Postoperative Radiation Therapy for Chest Wall Invading pT3N0 Non-small Cell Lung Cancer: Elective Lymphatic Irradiation May Not Be Necessary

摘要

PURPOSE: No general consensus has been reached regarding the necessity of postoperative radiation therapy (PORT) and the optimal techniques of its application for patients with chest wall invasion (pT3cw) and node negative (N0) non-small cell lung cancer (NSCLC). We retrospectively analyzed the pT3cwN0 NSCLC patients who received PORT because of presumed inadequate resection margin on surgical findings. MATERIALS AND METHODS: From Aug. 1994 till June 2000, 21 pT3cwN0 NSCLC patients received PORT at Samsung Medical Center; all of whom underwent curative en-bloc resection of the primary tumor plus the chest wall and regional lymph node dissection. PORT was typically started 3 to 4 weeks after operation using 6 or 10 MV X-rays from a linear accelerator. The radiation target volume was confined to the tumor bed plus the immediate adjacent tissue, and no regional lymphatics were included. The planned radiation dose was 54 Gy by conventional fractionation schedule. The survival rates were calculated and the failure patterns analyzed. RESULTS: Overall survival, disease-free survival, loco-regional recurrence-free survival, and distant metastases-free survival rates at 5 years were 38.8%, 45.5%, 90.2%, and 48.1%, respectively. Eleven patients experienced treatment failure: six with distant metastases, three with intra-thoracic failures, and two with combined distant and intra-thoracic failures. Among the five patients with intra-thoracic failures, two had pleural seeding, two had in-field local failures, and only one had regional lymphatic failure in the mediastinum. No patients suffered from acute and late radiation side effects of RTOG grade 3 or higher. CONCLUSION: The strategy of adding PORT to surgery to improve the probability, not only of local control but also of survival, was justified, considering that local control was the most important component in the successful treatment of pT3cw NSCLC patients, especially when the resection margin was not adequate. The incidence and the severity of the acute and late side effects of PORT were markedly reduced, which contributed to improving the patients' quality of life both during and after PORT, without increasing the risk of regional failures by eliminating the regional lymphatics from the radiation target volume.