[Maintenance chemotherapy in small cell lung cancer: reasons for not using it]

There is no consensus as the optimal duration for treatment in patients with small-cell lung cancer. In routine practice, 6 cycles of chemotherapy are usually delivered, but the rate of recurrence after achieving objective response has incited interest in several trials aimed at evaluating the effect of prolonged "maintenance" chemotherapy. Such prolonged regimens may use the same drugs as used in the induction protocol or call upon new drugs. No conclusion can be drawn from the 14 randomized studies conducted to date because of differences in the randomized populations as well as the nature of the treatments tested. Among 9 trials using a maintenance regimen with the same drugs as the induction protocol, there has been no significant difference in long-term survival. One study even found a lower 2-year survival with maintenance therapy. Among 5 trials where the maintenance protocol used drugs different from the induction protocol, survival rate favored maintenance chemotherapy in only 1. Most authors have observed a significant deterioration in quality of life in patients given maintenance chemotherapy, in addition to a number of deaths due to drug toxicity. Patient recruitment had to be interrupted in one study. The percentage of patients who received the entire maintenance protocol was also very low in many trials (20%). There may exit a theoretical advantage to giving maintenance chemotherapy, but does it counterbalance the risk of late complications? An increased risk of a second cancer has been demonstrated in patients given more than 6 cycles in the National Registry of long-term survival. Given the current state of our knowledge, it would not appear reasonable to propose maintenance chemotherapy for patients with small-cell lung cancer outside controlled clinical trial protocols.