[en] We examined the effects of postoperative radiation therapy on long-term prognosis for 207 patients who received either a curative or non-curative surgical operation for lung cancer, from 1973 to 1987 in our hospital. We excluded data on those patients who had distant metastasis and those patients who died due to other causes. For all pN0 or pN1 cases of pT3 that underwent curative resection, radiation therapy, with or without chemotherapy, was beneficial for prognosis when compared with those who received no radiation and chemotherapy only. We followed the long-term survival over 5 years, in 3 of 10 patients with a residual tumor at the surgical margin treated with radiation therapy combined with chemotherapy. However, all those who received chemotherapy died within only 3 years. (author)