[Clinical study on incidental renal cell carcinoma]

Between 1985 and 1992, 119 patients with renal cell carcinoma were treated at our hospital. Among these cases, 71 cases (59.7%) were incidentally detected in the absence of any suggestive clinical signs of a tumor, 41 cases (34.5%) presented urological or general signs suggestive of the tumor, and 7 cases (5.88%) were detected by metastatic lesions initially. We reviewed 71 cases of incidental carcinoma compared with 41 cases of symptomatic carcinoma. The ratio of incidental carcinoma has been increasing steadily for 8 years, and it was more than 70% of all cases in the last 3 years. The carcinoma was detected at routine health examinations in 25 cases, and during examination for unrelated diseases in 46 cases. Forty-seven cases (66.2%) were detected by ultrasonography, 24 cases (33.8%) by computerized tomography and none by intravenous pyelography. Tumor extension was within the renal capsule in 94.4% of the incidental carcinoma and the mean diameter was 4.39 cm, which was significantly smaller than that of symptomatic carcinoma (p < 0.0001). Peripheral tumors and clear cell subtype tumors were more frequently detected in incidental carcinoma (p < 0.0001 and p = 0.0018). Tumor stage and grade of tumor cell were significantly lower than symptomatic carcinoma (p < 0.0001). The five-year survival rate in incidental carcinoma was 98.5%. There was a significant difference in survival between the incidental and symptomatic carcinoma (p < 0.001).