In this population-based analysis, IMRT use was significantly associated with improved overall survival and reduced cardiac mortality in patients with esophageal cancer.
Steven H. Lin, MD, PhD, Ning Zhang, PhD, Joy Godby, BS, Jingya Wang, MD, Gary D. Marsh, BS, Zhongxing Liao, MD, Ritsuko Komaki, MD, Linus Ho, MD, Wayne L. Hofstetter, MD, Stephen G. Swisher, MD, Thomas A. Buchholz, MD, Linda S. Elting, PhD, Sharon H. Giordano, MD; UT MD Anderson Cancer Center
PURPOSE: We performed a population-based assessment for the all-cause and cardiopulmonary mortality risk in esophageal cancer (EC) patients treated with chemotherapy and radiation, comparing conventional radiotherapy (CRT) or advanced radiation modality defined by the use of intensity-modulated radiation therapy (IMRT).
PATIENTS AND METHODS: We identified 2,578 patients aged over 65 years from the Surveillance, Epidemiology, and End Results (SEER)/Texas Cancer Registry-Medicare databases who had nonmetastatic EC diagnosed between 2002 and 2009 (CRT = 2,265; IMRT = 313). We defined radiation modality by delivery claims, whether it was by conventional radiation therapy, which could either have been two-dimensional (2D) or three-dimensional (3D) (CRT: Healthcare Common Procedure Coding System [HCPCS]: 77401–77416) or by IMRT delivery (HCPCS: 77418, G0174) within 6 months of diagnosis. Patients in both cohorts were compared using propensity score–based adjustment. Cause-specific and overall mortality rates were evaluated using Kaplan-Meier LIFETEST and a multivariate (MVA) Cox proportional hazards model.
RESULTS: Except for marital status and SEER region, both radiation cohorts were well balanced for various patient, tumor, and treatment characteristics, including the distribution of the use of IMRT vs CRT in urban/metropolitan or rural areas. CRT was done primarily by 3D delivery (98.9%). IMRT use increased from 2.6% in 2002 to 30% in 2009, while 3D use decreased from 97.4% in 2002 to 70% in 2009. In the unadjusted analysis, all-cause mortality, EC-specific mortality, and cardiac mortality were significantly reduced in the IMRT group (all: 52.4% vs 74.5%, P < .0001; EC: 40.3% vs 55.6%, P < .0001; and cardiac: 1.6% vs 5.3%, P = .0043). However, no difference was seen in deaths from pulmonary (0.96% vs 1.55%; P = .419) or other causes (9.6% vs 12.1%; P = .204). On propensity score–adjusted MVA, IMRT was not associated with EC-specific mortality (hazard ratio [HR] = 0.87; 95% confidence interval [CI], 0.69–1.06), pulmonary (HR = 1.04; 95% CI, 0.29–3.79), or other-cause mortality (HR = 0.81; 95% CI, 0.54–1.22) but was significantly associated with higher overall survival (HR = 0.83; 95% CI, 0.70–0.98) and lower cardiac mortality (HR = 0.35; 95% CI, 0.14–0.88). Similar associations were seen even after adjusting for physician experience, the type of chemotherapy used, and sensitivity analysis removing hybrid radiation claims.
CONCLUSION: In this population-based analysis, IMRT use was significantly associated with improved overall survival and reduced cardiac mortality in patients with esophageal cancer.
Proceedings of the 97th Annual Meeting of the American Radium Society- americanradiumsociety.org