Medullary Carcinoma of the Thyroid

Oh, Seung Keun; Kim, Jee Soo

Abstract

BACKGROUND: Medullary thyroid cancers originate from parafollicular C-cells and metastasize to lymph nodes in an early stage. Operation is the only means to cure the patients. In this study, the authors analyzed the factors influencing the prognosis for the patients with medullary thyroid cancer.
METHODS
We performed a retrospective study of 18 patients with medullary thyroid carcinoma who were treated between January, 1981 and December, 1996 at the Seoul National University Hospital. We analyzed the clinical manifestation, pathologic features, 5-year disease-free survival rate and prognostic factors which might have an influence on disease-free survival.
RESULTS
The incidence of medullary thyroid carcinomas in thyroid cancer patients was 1.7%. The mean age at the time of diagnosis was 43.8 years, ranging from 19 to 68 years. The male-to-female ratio was 1:1.6. The two main symptoms and signs of the patients were anterior neck mass and a palpable cervical lymph node. The diagnosis was done preoperatively in 7 patients by using family history, symptoms, aspiration cytology, and elevated plasma calcitonin and/or CEA level and postoperatively in 9 patients by using pathologic examination. Five familial and 13 sporadic medullary thyroid carcinoma were analysed and compared. Compared with the sporadic carcinomas, familial medullary carcinomas seemed to be characterized by an early age of onset, a smaller tumor size and an increased incidence of bilaterality compared to sporadic cases. According to AJCC classification, 68.8% of patients were in an advanced stage, i.e., stage III or stage IV. At the time of the first operation, 7 patients underwent a total thyroidectomy and 9 patients a subtotal/near-total thyroidectomy. Modified radical neck dissections were performed in 9 patients. Five patients underwent more than two operation due to local recurrence. The mean follow up duration of the patients was 34.2 months. Five cases of local recurrences and one case of the disease associated death were found. The five-year disease-free survival rate was 74.8%.
CONCLUSION
Although there was no significant statistical difference, stage and postoperative calcitonin level seemd to influence disease-free survival.