Concurrent cis-diamminedichloroplatinum(II) and radiation treatment for melanoma metastases: a pilot study

Thirteen evaluable patients with 25 melanoma metastases were treated by radiotherapy, 6 X 6 Gy in 6 weeks (one fraction per week) and concomitant weekly cis-platinum infusion, 20, 30 or 40 mg/m2. Acute systemic toxicity was mainly gastro-intestinal, grade 1 to 3 (WHO-criteria) in all patients, and bone marrow toxicity grade 1-2 in four patients, not distinctly drug-dose related. Acute local skin reaction did not appear to be enhanced. Symptomatic bowel spasms occurred in 2 of 4 patients treated on an iliac-inguinal field, both having received a high drug dose (40 mg/m2). Late severe and disabling subcutaneous fibrosis was encountered in 2 of 8 patients with a minimal follow-up of 6 months, suggesting that cis-platinum concurrently given, enhances late radiation damage to connective tissue, although possible contribution of other factors cannot be ruled out. Initial response was observed in nine patients, but sustained local control (longer than 6 months) was obtained in only 3 of 8 patients. Concentrations of total platinum, measured in tumour at the time of first irradiation, approach the minimal concentration assumed to be required for radiosensitizing effects of cis-platinum.