Multivariate analysis of patients with medullary thyroid carcinoma: Prognostic significance and impact on treatment of clinical and pathologic variables

Abstract

BACKGROUND. The prognostic significance of the histologic and clinical features of medullary thyroid cancer (MTC) and their impact on therapy and outcome have been evaluated infrequently in the same series. METHODS. Fifty- three patients with MTC (32 females, 21 males; 44 sporadic, 9 familial MTC [4 families]; mean age: 46.11 ± 14.04 years) who were operated on consecutively between 1970 and 1992 were studied. All pathology slides were reviewed. Patients were followed with clinical examination, serum calcitonin (CT), and carcinoembryonic antigen (CEA) assay, and imaging procedures (median follow- up: 4 years; mean: 5.66 ± 4.85 years; range: 0-19 years). Impact on survival was evaluated with Kaplan-Meier survival curves compared with the log rank test for these variables: familiality, sex, age, pT, N, M, stage, histotype, necrosis, calcitonin gene-related peptide (CGRP), CT, CEA, thyroglobulin, chromogranin A, chromogranin A PHE5, neuron-specific enolase, amyloid, argyrophilia, synaptophysin Y38, external radiotherapy, chemotherapy, 131I therapy, postsurgical serum CT, and postsurgical serum CEA. Multivariate analysis was performed using Cox's proportional hazards model for statistically significant factors (P < 0.05). RESULTS. Ten- and 15-year cause-specific survival were 71% and 54%. Nineteen patients (35.8%) appeared to be cured and 8 (15.1%) were alive with high serum CT levels but no proven metastases. Eight recurrences at distant sites and four at the cervical region were diagnosed. Stage, M, N, necrosis, and postsurgical CT and CGRP were significant prognostic factors for survival by univariate analysis, but only the stage was significant by multivariate analysis. CONCLUSIONS. Stage and postsurgical serum CT level are the most powerful and the most useful prognostic factors for MTC, while survival did not correlated significantly with the majority of available immunohistochemical markers.