[en] Purpose/Objective: Analysis of a Phase II Trial, performed by RTOG to evaluate the feasibility, tolerance, toxicity and appreciation of response rates for an accelerated hyperfractionated regimen in bronchogenic carcinoma. Materials and Methods: 1.1 Gy fractions, uncorrected for increased lung transmission, were delivered three times a day with the boost field delivered mid day with the mediastinal field delivered 4 hours before and afterwards. 72 fractions were delivered in 24 treatment days; total dosage 79.2 cGy to the primary tumor and 52.8 cGy to the mediastinum. LQ model calculation suggests a 12% increase in bioeffect dose, as compared to 79.2 Gy in RTOG 8311 without increased late toxicity. Two-thirds of the patients had a KPS of 80, the rest 90. The tumor histologies were 15 squamous cell, 10 adenocarcinoma, 8 large cell and 2 NOS. 8 patients had T₂, 11 had T₃, 13 had T₄ primary tumors; 15 had N₀, 12 had N₂, 7 had N₃. 14 patients had AJC Stage IIIA tumors, 18 had Stage IIIB. Results: All 35 patients entered into the study were evaluable for treatment. There were only three cases with treatment related Grade III toxicities during treatment: Esophagitis at 28 days, lung at 13 days and skin reactions at 31 days. 4 chronic Grade III toxicities after treatment completion: Esophagus-day 65, 2 lung- day 239 and 337, and 1 thyroid-day 434. Initial evaluation of the median survival was 11.6 months, complete response rate was 6% and 79% having either stable disease or PR. Updated failure rates and survivals will be presented at the ASTRO Meeting in October 1995. Conclusion: This regimen was feasible and tolerable. Response rates are similar to other NSCLC radiotherapy only regimens. Early survival results are comparable to several RTOG B.I.D. regimens