Gain of visceral adipose tissue rather than low skeletal muscle mass is associated with overall survival in patients with colorectal liver metastases; results from the NewEPOC study

Introduction Sarcopenia and adiposity at diagnosis are important prognostic factors in cancer. Ongoing changes in body composition during chemotherapy treatment may have additional prognostic relevance. This study aimed to investigate the association between body composition changes during neoadjuvant treatment and survival in patients with colorectal liver metastases. Materials & methods In this subgroup analysis of the newEPOC RCT (NCT00482222), pre- and post-treatment CT-scans of patients undergoing neoadjuvant chemotherapy for colorectal liver metastases were studied. The total cross-sectional area of skeletal muscle tissue (SM), Visceral Adipose Tissue (VAT), Subcutaneous Adipose Tissue (SAT), Intra-Muscular Adipose Tissue (IMAT), and radiation attenuation for skeletal muscle (SM-RA) were determined. Results During neoadjuvant therapy, SM-index decreased from 50.6 +/- 8.7 to 47.6 +/- 8.6 cm(2)/m(2), p < 0.001 for men and 40.5 +/- 6.1 to 37.7 +/- 5.9 cm(2)/m(2), p = 0.002, for women. SM-RA decreased from 37.7 +/- 7.8 to 36.0 +/- 7.6 HU, p < 0.001 for men. VAT- and SAT-indices did not change significantly during treatment. Sarcopenia, SM-loss, SM-RA as baseline as well as change in SM-RA were not associated with overall survival, while intervention arm (HR1.96, 95 %CI1.21-3.19, p = 0.009), undergoing resection of the metastases (HR0.19, 95 %CI0.09-0.40, p < 0.001) and gaining >2 % VAT-index over 12 weeks (HR2.05, 95 %CI1.12-3.76, p = 0.025) were. Conclusions The body composition features SM and SM-RA decreased during chemotherapy, but were not associated with survival. On the contrary, although VAT did not significantly change, the gain of VAT was an independent prognostic factor for survival. These results should be validated in independent cohorts but may indicate that in this selected patient group, adipose tissue might be a more important prognostic factor than sarcopenia.