Computed Tomography-Defined Fat Composition as a Prognostic Marker in Gastric Adenocarcinoma: A Systematic Review and Meta-Analysis

Background: Computed tomography (CT)-defined fat quantification has been an emergent field of research in oncology. It was shown that this parameter is predictive and prognostic of several clinically relevant factors in several tumor entities. Objective: Our aim was to establish the effect of visceral (VFA) and subcutaneous fat areas (SFA) on overall survival (OS), disease-free survival (DFS), and postoperative complications in gastric cancer patients based on a large patient sample. Methods: MEDLINE library, EMBASE, and SCOPUS databases were screened for the associations between VFA and SFA defined by CT images and OS, DFS, and postoperative complications in gastric cancer patients up to August 2022. The primary endpoint of the systematic review was the hazard ratio for the outcome parameters. High VFA was, in most studies, defined by the threshold value of 100 cm2. In total, 9 studies were suitable for the analysis and included in the present study. Results: The included studies comprised 3,713 patients. The identified frequency of visceral obesity was 44.9%. The pooled hazard ratio for the effect of high VFA on OS was 1.28 (95% CI 1.09–1.49, p = 0.002). For SFA, it was 1.87 (95% CI 1.45–2.42, p < 0.0001). The pooled hazard ratio for the influence of high VFA on DFS was 1.17 (95% CI 0.95–1.43, p = 0.14). The pooled odds ratio for the associations between VFA and postoperative complications was 1.36 (95% CI 1.09–1.69, p = 0.006). Conclusion: CT-defined VFA and SFA influence OS in patients with gastric cancer. VFA also influences the occurrence of postoperative complications. Therefore, assessment of fat areas should be included in clinical routine in patients with gastric cancer.