PHASE I/II STUDY OF TREATMENT OF LOCALLY ADVANCED (T3/T4) NON-OAT CELL LUNG-CANCER WITH CONCOMITANT BOOST RADIOTHERAPY BY THE RADIATION-THERAPY ONCOLOGY GROUP (RTOG-83-12) - LONG-TERM RESULTS

Purpose: This pilot study was undertaken to evaluate the effect of high dose-per-fraction radiotherapy given to the tumor primary concurrently with conventional fractionated radiotherapy to the electively irradiated regional lymph nodes (concomitant boost), This article reports the late results of toxicity and survival. Methods and Materials: Fifty-nine patients with histologically proven clinical Stage T3-T4, N1-3 nonsmall cell lung cancer were prospectively enrolled in this study, Fifty-six were evaluable for late effects. The treatment delivered 2.68 Gy daily to the primary tumor, 5 days a week, to a total dose of 75 Gy in 28 fractions in 5.5 weeks. At the same treatment sessions, the electively irradiated nodal areas received 1.8 Gy daily, 5 days per week, to a total dose of 50.4 Gy. All doses were calculated with heterogeneity corrections for lung density. Results: Presently, one patient remains alive at 7.7 years. Median survival was 10.0 months with 1-, 2-, 3-, and 5-year survival rates of 41%, 25%, 18%, and 4%, respectively. Three patients developed severe late complications, including pulmonary fibrosis and osteonecrosis. The remainder of the patients, however, developed only grade 1 or 2 pulmonary fibrosis and/or pneumonitis. Conclusion: We conclude that concomitant boost radiotherapy in the manner reported resulted in acceptable late toxicity. The 2- and 3-year survivals compared favorably with the best-reported results in the literature with either hyperfractionated or chemoradiotherapy treatment. Studies that deliver higher radiotherapy doses to the gross tumor combined with chemotherapy are in order.