Between Jan. 1, 1976, and Dec. 31, 1985, at our institution, 37 patients who had undergone prior complete surgical resection of non-small-cell lung cancer received definitive thoracic radiation therapy (TRT) for locally recurrent disease. Of the 37 recurrences, 33 were in the pulmonary parenchyma or the hilar, mediastinal, or supraclavicular lymph nodes; the other 4 were in the chest wall. The initial stage of disease was I in 43%, II in 35%, and IIIA in 19%, whereas at the time of local recurrence, the stage was I in 8%, II in 11%, IIIA in 57%, IIIB in 22%, and IV in 3% (this patient had multiple pulmonary nodules encompassible within a single TRT field). The locally recurrent lesions were squamous cell carcinoma in 30%, adenocarcinoma or large-cell carcinoma in 46%, mixed types in 5%, and unknown type in 19%. All patients received megavoltage TRT, most often 4,000 cGy in 10 fractions administered in a split-course schedule. In addition, 15 patients received multiagent chemotherapy, usually a combination of cyclophosphamide, doxorubicin hydrochloride, and cisplatin or a regimen that included these drugs. The 2-year and 5-year survivals were 30% and 4%, respectively, and the median duration of survival was 13.7 months. Survival was not improved by the addition of chemotherapy. Approximately half of the patients had radiographic and symptomatic responses after TRT. Of 33 patients assessable for post-TRT patterns of failure, 46% had local failure only, 18% had local plus systemic failure, and 32% had systemic failure only. Two-thirds of the patients died as a direct consequence of progressive chest disease, despite receiving TRT.(ABSTRACT TRUNCATED AT 250 WORDS)