HEREDITARY CANCER IN CLINICAL PRACTICE
HCCP
RESEARCH
Molecular diagnosis and comprehensive treatment of multiple endocrine neoplasia type 2 in Southeastern Chinese
Jian-Qiang Zhao11, Zhen-Guang Chen21 and Xiao-Ping Qi2*
Abstract
Background: Multiple endocrine neoplasia type 2 (MEN2) is an autosomal dominant inherited endocrine malignancy syndrome. Early and normative surgery is the only curative method for MEN 2-related medullary thyroid carcinoma (MTC). In patients with adrenal pheochromocytoma, cortical-sparing adrenalectomy (CSA) can be utilized to preserve adrenocortical function.
Methods: We present twenty-six of 33 MEN2 patients underwent prophylactic thyroidectomy with varying neck dissection and eight of 24 MEN2A patients with PHEO underwent adrenal-sparing surgery. Direct sequencing of entire RET exons was performed in all participants.
Results: The RET mutations (p.C634Y [n = 10], p.C634R [n = 9], p.C634F [n = 2], p.C618Y [n = 8], p.C618R [n = 3], and p.M918T [n = 1]) were confirmed in 20 symptomatic patients and identified in 13 at-risk relatives (RET carriers). Twenty-six of 33 MEN2 patients underwent thyroidectomies with neck dissections; the mean age at the time of the first thyroid surgery and the tumor diameter of the 6 RET carriers was decreased compared with 20 symptomatic patients (P < 0.001 and P= 0.007, respectively), while the disease-free survival was increased (80% vs.10%, P = 0.0001). Seven RET carriers who were declined surgery. One of 20 symptomatic patients with MTC bone metastases after surgery received vandetanib therapy for 20 months and responded well. Additionally, 8 of 24 MEN2A patients who initially had unilateral pheochromocytomas underwent CSA, 1 developed contralateral pheochromo cytomas 10 years later, then also accepted and also agreed to a CSA. None of the patients required steroid replacement therapy.
Conclusions: Based on our results, integrated RET screening and the pre-operative calcitonin level is an excellent strategy to ensure earlier diagnosis and standard thyroidectomy. CSA can be utilized to preserve adrenocortical function in patients with pheochromocytomas.
Keywords: Multiple endocrine neoplasia type 2, Mutation screening, RET, Prophylactic thyroidectomy, Cortical-sparing adrenalectomy
Background
Multiple endocrine neoplasia type 2 (MEN2) is an auto- somal dominant inherited endocrine malignancy syndrome, with an occurrence of approximately 1 in 30 000; MEN2 is due to germline mutations in the REarranged during Transfection (RET) proto-oncogene (OMIM: 164761) [1,2], which includes the following three subtypes: MEN2A
(OMIM: 171400); familial medullary thyroid cancer (FMTC; OMIM: 155240); and MEN2B (OMIM: 162300) [3]. MEN2A mainly consists of MTC, adrenal pheochromo- cytoma (PHEO), and hyperparathyroidism (HPT). FMTC presents clinically as MTC, but four or more persons in a family or multiple generations must satisfy the diagnostic criteria for MTC without other endocrine gland neoplasm features [3,4]. MEN2B-related MTC has a higher invasive- ness than MEN2A or FMTC, and often accompanies PHEO, mucosal and gastrointestinal ganglioneuromas, corneal nerve thickening (CNT), and Marfan’s body hab- itus [5]. Of patients with MEN2, 95%-100% will develop
* Correspondence: qxplmd@vip.sina.com Equal contributors
2Department of Oncologic and Urologic Surgery, the 117th PLA Hospital, Wenzhou Medical University, 40 Jichang Road, Hangzhou, Zhejiang Province 310004, China
Full list of author information is available at the end of the article
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MTC, which is usually asymptomatic at an early stage; clinical symptoms usually present with lymph node metas- tasis (LNM) in the third or fourth decade of life. Distant metastases of MTC are the major cause of death [5-7].
MEN2 patients can be diagnosed early through system- atic pedigree investigation and RET proto-oncogene screening [3-5]. In the vast majority of cases, > 70 RET mutations accumulate that are related to MEN2, and > 98% of RET mutations are located in exons 5, 8, 10, 11, and 13-16 [4]. In 2009, the American Thyroid Association (ATA) performed a timing prophylactic total thyroidec- tomy (TT) procedure based on a model that utilized the following genotype-phenotype correlations to stratify mu- tations into four risk levels: ATA-A → D, A < B <C<D. It was recommended that ATA-B and -C level mutation car- riers should be considered for prophylactic TT, which should be performed before 5 years of age. However, it has been shown that family members with the same RET mu- tation may have different clinical phenotypes or offspring might exhibit earlier MTC phenotypes [4,5].
In recent years, combined detection of RET mutations and pre-operative calcitonin (pre-Ct) levels have been con- sidered for comprehensive decision-making regarding the timing or surgical extent of prophylactic TT [8-11]. More- over, phase III clinical trials have demonstrated that one oral drug (such as vandetanib), which is a small molecular multi-targeted tyrosine kinase inhibitor, provides a new therapeutic choice for advanced hereditary MTC patients whose disease cannot be resected or who present with metastatic lesions [12]. Because most of the MEN2A- related PHEO presentations are benign with bilateral mul- tiple onsets, it is currently preferred to perform laparo- scopic cortical-sparing adrenalectomy (CSA) [5,13,14].
In the present study, we report 33 MEN2 cases derived from 9 unrelated MEN2 families residing in southeastern China. Our aim was to analyze the feasibility of prophy- lactic TT based on predictive integrated screening of RET and pre-Ct levels. We also observed and evaluated the efficacy and safety of vandetanib in the treatment of one advanced case of MEN2A-MTC, and determined the clinical significance of managing unilateral CSA for MEN2A-related PHEO.
Methods
Patients
Nine MEN2 families from Zhejiang Province of southeast- ern China were recruited. All patients were diagnosed and treated at the Zhejiang Cancer Hospital or the 117th PLA Hospital between August 1989 and January 2013. System- atic family screening was performed between 2005 and 2013, and comprehensive medical data, including clinical profiles, surgical procedures, pre- and post-operative bio- chemical data, and follow-up records were studied. The patients diagnosed before 1993 were submitted to RET
genetic analysis at the time of family screening. All partici- pants and/or their legal guardians provided written in- formed consent, as required by the institution’s Ethical Committee.
Clinical approach
All RET gene mutation carriers underwent biochemical and imaging examinations to ascertain thyroid, parathy- roid, and adrenal gland involvement. The biochemical examination included Ct by chemiluminescence assay (normal male, <8.4 ng/L; and female, <5.0 ng/L), parathy- roid hormone (PTH) by electrochemical immunoassay, carcinoembryonic antigen by chemiluminescence assay, catecholamines, 3-methyl-4-hydroxy mandelic acid by radioimmunoassay, serum calcium by the arsenazo III method, and serum phosphate by UV molybdate. The im- aging examinations included thyroid ultrasound/CT, ad- renal gland and parathyroid gland nuclear magnetic resonance (MRI), emission computed tomography (ECT), and/or PET-CT scan assessments, if indicated.
Genetic testing
Genomic DNA was isolated from the peripheral blood of 86 family members. The coding region of RET exons 5, 8, 10, 11, and 13-16 was amplified and sequenced in sense and antisense directions with an ABI Prism 3730 automatic sequencer (Perkin-Elmer, USA).
Follow-up management
All patients were followed for evaluation of tumor recur- rence and metastasis after surgery. Since 2005, the standard follow-up for MTC has consisted of determin- ing the Ct level, plasma calcium level (every 6 months), and during the post-operative period under conditions in which the Ct level is abnormal, a detailed imaging examination may be considered (yearly). For MEN2A- related PHEO patients, biochemical and imaging exami- nations were repeated every 6-12 months, and life-time follow-up was then required. For RET mutation carriers without PHEOs, after initial screening at 20 years of age, repeat biochemical and imaging examinations were per- formed every year to screen for PHEOs and HPT [5].
Statistical analysis
All data were analyzed with SPSS (version 12.0) software. We carried out univariate analysis using the Fisher’s exact test. Student’s t-test was used to analyze differences be- tween mean values.
Results
Clinical and diagnostic data
The 33 MEN2 patients consisted of 9 index-cases (7 males and 2 females), 11 clinical patients (5 males and 6 females) and 13 asymptomatic carriers (4 males
and 9 females). The mean age at the time of diagnosis was 38.6 ± 10.7 years (range, 23-58 years), 38.8 ±16.6 years (range, 20-65 years), and 30.0 ± 18.5 years (range, 9-78 years), respectively. All patients derived from 9 unrelated MEN 2 families and harbored 1 of 6 heterozygous mis- sense mutations; 7 families had MEN2A (p.C634Y [n = 3], p.C634R [n=2], p.C634F [n=1], p.C618R [n=1]), 1 family had FMTC (p.C618Y [n =1]), and 1 family had MEN2B (p.M918T [n=1]). Of the 33 MEN2 patients, 32 (97%) were diagnosed with MTC (31) or C-cell hyperpla- sia (1) and 8 (33.3%) were diagnosed with PHEO (Table 1 and Figure 1). None of the 33 MEN2 patients had con- sistently evidence of any co-occurring related MEN2 clin- ical symptoms (pruritic cutaneous lichen amyloidosis or Hirschsprung’s disease), or HPT (serum PTH, Calcium or PTH/calcium rates, and serum phosphate levels ranged in all normal), except one MEN2B patient (F9-II3) had a broad spectrum of pathognomonic nonendocrine abnor- malities: a Marfanoid body habitus, tongue mucosal neur- omas, lips hypertrophy and CNT.
Genogram MTC
Of the 33 MEN2 patients, 32 (97% [20 symptomatic pa- tients including 9 index-cases and 11 clinical patients, and 12 asymptomatic carriers]) who were diagnosed with MTC or C-cell hyperplasia (CCH) clinically or based on pathologic evaluation, the mean diagnostic age was 34.6 ± 16.1 years; 1 RET-carrier (F8-III5) had no abnormalities.
Twenty symptomatic patients were admitted to the hos- pital for neck masses or neck pain and diagnosed with MTC before clinical screening. Thirteen of 20 (65%) pa- tients were subjected to sub-standard thyroid surgery: 8 patients underwent interval (at least 2 times) TT and bilat- eral VI region lymph node dissection [B-LND (VI)] or modified bilateral cervical lymph node dissection (MBND); 3 patients underwent bilateral sub-TT and/or MBND; and
2 patients underwent unilateral TT and B-LND (VI) with MBND. The other 7 patients were accepted for standard thyroid surgery, as follows: 5 patients underwent TT plus B-LND (VI) plus MBND; and 2 patients underwent TT plus B-LND (VI). The histopathologic results showed that 20 patients had bilateral MTC (1 patient with T2N0M0 and 19 patients with T1N1bM0 ~ T3N1bM0; Table 2). The median time of follow-up thus far is 115.6 ± 90.4 months (range, 21-384 months). The results of post- Ct levels were normal in 2 patients (10% [T2N0M0 and T1N1bM0]) and elevated in 18 patients (90%). Moreover, 2 of 20 patients (F6-II5 and F4-II1) had elevated Ct levels > 2000 ng/L. One patient (F6-II5), a 39-year-male-old with T3N1bM0, underwent surgery successively 4 times and eventually exhibited multiple bone metastases based on ECT and MRI examinations 11 years after the initial sur- gery. Vandetanib (ZD6474, Zactima™) was administered orally at an initial dose of 300 mg/d; bone pain resolved and the Ct levels decreased from 8755.3 ng/L to 873.6 ng/L after 2 months. Eight months later, the patient appeared uncomfortable and distressed. An electrocardio- gram showed Q-T interval prolongation and incomplete right bundle branch block. Subsequently, the dose of van- detanib was decreased from 300 mg to 200 mg once a day for 20 months (until the present). The Ct level increased to 5869.2 ng/L during therapy, while repeated PET-CT ex- aminations failed to show any obvious advance bone metastatic lesions. The patient developed erythema after vandetanib therapy, but had no pruritus, headaches, nausea, or reduction in the number of white blood cells. The other patients (F4-II1), a 50-year-male-old with T2N1bM0, declined further therapy and has survived with the tumor in situ for 19 years (until the present; Table 2).
Thirteen asymptomatic RET carriers were confirmed by clinical family screening, 12 of whom had elevated pre-Ct levels; 6 patients underwent prophylactic TT (n =2),
| Family | Numbers of patients | Sex ratio (M/F) | Age range (years) | RET mutation | MTC age at onset (mean years) | PHEO numbers/Age at diagnosis (mean years) |
|---|---|---|---|---|---|---|
| MEN2A | ||||||
| F1 | 2 | 1/1 | 28-58 | p.C634F | 43.0 | 1/26 |
| F2 | 1 | 1/0 | 35 | p.C634Y | 35.0 | 1/35 |
| F3 | 6 | 2/4 | 9-44 | p.C634Y | 30.2 | 1/36 |
| F4 | 3 | 2/1 | 18-44 | p.C634Y | 27.3 | 1/47 |
| F5 | 3 | 2/1 | 19-32 | p.C634R | 24.7 | 2/40.5 |
| F6 | 6 | 4/2 | 19-65 | p.C634R | 33.5 | 1/21 |
| F7 | 3 | 1/2 | 21-36 | p.C618R | 27.3 | 1/40 |
| FMTC F8 | 8 | 2/6 | 24-78 | p.C618Y | 45.3 | - |
| MEN2B | ||||||
| F9 | 1 | 1/0 | 33 | p.M918T | 33 | - |
F 1
F 2
F3
F7
11
12
11
12
11
12
11
12
Il 1
112
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114
115
116
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1119
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m 1
m12
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III 1
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m2
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F 4
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F 6
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Il1
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1112
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F 9
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gene carrier
MTC
Il 1
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II1
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PHEO
N
1111
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Figure 1 Genealogy of seven MEN2A families (F1-F7), one FMTC family (F8) and one MEN2B family (F9).
prophylactic TT plus B-LND (VI; n = 3), or prophylactic TT plus MBND (n =1). The histopathologic examin- ation revealed MTC in 5 patients (4 patients with T1N0M0 and 1 patient with T1N1bM0) and 1 26-year- old patient with CCH (F8-IV5; Table 3). The median time of follow-up thus far has been 19.6 ± 3.2 months (range, 17-26 months) and the results of post-Ct levels were normal in 5 patients. Unfortunately, a 21-year-old male (F6-III4) with T1N1bM0 still has an elevated Ct level. In addition, the remaining 7 patients declined/ awaited surgery, 6 of whom had progressively increased Ct levels, and only a 53-year-old male (F8-III5) has a normal Ct level and no thyroid nodules based on im- aging (Table 3).
The asymptomatic RET carriers who underwent sur- gery benefited greatly from genetic screening and were a significantly younger age at the time of surgery and had a smaller tumor diameter compared with symptomatic patients (P < 0.001 and P= 0.007, respectively). One RET carrier had lymph node metastasis compared with 19 of 20 symptomatic patients (P=0.0001). The disease-free survival (DFS) increased in the asymptomatic RET car- riers who underwent surgery compared to the symptom- atic patients (80% vs. 10%, P= 0.0001; Table 2).
PHEO
Of 24 MEN2A patients, 8 presented with PHEOs, includ- ing 5 males and 3 females (7 p.C634Y/R/F and 1 p.C618R RET-mutations) (Table 4). The mean age at the time of diagnosis was 35.8 ±9.2 years (range, 21-47 years). Among 8 PHEO patients, 5 were symptomatic and 3 were asymptomatic. The asymptomatic patients were diagnosed during systematic pedigree analysis. In addition, all 8 PHEO patients initially presented with unilateral disease. Unilateral CSA was initially performed, and 4 of 8 patients underwent a laparoscopic technique. The average max- imum diameter of the PHEOs was 3.9 ±2.5 cm (range, 2.3-10.0 cm), and all of the PHEOs were located within the adrenal glands. One patient (F5-II1) relapsed after ini- tially developing a contralateral tumor after 10 years, and underwent CSA on the opposite side (bilateral CSA). After surgery, none of the 8 patients required steroid replace- ment therapy. The median time of follow-up thus far has been 88.3 ± 84.1 months (range, 8-252 months). There were no surgical complications, such as hypoadrenalism, Addison’s crisis, local recurrence, or distant metastasis. Interestingly, the 58-year-old father (F1-I1) of a RET car- rier (F1-II4) with unilateral PHEO and MTC in the F1 family had presented with MTC as the only clinical
| Total (n =33) N (%) | Symptomatic patients (n = 20) N (%) | Mutation carriers (n = 13) N (%) | P value | |
|---|---|---|---|---|
| Female patients | 16 (48.5%) | 7(35%) | 9 (69.2%) | |
| Genotype | ||||
| p.C634F/Y/R | 21 | 12 | 9 | |
| p.C 618Y/R | 11 | 7 | 4 | |
| p.M 918 T | 1 | 1 | 0 | |
| Surgery | ||||
| Numbers of patients operated | 26 | 20 | 6 | |
| Age at first surgery, mean (years) | 34.6 ± 16.1 | 38.7 ± 13.9 | 20.7 ± 2.9 | <0.001 |
| TT with central and lateral LND | 14 | 13 | 1 | |
| TT with central LND | 5 | 2 | 3 | |
| TT without LND | 2 | 0 | 2 | |
| Inappropriate | 5 | 5 | 0 | |
| Histology | ||||
| Tumor diameter (cm, mean) | 2.2 ±1.2 | 2.6 ± 1.0 | 0.7 ±0.4 | 0.007 |
| CCH | 1 | 0 | 1 | |
| MTC | 25 | 20 | 5 | |
| Lymph node metastasis | ||||
| N0 | 6 | 1 | 5 | |
| N1 | 20 | 19 | 1 | 0.0001 |
| Distant metastasis | ||||
| M0 | 23 | 18 | 5 | |
| M1 | 2 | 2 | 0 | |
| Disease-free survival | 6 | 2 | 4 | 0.0001 |
symptom, but no evidence of a PHEO. Furthermore, in the F6 family, the first (I) and second (II) generation also had the only clinical manifestations of MTC, while only one patient in their offspring (III-2) had evidence of a PHEO.
Follow-up management
Seven asymptomatic RET carriers were strictly moni- tored and presented with gradually increasing Ct levels, but did not undergo surgery. The other 26 patients re- ceived thyroid hormone replacement therapy lifetime, and were given calcium and vitamin D3 as preventive supplements at least 1 year after surgery. Moreover, thy- roid, adrenal, and parathyroid function was normal, with no evidence of complications, such as tetany.
RET germline variants
All 33 RET mutation-positive patients (consisting of 20 symptomatic patients and 13 asymptomatic RET car- riers) harbored 1 of 6 heterozygous missense mutations within exons 10 (p.C618Y [n = 8] and p.C618R [n =3]), 11 (p.C634Y [n = 10], p.C634R [n = 9], and p.C634F [n = 2]), 16 (p.M918T [n =1]). It was surprising to find that in the F2 and F9 families, only proband (F2-II1 and F9- II3) had the p.C634Y or p.M918T mutation, while his consanguineous parents and brothers were shown not to harbor the mutations or MEN2A/MEN2B-related mani- festations, respectively (Table 1).
Discussion
In this study, the rate of occurrence of MEN2-related MTC/CCH, PHEO and the mean diagnostic age was similar to previously reported data [15,16]; however, MEN2-related HPT was not identified in the current study, which was different from Zhou et al. [17] re- ported that the prevalence of Chinese MEN2-related HPT was 10.8%, which is also lower compared with Western countries (20%-30%) [4]. The difference may be related to regional disparities, limited sample size and racial distribution.
Post-operatively, 17 of 20 (85%) symptomatic patients presented with residual MTC, metastases, and/or a re- currence. Five of 6 (83.3%) asymptomatic RET carriers underwent prophylactic TT had no abnormalities (P< 0.05). MEN2 had an age-related penetrance and metasta- sis of MTC with a variable intensity of expression. For the 10% of MEN2-related MTC patients with cervical LNM who were cured by TT and extensive lymph node excision, early standard surgery based on diagnostic RET testing might distinctly improve the cure rate of MEN2- related MTC [3-5,18,19]. In addition, even the same family has significant variability in the clinical expression of disease and development of MTC [for example, F8- III5, F8-IV5 and F8 other 6 with p.C618Y]. This may occur by the accumulation of genetic changes that have a dominant effect on the mutant allele or other affected factors [20,21].
In 2009, at the 9th meeting of the European Thyroid Association and Cancer Research Network (ETA-CRN), there were comments reported to the 2009 ATA guide- lines that pointed out that timing of prophylactic TT should be at best synthetically decided by combining the results of both RET gene testing and the ongoing pre-Ct level [9]. The timing of TT in RET carriers with a nega- tive Ct level can be personalized and safely planned when the stimulated Ct becomes positive. Intrathyroid MTCs were found when the pre-Ct level was <60 ng/L, and individualization of surgery in RET carriers with normal pre-Ct levels may be avoided B-LND (VI) [8,10]. QI et al. [11] also reported that MTC remained located
| Patient/Gender | RET mutation | Age | Pre-Ct (ng/L) | CEA (ng/ml) | Tumor size* (cm): L/R | Operative procedure | Histology | pTNM | LNM | Post-Ct (ng/L) | Interval time (years) |
|---|---|---|---|---|---|---|---|---|---|---|---|
| F3-III8/F | C634Y | 41 | 1744.0 | 57.9 | 1.4/3.2 | Reject operation | - | - | - | - | 18 |
| F3-III9/F | C634Y | 37 | 206.0 | 12.2 | 1.0/0.7 | Reject operation | - | - | - | - | 18 |
| F3-IV1/M | C634Y | 22 | 11.8 | 1.8 | -/0.3 | Reject operation | - | - | - | - | 18 |
| F3-IV4/F | C634Y | 9 | 9.8 | 0.7 | 0.3/0.2 | Reject operation | - | - | - | - | 18 |
| F4-III2/F | C634Y | 18 | 118.0 | 6.8 | 1.0/1.0 | TT + B-VI | MTC | T1N0M0 | 0/5 | <2.0 | 17 |
| F5-III4/F | C634R | 19 | 24.3 | 2.9 | 0.3/0.2 | TT | MTC | T1N0M0 | NO | <2.0 | 17 |
| F6-III2/M | C634R | 21 | 20.9 | 2.7 | 0.5/0.7 | TT + B-VI | MTC | T1N0M0 | 0/3 | <2.0 | 26 |
| F6-III4/M | C634R | 21 | 1769.0 | 119.6 | 1.1/1.0 | TT + B-VI + R-LND | MTC | T1N1bM0 | 20/59 | 975.0 | 23 |
| F6-III5/F | C634R | 19 | 71.4 | 3.3 | 0.5/1.0 | TT + B-VI | MTC | T1N0M0 | 0/1 | <2.0 | 26 |
| F7-III2/F | C618R | 26 | 487.6 | 25.9 | 2.0/2.5 | Reject operation | - | - | - | 17 | |
| F8-II2/F | C618Y | 78 | 1758.0 | 106.0 | 3.0/3.5 | Reject operation | - | - | - | 19 | |
| F8-III5/M | C618Y | 53 | <2.0 | 2.2 | -/- | Awaiting surgery | - | - | - | 19 | |
| F8-IV5/F | C618Y | 26 | 5.8 | 2.0 | -/- | TT | CCH | - | NO | <2.0 | 19 |
Note: Ct (basal serum Ct): normal <8.4 ng/L for male and <5.0 for female by FACLIA ; CEA (carcinoembryonic antigen): normal ≤5.0 ng/ml; Pre-Ct, pre-surgical Ct; Post-Ct, post-surgical Ct; TT, total thyroidectomy; B-VI, bilateral level VI lymph node dissection; R/ L -LND, right/ left lymph neck dissection. *Tumor size was measured by ultrasonography.
within the thyroid at low concentrations of Ct (<71.4 ng/L) in 17 asymptomatic RET carriers from the Chinese Han nationality. Here, the 3 patients (F4-III2, F6-III2, and F6-III5) might have avoided prophylactic B-LND (VI). More recently, Pelizzo et al. [22] demonstrated that RET carriers with normal basal Ct levels undergoing prophylactic TT after testing positive for stimulated Ct could not always be cured, particularly in 12% of all the level ATA-B/C RET mutations cases. The threshold for a definitive cure of MEN2-related MTC still needs to be empirically determined. The 7 asymptomatic RET carriers declined surgery or chose a watchful waiting approach, which offered us the unique opportunity to observe the natural history of MEN2-related MTC. Thus, it is import- ant to increase patient awareness to avoid treatment delay. Furthermore, our observation was also similar to reports detailing the use of vandetanib for advanced genetic MTC,
and the Q-T interval prolongation of drug toxicity was remarkable [12,23,24].
Moreover, in the early stages of research, the MEN2A family (F6, p.C634R) was mistaken for the FMTC family; however, it was soon shown that the F6-III2 family ac- companied PHEOs. FMTC is associated with mutations in codon 634 and is most commonly identified as p. C634Y, and almost never p.C634R [25]. It has been pre- viously suggested that it is important to use clinical screening and deeper genotype-phenotype correlations in intact pedigree analysis including long-term follow- up, which may avoid missed diagnoses of PHEOs and/or HPT and other endocrine adenomas besides the diagno- sis of MTC (FMTC). It has also been suggested that family members with the same RET mutation may dis- play different clinical phenotypes, and the offspring may display earlier PHEO phenotypes [4]. Our findings also
| Patient | Gender | RET mutation | Age at diagnosis PHEO | Temporal relation of PHEO to MTC | NE/E/DA (ng/L) | Tumor (size, cm) | Operative procedure | Follow-up |
|---|---|---|---|---|---|---|---|---|
| F1-II4 | F | C634F | 26 | Preceding | 246.0/36.3/61.5 | L, 3.3 | Left OPE | 163 |
| F2-II1 | M | C634Y | 35 | Concomitant | 399.0/48.2/43.0 | R, 2.5 | Right OPE | 74 |
| F3-III7 | F | C634Y | 36 | Preceding | 827.5/106.0/88.5 | R, 4.0 | Right OPE | 71 |
| F4-II3 | M | C634Y | 47 | Succeeding | 657.0/144.2/40.0 | L, 2.3 | Left LPE | 8 |
| F5-II1 | M | C634R | 34 | Succeeding | 1305.0/1270.3/ 243.6 | L, 10 ; R, 3.5 | heterochronous bilateral OPE | 252 |
| F5-II7 | M | C634R | 47 | Succeeding | 667.7/92.5/78.3 | R, 2.9 | Right LPE | 12 |
| F6-III2 | M | C634R | 21 | Concomitant | 69.9/12.6/10.2 | L, 3.5 | Left LPE | 24 |
| F7-II2 | F | C618R | 40 | Succeeding | 681.2/89.4/67.0 | L, 2.9 | Left LPE | 102 |
Note: OPE, open PHEO excision; LPE, laparoscopic PHEO excision; NE (norepinephrine): normal, 0 ~ 600 ng/L; E (epinephrine): normal, 0 ~ 100 ng/L; DA(dopamine): normal, 0 ~ 100 ng/L.
implied that MEN2-related PHEO occurrence may be affected by modifying factors from parents or the envi- ronment, and even by other mechanisms, such as errors in chromosomal replication during cell division or a sec- ond somatic mutation [4,26]. Additionally, sufficient pre- operative preparation before PHEO is necessary and pref- erential PHEO excision favors the avoidance of burst hypertensive crisis caused by PHEO during MTC or other non-PHEO surgical procedures or even death [4,5,26]. Unilateral MEN2A-related PHEO patients usually show contralateral PHEO over a period of 10 years and malig- nant MEN2A-related PHEO is rare (0.4%-5.0%) [4,27,28]. Based on a multi-institutional study, Castinetti et al. [28] recently reported 563 MEN2-related PHEO patients; re- currence of PHEOs in the same adrenal gland after CSA was only reported in 4 (3%) of 153 operated glands or in 4 (4%) of 114 patients after 6-13 years. Moreover, 47 of 82 (57%) patients with bilateral PHEO who underwent CSA did not become steroid-dependent. The CSA is a feasible surgical strategy for MEN2-related PHEOs, which may avoid or postpone the need for steroid replacement ther- apy and the associated risk of an Addisonian crisis [14,28]. The post-operative MEN2-related PHEOs should undergo follow-up, and monitored long-term for timely diagnosis and treatment options to prevent or reduce clinical risks [4,5]. In this study, our results also showed that initially unilateral CSA was technically safe and feasible, and may reduce steroid replacement therapy after a second/ contralateral CSA.
The de novo occurrence rate of MEN2A/FMTC was 5.6%-9.0% [29], while in MEN2B>90% of cases pre- sented with de novo germline RET mutations [30]. In the current study, in 2 (F2 [p.C634Y] and F9 [p.M918T]) of 9 families (Figure 1), only 2 probands harbored muta- tions; all the other consanguineous family members had no p.C634Y or p.M918T mutations, which suggested that both patients had de novo mutations or that the mutations existed in a parental germ cell mosaicism [31]. The age at which the p.M918T mutation was diag- nosed in our patient was advanced compared with the mean age (13 ± 9.3 years) reported by Brauckhoff et al. [30]. Thus, awareness of the clinical relevance of none- ndocrine manifestations, timely detection of RET gene and pre-Ct facilitate an early diagnosis and normalize surgery to improve the long-term outcome of MEN 2B.
Conclusions
In summary, systematic evaluation of MEN2 patients by means of integrated screening of RET and pre-Ct levels and implementation of individualized prophylactic TT favors a reduction in surgical complications and im- proves DFS. For advanced MTC, vandetanib provides novel treatment options. In patients with PHEOs, CSA can be utilized to preserve adrenocortical function.
Competing interests
The authors declare that they have no competing interests.
Authors’ contributions
JQZ performed the surgery and sequence analysis and reviewed the manuscript, ZGC oversaw collection of all patient samples and reviewed the manuscript, XPQ designed the project, performed the surgery, data analysis and wrote the manuscript. All authors read and approved the final manuscript.
Acknowledgements
This work was supported by the National Natural Science Foundation of China (81472861); the Key Project of Zhejiang Province Science and Technology Plan, China (2014C03048-1); the Medical Science and Technology Project of Zhejiang Province, China (2014KYB219); the Key Scientific Research Project of Nanjing Military Command, China (10Z036).
Author details
1Department of Head and Neck Surgery, Zhejiang Cancer Hospital, Hangzhou, Zhejiang Province 310022, China. 2Department of Oncologic and Urologic Surgery, the 117th PLA Hospital, Wenzhou Medical University, 40 Jichang Road, Hangzhou, Zhejiang Province 310004, China.
Received: 21 August 2014 Accepted: 7 January 2015 Published online: 20 January 2015
References
1. Donis-Keller H, Dou S, Chi D, Carlson KM, Toshima K, Lairmore TC, et al. Mutations in the RET proto-oncogene are associated with MEN 2A and FMTC. Hum Mol Genet. 1993;2:851-6.
2. Mulligan LM, Kwok JB, Healey CS, Elsdon MJ, Eng C, Gardner E, et al. Germ-line mutations of the RET proto-oncogene in multiple endocrine neoplasia type 2A. Nature. 1993;363:458-60.
3. Brandi ML, Gagel RF, Angeli A, Bilezikian JP, Beck-Peccoz P, Bordi C, et al. Guidelines for diagnosis and therapy of MEN type 1 and type 2. J Clin Endocrinol Metab. 2001;86:5658-71.
4. Wells Jr SA, Pacini F, Robinson BG, Santoro M. Multiple endocrine neoplasia type 2 and familial medullary thyroid carcinoma: an update. J Clin Endocrinol Metab. 2013;98:3149-64.
5. Kloos RT, Eng C, Evans DB, Francis GL, Gagel RF, Gharib H, et al. Medullary thyroid cancer: management guidelines of the American Thyroid Association. Thyroid. 2009;19:565-612.
6. Qi XP, Ma JM, Du ZF, Ying RB, Fei J, Jin HY, et al. RET germline mutations identified by exome sequencing in a Chinese multiple endocrine neoplasia type 2A/familial medullary thyroid carcinoma family. PLoS One. 2011;6:e20353.
7. Wiench M, Wygoda Z, Gubala E, Wloch J, Lisowska K, Krassowski J, et al. Estimation of risk of inherited medullary thyroid carcinoma in apparent sporadic patients. J Clin Oncol. 2001;19:1374-80.
8. Elisei R, Romei C, Renzini G, Bottici V, Cosci B, Molinaro E, et al. The timing of total thyroidectomy in RET gene mutation carriers could be personalized and safely planned on the basis of serum calcitonin: 18 years experience at one single center. J Clin Endocrinol Metab. 2012;97:426-35.
9. Jarzab B, Szpak-Ulczok S, Wloch J, Czarniecka A, Krajewska J. Timing and criteria for prophylactic thyroidectomy in asymptomatic RET carriers - the role of Ct serum level. Thyroid Res. 2013;6:59.
10. Machens A, Lorenz K, Dralle H. Individualization of lymph node dissection in RET (rearranged during transfection) carriers at risk for medullary thyroid cancer: value of pretherapeutic calcitonin levels. Ann Surg. 2009;250:305-10.
1. Qi XP, Zhao JQ, Du ZF, Yang RR, Ma JM, Fei J, et al. Prophylactic thyroidectomy for MEN 2-related medullary thyroid carcinoma based on predictive testing for RET proto-oncogene mutation and basal serum calcitonin in China. Eur J Surg Oncol. 2013;39:1007-12.
12. Thornton K, Kim G, Maher VE, Chattopadhyay S, Tang S, Moon YJ, et al. Vandetanib for the treatment of symptomatic or progressive medullary thyroid cancer in patients with unresectable locally advanced or metastatic disease: U.S. Food and Drug Administration drug approval summary. Clin Cancer Res. 2012;18:3722-30.
13. Cheng SP, Saunders BD, Gauger PG, Doherty GM. Laparoscopic partial adrenalectomy for bilateral pheochromocytomas. Ann Surg Oncol. 2008;15:2506-8.
14. Scholten A, Valk GD, Ulfman D, Borel Rinkes IH, Vriens MR. Unilateral subtotal adrenalectomy for pheochromocytoma in multiple endocrine neoplasia type 2 patients: a feasible surgical strategy. Ann Surg. 2011;254:1022-7.
15. Machens A, Gimm O, Hinze R, Hoppner W, Boehm BO, Dralle H. Genotype-phenotype correlations in hereditary medullary thyroid carcinoma: oncological features and biochemical properties. J Clin Endocrinol Metab. 2001;86:1104-9.
16. Machens A, Lorenz K, Dralle H. Peak incidence of pheochromocytoma and primary hyper-parathyroidism in multiple endocrine neoplasia 2: need for age-adjusted biochemical screening. J Clin Endocrinol Metab. 2013;98:E336-45.
17. Zhou Y, Zhao Y, Cui B, Gu L, Zhu S, Li J, et al. RET proto-oncogene mutations are restricted to codons 634 and 918 in mainland Chinese families with MEN2A and MEN2B. Clin Endocrinol (Oxf). 2007;67:570-6.
18. Roman S, Lin R, Sosa JA. Prognosis of medullary thyroid carcinoma: demographic, clinical, and pathologic predictors of survival in 1252 cases. Cancer. 2006;107:2134-42.
19. Skinner MA, Moley JA, Dilley WG, Owzar K, Debenedetti MK, Wells Jr SA. Prophylactic thyroidectomy in multiple endocrine neoplasia type 2A. N Engl J Med. 2005;353:1105-13.
20. Koch CA, Huang SC, Moley JF, Azumi N, Chrousos GP, Gagel RF, et al. Allelic imbalance of the mutant and wild-type RET allele in MEN 2A-associated medullary thyroid carcinoma. Oncogene. 2001;20:7809-11.
21. Agrawal N, Jiao Y, Sausen M, Leary R, Bettegowda C, Roberts NJ, et al. Exomic sequencing of medullary thyroid cancer reveals dominant and mutually exclusive oncogenic mutations in RET and RAS. J Clin Endocrinol Metab. 2013;98:E364-9.
22. Pelizzo MR, Torresan F, Boschin IM, Nacamulli D, Pennelli G, Barollo S, et al. Early, prophylacic thyroidectomy in hereditary medullary thyroid carcinoma: A 26-year monoinstitutional experience. Am J Clin Oncol. 2013; [Epub ahead of print].
23. Chau NG, Haddad RI. Vandetanib for the treatment of medullary thyroid cancer. Clin Cancer Res. 2013;19:524-9.
24. Massicotte MH, Borget I, Broutin S, Baracos VE, Leboulleux S, Baudin E, et al. Body composition variation and impact of low skeletal muscle mass in patients with advanced medullary thyroid carcinoma treated with vandetanib: results from a placebo-controlled study. J Clin Endocrinol Metab. 2013;98:2401-8.
25. Eng C, Clayton D, Schuffenecker I, Lenoir G, Cote G, Gagel RF, et al. The relationship between specific RET proto-oncogene mutations and disease phenotype in multiple endocrine neoplasia type 2. International RET mutation consortium analysis. JAMA. 1996;276:1575-9.
26. Qi XP, Chen XL, Ma JM, Du ZF, Fei J, Yang CP, et al. RET proto-oncogene genetic screening of families with multiple endocrine neoplasia type 2 optimizes diagnostic and clinical management in China. Thyroid. 2012;22:1257-65.
27. Lairmore TC, Ball DW, Baylin SB, Wells Jr SA. Management of pheochromocytomas in patients with multiple endocrine neoplasia type 2 syndromes. Ann Surg. 1993;217:595-601. discussion 601-593.
28. Castinetti F, Qi XP, Walz MK, Maia AL, Sansó G, Peczkowska M, et al. Outcomes of adrenal-sparing surgery or total adrenalectomy in phaeochromocytoma associated with multiple endocrine neoplasia type 2: an international retrospective population-based study. Lancet Oncol. 2014;15:648-55.
29. Schuffenecker I, Ginet N, Goldgar D, Eng C, Chambe B, Boneu A, et al. Prevalence and parental origin of de novo RET mutations in multiple endocrine neoplasia type 2A and familial medullary thyroid carcinoma. Le Groupe d’Etude des Tumeurs a Calcitonine. Am J Hum Genet. 1997;60:233-7.
30. Brauckhoff M, Machens A, Lorenz K, Bjøro T, Varhaug JE, Dralle H. Surgical curability of medullary thyroid cancer in multiple endocrine neoplasia 2 B: a changing perspective. Ann Surg. 2014;259:800-6.
31. Pho LN, Smith FJ, Konecki D, Bale S, McLean WH, Cohen B, et al. Paternal germ cell mosaicism in autosomal dominant pachyonychia congenita. Arch Dermatol. 2011;147:1077-80.
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