Comparative outcomes for 3D conformal versus intensity modulated radiation therapy for esophageal cancer.

Abstract

76 Background: Emerging data suggests a benefit for using intensity modulated radiation therapy (IMRT) for the management of esophageal cancer. Methods: We retrospectively reviewed patients treated at our institution who received definitive or preoperative chemoradiation with either IMRT or 3D conformal radiation therapy (3DCRT) between October 2000 and January 2012. Kaplan Meier analysis and the Cox proportional hazard model were used to evaluate survival outcomes. Results: We evaluated a total of 232 patients (138 IMRT, 94 3DCRT) who received a median dose of 50.4 Gy (range, 44-64.8) to gross disease. Median follow up for all patients, IMRT patients alone, and 3DCRT patients alone was 18.5 (range, 2.5-124.2), 16.5 (range, 3-59), and 25.9 months (range, 2.5-124.2), respectively. We observed no significant difference based on radiation technique (3DCRT vs. IMRT) with respect to median overall survival (OS) (29 vs. 32 months; p=0.78) or median relapse free survival (RFS) (20 vs. 25 months; p=0.74). On multivariable analysis (MVA), not undergoing surgical resection resulted in worse OS (HR 2.255; p <0.0001) and RFS (HR 1.893; p<0.0001). Superior OS was associated on MVA with stage I/II disease (HR 0.523; p=0.010) and tumor length ≤5 cm (HR 0.567; p=0.006). Improved RFS on MVA was associated with stage I/II disease (HR 0.663; p=0.070), tumor length ≤5 cm (HR 0.611; p=0.011), adenocarcinoma histology (HR 0.532; p=0.055), and 3DCRT(HR 0.524; p=0.002). IMRT was also associated on univariate analysis with a significant decrease in acute weight loss (mean 6%+4.3% vs 9%+7.4%, p=0.0001) and on MVA with a decrease in objective grade ≥ 3 toxicity, defined as any hospitalization, feeding tube, or >20% weight loss (OR 0.51; p=0.050). Conclusions: Our data suggest that while IMRT-based chemoradiation for esophageal cancer does not impact survival there was significantly less toxicity. In the IMRT group there was significant decrease in weight loss and grade ≥3 toxicity compared to 3DCRT.