Medullary thyroid carcinoma in Hong Kong Chinese patients.

ABSTRACT

OBJECTIVE: To study the clinical parameters and treatment outcome of medullary thyroid carcinoma in Hong Kong Chinese patients. DESIGN: Retrospective study. SETTING: Regional oncology unit, Hong Kong. PATIENTS Patients with medullary thyroid carcinoma who were identified among 1656 patients with thyroid malignancies seen in a single institute in Hong Kong from January 1960 to June 2003. MAIN OUTCOME MEASURES: Ten-year cause-specific survival, locoregional failure-free survival, and distant metastasis failure-free survival. RESULTS: Twenty-two (1.3%) patients with medullary thyroid carcinoma were identified. The mean age at diagnosis was 43.7 (standard deviation, 16.5) years. The sex ratio was 11. The 10-year cause-specific survival, locoregional failure-free survival, and distant metastasis failure-free survival were 75.4%, 82.0%, and 62.4%, respectively. Lymph node metastasis was present in seven (31.8%) patients at diagnosis. Distant metastasis developed in nine (40.9%) patients lung, 3 (13.6%); bone, 5 (22.7%); liver, 2 (9.1%); mediastinum, 4 (18.2%). Seven (31.8%) patients died of distant metastasis. Mediastinal (n=3) and bone metastases (n=3) were important causes of death. Genetic study confirmed multiple endocrine neoplasia type 2A in 3 (25.0%) of 12 patients who all had bilateral and multifocal diseases. Younger age (<45 years) was associated with better survival, better locoregional control, and less distant metastasis. Patients with pT1N0 disease (n=3) had an excellent prognosis all were disease-free following total thyroidectomy. Among eight patients who received external radiation therapy, seven achieved good locoregional control. In seven patients with lymph node metastasis, external radiation therapy gave 100% (4/4) locoregional control compared with 33.3% (1/3) in those without external radiation therapy. Chemotherapy using dacarbazine and 5-fluorouracil was tried in three patients with poor response. CONCLUSIONS: Early stage (T1N0) medullary thyroid carcinoma is associated with a very good prognosis. Postoperative external radiation therapy can achieve good locoregional control in patients with lymph node metastasis or locally advanced disease.