Postoperative 3D Conformal Radiation Therapy With Dose-Volume Histogram Assessment in Non Small-Cell Lung Cancer

Abstract

Purpose/Objective(s): Despite many randomized trials, the indication of postoperative radiation therapy (PORT) in non small cell lung cancer (NSCLC) is controversial. Involved-field conformal (3D) RT has never been studied prospectively. In this study, we aim to assess the outcome of patients treated with involved-field 3D PORT with or without chemotherapy in locally advanced NSCLC. Materials/Methods: From 1990 to 2006, data from 75 consecutive patients treated with curative surgery and PORT for NSCLC were retrospectively analyzed. Male to female ratio was 57/18, and median age was 58 years (38-76). There were 5 patients with stage I, 22 with stage II, and 48 with stage III disease. Pneumonectomy or lobectomy was realized in 24 and 51 patients, respectively. Mediastinal lymphadenectomy was performed in all patients. PORT indications were positive margins and/or positive mediastinal lymph nodes. Cisplatin-based chemotherapy was given in 15 patients. All patients had 3D conformal planning. Median RT dose was 60 Gy using at least 6-MV photons in 6 weeks, and CTV included bronchial stump and only positive nodal areas. Dose-volume histograms (DVH) assessing the pulmonary volume receiving 20 Gy (V20 Gy) were used in all patients. Results: Compliance to PORT was 100%. In a median follow-up period of 55 months, 26 (35%) patients are alive without disease. Median overall survival time was 24 months, with survival rate of 35% at 5 years (Fig. 1). The 5-year locoregional control and distant disease-free rates were 80% and 57%, respectively. Patients treated with pneumonectomy and those treated with at least 60-Gy PORT had better outcome (Fig. 2). Grade 3 or more CTC v3.0 toxicity was observed only in 4 (5%) pts. No lethal toxicity was observed. Conclusions: We conclude that involved-field 3D conformal 60-Gy PORT tailored with DVH V20 Gy assessment improves locoregional control without increasing lethal toxicity. Prospective studies using the above-mentioned criteria are warranted.