Low Skeletal Muscle Mass before Salvage-Line Chemotherapy Is a Poor Prognostic Factor in Patients with Refractory Metastatic Colorectal Cancer.

BACKGROUND

Regorafenib and TAS-102 are standard salvage-line treatment options for patients with chemorefractory metastatic colorectal cancer (mCRC). We aimed to evaluate the prognostic significance of skeletal muscle mass in mCRC patients receiving these salvage-line therapies.

METHODS

We conducted a retrospective analysis of 52 patients with mCRC who received regorafenib or TAS-102 as salvage-line treatment. Skeletal muscle cross-sectional area was measured by pretreatment CT to obtain the skeletal muscle index (SMI, cm2/m2). We divided patients into 2 groups (low-SM/high-SMI) based on the median value of SMI.

RESULT: The median SMI was 51.8 cm2/m2 in males and 39.2 cm2/m2 in females. In Kaplan-Meier analysis, patients in the low-SMI group showed significantly shorter overall survival (3.7 vs. 7.3 months, log-rank p = 0.002) and progression-free survival (1.9 vs. 2.8 months, log-rank test p = 0.009) than those in the high-SMI group. Subsequent multivariate analysis revealed that the SMI was an independent prognostic factor (hazard ratio = 2.381, 95% CI 1.189-4.944, p = 0.014). Patients in the low-SMI group had significantly more grade 3 or 4 adverse events than those in the high-SMI group (46 vs.12%, p = 0.013).

CONCLUSION

Low skeletal muscle mass is a negative factor for survival outcomes in mCRC patients treated with salvage-line chemotherapy.