Radiation Dose Is Significantly Associated With Overall Survival In Patients With Stage Iii Non-Small Cell Lung Cancer Treated With Combined Radiation And Chemotherapy

18074 Background: Radiation dose is an independent prognostic factor for survival in patients with early stage non-small cell lung cancer (NSCLC). We hypothesized that radiation dose is also a significant independent factor associated with survival in patients with stage III disease treated with combined radiation and chemotherapy. Methods: This is an Institutional Review Board approved retrospective study. Eligible subjects included those with stage III NSCLC registered in the radiation oncology database at University of Michigan Hospital between January 1992 and July 2004. Radiation was given using 3-dimensional conformal technique with doses ranging from 30 to 102.9 Gy, corresponding to a bioequivalent dose (BED) of 39 to 124.5Gy. Median age was 65 years (range, 36–89). There were 80 males and 67 females. Median follow-up was 13.0 months (range, 2.7–145.9). Results: For patients treated with radiation alone (n=40), sequential chemoradiation (n=42), and concurrent chemoradiation (n=65), median survival was 8.6 (95% CI: 5.7–11.5), 12.8 (95% CI: 9.5–16.0) and 15.4 (95% CI: 12.7–18.0) months, respectively (P =0 .011). Multivariate Cox-regression analysis showed that BED (HR=0.96, 95% CI: 0.95–0.97, P<0.001) and administration of chemotherapy (HR=0.44, 95% CI: 0.28–0.70, P=0.001) were independent prognostic factors associated with the risk of death. T stage was marginally significant (P=0.065). Age, gender and N stage were not independent factors (P>0.05). To isolate the BED effect, multivariate analysis was performed separately in patients treated with and without chemotherapy: the hazard ratios of BED for the risk of death were 0.97 (95% CI: 0.95–0.99, P=0 .013) and 0.95 (95% CI: 0.93–0.98, P=0.001), respectively. BED also remained a significant independent prognostic factor in patients treated with chemotherapy and radiation in the dose range of 60–66 Gy (HR=0.91, 95% CI: 0.84–0.99, P=0.041). Conclusions: Radiation dose is significantly associated with survival in patients with stage III NSCLC treated with combined radiation and chemotherapy. No significant financial relationships to disclose.