ABSTRACT
BACKGROUND: Accurate preoperative risk assessment for major colorectal cancer (CRC) surgery remains challenging. Body composition (BC) and cardiopulmonary exercise testing (CPET) can be used to evaluate risk. The relationship between BC and CPET in patients undergoing curative CRC surgery is unclear. METHODS: Consecutive patients undergoing CPET prior to CRC surgery between 2010 and 2020 were identified between two different UK hospitals. Body composition phenotypes such as sarcopenia, myosteatosis, and visceral obesity were defined using widely accepted thresholds using preoperative single axial slice CT image at L3 vertebrae. Relationships between clinicopathological, BC, and CPET variables were investigated using linear regression analysis. RESULTS: Two hundred eighteen patients with stage I-III CRC were included. The prevalence of sarcopenia, myosteatosis, and visceral obesity was 62%, 33%, and 64%, respectively. The median oxygen uptake at anaerobic threshold (VO2 at AT) was 12.2 mL/kg/min (IQR 10.6-14.2), and oxygen uptake at peak exercise (VO2 peak) was 18.8 mL/kg/min (IQR 15.4-23). On univariate linear regression analysis, male sex (P < 0.001) was positively associated with VO2 at AT. While ASA grade (P < 0.001) and BMI (P = 0.007) were negatively associated with VO2 at AT, on multivariate linear regression analysis, these variables remained significant (P < 0.05). On univariate linear regression analysis, male sex (P < 0.001) was positively associated with VO2 peak, whereas age (P < 0.001), ASA grade (P < 0.001), BMI (P = 0.003), sarcopenia (P = 0.015), and myosteatosis (P < 0.001) were negatively associated with VO2 peak. On multivariate linear regression analysis age (P < 0.001), ASA grade (P < 0.001), BMI (P < 0.001), and sarcopenia (P = 0.006) were independently and negatively associated with VO2 peak. CONCLUSIONS: The novel finding that sarcopenia is independently associated with reduced VO2 peak performance in CPET supports the supposition that reduced muscle mass relates to poor physical function in CRC patients. Further work should be undertaken to assess whether sarcopenia diagnosed on CT can act as suitable surrogate for CPET to further enhance personalized risk stratification.
ABSTRACT
BACKGROUND & AIMS: Patients with colorectal cancer who are more socio-economically deprived have worse outcomes; deprivation is also associated with higher obesity rates, defined as a body mass index (BMI) of greater than thirty. Body composition (BC) factors such as sarcopenia and myosteatosis are also known to predispose to poorer outcomes following colorectal cancer surgery. There is limited evidence to date to relate the effect of deprivation upon these host characteristics that are linked to prognosis. We aimed to examine the relationship between deprivation and body composition in colorectal cancer. METHODS: Analysis was performed on a prospectively collected database of preoperative primary colorectal cancer patients at St Mark's - The National Bowel Hospital, UK. Body composition characteristics were identified by analysing the L3 axial slices of Computer Tomogram (CT) slices of preoperative staging using Slice-O-Matic software with Automatic Body composition Analyser using Computed tomography image Segmentation (ABACS) L3 plug-in. Deprivation status for each patient was determined using their postal code which was linked to the Index of Multiple Deprivation (IMD). Each domain of the IMD was examined individually in relation to BC characteristics. Binary logistic regression analysis was performed on the data using a model developed from previous published analyses of this dataset. RESULTS: Four hundred and nineteen patients were included in the final analysis, the median age was 69 years and 57% of the patient population was male. Patients who were more deprived were significantly more likely to be sarcopenic [OR 1.56 (95% CI 1.01-2.41, p = 0.045)] and myosteatotic [OR 1.69 (95% CI 1.019-2.81, p = 0.042)]. More deprived patients were also more likely to have a lower BMI [OR 0.60 (95% CI 0.38-0.94, p = 0.026)] despite no significant difference in visceral obesity between the most and least deprived. CONCLUSIONS: Deprivation is an important independent determinant of sarcopenia in the colorectal cancer population. Identifying these patients early and addressing reversible factors may help improve post-operative surgical outcomes in this poor prognostic group. Sarcopenia may be a premorbid state in the deprived colorectal cancer patient that may not be wholly driven by tumour characteristics.
