Cyclic alternating combination chemotherapy for small cell bronchogenic carcinoma

Sixty-one protocol-eligible patients with small cell bronchogenic carcinoma received cyclic alternating combination chemotherapy with two or three non-cross-resistant drug combinations. No chest or prophylactic brain radiation therapy was used. Twenty-eight months after starting treatment, disease-free survival was 23% for patients achieving a complete response (CR) and 13% overall. Initial treatment consisted of high-dose cyclophosphamide, methotrexate, and CCNU (CMC) for 6 weeks. Patients then received vincristine, adriamycin, and procarbazine (VAP) for 6 weeks. The addition of VAP increased the CR rate from 42% to 74% in limited-disease patients and from 24% to 36% in extensive-disease patients. Half of the patients were randomized to a third combination of VO-16-213 and ifosfamide. These patients were cycled at 6-week intervals through the three drug regimens while the remaining patients were cycled between CMC and VAP. The addition of VP-16-213 and ifosfamide did not increase the CR rate or prolong survival. Only complete responders survived beyond 24 months. Sequential use of non-cross-resistant drug combinations represents one method for increasing the CR rate.