Association of Body Composition Parameters with the Short- and Long-Term Efficacy of Neoadjuvant Immunotherapy Combined with Chemotherapy in Advanced Gastric Cancer.

Abstract

Background: Immunotherapy has become a prevalent strategy in the neoadjuvant treatment of advanced gastric cancer (AGC). This study investigates the predictive value of computed tomography (CT)-derived body composition parameters on the efficacy of neoadjuvant immunotherapy for AGC.

Methods: Data on 103 patients with resectable AGC who received neoadjuvant immunotherapy combined with chemotherapy at a teaching hospital between March 2020 and August 2022 were collected. Body composition parameters, including the subcutaneous adipose index (SAI), visceral adipose index (VAI), and skeletal muscle index (SMI), were calculated from pretreatment CT images. Logistic regression and Cox proportional hazards models assessed the impact of these parameters on pathological responses and survival outcomes following treatment.

Results: Of the patients, 34 (33.0%) achieved a major pathological response (MPR). Higher SAI, VAI, and SMI values were significantly linked to an increased likelihood of achieving MPR (p < 0.05). Multivariate regression analysis revealed that only SAI independently predicted MPR (OR 1.042, 95% CI 1.009-1.077, p = 0.013). Furthermore, patients with a high SAI had significantly improved 2-year overall survival (76.9% vs. 54.9%, log-rank p = 0.012) and 2-year event-free survival (71.2% vs. 51.0%, log-rank p = 0.022) compared to those with low SAI. The survival benefit associated with high SAI was partly due to its higher MPR rate (mediating proportion: 37.5%, 95% CI: 12%-110%).

Conclusion: Pretreatment SAI independently correlates with MPR and better oncological outcomes in patients with AGC receiving neoadjuvant immunotherapy.