Cyclophosphamide, vincristine and sequential split-course radiotherapy in the treatment of small cell lung cancer.

Thirty-nine patients with small cell lung cancer were treated with large dose intravenous cyclophosphamide combined with vincristine. Sequential split-course radiotherapy was added when the gross disease was limited to one hemithorax and draining scalene nodes. Fifteen of 16 patients in the limited disease category showed objective response, eight of which were complete. Fourteen of 23 patients in the extensive disease category yielded an objective response, six of which were complete. The median survival for complete responders was 48 weeks, 38 weeks for partial responders and 14 weeks for non-responders. The difference between responders and non-responders was statistically significant. The major toxicity was myelosuppression with a median leukocyte nadir of 500/mm-3 noted on treatment day no. 15. Prompt recovery was the rule. Toxicity appeared to be cumulative for patients receiving radiotherapy. These results are superior to those evolving from treatment with cyclophosphamide as a solitary agent.