Impact of tumor size on the outcome of patients with small renal cell carcinoma

Background: This study aims to establish potential correlation between tumor size and outcomes in patients with T1a kidney cancer registered within the surveillance, epidemiology and end results (SEER) database. Methods: SEER database (2004-2013) has been accessed through SEER*Stat program to determine the correlation between tumor size and cancer-specific survival in patients with T1a kidney cancer. Survival analysis was conducted through Kaplan-Meier analysis and log-rank testing. Results: Five year kidney cancer-specific survival rates show progressive decline with increasing tumor size. Moreover, kidney cancer-specific survival has been compared according to the initial local treatment modality (observation, ablation, partial or radical nephrectomy) across different size categories (< 1 cm, 1-2 cm, 2-3 cm and 3-4 cm). Survival curves of different treatment modalities were almost overlapping for patients with renal mass < 1cm. For patients with tumor size 1-2 cm, treatment modalities were overlapping at the first 60 months then the curve of observation diverged (P < 0.0001). For patients with tumor size 2-3 cm and 3-4 cm, the curve of observation diverged early in the time course (P < 0.0001). Conclusion: Primary tumor size is an important factor that should be taken into consideration when evaluating the different treatment options for patients with small kidney cancers.