Background. Small cell lung cancer (SCLC) is highly sensitive to chemotherapy. Despite the introduction of intensive combination chemotherapy, long-term disease-free survivors are still rare. The emergence of drug-resistant tumor cells during chemotherapy is presumed to be the major cause of poor outcome.
Methods. A pilot Phase II study of hybrid chemotherapy for patients with SCLC was conducted between October 1986 and March 1988. Dose and schedule for each drug in the regimen were as follows: cyclophosphamide, 700 mg/m2 intravenously (IV), day 1; doxorubicin, 30 mg/m2 IV, day 1; vincristine, 1.4 mg/m2 IV, day 1; cisplatin, 60 mg/m2 IV, day 8; and etoposide, 100 mg/m2 IV, days 8 and 9. Courses were repeated every 4 weeks for up to six cycles. Patients with limited disease (LD) received chest irradiation of 5000 cGy when a maximal response was achieved. Only patients with LD who achieved a complete response (CR) received prophylactic cranial irradiation of 3000 cGy.
Results. Thirty-six patients were enrolled and fully evaluated for tumor response and toxicity. All 20 patients with LD responded to the regimen, and 14 (70%) of those achieved a CR. Of 16 patients with.extensive disease (ED), 7 CR and 7 partial responses were noted, indicating an overall response rate of 88%. The median survival time was 23.6 months for patients with LD and 12.6 months for those with ED. Myelosuppression was the major toxicity, but it was generally well tolerated.
Conclusions. These results indicate that the hybrid regimen is a highly active one for the treatment of patients with SCLC and warrants additional clinical trials.