Postoperative weight loss and survival after curative resection for gastric cancer in elderly patients

Weight loss after gastrectomy for gastric cancer is common and elderly patients are particularly vulnerable. This study aimed to investigate the association between postoperative weight loss and overall survival (OS) in elderly patients undergoing curative gastrectomy for primary gastric cancer. We retrospectively analyzed 378 patients aged ≥ 70 who underwent gastrectomy at Boramae Medical Center between 2013 and 2022. Preoperative weight, BMI and postoperative changes at 3, 6, and 12 months were collected. After patients were stratified into the E group (n = 289, aged 70 ~ 79) and the ME group (n = 89, aged ≥ 80), survival analysis were performed. Mean weight loss t 1 month and 3 months postoperatively were greater in the E group than in the ME group (4.4 kg vs. 3.3 kg, P = 0.003 and 5.2 kg vs. 4.2 kg, P = 0.04, respectively). Mean weights in both groups remained relatively stable from 6 months through 24 months. However, the percentage of weight loss from the preoperative weight at 1 month was higher in the ME group (P = 0.014). In multivariate analysis of all patients, ECOG performance status (≥ 2), invasive surgery (open surgery), tumor stage (stage II/III) and weight loss > 15% at 6 months postoperatively (Yes) were independent prognostic factors for OS (HR (95% Confidence Interval (CI) 12.964 (2.982–56.369), P = 0.001, HR (95% CI) 2.491 (1.088-5.700), P = 0.031, HR (95% CI) 6.960 (2.742–17.664), P < 0.001, and HR (95% CI) 3.603 (1.617–8.030), P = 0.002, respectively). Multivariate subgroup analysis revealed that weight loss > 15% of preoperative weight at 6 months postoperatively, along with tumor stage (I vs. II/III) were independent predictors for 5-year OS in the E group (HR (95% CI) 2.887 (1.171–7.113) P = 0.021, HR (95% CI) 9.125 (2.862–29.091) P < 0.001, respectively). In elderly patients, weight loss exceeding 15% of preoperative weight at 6 months after curative gastrectomy for gastric cancer is associated with poorer OS, which emphasize the importance of close monitoring in these patients.