Retreatment with dose-dense weekly cisplatin after previous cisplatin chemotherapy is not complicated by significant neuro-toxicity

Abstract

Cisplatin induces a cumulative dose-dependent axonal sensory neuropathy. With a cumulative dose over 600 mg/m2, a significant percentage of patients will develop a moderate or severe neuropathy. We retreated patients with progressive or recurrent ovarian cancer after previous platinum-containing chemotherapy with weekly 50-70 mg/m2 cisplatin for six cycles. This group was prospectively followed for the development of neuropathy. Patients received six weekly cycles of either 50 or 70 mg/m2 cisplatin, combined with oral etoposide. Responding patients continued treatment with daily oral etoposide for nine months. Neurological toxicity was assessed with a sensory sum score, the sensory neuropathy common toxicity criteria (CTC) and quantitated sensory analysis of the vibration perception threshold (VPT). Neurological assessment was scheduled at baseline, after three cycles, at the end of cisplatin chemotherapy and at 3 monthly intervals until 1 year after the discontinuation of chemotherapy. The first evaluation carried out in the interval of 1-4 months after the end of weekly cisplatin therapy was taken as the principle evaluation for neurotoxicity because during this time interval the nadir of cisplatin neurotoxicity is to be expected. Of 89 patients evaluated for neurological toxicity, 80 patients were fully evaluable. Forty-nine had received prior cisplatin (median cumulative dosage 450 mg/m2); the others had received prior treatment with carboplatin. Cisplatin pretreated patients had slightly higher neuropathy scores at the start of weekly cisplatin. Almost all cisplatin pretreated patients received six cycles of cisplatin, 29 at 50 mg/m2 and 20 at 70 mg/m2 per cycle. Despite treatment up to an overall cumulative dose of 750-900 mg/m2 cisplatin, only 1 patient discontinued treatment due to neurotoxicity. One other patient developed a grade 3 neuropathy during follow-up. Only a marginal increase of neuropathic signs and symptoms were observed in all the other patients. In multiple regression analysis, the increase in VPT or the sensory sum score was not related to prior treatment (cisplatin or carboplatin). Patients with mild signs of neuropathy after prior treatment with cisplatin to a cumulative dose level of 400-450 mg/m2 can be retreated with weekly cisplatin to a cumulative dose of 420 mg/m2 (overall cumulative dose up to 800-900 mg/m2) with only a minimal risk of significant neurotoxicity.