Comparative study of prophylactic cranial irradiation in patients with small cell lung cancer achieving a complete response: a long-term follow-up result.

Between 1981 and 1986, a total of 46 patients with small cell lung cancer (SCLC) achieving a complete response by chemotherapy with or without chest irradiation were randomized either to receive prophylactic cranial irradiation (PCI) or not. With a median follow-up time of 8.5 years for both groups, only five of 23 patients (22%) in the PCI group developed brain relapse, while 12 out of 23 (52%) in the no PCI group did so (P < 0.05). The frequency of patients developing a sole brain relapse during their whole clinical course was 4% for the PCI group and 17% for the no PCI group, however, the difference was not statistically significant. Patient survival was better for the PCI group (median survival time of 21 months, and 5-year survival rate of 22%) as compared with the no PCI group (median survival time of 15 months, and 5-year survival rate of 13%), showing a marginal significance (P = 0.097). Late neurologic toxicity was infrequent; only one developed a mild deterioration among seven long-term disease-free survivors in the PCI group. These results appear to warrant further clinical trials to clarify the utility of PCI in patients with SCLC achieving a complete response.