Diagnosis and prevalence of sarcopenic obesity in patients with colorectal cancer: A scoping review

Sarcopenic obesity (SO) is associated with worse outcomes in patients with colorectal cancer (CRC); however, the diagnostic methods and prevalence of SO vary among studies. Therefore, we conducted this scoping review to investigate the diagnosis of SO in CRC, identify the associated problems, and determine its prevalence.A systematic review was conducted according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses Extension for Scoping Reviews reporting guidelines. A literature search was performed by two independent reviewers on studies that diagnosed SO in CRC using the MEDLINE, EMBASE, CINAHL, CENTRAL, Web of Science, and Ichushi-Web (in Japanese) databases. Observational, longitudinal, cross-sectional, and clinical trials written in English or Japanese as of July 2022 were included. Studies that did not define SO were excluded from the analysis. The study protocol was pre-registered in Figshare.In total, 670 studies were identified, 22 of which were included. Eighteen studies used sarcopenia in combination with obesity to diagnose SO. Sarcopenia was mainly diagnosed using skeletal muscle mass index (SMI), and only one combined with grip strength or gait speed. Obesity was diagnosed based on the body mass index (BMI; n = 11), followed by visceral fat area (VFA; n = 5). The overall prevalence of SO in patients with CRC was 15% (95%CI, 11-21%). The prevalence of SO in surgical resection and colorectal cancer liver metastases was 18% (95%CI, 12-25%) and 11% (95%CI, 3-36%), respectively.SO in patients with CRC was mainly diagnosed based on a combination of SMI and BMI, and muscle strength and body composition were rarely evaluated. The prevalence of SO was approximately 15%, depending on the diagnostic methods used. Since SO in patients with CRC is associated with poor prognosis, further research on diagnostic methods for the early detection of SO and its clinical outcomes is needed.