Purpose: Dose intensity (DI, expressed in mg/m2/wk) may be an important factor in the clinical use of cisplatin (DDP). We have explored the shortening of the cycle interval as a way to increase the DI of DDP.
Patients and methods: DDP 180 mg/m2 was given intravenously (i.v.) over 4 hours; sodium thiosulfate (STS) was given i.v. in the opposite arm at a loading dose of 4 g/m2, followed by 12 g/m2 over 6 hours. Each cycle was repeated every two weeks. Seventy-five cycles were administered to 28 patients in this clinical trial.
Results: In 19 patients who received 2 or more cycles of chemotherapy, a delay of three or more days was required on 17/66 courses (26%); the mean DDP DI actually received by these patients was 83 mg/m2/wk (88% of the planned DI). The major side effect was ototoxicity; this occurred in 9 patients (33%), but none required a hearing aid. Myelosuppression was moderate with thrombocytopenia greater than neutropenia. Nephrotoxicity (creatinine > 2 mg/dl) occurred on only 2 cycles (3%). Three patients (11%) developed symptoms of peripheral neuropathy. In 23 evaluable patients, the overall response rate was 39%.
Conclusion: It is feasible to give 180 mg/m2 of DDP and STS every two weeks with tolerable nephrotoxicity but without blocking other types of toxicity, such as myelosuppression and ototoxicity. The shortening of cycle intervals resulted in a markedly increased DI.