Radiation therapy for chest recurrences following induction chemotherapy in small cell lung cancer

Once small cell lung cancer fails induction chemotherapy, second line drugs are usually ineffective, accounting for mostly partial responses in the order of 0-20% and a median survival of 6-10 weeks. A review of patients with relapsed small cell lung cancer was carried out at the University of Maryland. Of 51 such patients, 44 received thoracic irradiation at the time of relapse. Excluding 8 patients who received insufficient treatment, the series consists of 36 patients (27 with limited and 9 with extensive disease) and represents the largest experience with relapsed small cell lung cancer subjected to radiation alone. Total radiation doses were 60 Gy in 11, 45-55 Gy in 14, and 38-42 Gy in the remaining 11 patients. No second line chemotherapy was given simultaneously with radiation at time of relapse and it was only given subsequently during the course of the disease to four patients. Responses to radiation were seen in 28 (77%) with 9 (25%) complete and 19 (52%) partial. The median survival was 16-40 weeks varying with disease extent, response, and total dose. Subsequent failures occurred in chest (34%) and distant sites (66%). A dose-response curve was attempted; the higher doses achieved as much as 75% local control. A poor response to induction chemotherapy did not predict a poor radiation response at time of relapse. Nearly 2/3 of patients who had not responded to induction chemotherapy responded to radiation at the time of relapse. The post-recurrence survival after radiation therapy was as long as or longer than the recurrence-free interval after induction chemotherapy, and this clearly demonstrates the value of radiation in achieving excellent palliation and good quality of life in these patients. Thoracic irradiation is recommended as a therapeutic alternative for locally recurrent small cell lung cancer after induction chemotherapy.