Clinicopathological Characteristics and Prognostic Factors of Medullary Thyroid Carcinoma

ABSTRACT

BACKGROUND: Studies on the clinicopathological characteristics and prognostic factors of medullary thyroid carcinoma (MTC) in Korea are very rare. METHODS: We enrolled 56 MTC patients who underwent surgery at Samsung Medical Center from 1995 to 2006. We analyzed their gender, age at diagnosis, the pathologic findings, the TNM stage, the association with multiple endocrine neoplasia (MEN), RET protooncogene mutation and the, serum basal calcitonin levels before and after the surgery. We investigated the overall survival and the prognostic factors. RESULTS: The mean age at diagnosis was 46 years and the male/female ratio was 1:2.7. Fine needle aspiration cytology detected 61% of the MTC. The mean tumor size was 2.6 cm (range: 0.2-9.0 cm). Fifty-two percent of patients had the TNM stage more than III at the time of diagnosis. Distant metastasis was found in 5.3% (3/56) of the patients, either at the time of diagnosis or during the follow-up period. Hereditary MTC comprised of 23% of the patients and the disease developed at a younger age (38 years vs. 48 years, respectively, P < 0.05) with more bilaterality. RET protooncogene mutations were found in 27% (9/33) of the patients and most of them were in codon 634. After the primary surgery, the serum basal calcitonin levels were persistently elevated over 13 ng/L in 49% of the patients. The overall 5-year survival rate was 95.5%. Tumor size and distant metastasis were the significant prognostic factors for survival by univariate analysis (P < 0.05). CONCLUSION: There were no significant differences in the clinicopathological characteristics of MTC and survival in Korea compared to those of the Western countries.