DISEASE CHARACTERISTICS: Histologically proven stage III or IV renal cancer that has been completely resected and is at high risk for recurrence, including at least one of the following: Tumor invades adrenal gland or perinephric tissues but not beyond Gerota's fascia (T3a) OR Tumor extending into renal vein, vena cava (T3b) OR Tumor grossly extends into vena cava above diaphragm (T3c) OR Tumor invades beyond Gerota's fascia (T4) OR Any lymph node involvement totally resected (N1-3) OR Completely resected metastases of all sites No brain metastases