Prognostic Value of Baseline Skeletal Muscle Index in Colorectal Cancer Patients Treated with Fruquintinib: A multi-center real world analysis.

Background: The Skeletal Muscle Index (SMI) serves as an objective metric for assessing nutritional status in patients with malignant tumors. Research has found baseline nutritional status can influence both the efficacy and prognosis of targeted anti-tumor therapies, with growth factor tyrosine kinase inhibitors frequently inducing drug-related sarcopenia. Fruquintinib has received approval for the treatment of metastatic colorectal cancer. This study examines the prognostic significance of baseline SMI in patients with metastatic colorectal cancer undergoing treatment with fruquintinib. Additionally, the study investigates the incidence of SMI reduction following fruquintinib therapy to assess its impact on patient prognosis.

Methods: A retrospective multicenter study was conducted to analyze patients with metastatic colorectal cancer who received fruquintinib treatment across eight medical centers in Eastern China. The muscle area at the third lumbar vertebra was assessed, and both baseline and post-treatment SMI values were calculated independently. The relationship between SMI and patient survival was subsequently examined.

Results: The median progression-free survival (PFS) for the cohort of 105 patients was 4.2 months (95% CI, 3.7 to 4.9 months), while the median overall survival (OS) was 10.2 months (95% CI, 9.0 to 12.7 months). Notably, the baseline SMI prior to the initiation of fruquintinib therapy exhibited a significant correlation with OS (P = 0.0077). Multivariate analysis indicated that baseline SMI serves as an independent prognostic factor for OS (P = 0.005). Furthermore, after Propensity Score Matching (PSM) analysis, there was still a significant correlation between baseline SMI and OS. Among the patients, 28.87% developed sarcopenia following oral administration of fruquintinib. However, no statistically significant difference in OS was observed between the group with reduced SMI and the group without SMI reduction after treatment with fruquintinib.

Conclusion: The baseline SMI was identified as an independent prognostic factor for OS and may influence the survival outcomes of patients with metastatic colorectal cancer undergoing treatment with fruquintinib. Despite the potential of fruquintinib to induce sarcopenia, no significant correlation was observed between changes in SMI following treatment and patient survival.