Second-line chemotherapy with low-dose CPT-11 and cisplatin for colorectal cancer resistant to 5-FU-based chemotherapy.

Purpose: With the aim of reducing the toxicities of irinotecan (CPT-11) while maintaining its antitumor effect, we treated colorectal cancer patients resistant to chemotherapy based on 5-fluorouracil (5-FU) with low-dose CPT-11 and cisplatin (CDDP).
Methods: CPT-11 (27 mg/m2) and CDDP (6 mg/m2) were administered on days 1, 8 and 15 every 4 weeks to 20 patients with recurrent or metastatic colorectal cancer. When toxicities were noted, administrations were delayed or the dose was reduced.
Results: No severe toxicity (i.e. grade 3 or more) was observed in this study. Nausea was observed in 50% of patients (10/20) and fatigue in 30% (6/20). Only four patients developed leukopenia (three grade 1 and one grade 2). Although the overall response rate was 15% (three partial response, seven no change, and ten progressive disease), the median time to progression was 7.0 months and the median survival time was 18.0 months. The treatment was well tolerated as outpatient therapy.
Conclusion: Low-dose CPT-11 and CDDP treatment should be considered as second-line chemotherapy for patients with recurrent or metastatic colorectal cancer resistant to 5-FU-based chemotherapy.