Nephron sparing surgery in incidental versus suspected renal cell carcinoma.

From 1956 to 1992 nephron sparing surgery was performed in 216 patients with sporadic renal cell carcinoma. Renal cell carcinoma was suspected in 121 patients and was an incidental finding in 95. Compared to suspected renal cell carcinoma, incidental tumors were smaller (p = 0.0004), more often unilateral (p = 0.001) and of lower pathological stage (p = 0.001). Incidental tumors were also associated with improved 5-year cancer-specific survival (p = 0.003) and a lower rate of postoperative tumor recurrence (p = 0.001). The overall 5-year cancer-specific survival rate was improved in patients with stage I versus higher stage renal cell carcinoma (p = 0.0002), unilateral versus bilateral disease (p = 0.0001), a single versus multiple tumors in the operated kidney (p = 0.01) and tumors smaller than 4 cm. versus larger tumors (p = 0.03). There were no postoperative tumor recurrences and the 5-year cancer-specific survival rate was 100% in patients with unilateral, stage I tumors smaller than 4 cm. These data define specific eligibility criteria for nephron sparing surgery in patients with localized unilateral renal cell carcinoma and a normal contralateral kidney.