The importance of staging systems for the determination of prognosis of well-differentiated thyroid cancer.

OBJECTIVE In this study, we aimed to determine the significance of the staging systems (EORTC, De Groot, MACIS, and TNM) on the prognosis of well-differentiated thyroid cancer patients who underwent surgery in our clinics. MATERIAL AND METHODS This retrospective study included 181 patients who were operated between December 1995-December 2007, with a diagnosis of thyroid cancer. In order to obtain data related to cancer staging, a computer program for PDA was developed to facilitate parameter recording. Survival analysis was performed. The findings were compared to the predicted rates by the staging systems. RESULTS According to the De Groot staging system, stage 1 and stage 2 patients' results were compatible, but stage 3 and 4 patients' results were different (stage 3; 87% versus 66.6%, stage 4; 35% versus 100%, p=0.04). In the MACIS staging system, 20-year survival rates are determined and comparison should not be made due to insufficient follow-up period in this study. When compared to the EORTC staging system, stage 3 and stage 4 patients' results were determined different (stage 3; 51% versus 100%, stage 4; 33% versus 50%, p=0.02). The most consistent results in terms of prognosis was determined in comparison with the TNM staging system (stage 1; 100% versus 97.8%, stage 4; 45.3% versus 50%). CONCLUSION Many classification systems are proposed for well-differentiated thyroid cancer, to predict the behavior of the tumor. In this study, we concluded that for determination of prognosis in well-differentiated thyroid cancer, the TNM staging system could best predict prognosis consistent with clinical findings.