OBJECTIVE Assessment of cisplatin (CDDP) tolerance in patients more than 80 years old in good general condition who may benefit from CDDP-based treatment. METHODS Data on 35 patients older than 80 years who received one to six chemotherapy cycles (median, three cycles; total number of cycles, 98) including CDDP (60 to 100 mg/m2) were analyzed retrospectively. Before treatment, all patients had normal renal function as defined by serum creatinine (SC) levels below 132 mumol/L. Renal function was evaluated by measurement of SC and creatinine clearance (CC) before and after each course of chemotherapy. CC was calculated according to the Cockroft and Gault formula, where CC = (140 - age) x weight kg/0.814 x SC mumol/L. Renal toxicity was evaluated by the difference between prechemotherapy SC and the maximum SC level observed (delta SC) and by the difference between prechemotherapy CC and the minimal CC observed after treatment with CDDP (delta CC). The evolution of SC and CC during repeated courses of CDDP was analyzed, as were any extrarenal toxicities. RESULTS Renal function remained stable in 19 patients (54%) with delta SC less than 18 mumol/L and 18 of 35 patients (51%) with delta CC less than 9 mL/min. A slight deterioration in renal function was observed in 13 patients (37%) with delta SC greater than 18 mumol/L and less than 60 mumol/L, and with a delta CC greater than 11 mL/min and less than 21 mL/min. In three patients (9%), delta SC was greater than 60 mumol/L (71, 73, 115 mumol/L) and delta CC was greater than 21 mL/min (25, 26, 36 mL/min). There were no cases of severe renal insufficiency, clinical ototoxicity, or neurotoxicity > or = grade 2. Treatment was terminated after one or two courses in three patients because of grade 2 or 3 hematologic toxicity and in two patients for grade 3 nausea or vomiting. CONCLUSIONS CDDP at moderate doses can reasonably be administered to patients older than 80 years who may benefit from antineoplastic chemotherapy.