Validation of a postoperative prognostic model consisting of tumor microvascular invasion, size, and grade to predict disease-free and cancer-specific survival of patients with surgically resected renal cell carcinoma.

OBJECTIVES

To determine the value of microvascular invasion, tumor size, and Fuhrman grade to predict the survival of patients with surgically resected renal cell carcinoma (RCC).

METHODS

A total of 771 consecutive patients (T1-4, Nx, M0) were retrospectively reviewed. For each patient with RCC, the prognostic Sao Paulo score (SPS) was calculated using the following variables: tumor size (>7 cm vs <or=7 cm), nuclear grading, and microvascular invasion. On the basis of SPS, patients were subdivided into low-risk (LR), intermediate-risk (IR), and high-risk (HR) groups. Disease-free survival (DFS) and cancer-specific survival (CSS) were estimated using the Kaplan-Meier method. Median follow-up was 80 months.

RESULTS

Median follow-up was 80 months. DFS rates after 5 years were 91.2%, 61.3%, and 51.9% in the original SPS LR, IR, and HR groups, respectively. CSS rates after 5 years were 94.3%, 79.8%, and 58.7%, respectively (P < 0.001). Each original SPS constituent revealed a significant influence on DFS and CSS in the multivariate analysis. By modification of the cut-off value of the maximum tumor size from 7 to 5 cm the predictive value of the SPS sum score was marginally enhanced. Using a cut-off value of 5 cm also resulted in a relatively better discrimination between the IR and the HR group regarding DFS and CSS.

CONCLUSIONS

Stratifying RCC patients by SPS into LR, IR, and HR groups provides a clinically useful tool for outcome analysis and risk assessment. However, the prognostic value of the SPS could be enhanced by including a maximum tumor size with a cut-off at 5 cm into the sum score.