Induction therapy for locally advanced distal esophageal adenocarcinoma: Is radiation Always necessary?

Abstract

ObjectiveTo compare outcomes between induction chemotherapy alone (ICA) and induction chemoradiation (ICR) in patients with locally advanced distal esophageal adenocarcinoma. MethodsPatients in the National Cancer Database treated with ICA or ICR followed by esophagectomy between 2006 and 2012 for cT1-3N1M0 or T3N0M0 adenocarcinoma of the distal esophagus were compared using logistic regression, Kaplan-Meier analysis, and Cox proportional hazards methods. ResultsThe study group included 4763 patients, of whom 4323 patients (90.8%) received ICR and 440 patients (9.2%) received ICA. There were no differences in age, sex, race, Charlson Comorbidity Index, treatment facility type, clinical T or N status between the 2 groups. Tumor size ≥5 cm (odds ratio, 1.46; P = .006) was the only factor that predicted ICR use. Higher rates of T downstaging (39.7% vs 33.4%; P = .012), N downstaging (32.0% vs 23.4%; P < .001), and complete pathologic response (13.1% vs 5.9%; P < .001) occurred in ICR patients. Positive margins were seen more often in ICA patients (9.6% vs 5.5%; P = .001), but there was no difference in 5-year survival (ICR 35.9% vs ICA 37.2%; P = .33), and ICR was not associated with survival in multivariable analysis (hazard ratio = 1.04; P = .61). ConclusionsICR for locally advanced distal esophageal adenocarcinoma is associated with a better local treatment effect, but not improved survival compared with ICA, which suggests that radiation can be used selectively in this clinical situation.