Limited small cell lung cancer: the effect of radiotherapy on local control following response to chemotherapy.

The survival and rate of chest infield relapse was examined in 48 patients with limited disease small cell lung cancer (LSCLC) who had achieved complete (CR) or partial response (PR) following three courses of chemotherapy. During 1985-1986 chemotherapy consisted of carboplatin and etoposide and during 1986-1987, of etoposide, carboplatin, cyclophosphamide, and vincristine (ECCO). After three courses of chemotherapy, chest irradiation (50 Gy in 25 fractions over 5 weeks) was given to encompass the original tumor volume. Complete responders were also given prophylactic cranial irradiation, 30 Gy in 10 fractions over 2 weeks. Overall median survival of all patients receiving chest irradiation was 17 months from commencement of radiotherapy. The infield relapse-free survival at 24 months was 49% (95% confidence interval: 32-66%). Patients who had only achieved a PR at the time of irradiation were more likely to relapse in the chest than complete responders (p = 0.09). We conclude that local relapse remains a major cause of failure in patients with LSCLC in spite of sequential high dose radiotherapy given to patients who have responded to chemotherapy.