Background/aim: Reduction in skeletal muscle mass during chemotherapy is associated with poor outcomes. This study investigated the impact of changes in the psoas muscle index (PMI) on the prognosis of patients with unresectable colorectal liver metastases (CRLM) undergoing chemotherapy, including subgroup analyses based on the initial treatment response assessment.
Patients and methods: We evaluated 47 patients with unresectable CRLM who underwent systematic chemotherapy and assessed changes in PMI to determine their prognosis.
Results: Changes in PMI were significantly associated with the presence or absence of primary tumor resection and the chemotherapeutic responses to first-line chemotherapy. The PMI reduction group was significantly associated with poor prognosis in both overall survival (OS) and progression-free survival (PFS) in patients with CRLM, and in both OS and PFS in the partial response (PR) group at the initial chemotherapy response assessment.
Conclusion: Skeletal muscle loss at chemotherapy initiation was significantly associated with poorer survival in patients with unresectable CRLM. Maintaining muscle mass could serve as a new indicator for identifying patients with a PR at the initial chemotherapy response assessment for prognosis. Personalized interventions should be investigated to determine whether they can improve muscle mass and lead to better clinical outcomes.
Keywords: Colorectal cancer; chemotherapy; liver metastases; prognosis; psoas muscle index; skeletal muscle mass; systemic therapy.
©2025 The Author(s). Published by the International Institute of Anticancer Research.