Is the EORTC prognostic index of thyroid cancer valid in differentiated thyroid carcinoma? Retrospective multivariate analysis of differentiated thyroid carcinoma with long follow-up

Abstract

The European Organization for Research on Treatment of Cancer (EORTC) Thyroid Cancer Cooperative Group presented a prognostic index in 1979 that included all histologic groups of thyroid carcinomas, and was based on a multivariate analysis of 507 patients with a median follow-up of 40 months. The current report not only uses a multivariate analysis to study the clinical validity and reproducibility of this index on case material consisting of 226 differentiated thyroid carcinomas with a considerably long follow-up (11 years), but also it investigates possible prognostic factors, other than those proposed by the EORTC. Three EORTC variables could be reproduced as important: age at diagnosis, locally advanced disease, and distant metastases. Of the additional histopathologic variables tested, microscopic tumor invasion beyond thyroid capsule (pT4) and marked cellular atypia (MCA) proved to be significant. When the effect of the age-correlated tumor factors pT4 and MCA of differentiated thyroid carcinomas were taken into consideration, age alone lost its prognostic importance as a guide for treatment.

European consensus for the management of patients with differentiated thyroid carcinoma of the follicular epithelium

“…Postoperative staging allows risk stratification of individual patients, which in turn will dictate the frequency and type of follow-up (16,(55)(56)(57)(58)(59)(60). In most staging systems, but not all (58,61), age is considered an independent risk factor.…”

Are prognostic scoring systems of value in patients with follicular thyroid carcinoma?

“…Kerr et al (40) applied this system in 441 patients with thyroid cancer and found that it had greater predictive value compared with the pTNM classification system. However, Tennvall et al (41), using the original patients of Byar et al (11), adding a further 11 years of follow-up and only focusing on differentiated cancers, suggested that the EORTC system places too much emphasis on age, inappropriately mixing non-differentiated tumors with differentiated ones in the analysis, which is the reason why they consider it to be ineffective for clinical practice. In our study, the EORTC has proved to be the most useful system for the prognostic assessment of follicular carcinoma.…”

Prognostic Factors for Well Differentiated Thyroid Cancer in an Endemic Area

“…(5,10,18) The extent of the disease also contributes to prognosis; advanced lesions all confer a worse prognosis. (3,5,6,7,11,12,18) A study of 157 differentiated thyroid cancers included in the multicentric EORTC trial, places tumour stage in first place as a prognostic factor. (13) Our findings of the extent of the disease as a predictor of death is in agreement with these reports.…”

“…However, except amongst papillary cancers, where the prognosis was significantly better in patients below 40 years, age did not affect survival in patients with follicular cancers. Sex as a prognostic factor is being debated (5,7,8,9,18) some authors claim the importance of sex as one of the major determinants of survival in differentiated thyroid cancers with males having a poorer prognosis. (3,5,7) However, we could not confirm this finding since survival in our patients was not found to be different between the two sexes, a finding which is confirmed by other authors.…”