Radiation therapy is the only potentially curative form of therapy for patients with carcinoma of the lung who are not surgical candidates. Previous studies have evaluated response by evaluating survival. Evaluation of local control of disease is essential if one is to understand and modify therapeutic approaches in an effort to increase survival. Clinical data are presented on 197 patients with primary epithelial tumors of the lung. An analysis of local control data is presented using the concept of nomial standard dose (NSD). If local failure is to occur, it is manifest by 15 months. Survival is affected by the ability or inability to achieve local control. Above a dose of 1450 ret, no correlation between increasing ret dose and increasing local control is observed.