Proceedings of the 41st Annual ASTRO Meeting 319 question of the necessity of the last cycle of chemotherapy. The efficacy of this aggressive concomitant thoracic radiation therapy/daily chemotherapy regimen with early prophylactic cranial irradiation will be determined after adequate follow-up. 2 1% A TRIAL COMPARING HYPERFRACTIONATED PROPHYLACTIC CRANIAL IRRADIATION VERSUS NO PROPHYLACTIC CRANIAL IRRADIATION IN PATIENTS WITH LIMITED STAGE SMALL CELL LUNG CANCER WITH COMPLETE RESPONSE TO CHEMOTHERAPY AND CONSOLIDATIVE RADIOTHERAPY Bains YS, Wolfson AH: Lu JD, Sridhar K, Raub WA, Markoe AM University of Miami/Jackson Memorial Hospital, Miami, FL, USA Purpose: Prophylactic cranial irradiation (PCI) has been demonstrated to significantly reduce the incidence of failure in the brain from limited stage small cell lung cancer but concerns exist about the neurological toxicity. This prospective study explored the impact of hyperfractionated PC1 XRT on disease free survival, overall survival and neurological toxicity. Materials & Methods: Patients with limited stage small cell lung cancer (LSSCLC) with a complete response to chemo- irradiation from April 1992 to April 1997 were offered enrollment into this protocol. The whole brain was treated with twice daily fractions of 1.5 Gray separated by at least 6 hours using 4 or 6 MV photons to a total dose of 30-36 Gy. Endpoints for assessment included disease-free-survival (DFS), overall survival (OS), and CNS toxicity. Neurological function was evaluated using the General Performance Status (GPS) and Neurological functional class (NFC). Patients declining enrollment into the protocol served as the control group. Results: Fifteen patients accepted the hyperfractionated PC1 and twelve patients deferred treatment. Median follow up was 20 months. Using the Kaplan-Meier method, a statistically significant longer DFS (p=O.O373) and OS (~~0.0463) was found in favor of the patients receiving PC1 (See Table 1). The Mode of the initial GPS and NFC for the 15 PC1 patients was Class I. The Mode of the GPS and NFC at the last known follow up was Class I. No clinical or statistically significant neurological deterioration was seen in the PC1 group post treatment. Conclusion: Hyperfractionated PC1 for LSCCLC patients with a complete response to chemo-irradiation was effective in improving both DFS and OS. No significant neurological toxicity was observed in the long-term PC1 survivors. PC1 No PC1 DFS lyr DFS 2yr OS lyr OS 2yl 94% 46% 94% 56% 50% 0% 56% 0% 2 197 A PHASE III STUDY EVALUATING THE EFFICACY OF CONVENTIONAL RADIATION THERAPY WITH OR WITHOUT RECOMBINANT P-INTERFERON FOR PATIENTS WITH LOCALLY ADVANCED NON-SMALL CELL LUNG CANCER AND POOR PROGNOSTIC CHARACTERISTICS (RTOG 93-04) McDonald S’, Scott C2, Rubin Pi. Paris K3, Demas W4, Machtay Mi, Komaki R6, Movsas B’ University of Rochester, Rochester, NY, USA’; RTOG, Philadelphia, PA, USA’; Washington University, St. Louis, MO, U.SA3; Akron City Hospital, Akron, OH, lJSA4; University of Pennsylvania Health System, Philadelphia, PA, USA’; M.D. Anderson Hospital, Houston, TX, USA6; Fox Chase Cancer Center, Philadelphia, PA, USA7 Purpose: The purpose of this study was to evaluate overall survival and toxicity in patients with poor prognostic features who have locally advanced non-small cell lung cancer treated with irradiation or irradiation and p-interferon. Methods and Materials: This study was a prospective randomized Phase III trial performed by the Radiation Therapy Oncology Group (RTOG). Between September 1, 1994 and March 17, 1998 123 patients with locally advanced non-small cell lung cancer without evidence of hematogenous metastases were randomized to receive either standard irradiation or standard irradiation and p-interferon. Eligible patients were required to have poor prognostic characteristics i.e., Karnofsky Performance Status (KPS) <70 and/or weight loss of more than 5% in the past three months. Irradiation consisted of 60 Gy to the chest, given over 6 weeks in 2 Gy fractions. p-interferon was administered at 16 x 106 IU given by i.v. bolus three days a week (Mon.-Wed.) on weeks one, three and five. Patients in the two groups were evenly distributed by KPS, weight loss and stage. Results: Sixty-one patients were treated with irradiation alone and 62 received irradiation and p-interferon. Fifty-seven in each group were eligible and analyzable. Survival at one and two years was 50% and 21% for the irradiation alone group and 41% and 11% for the p-interferon group (p = 0.2816). Median survival was 10.9 months for the irradiation alone group and 10.3 months for the p-interferon group. Grade 3 and 4 acute toxicity was seen in 20% of the irradiation alone group compared to 32% in the p-interferon group (p = 0.15). Acute toxicity was not related to prognostic characteristics. Eleven percent of the control group had grade 3 late toxicity. The only grade 4 or 5 late toxicities were seen in the p-interferon group where grades 3, 4 and 5 late toxicities were 6%, 6%, 2% respectively. Conclusions: There was no statistically significant difference in survival or acute toxicity between patients treated on this study