Histology does not influence prognosis in differentiated thyroid carcinoma when accounting for age, tumour diameter, invasive growth and metastases

Abstract

Objective: Papillary thyroid carcinoma (PTC) and follicular thyroid carcinoma (FTC) show considerable differences in disease stage at initial presentation. The aim of this study was to investigate whether there are differences in tumour-specific survival if initial staging is accounted for. Design: Retrospective chart review study. Patients: The study sample comprised 875 PTC and 350 FTC patients (856 females, 369 males, mean age 47.8 years) treated in our hospital from 1978 to 2002. All patients received total thyroidectomy with subsequent I-131 ablation except for those patients with an isolated papillary microcarcinoma. Methods: Kaplan-Meier analyses and Cox-regression analyses were performed to assess the influence of histology on thyroid cancer-specific survival. Results: FTC patients were on average older, more likely to be male, presented with a larger tumour and more frequently had multifocal carcinoma and distant metastases than PTC patients, whereas they presented less frequently with extrathyroidal invasion or lymph node metastases. Twenty-year tumour-specific survival in PTC was 90.6% and in FTC 73.7% (P<0.001). In multivariate analysis the presence of distant metastases (P<0.001), age (P<0.001), tumour size (P=0.001) and the presence of extrathyroidal invasion (P=0.007), but not histology (P=0.26), were independent determinant variables for tumour-specific survival. Conclusion: There is no difference in tumour-specific survival between PTC and FTC when accounting for the presence of metastases, age, tumour size and the presence of extrathyroidal invasion. © 2009 European Society of Endocrinology.