Clinical Significance of the Psoas Muscle Index in Patients with Locally Advanced Gastric Cancer Receiving Perioperative Chemotherapy

Objective: The psoas muscle index (PMI) obtained with a single muscle measurement on routine computed tomography (CT) performed for staging in locally advanced gastric cancer (LAGC) is helpful in predicting whole-body sarcopenia. The objective of this trial was to determine the relationship between PMI and overall survival (OS) and disease-free survival (DFS). Methods: This retrospective cohort was conducted with 122 patients with LAGC who underwent perioperative chemotherapy and curative surgery in our center between January 2015 and December 2021. PMI and psoas muscle density were calculated at the L3 vertebra level using routine CT performed for staging after the LAGC diagnosis, and its relationship with OS and DFS was examined. Results: Twenty-nine of 122 patients were women. FLOT was the most common chemotherapy regimen and total gastrectomy was performed most frequently. The patients were divided into two groups according to the PMI values. OS and DFS were unachievable in the high PMI group, while OS and PFS were determined as 19 and 16 months, respectively, in the low PMI group. There was a statistically significant difference between the high and low PMI groups in terms of the two survival parameters (p=0.03 and p=0.001, respectively). Conclusion: PMI measured on CT performed for staging in patients diagnosed with LAGC is an important and practical method in predicting the prognosis of the disease. ABSTRACT