MULTIVARIATE-ANALYSIS OF PROGNOSTIC FACTORS IN SPORADIC MEDULLARY CARCINOMA OF THE THYROID - A RETROSPECTIVE STUDY OF 109 CONSECUTIVE PATIENTS

BACKGROUND. Because of the rarity of medullary thyroid carcinoma, adeq uate information for determination of the prognostic characteristics a nd clinical course of this disease can be obtained only from a databas e that serves a large population. METHODS. A retrospective review of 1 09 patients with sporadic medullary thyroid carcinoma was conducted; a ll were diagnosed and treated at a single institution over a 30-year p eriod. The series included 57 males and 52 females with a median follo w-up of 5.3 years. Statistical univariate analysis of relapse free sur vival and overall survival was done for 18 clinicopathologic variables , including sex, age, TNM staging, completeness of surgical resection, postoperative calcitoninemia, histologic subtype, tumor size, thyroid capsule invasion, amyloid, katacalcin, calcitonin, and calcitonin gen e-related peptide immunostaining patterns of the primary tumor. RESULT S. Risk factors for unfavorable outcome were male sex, age > 60 years, incomplete tumor resection, mixed cell subtype, tumor size > 4 cm, ex trathyroid tumor invasion, lack of amyloid, N1 and M1 categories, and heterogenous calcitonin and katacalcin immunostaining pattern. In the multivariate analysis, only capsule status, M category, and age at dia gnosis remained in the final model for overall survival. In the final model for relapse free survival, capsule status remained, together wit h sex and amyloid status. CONCLUSIONS. Extrathyroid tumor invasion, th e presence of distant metastases, and age > 60 years are characteristi c of patients at high risk of death from disease sooner, whereas extra thyroid invasion, male sex, and the absence of amyloid characterize pa tients who are at high risk for recurrence. Extrathyroid tumor invasio n appears to be the worst prognostic factor and may allow for the brea kdown of patients into two categories, amenable to different therapeut ic regimens. (C) 1996 American Cancer Society.