Treatment burden following standard of care open versus robotic D2 gastrectomy plus neoadjuvant chemotherapy (NAC) for locally advanced gastric cancer (LAGC).

Abstract

303 Background: Phase III trials demonstrate improved short-term outcomes after laparoscopic gastrectomy for LAGC compared to open. We hypothesized that robotic D2 gastrectomy after NAC (NAC/RG) yields benefits across multiple outcome domains vs standard of care treatment for LAGC. Methods: Single institution, interrupted time series comparing SOC plus open gastrectomy (OG,2008-2013) for LAGC (T2-4Nany/TanyN+) vs universal neoadjuvant plus RG (2013-2018). Treatment burden was a composite of adverse events affecting: efficiency (postoperative length of stay, reoperation or 90 d readmission), oncology (positive margins, < 16 resected nodes), cumulative major morbidity (90 d comprehensive complication index) and pain (narcotic consumption). Predictors were evaluated via multivariate modeling, and 2-year overall survival was estimated by Kaplan-Meier/log-rank tests. Results: After exclusions, 87 subjects underwent surgical resection (55 OG; 32 RG) with equivalent baseline characteristics: demographics, BMI, comorbidity (Charlson), tumor size, and clinical AJCC staging; male sex was more likely in RG (69% vs. 44%, p = 0.02). NAC administration increased from 35% in SOC/OG cohort to 100% in NAC/RG. All four domains of efficiency, oncologic efficacy, morbidity, and pain (narcotic use) improved. Treatment burden declined from 86% in OG to 56% after RG (p = 0.003). Multivariable modeling demonstrated OR 0.23 for treatment burden in RG compared to OG (95% CI 0.07-0.72, p = 0.012), whereas sex, extent of resection (total vs subtotal), tumor size, and T stage had no effect. These differences persisted in NAC subgroup (n = 51) comparisons between RG and OG treatment burden, as well as pathologic T stage, tumor size, and AJCC stage. No detriment in 2-year overall survival was observed after adoption of NAC/RG (80% RG vs. SOC 60%, p = 0.048). Conclusions: After NAC, robot-assisted D2 gastrectomy was associated with decreased treatment burden relative to OG. Frequencies of unfavorable hospitalization, adverse oncological outcomes, major morbidity, and narcotic consumption all improved after RG in this interrupted time series. Prospective trials are needed.