Can sarcopenia be a predictor of prognosis for patients with non-metastatic colorectal cancer? A systematic review and meta-analysis

We aimed to explore whether sarcopenia diagnosed with the third lumbar vertebra skeletal muscle index (L3 SMI) can be a predictor of prognosis for colorectal cancer (CRC) patients. A systematic review and meta-analysis was conducted using PubMed, Embase, and the Web of Science databases. All original comparative studies published in English that were related to sarcopenia versus non-sarcopenia in non-metastatic CRC patients based on postoperative and survival outcomes were included. Data synthesis and statistical analysis were carried out using Stata software. A total of 12 studies including 5337 patients were included in our meta-analysis. In our overall analyses of postoperative outcomes, we indicated that CRC patients with sarcopenia would have longer hospital stays, higher incidence of total postoperative morbidity (OR = 1.70, 95% CI = 1.07-2.70, P < 0.01), mortality (OR = 3.45, 95% CI = 1.69-7.02, P < 0.01), and infection (OR = 2.21, 95% CI = 1.50-3.25, P < 0.01) but not anastomosis leakage or intestinal obstruction when compared to non-sarcopenia patients. Regarding survival outcomes, our results showed that sarcopenia predicted a decreased overall survival (HR = 1.63, 95% CI = 1.24-2.14, P < 0.01), disease-free survival, and cancer-specific survival for non-metastatic CRC patients. Moreover, our subgroup analyses showed similar tendency with our overall analyzed results. Sarcopenia diagnosed with L3 SMI can be a negative predictor of postoperative and survival outcomes for non-metastatic CRC patients. Prospective studies with a uniform definition of sarcopenia are needed to update our findings.