n=0)
300 d (n=7)
330 d (n=5)
1080 d / 3 years (n=1)
1110 d (n=2)
360 d / 1 year (n=10)
Complete and partial recovery
1140 d (n=0) 1170 d (n=0) 1200 d (n=1)
100
390 d (n=6)
420 d (n=3) 450 d (n=1)
80
480 d (n=6)
510 d (n=4)
Downloaded from https://academic.oup.com/ejendo/article/190/2/139/7581943 by WT Cox Information Services user on 03 April 2026
60
540 d (n=1)
570 d (n=3)
40
Days from discontinuation
600 d (n=0)
630 d (n=3)
660 d (n=4) 690 d (n=1)
20
720 d / 2 years (n=0)
0
750 d (n=0)
complete adrenal recovery only.
780 d (n=1)
0
810 d (n=0)
840 d (n=1)
365
870 d (n=0)
900 d (n=1)
730 Time to adrenal recovery (days) 1095 1460 1825 2190 2555 2920
930 d (n=1)
960 d (n=1)
Censored
Complete and partial recovery
B
990 d (n=0) 1020 d (n=0)
1050 d (n=0)
Complete adrenal recovery (%)
1080 d / 3 years (n=1)
1110 d (n=2)
100
1140 d (n=0)
80
Complete recovery
1170 d (n=0) 1200 d (n=1)
60
40
20
0
0
365
Time to adrenal recovery (days)
730
Censored
Complete recovery
1095
1460
825 21
2190
2555
2920
| Variable | n patients | Median time to recovery (days) | HR | 95% CI | P |
|---|---|---|---|---|---|
| Sex | |||||
| M | 20 | 1540 | 1 | ||
| F | 36 | 747 | 1.47 | 0.69-3.12 | .31 |
| ACC-induced hormone secretion | |||||
| Inactive | 18 | 771 | 1 | ||
| Androgens or aldosterone | 10 | 1540 | 0.84 | 0.30-2.33 | 0.74 |
| Glucocorticoid | 13 | 747 | 0.85 | 0.31 | 0.76 |
| Median BMI at diagnosis | |||||
| <26 kg/m2 | 23 | 783 | 1 | ||
| ≥26 kg/m2 | 25 | 906 | 0.89 | 0.42-1.91 | .78 |
| Median age at stop mitotane | |||||
| <52.5 years | 28 | 1540 | 1 | ||
| >52.5 years | 28 | 783 | 1.25 | 0.62-2.53 | .53 |
| Median duration of mitotane treatment | |||||
| <768 d | 28 | 792 | 1 | ||
| ≥768 d | 28 | 783 | 0.89 | 0.44-1.79 | .75 |
| Median AUC of mitotane levels during the treatment | |||||
| <11 624 mg × d/L | 22 | 609 | 1 | ||
| ≥11 624 mg × d/L | 23 | 771 | 0.49 | 0.23-1.03 | .06 |
| Median AUC mitotane dose | |||||
| <2528 gxd | 22 | 623 | 1 | ||
| ≥2528 gxd | 21 | 747 | 0.82 | 0.39-1.73 | .61 |
| Maximum peak of mitotane plasma level | |||||
| <20 mg/L | 15 | 458 | 1 | ||
| ≥20 and <27 mg/L | 21 | 693 | 0.54 | 0.25-1.17 | .17 |
| ≥27 mg/L | 8 | Not reached | 0.24 | 0.07-0.85 | .03 |
| Median last mitotane concentrations at discontinuationa | |||||
| ≤14 mg/L | 16 | 602 | 1 | ||
| >14 mg/L | 16 | 700 | 0.75 | 0.34-1.70 | .50 |
| Median cumulative mitotane dose | |||||
| <2670 g | 21 | 623 | 1 | ||
| ≥2670 g | 22 | 771 | 0.83 | 0.39-1.74 | .61 |
| Median cumulative mitotane dose/BSA | |||||
| <1414 g/m2 | 21 | 693 | 1 | ||
| ≥1414 g/m2 | 21 | 700 | 0.80 | 0.38-1.69 | .56 |
| Median average mitotane daily dose | |||||
| <2.8 g/d | 22 | 783 | 1 | ||
| ≥2.8 g/d | 21 | 693 | 1.66 | 0.77-3.55 | .19 |
| Median cumulative HCeq dose | |||||
| <44 030 mg | 18 | 693 | 1 | ||
| ≥44 030 mg | 19 | 623 | 0.86 | 0.39-1.93 | .72 |
| Median cumulative HCeq dose/BSA | |||||
| <26 738 mg/d xm2 | 19 | 693 | 1 | ||
| ≥26 738 mg/d xm2 | 18 | 747 | 0.95 | 0.43-2.13 | .91 |
| Median average HCeq dose | |||||
| <49.4 mg/d | 19 | 747 | 1 | ||
| ≥49.4 mg/d | 18 | 609 | 1.16 | 0.52-2.60 | .71 |
| Last HCeq daily dose at stop mitotane | |||||
| <50 mg/d | 13 | 792 | 1 | ||
| ≥50 mg/d | 30 | 623 | 1.38 | 0.58-3.28 | .45 |
| Median HCeq daily dose at stop mitotane/BSA | |||||
| <28.6 mg/d xm2 | 22 | 747 | 1 | ||
| ≥28.6 mg/d x m2 | 21 | 623 | 1.19 | 0.56-2.55 | .64 |
| Median HCeq daily dose after 6 months stop mitotane | |||||
| <25.0 mg/d | 13 | 693 | 1 | ||
| ≥25.0 mg/d | 18 | 623 | 1.12 | 0.46-2.71 | .79 |
| Median HCeq daily dose/BSA after 6 months stop mitotane | |||||
| <11.4 mg/d xm2 | 11 | 693 | 1 | ||
| ≥11.4 mg/d xm2 | 17 | 771 | 0.72 | 0.28-1.87 | .51 |
| Median ACTH at stop mitotane | |||||
| <3.4 pmol/L | 18 | 771 | 1 | ||
| ≥3.4 pmol/L | 17 | 693 | 0.93 | 0.40-2.15 | .86 |
| Median ACTH after 6 months stop mitotane | |||||
| <14.4 pmol/L | 15 | 792 | 1 | ||
| ≥14.4 pmol/L | 16 | 602 | 1.45 | 0.63-3.30 | .38 |
| Fludrocortisone therapy | |||||
| No | 40 | 623 | 1 | ||
| Yes | 8 | 906 | 0.45 | 0.16-1.31 | .14 |
(continued)
| Variable | n patients | Median time to recovery (days) | HR | 95% CI | P |
|---|---|---|---|---|---|
| Median GGT at stop mitotane | |||||
| <140 U/L | 16 | 771 | 1 | ||
| ≥140 U/L | 19 | 693 | 0.89 | 0.38-2.06 | .78 |
| Follow-up in reference center | |||||
| No | 18 | Not reached | 1 | ||
| Yes | 38 | 623 | 4.51 | 1.71-11.89 | .002 |
Abbreviations: ACTH, adrenocorticotropic hormone; AUC, area under the curve; BMI, body mass index; BSA, body surface area; d, days; GGT, gamma-glutamyl transferase; HCeq, hydrocortisone equivalent; HR, hazard ratio; n, number of patients; 95% CI, 95% confidence interval. “For this calculation, only patients with available last plasma levels measured within 1 month before the discontinuation of the treatment were considered.
A
Treatment in reference center
B
Median AUC of mitotane
100
100
Adrenal recovery (%)
reference center (n=38)
Adrenal recovery (%)
80
80
AUC <11624 mgxd/L (n=22)
60
60
40
non-reference center (n=18)
AUC >11624 mgxd/L (n=23)
40
20
20
0
p<0.01
0
p=0.06
0
365
730
1095
1460
1825
2190
2555
2920
0
365
730
1095
1460
1825
2190
2555
2920
Time to adrenal recovery (days)
Time to adrenal recovery (days)
C
Maximum peak of mitotane
D
Last mitotane level
100
<20mg/L (n=15)
100
Adrenal recovery (%)
Adrenal recovery (%)
<14 mg/L (n=16)
80
80
60
20-27mg/L (n=21)
>14 mg/L (n=16)
60
40
40
>27mg/L (n=8)
20
20
0
p=0.042
0
p=0.50
0
365
730
1095
1460
1825
2190
2555
2920
0
365
730
1095
1460
1825
2190
2555
2920
Time to adrenal recovery (days)
Time to adrenal recovery (days)
discontinuation, the longer it takes until mitotane disappears. Even in patients with last concentrations < 11 mg/L, about 200 days are required until mitotane is undetectable, whereas this duration is more than 550 days in the group with last mi- totane level > 16.5 mg/L.
Most of our patients (84%) presented low median ACTH lev- els (2.5 pmol/L) at the time of mitotane discontinuation, and their increase after treatment stop might point toward partial corticotropic insufficiency as a result of the inhibitory effect of mitotane on the HPA axis associated with a potential SAI.23,24 In our cohort, a slightly higher proportion of patients with poten- tial SAI achieved complete adrenal recovery compared with those with potential PAI. However, the higher than usual gluco- corticoid replacement doses during mitotane therapy with me- dian HCeq dose of 50 mg/d (corresponding to a median of 28.6 mg HCeq dose/BSA) instead of 15-25 mg/d (corresponding
to 5-8 mg HCeq dose/BSA) recommended for patients with ad- renal insufficiency,35 due to a higher metabolic clearance of glu- cocorticoids induced by mitotane, 19-21 could also be responsible for low ACTH levels. Therefore, we would assume that in some patients a mixed picture of corticotropic insufficiency and gluco- corticoid overtreatment is present and a definitive conclusion on potential primary or secondary adrenal insufficiency in this set- ting is difficult to draw.
The effects of mitotane on the inhibition of the secretion of adrenal hormone levels are well known.16,22 However, until now, no data have been reported on potential restoration of other adrenal hormones. Therefore, a secondary outcome of our study was the evaluation of hormone changes after mito- tane stop. Dehydroepiandrosterone sulfate levels increased very slowly after mitotane discontinuation only in few cases and remained below the normal range in most patients, even
for more than 4 years after mitotane stopping. This observation is in line with previous studies reporting low or suppressed DHEAS levels for months to years after discontinuation of glucocorticoid treatment in patients with adrenal insufficiency or after normalization of cortisol levels in patients with en- dogenous hypercortisolism, even after endogenous glucocortic- oid secretion has returned to normal.39,40 Moreover, it should be considered that in our cohort the median age is 52 years old. It is well demonstrated that DHEAS levels decline gradually with age.41,42 Considering the observations above, low DHEAS levels are not a reliable parameter to evaluate HPA axis suppression.
Regarding the changes in aldosterone and renin concentration after stopping mitotane, we were able to analyze only a small number of patients without antihypertensive drugs interfering with the renin-angiotensin-aldosterone axis (n = 9 and 8 for al- dosterone and renin, respectively). However, we observed that aldosterone levels significantly increased at the time of adrenal re- covery, whereas no change was observed for renin levels, which remained mostly below the normal range.
Our study has obvious limitations. First, the retrospective nature might have led to some selection bias and not all pa- tients were treated in a standardized manner leading also to missing data on certain time points. Second, the total number of analyzed patients with just 56 is still low. However, due to the rarity of the disease and the small percentage of patient who are discontinuing mitotane without evidence of disease, the number is significant. A third limitation is the incomplete follow-up in some patients, particularly among those without a glucocorticoid discontinuation. Therefore, one could as- sume that the failure for adrenal recovery could be due to poor education on how to reduce glucocorticoid replacement after mitotane discontinuation. Furthermore, we have to ac- knowledge that the calculated average dosage of mitotane and HC is based on the documented dosage in the clinical re- cords and might not be 100% accurate. However, we would expect that this approach did not lead to a systematic over- or underestimation of the dosage.
In conclusion, our results suggest that adrenal function will recover in the vast majority of patients, particularly in those who are adequately followed up. We provide also evidence that complete recovery was delayed in a subset of patients (31%) for more than 2 years after stopping mitotane. Therefore, tapering the glucocorticoid dosage and repeated corticotropin stimulation tests seems justified for up to 5 years before declaring a patient as permanent adrenal insufficient. In general, better patient education on glucocorticoid reduction is recommended, because this is probably associated with a higher rate of adrenal recovery after mitotane discontinuation. However, in few patients, yet unknown factors lead to per- manent adrenal insufficiency. We have also demonstrated that that mitotane plasma levels decline slowly after discon- tinuation of mitotane, albeit with a wider inter-patient vari- ability. The median time until mitotane is undetectable is slightly more than 1 year. This information might be crucial for planning future therapies with drugs that are metabolized by the cytochrome 3A4 in patients with ACC who have pro- gressive disease under mitotane treatment.
Acknowledgments
We are grateful to Michaela Haaf for coordinating the ENSAT Registry in Würzburg.
Supplementary material
Supplementary material is available at European Journal of Endocrinology online.
Funding
This study was supported by the Deutsche Forschungsgemeinschaft (DFG) (project number: 314061271 TRR-CRC 205) and the Else Kroner-Fresenius-Stiftung & the Eva Luise und Horst Köhler Stiftung, Clinician Scientist Program “Rare Important Syndromes in endocrinology (RISE)“.
Conflict of interest: O.K. received speaker honoraria from HRA Pharma. The other authors declare that there is no con- flict of interest that could be perceived as prejudicing the im- partiality of the research reported.
Authors’ contributions
Barbara Altieri (Conceptualization [equal], Data curation [lead], Formal analysis [lead], Investigation [lead], Methodology [lead], Visualization [lead], Writing-original draft [lead], Writing-re- view & editing [lead]), Otilia Kimpel (Conceptualization [equal], Data curation [lead], Formal analysis [equal], Investigation [lead], Methodology [equal], Visualization [lead], Writing-ori- ginal draft [lead], Writing-review & editing [lead]), Felix Megerle (Data curation [equal, Investigation [supporting], Writing-review & editing [equal]), Mario Detomas (Data cur- ation [supporting], Investigation [supporting], Writing-review & editing [equal]), Irina Chifu (Data curation [supporting], Investigation [supporting], Writing-review & editing [equal]), Carmina Fuss (Data curation [supporting], Investigation [sup- porting], Writing-review & editing [equal]), Marcus Quinkler (Data curation [equal], Investigation [equal], Methodology [supporting], Writing-review & editing [equal]), Matthias Kroiss (Data curation [equal], Investigation [equal], Methodology [supporting], Writing-review & editing [equal]), and Martin Fassnacht (Conceptualization [lead], Data curation [lead], Investigation [lead], Methodology [lead], Resources [lead], Supervision [lead], Visualization [lead], Writing-original draft [lead], Writing-review & editing [lead]).
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