The surgical treatment of medullary thyroid carcinoma

Prediction of lateral neck lymph node metastasis according to preoperative calcitonin level and tumor size for medullary thyroid carcinoma

Medullary thyroid carcinoma (MTC) accounts up to 10% of all thyroid cancers, but is responsible for a disproportionate number of deaths. While surgery is the only curative treatment for MTC, indications for lateral neck lymph node (LLN) dissection are controversial. We performed a retrospective review to describe clinical outcomes in 93 MTC patients from July 1995 to March 2015. We analyzed their clinicopathologic factors, and cut-off values of tumor size and calcitonin levels were calculated using a receiver operating characteristic curve. Using the instances of lymph node metastases, the tumor size cut-off value was 0.95 cm (area under curve, AUC = 0.697) in patients with ipsilateral central lymph node (CLN) metastases, 2.25 cm (AUC = 0.793) in contralateral CLN metastases, and 1.75 cm (AUC = 0.753) in ipsilateral LLN metastases. The cut-off values of preoperative calcitonin levels were 226.6 pg/mL (AUC = 0.746) in ipsilateral CLN, 755.0 pg/mL (AUC = 0.840) in contralateral CLN metastases, and 237.0 pg/mL (AUC = 0.775) in ipsilateral LLN metastases. This study supports the notion that ipsilateral LLN metastases occur before contralateral CLN metastases. Therefore, ipsilateral LLN dissection should be considered in patients with contralateral CLN metastases. The extent of surgery should be based on the status of LN metastases, preoperative basal calcitonin level, and tumor size to help individualize the extent of surgery.

Systemic treatment and management approaches for medullary thyroid cancer

Although rare, medullary thyroid cancer (MTC) exemplifies the value that ever-expanding knowledge of molecular pathways and mechanisms brings to managing challenging cancers. Although surgery can be curative for MTC in many patients, a substantial proportion of patients present with locoregional or distant metastatic disease. Once distant disease occurs, treatment options are limited, and conventional cancer treatments such as cytotoxic chemotherapy are of minimal benefit. Biomarkers such as calcitonin and carcinoembryonic antigen are important correlates of disease burden as well as predictors of disease progress, including recurrence and survival. MTC is either sporadic (∼75%) or inherited (∼25%) as an autosomal dominant disease. Regardless, germline and somatic mutations, particularly in the rearranged during transfection (RET) proto-oncogene, are key factors in the neoplastic process. Gain-of-function RET mutations result in overactive proteins that lead to abnormal activation of downstream signal transduction pathways, resulting in ligand-independent growth and resistance to apoptotic stimuli. Specific RET mutation variants have been found to correlate with phenotype and natural history of MTC with some defects portending a more aggressive clinical course. Greater understanding of the consequence of the aberrant signaling pathway has fostered the development of targeted therapies. Two small-molecule tyrosine kinase inhibitors, vandetanib and cabozantinib, are currently available as approved agents for the treatment of advanced or progressive MTC and provide significant increases in progression-free survival. Since there have been no head-to-head comparisons, clinicians often select between these agents on the basis of familiarity, patient characteristics, comorbidities, and toxicity profile.

Retrospective analysis of 140 cases of medullary thyroid carcinoma followed-up in a single institution

Familial cases of medullary thyroid carcinoma (MTC) may be diagnosed by genetic screening, while in sporadic tumors the diagnosis relies mainly on fine-needle aspiration cytology. The aim of the present study was to determine the demographic, clinical and pathological characteristics of MTC patients followed-up at the Portuguese Institute of Oncology Francisco Gentil (Lisbon, Portugal). For that purpose, a retrospective analysis of 140 MTC patients diagnosed between 1990 and 2010 was performed. The results indicated that patients with hereditary MTC (11.4%) were significantly younger than patients with sporadic MTC. Of the latter, 34.3% had no clinical suspicion of MTC prior to surgery. The sensitivity of cytology and calcitonin (CT) assay in diagnosing MTC were 51.3 and 98.7%, respectively. All familial index cases and 69.0% of sporadic cases presented with advanced stage disease at the time of diagnosis, while 73.0% of familial MTC detected by genetic/pentagastrin screening were diagnosed at the early stage of the disease. Biochemical cure (BC) was achieved in 39.7% of patients and, of these, only 6.5% relapsed. The 5 and 10-year survival rates were 79.3 and 73.6%, respectively. Age >45 years (P=0.026), advanced stage at diagnosis (P<0.001) and absence of BC (P<0.001) were predictors of a worse prognosis on univariate analysis. However, when the patients detected by genetic/pentagastrin screening were excluded from the analysis, age was no longer a prognostic factor, although disease stage remained a significant prognostic factor. On multivariate analysis, BC was the only factor with a significant impact on prognosis (P=0.031). In addition, the present study confirmed that the majority of patients were diagnosed at advanced stages, and CT determination was observed to be more sensitive than cytology to diagnose MTC. Patients at early stages were more prone to achieve BC, which was a favorable prognostic factor. To the best of our knowledge, the present study reports for the first time that age at diagnosis is not a predictor of survival for patients with MTC when cases diagnosed by genetic/pentagastrin screening (who are usually young patients at the initial stages of the disease), are excluded from the analysis.

Great cervical venous tumoral thrombosis of melanotic medullary carcinoma thyroid: Fluorine-18 fluorodeoxyglucose positron emission tomography/computed tomography enabled diagnosis and radiotherapy planning

The authors report an extremely rare occurrence of a massive tumor thrombus involving right internal and external jugular veins extending into superior vena cava from a still rarer melanotic medullary carcinoma thyroid in the postoperative follow-up. The case was managed by hypofractionated intensity modulated radiotherapy technique with gratifying results.

Surgery for lymph node metastases of medullary thyroid carcinoma: A review

Medullary thyroid carcinoma (MTC) is a neuroendocrine malignancy of the thyroid C cells that occurs in hereditary and sporadic clinical settings. Metastatic spread commonly occurs to cervical and mediastinal lymph nodes. MTC cells do not concentrate radioactive iodine and are not sensitive to hormonal manipulation, and therefore surgery is the most effective option for curative therapy, reduction in tumor burden, or effective palliation. In patients undergoing preventative surgery for hereditary MTC, central lymph node dissection should be considered if the calcitonin level is elevated. Preservation of parathyroid function in these young patients is of paramount importance. In patients with established primary tumors, systematic surgical removal of lymph node basins (compartmental dissection) should be guided by ultrasound mapping of lymph node metastases and level of serum calcitonin. A "berry-picking" approach is discouraged. Newly approved targeted molecular therapies offer wider treatment options for patients with progressive or metastatic disease.

Surgery for lymph node metastases of medullary thyroid carcinoma

Medullary thyroid carcinoma (MTC) is a neuroendocrine malignancy of the thyroid C cells, and can commonly spread to cervical and mediastinal lymph nodes. MTC cells do not concentrate radioactive iodine and are not sensitive to hormonal manipulation, and therefore surgery is the only effective option for curative therapy, reduction in tumor burden or effective palliation. In patients undergoing preventative operations for hereditary MTC, central lymph node dissection should be considered if the calcitonin level is above 40 pg/ml. Systematic removal of at-risk or involved lymph node compartments should be performed in all patients with palpable primary tumors and recurrent disease, and a ‘berry-picking’ approach should be avoided.

Alternative surgical strategies in patients with sporadic medullary thyroid carcinoma: Long-term follow-up

The extent of surgical resection in patients with sporadic medullary thyroid carcinoma (SMTC) remains controversial. The aim of the present study was to discuss the prognosis of sporadic medullary thyroid carcinoma with different surgical treatments. Of 73 patients with SMTC (mean age of 43.78 years at diagnosis), 70 patients were followed up for 12.0-169.0 months (median 90.0). Having given their informed consent, 12 patients underwent total thyroidectomy with bilateral central neck dissection (group A), 40 underwent subtotal thyroidectomy preserving contralateral thyroid tissue on the entrance point of the recurrent laryngeal nerve into the larynx with ipsilateral modified radical neck dissection (group B), and 18 patients underwent subtotal thyroidectomy preserving contralateral thyroid tissue on the entrance point of the recurrent laryngeal nerve into the larynx with bilateral modified radical neck dissection (group C). The diagnosis was confirmed by a pathology examination. The incidences of hypoparathyroidism and recurrent laryngeal nerve injury, the cancer recurrence rates and survival time were investigated post-operatively. Significant differences were found between groups A, B and C in the incidence of hypoparathyroidism (χ(2)=40.9, P<0.01), as well as that of recurrent laryngeal nerve injury (χ(2)=32.9, P<0.01). The cancer recurrence rates in groups A, B and C were 75.0% (9/12), 2.5% (1/40) and 44.4% (8/18) respectively, (χ(2)=31.1, P<0.01) and the cure rates were 25, 97.5 and 55.6% respectively (χ(2)=31.1, P<0.01). The mean survival times in groups A, B and C were 77.8, 106.1 and 111.0 months respectively, but significant difference was noted (χ(2)=3.2, P>0.05). In conclusion, compared to total thyroidectomy with bilateral central neck dissection, subtotal thyroidectomy with ipsilateral/bilateral modified radical neck dissection showed a lower incidence of hypoparathyroidism, recurrent laryngeal nerve injury and lower rates of recurrence, along with a similar cumulative survival.

The surgical management of medullary thyroid cancer

Medullary thyroid cancer (MTC), accounts for approximately 5% to 10% of all thyroid cancers. Significant advances in the understanding of the biology and clinical outcomes of MTC have been made over the last decade, culminating most recently in the publication of treatment guidelines by the American Thyroid Association that follow an evidence-based approach that is summarized in this presentation. Prognosis, genetic testing, surgical technique, and re-operation are also discussed.

[Hereditary thyroid cancer]

Hereditary thyroid carcinomas are present in about 5% of differentiated (DTC) and 25% of medullary thyroid carcinomas (MTC). They are part of a multiorgan tumour syndrome (e. g. FAP Gardner's syndrome with DTC and MEN 2 syndrome with MTC) or confined to the thyroid gland. Hereditary thyroid carcinomas typically show multifocal growth and occur in young patients. Due to germ cell mutations as the underlying cause of disease, partial thyroidectomies that may be justified in early sporadic carcinomas are not indicated in this type of tumours. In the case of hereditary DTC, the genetic basis of the disease has been demonstrated only in syndromatic tumour variants. In most nonsyndromatic cases, specific genetic alterations have not yet been identified. In both types of hereditary DTC, prophylactic thyroidectomy is not warranted due to the favourable prognosis of tumours that do not differ from sporadic ones. Point mutations of the RET proto-oncogene have been known for 15 years to be the genetic basis of hereditary MTC. Recently several new mutations were discovered; however, final conclusions regarding their clinical significance are not possible at present. Basically it has been shown that the clinical aggressivity of tumour development follows a genotype-phenotype correlation (risk groups 1-3). However, in mutations of all risk classes there exists a wide spectrum of different stages of hereditary C-cell disease in individual risk groups. Regarding time and extent of prophylactic thyroidectomy (without or with lymph node dissection) a combined molecular-biochemical concept including the use of pentagastrin-stimulated calcitonin values is therefore recommended.

Management of medullary thyroid carcinoma

Medullary thyroid carcinoma (MTC) is responsible for 13.4% of the total deaths attributable to thyroid cancer in human beings and research on MTC over the last 40 years has identified the RET proto-oncogene as a very relevant component of development of both sporadic and hereditary MTC. An activating germline RET proto-oncogene mutation responsible for a multiple endocrine neoplasia syndrome type 2 (MEN2) or a familial hereditary MTC syndrome is carried by 25% to 35% of patients with MTC. The recognition of RET proto-oncogene mutations by genetic sequencing has allowed us to differentiate hereditary from sporadic MTC, so that it is now possible to identify and treat children at risk for this disease before development of metastasis. Thanks to this discovery, we can now establish the association of MTC with other tumors in the context of MEN2 syndrome; determine adequate follow-up, prognosis, and treatment for patients with hereditary disease; and use this information to develop new therapies against both sporadic and hereditary MTCs.

Neck management in medullary thyroid carcinoma

AIMS

The aims of this study were to retrospectively evaluate incidence and patterns of lymph node metastases, surgical treatment and prognostic factors of medullary thyroid carcinoma.

METHODS

Out of a group of 70 MTC patients data of 67 patients were collected. Sixty-two of these patients underwent surgery. Apart from thyroidectomy, 16 patients underwent a bilateral neck dissection, 21 a unilateral neck dissection and 29 a paratracheal dissection or node-picking operation. Thirty-six patients were irradiated, of which 31 postoperatively and five with palliative intent.

RESULTS

Lymph node metastases were found in 91% of the ipsilateral neck dissection specimens, 91% of the paratracheal dissections and 63% of the contralateral dissections. Of the 12 elective neck dissections, 5 were tumor positive. Level VI was positive in 91% of the cases where a dissection was done, whereas preoperatively only 16% were scored tumor positive. During follow-up 22 of the 67 patients developed one or more locoregional recurrences (in total 28 recurrences). The most important factors that were correlated with a worse prognosis of survival were late stage of disease (stage III and IV) (p=0.0014), high number of positive lymph nodes (p=0.0023) and incomplete surgical resection (p=0.0002).

CONCLUSIONS

The high rate of locoregional recurrences in this study are a strong argument for a more aggressive approach to the primary and neck. A routine central and ipsilateral selective neck dissection of levels II-V should be considered in all MTC patients based on the high incidence of metastases and the relative low morbidity of a unilateral neck dissection. Patients referred after thyroidectomy alone with elevated (stimulated) calcitonin levels should be re-operated, performing an elective or therapeutic central and unilateral neck dissection.

Failure to recognize multiple endocrine neoplasia 2B: more common than we think?

BACKGROUND

Multiple endocrine neoplasia 2B (MEN2B) has a classic childhood phenotypic presentation characterized by mucosal neuromas and marfanoid habitus. However, the diagnosis of MEN2B is often delayed beyond childhood, at which time medullary thyroid carcinoma (MTC) may be regionally advanced or metastatic. We examined the extent of this delay and its impact on the treatment of MTC.

METHODS

Patients in the MEN database were retrospectively analyzed to determine the age at first presentation for a MEN2B-related complaint and the subsequent time to correct diagnosis. Operative and pathology reports were reviewed to determine the extent of thyroidectomy and cervical lymphadenectomy during the initial and subsequent neck operations.

RESULTS

We identified 22 patients with MEN2B, 20 were de novo cases and a M918T RET gene mutation was confirmed in 18 of the 22 patients. Median age at diagnosis of MTC was 13 years (range 6-25 years). The median delay in diagnosis was 26 months (range 0-18 years). Persistent local-regional MTC was present following the initial cervical operation in 12 of 22 patients (55%); including 4 of 13 with MEN2B diagnosed prior to initial surgery and 8 of 9 with MEN2B diagnosed after initial surgery.

CONCLUSIONS

Most patients displayed phenotypic characteristics of MEN2B long before the correct diagnosis was made. Half of the patients failed to undergo complete resection of MTC at their initial thyroid surgery. Early recognition of the MEN2B phenotype with a thoughtful approach to preoperative staging and surgery will maximize control of MTC and minimize the need for reoperation.

Medullary Thyroid Carcinoma

Medullary thyroid carcinoma is a neuroendocrine tumor derived from the C cells of the thyroid gland and accounts for approximately 5% of all thyroid carcinomas. Approximately 30% of the cases are associated with an autosomal dominant syndrome called multiple endocrine neoplasia type 2, and the identification of these individuals is important because affected family members may benefit from an early diagnosis. The treatment of this disease is predominantly surgical, and the impact of radiotherapy and chemotherapy is limited. The identification of the associated molecular events has lead to the development of specific molecular targeted agents that may change the way this disease is treated in the near future.

Initial Lymph Node Dissection Increases Cure Rates in Patients with Medullary Thyroid Cancer

OBJECTIVE

Medullary thyroid carcinoma (MTC) is the third most common type of thyroid cancer. MTC spreads early to local lymph nodes, and most endocrine surgeons recommend total thyroidectomy with central lymph node dissection (CLND) as the minimum initial operation. We reviewed our experience to determine if the initial operation influences clinical outcomes.

METHODS

Twenty-two patients with sporadic or inherited MTC who received surgery at one academic centre between 1994 and 2004 were identified. Clinical, operative, and pathology findings were reviewed.

RESULTS

Ten patients had prophylactic thyroidectomy for hereditary MTC, while 12 patients underwent therapeutic operations for sporadic MTC. The average age of the prophylactic group was 11 +/- 3, and 43 +/- 6 years for the therapeutic group. All patients in the prophylactic group received thyroidectomy without neck dissection. No patient in the prophylactic group had residual disease or required re-operation. In the therapeutic surgery group, three patients were treated with thyroidectomy plus CLND, and nine patients received thyroidectomy alone. The CLND group had a significantly higher cure rate as demonstrated by a lower incidence of residual disease (0% vs. 89%, p = 0.018), and re-operations (0% vs. 78%, p = 0.045).

CONCLUSION

Initial CLND for MTC increases cure rates by reducing residual disease and re-operations.

Mutation analysis of the RET proto-oncogene and early thyroidectomy: results of a Portuguese cancer centre

BACKGROUND

Evidence that germline mutations in the RET proto-oncogene are the underlying cause of the familial form of medullary thyroid carcinoma (MTC) made it possible to identify gene carriers with a very high degree of accuracy. Aiming to define the mutational profile observed in our patients and to assess gene carriers' compliance with an early surgery, we reviewed results of molecular analysis of RET performed at our institution since 1994.

METHODS

One hundred fifty-eight individuals were screened for germline mutations of the RET proto-oncogene. Seventy-seven patients had apparently sporadic MTC; 8 patients had both MTC and pheochromocytoma or MTC and clinical features of multiple endocrine neoplasia type 2B despite a negative family history; 8 patients were known to belong to affected kindreds; and 65 individuals were at-risk individuals to develop MTC.

RESULTS

A germline mutation in RET was identified in 4% of apparently sporadic MTC patients, in 100% of patients with MTC and pheochromocytoma or MTC and clinical features of multiple endocrine neoplasia type 2B, and in 100% of probands of clinically established kindreds. The most affected codon was 634 (58%) followed by codon 804 (16%). Among at-risk individuals, 49% were identified as gene carriers. Seven individuals were submitted to prophylactic thyroidectomy (mean age, 17.7 +/- 12.5 years; range: 3-42 years), and all but 1 had MTC.

CONCLUSIONS

RET mutational spectrum observed in the present population disclosed a higher frequency of codon 804 mutations than expected. Compliance with an early prophylactic surgery seemed to be influenced not only by medical advice and cultural factors but also by the aggressiveness of disease in gene carriers' families.

Medullary thyroid carcinoma: multivariate analysis of prognostic factors influencing survival

BACKGROUND

Medullary thyroid carcinoma (MTC) is a rare development of thyroid cancer with a no negligible mortality rate. Our aim was to determine factors that predict outcome in patients with MTC.

METHODS

We reviewed the records of all patients with MTC (n=56) who underwent treatment at our institution between January 1990 and December 2000. Univariate and multivariate analysis of clinicopathologic predictors of MTC outcome were performed to identify subsets of patients with different probabilities in terms of overall survival, local recurrence, and distant metastases.

RESULTS

Multivariate analysis demonstrated that a statistically significant decrease in overall survival is associated with T4b tumours (p=0.06), the presence of distant metastases at the time of presentation (p=0.033), lymphatic invasion (p=0.099), and postoperative treatment (p=0.045).

CONCLUSIONS

The analysis of survival curves of patients with MTC shows that the occurrence of locoregional and distant metastases occurs preferentially within the first 5 years, which identifies this as a crucial period for follow-up. In this series of patients with MTC, the tumours classified as T4b, metastases at presentation, the presence of lymphovascular invasion, and postoperative treatment were the most important prognostic features. At present, there is no available beneficial adjuvant therapy. However, as the development of molecular therapy progresses, it should be tested in clinical trials with the purpose of achievement of novel targeted therapies for selected MTC patients with risk factors.

Hereditary medullary thyroid cancer in Slovenia – genotype-phenotype correlations

BACKGROUND

Medullary thyroid cancer (MTC) is a rare endocrine tumor that may be sporadic or inherited in settings of MEN2A, MEN2B and FMTC. Germline point mutations in the RET proto-oncogene are responsible for tumor occurrence, inheritance and great clinical variability. The aim of this study was to correlate the genotype and phenotype of patients with hereditary MTC (age at diagnosis, sex, TNM classification and clinical features).

PATIENTS

Between 1997 and 2003 genetic testing was performed in 69 out of 98 patients with "sporadic" MTC. Carriage of mutation was found in 14 (20.2%) patients (index patients) and in 16 out of 31 (51.6%) of their relatives. One patient with MEN2B and codon 918 mutation was excluded from further analysis.

METHODS

Genomic DNA was isolated from peripheral blood leukocytes. Exons 10, 11, 13, 14, 15 and 16 of the RET proto-oncogene were amplified in polymerase chain reactions. Point mutations of the RET gene were detected with single-strand conformation analysis and DNA sequencing. Detected mutations were confirmed with restriction enzyme analysis.

RESULTS

Codon 634 mutations were detected in 15 patients (50%; aged 18-76 years; 6 families), codon 618 in nine patients (30%; aged 12-65 years; 4 families) and codon 790 in five patients (16.6%; aged 16-74 years; 3 families). The median age at diagnosis was 31 +/- 17.3, 33 +/- 15.9 and 36 +/- 23.8 years for patients with codon 618, 634 and 790 mutations. Selected by sex, females with codon mutations 618 and 634 versus 790 had median age at diagnosis of 34.5 +/- 15.6 years and 43.5 +/- 22.9 years, whereas the inverse result was observed in males (26.5 +/- 18.0 versus 16 years). The male/female ratio was 1:2 for patients with codon 618 and 634 mutations and 1:4 for patients with codon 790 mutations. Some of the data suggested correlation between specific genotypes, tumor size, stage of MTC and age at diagnosis. Pheochromocytoma (12 out of 15 patients) and primary hyperparathyroidism (6 out of 15 patients) were diagnosed solely in patients with codon 634 mutations. One patient with FMTC and Hirschprung disease was found in a family with codon 618 mutations.

CONCLUSION

Correlation between tumor size, stage of MTC at diagnosis in view of patient's age, and specific genotype were indicated in our limited series and were more evident in female patients with codon 790 mutations. Later onset and a probably less aggressive course of MTC in these patients than in patients with other mutations should be considered in planning prophylactic thyroid surgery. MEN2A syndrome was related solely to codon 634 mutations.

Activity of irinotecan and the tyrosine kinase inhibitor CEP-751 in medullary thyroid cancer

CONTEXT

Medullary thyroid cancer (MTC) is a cancer of the parafollicular C cells that commonly presents with an inherited or acquired RET gene mutation. There is currently no effective systemic treatment for MTC.

OBJECTIVE

The objective of this study was to investigate a systemic therapeutic approach to treat MTC. We studied the sensitivity of an MTC cell line and xenograft to irinotecan, alone and in combination with the tyrosine kinase inhibitor, CEP-751.

RESULTS

In TT cell culture and xenografts, irinotecan treatment was highly effective. This effect was augmented by treatment with CEP-751. Treatment of TT cell xenografts resulted in durable complete remission in 100% of the mice, with median time to recurrence of 70 d for irinotecan alone and more than 130 d for irinotecan plus CEP-751. Although irinotecan induced an S phase checkpoint arrest in TT cells, CEP-751 in combination with irinotecan resulted in a loss of this arrest. CEP-751 induced a loss in the induction of the DNA repair program marked by phospho-H2AX and the checkpoint pathway marked by the activated Chk1 pathway.

CONCLUSIONS

Irinotecan treatment was highly effective in a preclinical model of human MTC, resulting in complete remission in 100% of the xenografts treated. The duration of remission was further enhanced by combination with the kinase inhibitor, CEP-751. These results suggest that irinotecan, alone or in combination, may be useful for the treatment of MTC.

Preoperative diagnosis of medullary thyroid carcinoma: fine needle aspiration cytology as compared with serum calcitonin measurement

BACKGROUND AND OBJECTIVES

Preoperative diagnosis of sporadic medullary thyroid carcinoma (MTC) has mainly relied on fine needle aspiration cytology (FNAC). The present study aimed to compare the sensitivity of this technique with serum calcitonin (CT) measurement and to assess the therapeutic implications of an inadequate preoperative diagnosis.

METHODS

We reviewed the clinical records of 91 MTC patients treated and/or followed at our institution between January 1990 and December 2003.

RESULTS

After revision of clinical records, 77 individuals were considered eligible for the study. FNAC was performed in 67 patients (87%) with a sensitivity of 63%; serum CT was measured in 56 patients (73%) with a sensitivity of 98%. Both FNAC and serum CT were assessed in 51 patients (66%). FNAC detected only 74.5% of MTCs suspected by elevated serum CT. Among patients with a cytological diagnosis of MTC, total thyroidectomy (TT) was performed in 95% of patients. Among patients without a cytological diagnosis of MTC, TT was performed in 83% of patients in whom serum CT was evaluated prior to surgery whereas it was performed in only 46% of patients in whom CT evaluation was lacking.

CONCLUSIONS

Despite the higher sensitivity of serum CT measurement, as compared with FNAC to diagnose MTC (98% vs. 63%), only 9% of patients might have escaped to surgery based on FNAC results. However, indication for surgery based on suspicious FNAC may not alert the surgeon for the need of a TT and exploration of nodes at least in the central compartment.

Thyroid carcinoma

Thyroid carcinomas are fairly uncommon and include disease types that range from indolent localised papillary carcinomas to the fulminant and lethal anaplastic disease. Several attempts to formulate a consensus about treatment of thyroid carcinoma have resulted in published guidelines for diagnosis and initial disease management. Multimodality treatments are widely recommended, although there is little evidence from prospective trials to support this approach. Surgical resection to achieve local disease control remains the cornerstone of primary treatment for most thyroid cancers, and is often followed by adjuvant radioiodine treatment for papillary and follicular types of disease. Thyroid hormone replacement therapy is used not only to rectify postsurgical hypothyroidism, but also because there is evidence to suggest that high doses that suppress thyroid stimulating hormone prevent disease recurrence in patients with papillary or follicular carcinomas. Treatment for progressive metastatic disease is often of limited benefit, and there is a pressing need for novel approaches in treatment of patients at high risk of disease-related death. In families with inherited thyroid cancer syndromes, early diagnosis and intervention based on genetic testing might prevent poor disease outcomes. Care should be carefully coordinated by members of an experienced multidisciplinary team, and patients should be provided with education about diagnosis, prognosis, and treatment options to allow them to make informed contributions to decisions about their care.

Medullary thyroid cancer

Medullary thyroid cancer is a rare neoplasm that arises from the parafollicular C cells. It occurs in a sporadic form, or less commonly as a hereditary form, as part of multiple endocrine neoplasia syndromes types 2A and 2B. The RET proto-oncogene is currently the primary factor that is implicated in the hereditary forms of this neoplasm. The knowledge about the genetic makeup of the neoplasm impacts upon management as it allows for screening, early detection, and prophylactic treatment. Surgery is the main modality that offers a cure. This entails a total thyroidectomy and vigilant management and surveillance of the neck. Prognosis of patients with MTC is variable, but the more constant factors that affect it are the stage of disease and the age of the patient. The emerging molecular genetic understanding of this malignancy will provide the foundation for prognostic and therapeutic decision-making in the future. Interdisciplinary management by surgeons, endocrinologists, pathologists, radiotherapists, radiologists, and medical oncologists should be sought.

Prolonged survival of a patient with multiple endocrine neoplasia type 2b and stage IV medullary thyroid carcinoma

OBJECTIVE

To present a case of multiple endocrine neoplasia type 2B (MEN2B) with a prolonged course.

METHODS

We describe the clinical, laboratory, and radiologic findings in a patient with MEN2B and review the various interventions during a period of approximately 3 decades.

RESULTS

In 1962, a 19-year-old man with a marfanoid body habitus presented with multiple thyroid nodules and neurofibromas of the tongue. Total thyroidectomy demonstrated multicentric medullary thyroid carcinoma with cervical lymph node metastatic involvement. At the time of the first description of the MEN2B syndrome, the patient was enrolled in a surveillance program. An increase in urinary metanephrines resulted in bilateral adrenalectomy for multinodular pheochromocytoma in 1972. Increased serum calcitonin levels and the appearance of cervical lymphadenopathy led to modified radical neck dissection 12 years after the initial diagnosis of medullary thyroid carcinoma. In 1975, angiography revealed extensive hepatic lesions metastatic from the medullary thyroid carcinoma; this finding was confirmed by open liver biopsy in 1988. The patient lived 16 years after the initial diagnosis of liver metastatic disease and died 29 years after the initial examination.

CONCLUSION

The 3-decade course of this patient not only represents a classic case of MEN2B but also allows us to present the history of this disease from its discovery to the current era of genetic testing and exemplifies the possibility of long-term survival in a patient with liver metastatic involvement from medullary thyroid carcinoma.

Early onset of medullary thyroid carcinoma in a kindred with multiple endocrine neoplasia type iia associated with cutaneous lichen amyloidosis

OBJECTIVE

To describe the molecular characterization of a kindred affected by the rare variant of multiple endocrine neoplasia type IIA (MEN IIA) associated with cutaneous lichen amyloidosis and to discuss the clinical implications in the management of this syndrome.

METHODS

A kindred with four affected family members was identified, and DNA analysis was performed by sequencing exon 11 of the RET proto-oncogene. Presymptomatic genetic screening was offered to all first-degree relatives.

RESULTS

Sequencing analysis of the RET proto-oncogene revealed a Cys634Trp (TGC->TGG) mutation in all clinically affected family members and in an asymptomatic 5-year-old child who, after thyroidectomy, was found to have multicentric medullary thyroid carcinoma and C-cell hyperplasia. A Gly691Ser (GGT->AGT) polymorphism was also detected in this family but did not segregate with the disease.

CONCLUSION

To our knowledge, this is the earliest detection of medullary thyroid carcinoma reported thus far in a kindred with MEN IIA associated with cutaneous lichen amyloidosis, and this finding suggests that prophylactic thyroidectomy, in kindreds with this variant, should be performed before the age of 5 years.

Radiopeptide transmitted internal irradiation of non-iodophil thyroid cancer and conventionally untreatable medullary thyroid cancer using

AIM

Differentiated thyroid carcinomas (DTC) and medullary thyroid carcinomas (MTC) overexpress somatostatin receptor subtypes (sstr). The aim of this pilot study was to evaluate the tumour response of thyroid carcinomas to targeted irradiation with the radiolabelled somatostatin analogue [90Y]-1,4,7,10-tetra-azacyclododecan-4,7,10-tricarboxy-methyl-1-yl-acetyl-D-Phe1-Tyr3-octreotide ([90Y]-DOTA-D-Phe1-Tyr3-octreotide, or 90Y-DOTATOC) which has a high affinity to subtype 2 and a low affinity to subtype 5. It shows no affinity to sstr1, sstr3 and sstr4.

PATIENTS AND METHODS

Twenty patients (mean age 58 years; 50% female, 50% male) with thyroid cancer were included (medullary thyroid cancer (MTC), 12 patients; differentiated thyroid cancer (DTC), seven patients; papillar carcinoma (PC), four patients; follicular carcinoma (FC), three patients; anaplastic carcinoma (AC), one patient). All patients had been therapy resistant and had progressive disease before 90Y-DOTATOC therapy. The dose applied was between totals of 1700 MBq x m(-2) to 7400 MBq x m(-2) 90Y-DOTATOC, administered in one to four injections at intervals of 6 weeks. In the case of tumour progression under therapy, treatment was terminated.

RESULTS

The overall antitumour effect (objective response and stable disease) was 35%; in MTC 42%, in DTC 29%, and in AC 0%. The objective overall response rate was 0%. A stable disease was achieved in 35% (7/20), and progressive disease was found in 65% (13/20). The median time to progression was 8 months, with a median follow-up of 15 months. The treatment was very well tolerated. There were no grade III/IV haematological or renal toxicities.

CONCLUSION

Targeted radiotherapy using 90Y-DOTATOC is able to stop tumour progression in a small number of patients and therefore may be an alternative treatment option for resistant disease. More significant tumour responses in thyroid and medullary thyroid cancer may be obtained by using radiopeptides with pan-somatostatin characteristics.

[Usefulness of RET proto-oncogene in the diagnosis of hereditary-type medullary carcinoma of the thyroid. Correlation with surgical findings]

In about 25% of cases medullary thyroid carcinoma (MTC) is hereditary. In this group is possible to detect germline point mutations of the RET proto-oncogene in about 95% of the studied cases. The purpose of the present paper is to confirm the value of the RET in the screening of the hereditary MTC. We studied 43 subjects at risk for a Multiple Endocrine Neoplasia Type 2A Syndrome. RET analysis was positive for MEN 2A in 22 subjects. Fifteen of the 22 have undergone a total thyroidectomy at our facility. Histopathological study of the surgical specimens confirmed the presence of a MTC in all the cases. According with our experience. RET analysis is a 100% sensitive and specific method of hereditary MTC screening, and we think it has obvious advantages over the calcitonin tests in technical, economic and ethic aspects.

Improved diagnostic methods in the follow-up of medullary thyroid carcinoma by highly specific calcitonin measurements

Calcitonin (CT) is an important tumor marker for medullary thyroid carcinoma (MTC). Recent CT assays chiefly recognize the monomeric form of CT (mCT). It was the objective of this study to examine the consequences of the higher specificity of the assay for interpretation of the postoperative CT values in MTC patients. The postoperative mCT concentration was measured in 214 patients with differentiated thyroid carcinoma (MTC excepted; non-MTC patients) to determine a reference range of mCT in totally thyroidectomized patients. Monomeric CT was also determined with a two-site chemiluminescence immunoassay (Nichols) in 94 healthy subjects and in 68 MTC patients. The mCT concentrations were below the detection limit in all examined completely thyroidectomized non-MTC patients. Basal and stimulated mCT values were also below the detection limit in 32 of the 68 MTC patients. The biochemical and imaging diagnosis of the latter patients did not give any indication of tumor recurrence. We conclude that completely thyroidectomized patients with non-MTC do not show any measurable mCT concentrations. In comparison with an unspecific CT-RIA, the more specific mCT determination by immunoluminometric assay permits a more precise differentiation between postoperative normal and pathological values and an earlier diagnosis of recurrent MTC.

Medullary carcinoma of the thyroid

Medullary thyroid cancer (MTC) is a distinct C-cell tumor of the thyroid. We review the oncogenesis and management of both sporadic tumors and those tumors arising as part of specific inherited syndromes. The RET proto-oncogene plays a role in the development of inherited forms of MTC and has become important in the clinical management of patients and their families. The recognition of the high rate of regional nodal involvement has led to lymphadenectomy being strongly considered for patients undergoing thyroidectomy for MTC.

Is medullary thyroid cancer predictable? A prospective study of 86 patients with abnormal pentagastrin tests

BACKGROUND

The aim of this prospective study was to distinguish biochemically between C-cell hyperplasia (CCH) and medullary thyroid cancer (MTC) before surgery.

METHODS

Eighty-six consecutive patients with an abnormal stimulated calcitonin level (> 100 pg/mL) underwent thyroidectomy and lymph node dissection. In sporadic MTC, histopathologic findings and postoperative biochemical outcomes were documented prospectively and correlated with preoperative basal and stimulated calcitonin levels.

RESULTS

Analysis of variance revealed a highly significant difference in basal/stimulated calcitonin levels (P < .0001), with a comparison of CCH (n = 39 patients) and sporadic MTC (n = 38 patients). With a comparison of sporadic MTC N0 M0 (n = 25 patients) and N1 M0/1 (n = 12 patients), the basal calcitonin level was significantly different (P < .05). There was a close correlation between the n-log of basal/stimulated calcitonin level and the n-log of the tumor volume; there were also different distributions of the n-log of basal/stimulated calcitonin level among CCH, MTC N0, and MTC N1. Assuming that a basal calcitonin level of more than 64 pg/mL and/or a stimulated calcitonin level of more than 560 pg/mL implies MTC, 31 of 38 patients with sporadic MTC were detected before surgery. Three patients were predicted false positive (neoplastic CCH). Patients with stimulated calcitonin levels of less than 129 pg/mL had CCH only. Patients with basal calcitonin levels of less than 22 pg/mL and sporadic MTC (7/38 patients) were node negative.

CONCLUSIONS

All patients with abnormal pentagastrin tests showed C-cell pathologic evidence. Sporadic MTC was predicted in 81% of the patients; CCH or N0 was predicted in 36% of the patients. Central neck dissection is recommended to avoid difficult reoperations. Lateral neck dissection is possible "on demand."