Objective: To identify prognostic factors of clinical outcome and long-term survival in medullary thyroid cancer (MTC).
Design: Retrospective case series of 51 consecutive patients (mean age 46.9 years, 57% female) treated at a single tertiary university medical center from 1970 to 2005. Medical records were reviewed for demographic data, laboratory and clinical course, treatment, and long-term outcome.
Main outcome: At presentation, 25 patients (49%) had local disease and 26 (51%) had metastatic disease (three with distant metastases). RET mutations were identified in nine of 23 patients tested. The patients with hereditary disease were younger than the patients with sporadic disease (p < 0.001) and had lower calcitonin levels at diagnosis (p = 0.004) and more multicentric tumors (p = 0.02). Initial surgery consisted of total thyroidectomy in 47 patients, with neck dissection in 26; 22 patients achieved long-term remission. The 5-, 10- and 15-year survival rates were 88%, 85%, and 77%, respectively. On univariate analysis, distant metastases during the course of the disease and elevated calcitonin levels postoperatively were significant prognostic factors of reduced survival (p = 0.001 and 0.016, respectively). Lymph node involvement at initial surgery was associated with a lower remission rate (p = 0.016) but had no impact on long-term survival (p = 0.269).
Conclusion: Patients with MTC have a generally favorable outcome, perhaps owing to recent advances in diagnosis and treatment. Although postoperative serum calcitonin level and distant metastases are the only determinants of long-term survival, the presence of cervical metastases is predictive of a higher risk of recurrent or persistent disease.