Medullary thyroid carcinoma: multivariate analysis of prognostic factors influencing survival

A Proposed Modified Staging System for Medullary Thyroid Cancer: A SEER Analysis With Multicenter Validation

BACKGROUND

The 8th edition of the American Joint Committee on Cancer (AJCC) staging system for medullary thyroid cancer (MTC) was implemented in 2018. However, its ability to predict prognosis remains controversial.

PATIENTS AND METHODS

Patient data were obtained from the Surveillance, Epidemiology, and End Results (SEER) database and multicenter datasets. Overall survival was the primary end-point of the present study. The concordance index (C-index) was used to assess the efficacy of various models to predict prognostic outcomes.

RESULTS

A total of 1450 MTC patients were selected from the SEER databases and 349 in the multicenter dataset. According to the AJCC staging system, there were no significant survival differences between T4a and T4b categories (P = .299). The T4 category was thus redefined as T4a' category (≤3.5 cm) and T4b' category (>3.5 cm) based on the tumor size, which was more powerful for distinguishing the prognosis (P = .003). Further analysis showed that the T category was significantly associated with both lymph node (LN) location and count (P < .001). Therefore, the N category was modified by combining the LN location and count. Finally, the above-mentioned novel T and N categories were adopted to modify the 8th AJCC classification using the recursive partitioning analysis principle, and the modified staging system outperformed the current edition (C-index, 0.811 vs. 0.792).

CONCLUSIONS

The 8th AJCC staging system was improved based on the intrinsic relationship among the T category, LN location, and LN count, which would have a positive impact on the clinical decision-making process and appropriate surveillance.

Competing-risks model for predicting the prognostic value of lymph nodes in medullary thyroid carcinoma

BACKGROUND

Medullary thyroid carcinoma (MTC) is an infrequent form malignant tumor with a poor prognosis. Because of the influence of competitive risk, there may suffer from bias in the analysis of prognostic factors of MTC.

METHODS

By extracting the data of patients diagnosed with MTC registered in the Surveillance, Epidemiology, and End Results (SEER) database from 1998 to 2016, we established the Cox proportional-hazards and competing-risks model to retrospectively analyze the impact of related factors on lymph nodes statistically.

RESULTS

A total of 2,435 patients were included in the analysis, of which 198 died of MTC. The results of the multifactor competing-risk model showed that the number of total lymph nodes (19-89), positive lymph nodes (1-10,11-75) and positive lymph node ratio (25%-53%,>54%), age (46-60,>61), chemotherapy, mode of radiotherapy (others), tumor size(2-4cm,>4cm), number of lesions greater than 1 were poor prognostic factors for MTC. For the number of total lymph nodes, unlike the multivariate Cox proportional-hazards model results, we found that it became an independent risk factor after excluding competitive risk factors. Competitive risk factors have little effect on the number of positive lymph nodes. For the proportion of positive lymph nodes, we found that after excluding competitive risk factors, the Cox proportional-hazards model overestimates its impact on prognosis. The competitive risk model is often more accurate in analyzing the effects of prognostic factors.

CONCLUSIONS

After excluding the competitive risk, the number of lymph nodes, the number of positive and the positive proportion are the poor prognostic factors of medullary thyroid cancer, which can help clinicians more accurately evaluate the prognosis of patients with medullary thyroid cancer and provide a reference for treatment decision-making.

External Beam Radiotherapy for Medullary Thyroid Cancer Following Total or Near-Total Thyroidectomy

OBJECTIVES

Medullary thyroid carcinoma (MTC) often presents with advanced disease and takes an aggressive course as compared with more well-differentiated thyroid cancers. The role of adjuvant therapy, specifically external beam radiotherapy (EBRT), remains disputed. This study investigated the impact of EBRT on survival in MTC.

STUDY DESIGN

Cross-sectional analysis of a national database.

SETTING

Patients with MTC were identified from the SEER program (Surveillance, Epidemiology, and End Results).

METHODS

Collected variables included age, sex, race, T and N stages, lymph node yield, and use of EBRT. Propensity score matching was performed to determine the association of EBRT with overall and disease-specific survival.

RESULTS

A total of 2046 patients with locoregional MTC were identified. Of these, 152 received EBRT. Patients receiving EBRT were older and had more advanced disease. EBRT was not associated with differences in overall survival (hazard ratio, 1.12; 95% CI, 0.76-1.65) or disease-specific survival (1.66; 0.93-2.95), as well as in subset analysis of age and disease extent. Long-term overall survival was similar, with 77.3% (95% CI, 70.1%-85.3%) and 58.3% (48.2%-70.5%) of patients without EBRT alive at 5 and 10 years, respectively (vs 70.7% [63.2%-79.1%] and 52.3% [43.3%-63.2%] of patients with EBRT). There were no differences in 5- and 10-year disease-specific survival.

CONCLUSION

EBRT was not associated with improved overall or disease-specific survival in patients with MTC. Decisions regarding EBRT must be made with consideration of morbidity relative to benefit for individual patients.

Anlotinib for the Treatment of Patients with Locally Advanced or Metastatic Medullary Thyroid Cancer

BACKGROUND

The prognosis of advanced or metastatic medullary thyroid carcinoma (MTC) is poor, and there are few therapeutic options. Anlotinib has previously shown promising antitumor activity on MTC in preclinical models and a Phase I study. This Phase II clinical trial was devised to confirm the antitumor activity of anlotinib in patients with advanced or metastatic MTC.

METHODS

Patients with unresectable locally advanced or metastatic MTC received once daily oral anlotinib 12 mg, two weeks on/one week off, until disease progression, death, unacceptable toxicity, or withdrawal of consent for any reason. The dose was adjusted on the basis of observed toxicity. The primary endpoint was progression-free survival (PFS).

RESULTS

Fifty-eight patients received anlotinib treatment. The primary endpoint PFS has not yet been reached at the time of analysis. On the basis of investigator assessments, 56.9% of patients experienced a partial response. PFS rate at 48 weeks was 85.5%. Forty-five patients had a ≥50% decrease in serum calcitonin concentration from baseline. The most common adverse events were hand-foot syndrome, hypertriglyceridemia, cholesterol elevation, fatigue, and proteinuria.

CONCLUSIONS

Anlotinib demonstrated a durable antitumor activity with a manageable adverse event profile in locally advanced or metastatic MTC.

A multicenter phase II study of sunitinib in patients with locally advanced or metastatic differentiated, anaplastic or medullary thyroid carcinomas: mature data from the THYSU study

PURPOSE

Patients with advanced radioactive iodine resistant differentiated (MDTC) or medullary (MMTC) thyroid cancer had an unmet need. Early data showed promising efficacy of vascular endothelial growth factor receptor inhibitors. We investigated sunitinib in this setting.

PATIENTS AND METHODS

This phase 2 trial enrolled MDTC, anaplastic (MATC) and MMTC patients in 1st line anti-angiogenic therapy with sunitinib at 50 mg/d, 4/6w. Objective response rate was the primary end-point. Secondary end-points were progression-free survival, overall survival and safety.

RESULTS

Seventy-one patients were enrolled from August 2007 to October 2009, 41 MDTC/4 MATC patients and 26 MMTC patients. Patients received a median of 8 and 9 cycles, respectively. In the MDTC/MATC group, 13% of patients and 43% of cycles and in the MMTC group, 23% of the patients and 48.8% of cycles remained at 50 mg/d, respectively. The primary end-point was reached with an objective response rate of 22% (95% CI: 10.6-37.6) in MDTC patients and in 38.5% (95% CI: 22.6-56.4) in MMTC patients. No objective response was seen in MATC patients. Median progression-free survival and overall survival were 13.1 and 26.4 months in MDTC patients, 16.5 and 29.4 months in MMTC patients. The most frequent side effects were asthenia/fatigue (27.8% ≥ grade 3), mucosal (9.9% ≥ grade 3), cutaneous toxicities, hand-foot syndrome (18.3% ≥ grade 3). Of all, 14.1% had a cardiac event. Nine unexpected side effects were reported, out of which, five induced deaths.

CONCLUSION

Sunitinib is active in MDTC and MMTC patients. Side effects were more severe than with previous reports. If using sunitinib, alternative schedule/dosage should be considered.

RAS proto-oncogene in medullary thyroid carcinoma

Medullary thyroid carcinoma (MTC) is a rare malignancy originating from the calcitonin-secreting parafollicular thyroid C cells. Approximately 75% of cases are sporadic. Rearranged during transfection (RET) proto-oncogene plays a crucial role in MTC development. Besides RET, other oncogenes commonly involved in the pathogenesis of human cancers have also been investigated in MTC. The family of human RAS genes includes the highly homologous HRAS, KRAS, and NRAS genes that encode three distinct proteins. Activating mutations in specific hotspots of the RAS genes are found in about 30% of all human cancers. In thyroid neoplasias, RAS gene point mutations, mainly in NRAS, are detected in benign and malignant tumors arising from the follicular epithelium. However, recent reports have also described RAS mutations in MTC, namely in HRAS and KRAS. Overall, the prevalence of RAS mutations in sporadic MTC varies between 0-43.3%, occurring usually in tumors with WT RET and rarely in those harboring a RET mutation, suggesting that activation of these proto-oncogenes represents alternative genetic events in sporadic MTC tumorigenesis. Thus, the assessment of RAS mutation status can be useful to define therapeutic strategies in RET WT MTC. MTC patients with RAS mutations have an intermediate risk for aggressive cancer, between those with RET mutations in exons 15 and 16, which are associated with the worst prognosis, and cases with other RET mutations, which have the most indolent course of the disease. Recent results from exome sequencing indicate that, besides mutations in RET, HRAS, and KRAS, no other recurrent driver mutations are present in MTC.

Diagnóstico, tratamento e seguimento do carcinoma medular de tireoide: recomendações do Departamento de Tireoide da Sociedade Brasileira de Endocrinologia e Metabologia

Introdução O carcinoma medular de tireoide (CMT) origina-se das células parafoliculares da tireoide e corresponde a 3-4% das neoplasias malignas da glândula. Aproximadamente 25% dos casos de CMT são hereditários e decorrentes de mutações ativadoras no proto-oncogene RET (REarranged during Transfection). O CMT é uma neoplasia de curso indolente, com taxas de sobrevida dependentes do estádio tumoral ao diagnóstico. Este artigo descreve diretrizes baseadas em evidências clínicas para o diagnóstico, tratamento e seguimento do CMT. Objetivo O presente consenso, elaborado por especialistas brasileiros e patrocinado pelo Departamento de Tireoide da Sociedade Brasileira de Endocrinologia e Metabologia, visa abordar o diagnóstico, tratamento e seguimento dos pacientes com CMT, de acordo com as evidências mais recentes da literatura. Materiais e métodos: Após estruturação das questões clínicas, foi realizada busca das evidências disponíveis na literatura, inicialmente na base de dados do MedLine-PubMed e posteriormente nas bases Embase e SciELO – Lilacs. A força das evidências, avaliada pelo sistema de classificação de Oxford, foi estabelecida a partir do desenho de estudo utilizado, considerando-se a melhor evidência disponível para cada questão. Resultados Foram definidas 11 questões sobre o diagnóstico, 8 sobre o tratamento cirúrgico e 13 questões abordando o seguimento do CMT, totalizando 32 recomendações. Como um todo, o artigo aborda o diagnóstico clínico e molecular, o tratamento cirúrgico inicial, o manejo pós-operatório e as opções terapêuticas para a doença metastática. Conclusões O diagnóstico de CMT deve ser suspeitado na presença de nódulo tireoidiano e história familiar de CMT e/ou associação com feocromocitoma, hiperparatireoidismo e/ou fenótipo sindrômico característico, como ganglioneuromatose e habitus marfanoides. A punção aspirativa por agulha fina do nódulo, a dosagem de calcitonina sérica e o exame anatomopatológico podem contribuir na confirmação do diagnóstico. A cirurgia é o único tratamento que oferece a possibilidade de cura. As opções de tratamento da doença metastática ainda são limitadas e restritas ao controle da doença. Uma avaliação pós-cirúrgica criteriosa para a identificação de doença residual ou recorrente é fundamental para definir o seguimento e a conduta terapêutica subsequente.

Cabozantinib in progressive medullary thyroid cancer

PURPOSE

Cabozantinib, a tyrosine kinase inhibitor (TKI) of hepatocyte growth factor receptor (MET), vascular endothelial growth factor receptor 2, and rearranged during transfection (RET), demonstrated clinical activity in patients with medullary thyroid cancer (MTC) in phase I.

PATIENTS AND METHODS

We conducted a double-blind, phase III trial comparing cabozantinib with placebo in 330 patients with documented radiographic progression of metastatic MTC. Patients were randomly assigned (2:1) to cabozantinib (140 mg per day) or placebo. The primary end point was progression-free survival (PFS). Additional outcome measures included tumor response rate, overall survival, and safety.

RESULTS

The estimated median PFS was 11.2 months for cabozantinib versus 4.0 months for placebo (hazard ratio, 0.28; 95% CI, 0.19 to 0.40; P < .001). Prolonged PFS with cabozantinib was observed across all subgroups including by age, prior TKI treatment, and RET mutation status (hereditary or sporadic). Response rate was 28% for cabozantinib and 0% for placebo; responses were seen regardless of RET mutation status. Kaplan-Meier estimates of patients alive and progression-free at 1 year are 47.3% for cabozantinib and 7.2% for placebo. Common cabozantinib-associated adverse events included diarrhea, palmar-plantar erythrodysesthesia, decreased weight and appetite, nausea, and fatigue and resulted in dose reductions in 79% and holds in 65% of patients. Adverse events led to treatment discontinuation in 16% of cabozantinib-treated patients and in 8% of placebo-treated patients.

CONCLUSION

Cabozantinib (140 mg per day) achieved a statistically significant improvement of PFS in patients with progressive metastatic MTC and represents an important new treatment option for patients with this rare disease. This dose of cabozantinib was associated with significant but manageable toxicity.

A role for radiotherapy in the management of advanced medullary thyroid carcinoma: the mayo clinic experience

Outcomes of external beam radiotherapy (EBRT) in advanced medullary thyroid carcinoma (MTC) are largely unknown. Retrospective review of data from patients with MTC, diagnosed from June 1, 1970, through December 31, 2007. Overall survival and locoregional tumor control rates were calculated. Seventeen patients had adjuvant or palliative EBRT delivered to 41 sites. Six patients initially had adjuvant EBRT (median, 60.80 Gy); none had relapse in the treated area. Five patients with locoregional recurrence after surgery were treated (median, 59.40 Gy), and durable disease control was achieved in 3. Twelve patients received palliative EBRT to 29 sites of metastatic disease (median, 30.00 Gy), which provided sustained symptom relief at 45% of sites. Five- and ten-year overall survival rates were 44% and 19%, respectively. Adjuvant EBRT may be most effective for prevention of locoregional recurrence. EBRT may provide sustained control of advanced, metastatic disease in select patients.

Prognostic influence of clinical and pathological factors in medullary thyroid carcinoma: a study of 53 cases

OBJECTIVES AND INTRODUCTION: Medullary thyroid carcinoma, a neoplasia of intermediate prognosis and differentiation, does not always respond predictably to known treatments. This study aimed to correlate the clinical progression of surgically treated patients with clinical and pathological data.

METHODS

A total of 53 patients were followed for 75 months (mean average) in tertiary-care hospital. The clinical status of patients at the end of the study period was characterized to determine correlations with a range of disease aspects. A value of p < 0.05 was considered statistically significant.

RESULTS

Twenty-two patients (41.5%) were alive and disease-free at the end of the follow-up period; twenty-three patients (43.4%) had persistent disease; and eight patients (15.1%) had recurrent disease. Four patients (7.6%) died from medullary thyroid carcinoma with clinical and/or imaging evidence of neoplasia. The following aspects demonstrated statistically significant correlations with the final medical condition: positive initial cervical examination (p = 0.002); neoplastic extensions to the thyroid capsule (p = 0.004) and adjacent tissues (p = 0.034); cervical lymph node metastases (p < 0.001); diameter of neoplasia (p = 0.018); TNM (tumor, node and metastasis) Stage (p = 0.001) and evidence of distant and/or cervical diseases in the absence of a cure (p = 0.011). Through logistic regression, the presence of cervical lymph node metastases was considered an independent variable (p < 0.001).

CONCLUSIONS

Clinical and pathological aspects of patients with surgically treated medullary thyroid carcinomas are predictors of disease progression. Specifically, even treated cervical lymph node metastases are significantly correlated with disease progression.

Postoperative radiotherapy for advanced medullary thyroid cancer--local disease control in the modern era

BACKGROUND

The purpose of this study is to catalog modern-era postoperative radiotherapy (external beam radiotherapy [EBRT]) outcomes for advanced medullary thyroid cancer.

METHODS

Thirty-four consecutive patients with stage IVa-c disease were evaluated. Ten patients had recurrent disease, 16 had mediastinal involvement, and 10 had distant metastasis. Positive surgical margins were present in 12 cases. Median pre-EBRT serum calcitonin was 556. All patients received conformal EBRT or intensity-modulated radiotherapy. Median EBRT dose was 60 Gy and median follow-up was 46.5 months.

RESULTS

Kaplan-Meier estimates of locoregional relapse-free survival, disease-specific survival, and overall survival at 5 years were 87%, 62%, and 56%, respectively. Disease in 3 patients with gross residual disease was controlled locoregionally. Distant disease at the time of EBRT did not predict survival. Two (9%) patients reported symptomatic chronic morbidity.

CONCLUSION

Surgery followed by EBRT provided durable locoregional disease control with limited morbidity. Postoperative EBRT merits consideration in cases of advanced disease at high risk for locoregional recurrence.

Four patients with cutaneous metastases from medullary thyroid cancer

Cutaneous metastasis from thyroid cancer, especially medullary thyroid cancer (MTC) is rare. We report four patients with cutaneous metastases from sporadic MTC, three women and one man, aged 50 to 69 years. They presented different cutaneous lesions phenotypes. The first patient had a remote history of MTC and initial presentation of the recurrence was a rapidly progressing cutaneous lesion; on subsequent disease staging, widely metastatic disease was discovered. The other three patients developed cutaneous metastases in the presence of known distant metastases, indicating systemic spread of thyroid cancer. Definitive diagnosis of cutaneous metastases of MTC was made on biopsy of the lesions with cells that stained positive for neuroendocrine markers. Accurate diagnosis of cutaneous metastasis from MTC is important because it is a negative prognostic factor indicative of multisystemic disease. Thus, MTC metastases should be included in the differential diagnosis of erythematous maculopapular eruptions and nodular lesions of the skin, especially when these metastases occur in the upper part of the body and if the patient has a history of MTC. The appearing of cutaneous metastasis is a negative prognostic factor since all the patients here described died within one year from the diagnosis of cutaneous metastases.

Medullary thyroid carcinoma: surgical treatment advances

PURPOSE OF REVIEW

In recent years new technologies have been proposed and applied in thyroid surgery, among these molecular diagnosis and endoscopic procedures. The authors review relevant medical literature published on the influence of these new techniques in the treatment of medullary thyroid cancer. Searches were last updated in October 2007.

RECENT FINDINGS

Mutations of the RET proto-oncogene have been demonstrated to be causative of the familial form of medullary thyroid cancer. The number and type of recognized RET genetic mutations have grown over the last years, especially after the introduction of genetic screening in the work-up of all patients with medullary thyroid cancer. Prophylactic surgery for patients carrying a positive RET proto-oncogene is highly effective. Cervical endoscopic procedures have been recently described and applied for positive RET carriers: a video-assisted thyroidectomy with central compartment dissection (level 6) has proved feasible, safe and effective for these patients.

SUMMARY

There have been some important papers in the recent literature that apply to many aspects of new technologies for medullary thyroid cancer treatment. This article discusses some of these articles, emphasizing where this literature makes new contributions and supports established recommendations.

Lymphadenektomie beim Schilddrüsen- und Nebenschilddrüsenkarzinom

In general, primary surgery of thyroid carcinoma should consist of total thyroidectomy and lymph node dissection of the cervicocentral compartment. Exceptions are cases of papillary microcarcinoma and prophylactic surgery due to multiple type 2A endocrine neoplasia. Lymph node dissection beyond the cervicocentral compartment also should be compartment-oriented. It is generally indicated if lymph node metastases have been proven. Concerning clinically proven medullary thyroid carcinoma, bilateral cervicolateral lymph node dissection is generally indicated, since lymph node metastases may be missed preoperatively but are often found histologically. In patients with parathyroid carcinoma, en bloc ipsilateral cervicocentral lymph node dissection should be performed in addition to parathyroidectomy and hemithyroidectomy. Lymph node dissection should always be performed systematically, since lymph node metastases may be missed both clinically and by imaging techniques.