Canadian multicenter randomized trial comparing sequential and alternating administration of two non-cross-resistant chemotherapy combinations in patients with limited small-cell carcinoma of the lung.

In order to assess the effect of scheduling of chemotherapy on the outcome of patients with limited small-cell lung cancer (SCLC), the Clinical Trials Group of the National Cancer Institute of Canada carried out a randomized trial comparing the alternation of cyclophosphamide, Adriamycin (Adria Laboratories, Columbus, OH; doxorubicin) and vincristine (CAV) with etoposide (VP-16) and cisplatin for six cycles to the administration of these two combinations in a sequential fashion (three cycles of CAV followed by three of VP-16/cisplatin). Three hundred eligible patients were enrolled on the trial from September 1981 to October 1984. All responding patients were also treated after completion of chemotherapy with thoracic irradiation in randomly allocated doses of 2,000 and 3,750 cGy. The complete response (CR) rate to chemotherapy was slightly, but not significantly, higher on the alternating arm (52% v 44%, P = .20). However, there was no difference in disease-free or overall survival on the alternating and sequential arms, respectively (47.3 weeks v 45.1 weeks, P = .26; 61.7 weeks v 59.5 weeks, P = .56). Data on the effect of radiotherapy dose on survival are not yet mature, but it does not appear the results of this portion of the trial will alter the interpretation of the chemotherapy comparison. Patient characteristics favorably influencing survival were female sex, good performance status, younger age, and absence of supraclavicular node involvement. Two interpretations of these and other results in SCLC are suggested: (1) the difference between the schedules used is too small for the predictions of the Goldie-Coldman model to be realized in a trial of this size, or (2) VP-16/cisplatin is actually a superior regimen and any schedule that exposes patients to these drugs early in treatment will produce improved results.