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.