Multi-institutional analysis of radiation modality use and postoperative outcomes of neoadjuvant chemoradiation for esophageal cancer.

PURPOSE: Relative radiation dose exposure to vital organs in the thorax could influence clinical outcomes in esophageal cancer (EC). We assessed whether the type of radiation therapy (RT) modality used was associated with postoperative outcomes after neoadjuvant chemoradiation (nCRT).

PATIENTS AND METHODS: Contemporary data from 580 EC patients treated with nCRT at 3 academic institutions from 2007 to 2013 were reviewed. 3D conformal RT (3D), intensity modulated RT (IMRT) and proton beam therapy (PBT) were used for 214 (37%), 255 (44%), and 111 (19%) patients, respectively. Postoperative outcomes included pulmonary, GI, cardiac, wound healing complications, length of in-hospital stay (LOS), and 90-day postoperative mortality. Cox model fits, and log-rank tests both with and without Inverse Probability of treatment Weighting (IPW) were used to correct for bias due to non-randomization.

RESULTS: RT modality was significantly associated with the incidence of pulmonary, cardiac and wound complications, which also bore out on multivariate analysis. Mean LOS was also significantly associated with treatment modality (13.2days for 3D (95%CI 11.7-14.7), 11.6days for IMRT (95%CI 10.9-12.7), and 9.3days for PBT (95%CI 8.2-10.3) (p<0.0001)). The 90day postoperative mortality rates were 4.2%, 4.3%, and 0.9%, respectively, for 3D, IMRT and PBT (p=0.264).

CONCLUSIONS: Advanced RT technologies (IMRT and PBT) were associated with significantly reduced rate of postoperative complications and LOS compared to 3D, with PBT displaying the greatest benefit in a number of clinical endpoints. Ongoing prospective randomized trial will be needed to validate these results.