Is patient's age a prognostic factor for follicular thyroid carcinoma in the TNM classification system?

The knowledge of prognostic factors is essential for an optimal treatment of patients. The aim of our study was to find out if age is an independent prognostic factor for patients with follicular or Hürthle cell carcinoma. This retrospective study was carried out in 261 patients (median age, 62 years) with follicular or Hürthle cell thyroid carcinoma treated at our institute from 1972-2002. For all patients the follow-up was performed at our institute at least once per year. The data on gender and age of the patients, disease history, extent of disease, morphologic characteristics, mode of therapy, outcome, and survival were collected. Statistical correlation between possible prognostic factors and cause-specific survival was analyzed by univariate and Cox's multivariate survival analysis. The 10-year and 20-year survival of all 261 patients were 70% and 42%, respectively. Even 10 of 49 (20%) of our patients who were under 45 years of age (i.e., in stage II of the tumor, node, metastases [TNM] classification system) died of disease. Multivariate analysis showed that primary tumor size and distant metastases were independent prognostic factors for survival. Lymph node metastases as well as the age of patients were not found to be independent prognostic factors. Therefore, the patients with distant metastases or tumor stage T4 who are under 45 years of age cannot be considered to have favorable prognosis.