Lung cancer: Clinical trial of radiotherapy alone vs. Radiotherapy plus cyclophosphamide

Abstract

Patients with non‐resectable lung cancer confined to the central area of the thorax were randomly assigned treatment with radiotherapy to the primary lesion and mediastinum (group C), and radiotherapy plus either four (group B) or eight (group A) courses of high‐dose intermittent cyclophosphamide. Cyclophosphamide therapy delayed the progression of metastatic lesions outside the irradiated field (median interval to progression 192 days for groups A and B vs. 114 days for group C), and prolonged survival (median 306 days for groups A and B vs. 216 days for group C). Assuming a tumor‐doubling time of 18 days, the improved survival of the cyclophosphamide‐treated patients could be explained by the inhibition of 90/18 = 5 tumor doublings or a tumor cell kill of 10^1,5. This result indicates that cyclophosphamide is only minimally effective in the treatment of lung cancer, but it is an active drug and it should be considered for inclusion in future trials of drug combinations.