LONG-TERM OUTCOMES OF INTRAOPERATIVE RADIATION THERAPY FOR NON-SMALL CELL LUNG CANCER

The purpose of the study was to analyze long-term outcomes of intraoperative radiation therapy (IORT) in patients with stage III non-small cell lung cancer (NS CLC).Material and Methods. The study included 103 patients with stage III NS CLC treated at the Cancer Research Institute (Tomsk, Russia). All patients were divided into two groups. Group I consisted of 51 patients, who underwent radical surgery and IORT at a single dose of 15 Gy. Group II (control group) comprised 52 patients, who underwent radical surgery alone. There were 34 (33 %) pneumonectomies, 39 (37.9 %) lob-, bilobectomies, 9 (8.7 %) reconstructive surgeries and 21 (20.4 %) combined surgeries. A compact pulsed betatron MIB-6E with the average electron energy of 6 MeV, located directly in the operating unit, was used for performing IORT. The Kaplan-Meier method was used for survival analysis. The significance of differences in survival between groups was assessed using the log rank test.Results. Excluding the cases lost to follow-up and deaths from concomitant non-malignant diseases, treatment outcomes were followed up in 97 of 103 patients with NS CLC for 3, 5, and 10 years. The 3-year and disease-free survival rates were significantly higher in the IORT group than in the control group (p<0.05). The IORT reduced the frequency of locoregional recurrence from 28.6 % to 20.8 % and increased recurrence-free survival from 12 to 17.1 months. In patients with stage III NS CLC, who received combined modality treatment including IORT, the 5and 10-year disease-free survival rates were 18.7 % and 12.5 %, respectively. In the control group patients, the corresponding values were 14.3 % and 6.1 %, respectively (р<0.05). The 5and 10-year overall survival rates were 29.2 % and 18.7 % versus 20.4 % and 8.2 %, respectively (р<0.05).Conclusion. In patients with stage III NS CLC, combined modality treatment, including radical surgery and IORT, results in a better local control and higher long-term survival rates compared to surgery alone