Retreatment with the induction regimen in small cell lung cancer relapsing after an initial response to short term chemotherapy.

In 37 patients with small cell lung cancer treatment with five cycles of cyclophosphamide, doxorubicin and etoposide (CDE), resulted in 23 complete (CR) and 14 partial responses (PR). Median response duration was 34 weeks. At relapse all patients were retreated with CDE. In 23 (62%) patients this gave a second response (6 CR, 17 PR). Factors influencing the occurrence of a second response were: 1. a CR after the first five cycles of CDE; 18 out of 23 CR patients responded again whereas only five of the 14 PR patients responded (P less than 0.01). 2. 15 out of 19 patients with a first response duration greater than 34 weeks reached a second response and in eight of the other 18 patients retreatment was successful (P less than 0.05). Reinduction at relapse, after short term chemotherapy and a treatment-free interval, with the induction regimen is an effective second line treatment in patients with an initial CR and a first response duration of greater than 34 weeks.