Body mass index and overall survival in patients with gastric cancer: stage-specific associations and prognostic implications
Year: 2026
Type: article
Study design: Observational Study
Abstract: Introduction Nutritional impairment is common in gastric cancer and may affect treatment outcomes and overall survival (OS). However, the prognostic significance of body mass index (BMI), particularly across disease stages, remains uncertain. This study aimed to evaluate the association between baseline BMI and OS, examine potential stage-specific differences, and assess the additional prognostic value of nutritional and functional indicators. Methods This observational cohort study included 380 adults with histologically confirmed gastric cancer, categorized as underweight (BMI <18.5 kg/m 2 ), normal weight (18.5–23.9 kg/m 2 ), overweight (24.0–27.9 kg/m 2 ), or obese (≥28.0 kg/m 2 ). Associations with OS were evaluated using Kaplan–Meier analysis, multivariable Cox regression, BMI-by-stage interaction testing, parsimonious stage-specific sensitivity analyses, and restricted cubic splines. Prognostic performance was assessed using bootstrap-corrected concordance indices (C-indices) and time-dependent areas under the curve (AUCs). Results Among 374 patients included in the primary multivariable analysis, 202 deaths occurred. After adjustment for clinical, nutritional, and treatment-related factors, overweight was associated with lower mortality than normal weight (hazard ratio [HR], 0.62; 95% confidence interval [CI], 0.41–0.93; p = 0.020), whereas underweight and obesity were not significantly associated with OS. The BMI-by-stage interaction was not significant ( p = 0.173). In stage-specific sensitivity analyses, overweight was associated with lower mortality in stage III–IV disease (HR, 0.61; 95% CI, 0.41–0.93), whereas the early-stage estimate for underweight was imprecise (HR, 5.19; 95% CI, 1.42–18.96; 26 deaths). The extended clinical-nutritional model achieved an optimism-corrected C-index of 0.681 after 1,000 bootstrap resamples, compared with 0.646 for the clinical reference model. Its 1-, 3-, and 5-year time-dependent AUCs were 0.744, 0.748, and 0.702, respectively. Discussion Overweight BMI was associated with lower mortality in patients with gastric cancer, while incorporating nutritional and functional indicators modestly improved prognostic discrimination. However, the nonsignificant BMI-by-stage interaction and limited early-stage events preclude definitive conclusions regarding effect modification by disease stage. These findings highlight the potential value of integrating BMI and nutritional assessments into prognostic evaluation.
Source: Frontiers in Nutrition
Institutions: Fujian Medical University, Fujian Provincial Cancer Hospital
Language: English
Subfield: Oncology
Field: Medicine
Domain: Health Sciences
Open Access status: gold
Estimated APC paid: $3,801
Funder: Fujian Medical University
OpenAlex ID: W7223100495