Risk of death from intercurrent disease is not excessively increased by modern postoperative radiotherapy for high-risk resected non-small-cell lung carcinoma

Purpose : Some studies report a high risk of death from intercurrent diseas e (DID) after postoperative radiotherapy (XRT) for non-small-cell lung canc er (NSCLC). This study determines the risk of DID after modern-technique po stoperative XRT. Patients and Methods: A total of 202 patients were treated with surgery and postoperative XRT for NSCLC. Most patients (97%) had pathologic stage II o r III disease. Many patients (41%) had positive/close/uncertain resection m argins. The median XRT dose was 55 Gy with fraction size of 1.8 to 2 Gy. Th e risk of DID was calculated actuarially and included patients who died of unknown/uncertain causes. Median follow-up was 24 months for all patients a nd 62 months for survivors. Results: A total of 25 patients (12.5%) died from intercurrent disease, 16 from confirmed noncancer causes and nine from unknown causes. The 4-year ac tuarial rate of DID was 13.5%. This is minimally increased compared with th e expected rate for a matched population (approximately 10% at 4 years). On multivariate analysis, age and radiotherapy dose were borderline significa nt factors associated with a higher risk of DID (P = .06). The crude risk o f DID for patients receiving less than greater than or equal to 54 Gy was 2 % (4-year actuarial risk 0%) versus 17% for XRT dose a 54 Gy The 4-year act uarial overall survival was 34%; local control was 84%; and freedom from di stant metastases was 37%. Conclusion: Modern postoperative XRT for NSCLC does not excessively increas e the risk of intercurrent deaths. Further study of postoperative XRT, part icularly when using more sophisticated treatment planning and reasonable to tal doses, for carefully selected high-risk resected NSCLC is warranted. (C ) 2001 by American Society of Clinical Oncology.