The impact of neoadjuvant chemotherapy on skeletal muscle depletion and preoperative sarcopenia in patients with resectable colorectal liver metastases

Background: Preoperative skeletal muscle depletion or sarcopenia has been suggested to predict worse outcome after resection of colorectal liver metastases. The aim of the present study was to investigate the impact of neoadjuvant chemotherapy on preoperative skeletal muscle mass prior to liver resection. Methods: Patients operated with liver resection for colorectal liver metastases between 2010 and 2014 were retrospectively reviewed. Muscle mass was evaluated by measuring muscle area on a cross-sectional computed tomography image at the level of the third lumbar vertebra, and normalized for patient height, presenting a skeletal muscle index. Results: Preoperative skeletal muscle mass was analysed in 225 patients, of whom 97 underwent neoadjuvant chemotherapy. In total 147 patients (65%) were categorized as sarcopenic preoperatively. Patients receiving neoadjuvant chemotherapy decreased in skeletal muscle mass (decrease by 5.5 (-1.1 to 11) % in skeletal muscle index, p < 0.001). Patients with muscle loss >5% during neoadjuvant chemotherapy were less likely to undergo adjuvant chemotherapy than others (68% vs 85%, p = 0.048). A >5% muscle loss did not result in worse overall (p = 0.131) or recurrence-free survival (p = 0.105). Conclusion: Skeletal muscle mass decreases during neoadjuvant chemotherapy. Skeletal muscle loss during neoadjuvant chemotherapy impairs the conditions for adjuvant chemotherapy.