Survival After Trimodality Therapy in Patients With Locally Advanced Esophagogastric Adenocarcinoma: Does Only a Complete Pathologic Response Matter?

To evaluate whether pCR exclusively defines major pathologic response to treatment with improved survival. pCR after trimodality therapy for EAC is infrequent but associated with improved prognosis. Yet most clinical trials and correlative studies designate pCR as the primary endpoint. We analyzed our prospectively maintained database for patients who underwent trimodality therapy for locally advanced esophageal adeno-carcinoma between 1995 and 2017. Overall survival (OS) was examined by percentage TR in the primary tumor bed and pathologic nodal stage (ypN0) using Kaplan-Meier plots. Optimal thresholds of TR for differentiating patients in terms of OS were investigated with descriptive plots using restricted cubic spline functions; associations were quantified using Cox multivariable analysis. Among 788 patients, median follow-up was 37.5 months (range, 0.4210.6); median OS was 48.3 months (95% CI, 42.2-58.8). Absence of residual nodal disease was independently associated with improved survival ( P < 0.001). Survival curves for 90% to 99% TR and 100% TR were similar, and a change in probability of improved OS was observed at 90% TR. On multivariable analysis, combining 90% to 99% and 100% TR was independently associated with improved OS, compared with 50% to 89% and 90% TR in the primary tumor bed. These findings may allow the definition of major pathologic response to be expanded, from pCR to > 90% TR and ypN0. This has meaningful implications for future clinical trials and correlative studies.