Definitive Chemoradiation for Rectal Cancer: Is There a Role for Dose Escalation? A National Cancer Database Study

BACKGROUND: Surgery remains the standard of care in rectal cancer. Select patients will not undergo surgery for reasons such as medical inoperability or a watch-and-wait approach and instead are managed with definitive chemoradiation. OBJECTIVE: We used the National Cancer Database to identify overall survival and predictors thereof in the nonoperative management of patients with rectal cancer. DESIGN: This was a retrospective review. SETTINGS: This study used deidentified data from the National Cancer Database. PATIENTS: We queried the national cancer database from 2004 to 2014 for stage 1 to 3 rectal adenocarcinoma treated with only chemotherapy and radiation to definitive doses. Dose escalated therapy was defined as >54 Gy. MAIN OUTCOME MEASURES: Univariable and multivariable analyses were performed to identify sociodemographic, treatment, and tumor characteristics predictive of dose escalation and overall survival. Propensity-adjusted Cox proportional hazard ratios for survival were used to account for indication bias. RESULTS: Among the 6311 patients eligible for the study, 11% were treated with doses >54 Gy. Earlier stage and increased age/comorbidity patients were more likely to receive dose escalation, and patients with more recent treatment and treatment at an academic facility were less likely. The median follow-up time was 31 months (range, 2-154 mo). Three- and 5-year overall survival rates for all patients were 60% and 46%. Patients treated with dose escalation had a median survival of 33 months compared with 56 months for those treated with <= 54 Gy (p < 0.0001). LIMITATIONS: The main limitation is the inherent selection bias present in National Cancer Database studies. Important treatment details and outcomes as they relate to a definitive chemoradiation approach in rectal cancer are lacking. Salvage therapy was also not recorded, which in this population could be surgery. CONCLUSIONS: In this analysis, dose escalation in the nonoperative management of rectal cancer was associated with a lower overall survival compared with more conventional doses. Careful patient selection and enrollment on appropriate clinical trials may be warranted in the nonoperative setting. See Video Abstract at http://links.lww.com/DCR/B15.