Prognostic Role of the Total Psoas Area Index (TPAI) and Its Association with Survival After Gastric Cancer Surgery

Objectives: Gastric cancer is one of the leading causes of cancer-related mortality. Sarcopenia, characterized by reduced skeletal muscle mass, strength, and physical performance, is associated with poorer outcomes in gastrointestinal cancers. This study aimed to evaluate the prevalence of sarcopenia, including the Total Psoas Area Index (TPAI), and its association with tumor stage, postoperative complications, and survival in patients with gastric adenocarcinoma. Methods: A retrospective study was conducted, including 79 patients who underwent surgery for gastric adenocarcinoma. Sarcopenia was assessed using a combination of CT-derived muscle mass (TPAI), muscle strength (dynamometry), and functional status (SARC-F). Patients were divided into sarcopenic (SG) and non-sarcopenic (NSG) groups. Clinical and survival data were compared between groups. Results: Sarcopenia was identified in 36.7% of patients. Early-stage disease (I–II) was less frequent in the SG (20.7%) compared to the NSG (44%), whereas stage IV tumors were more common in the SG (20.7% vs. 6%). Sarcopenic patients had a lower body mass index and underwent fewer laparoscopic procedures (44.8% vs. 68%, p = 0.03). Postoperative complications, such as pneumonia and ileus, were more frequent in the SG. Overall survival was significantly lower in the SG (17 vs. 21 months, respectively, p = 0.042), with a reduction in disease-free survival as well. Postoperative TPAI values remained lower in the SG. Conclusions: Sarcopenia, as defined by combined assessment including TPAI, was associated with advanced tumor stage, increased postoperative risk, and reduced survival in patients with gastric cancer. Preoperative assessment of muscle mass may help identify high-risk patients and optimize clinical management.