Role of body composition in early stage colorectal cancer (CRC) outcomes

Abstract

Background: CRC is the 3rd most common cancer worldwide. Novel prognostic factors are needed to allow practitioners to stratify and personalize treatment and surveillance options to patients (pts). The objective of this study was to determine associations between body composition and disease-specific outcomes in early stage CRC. We hypothesized that pts with sarcopenia or reduced muscle radiodensity (SMD) at time of surgery will have worse overall outcomes, specifically in their 5-year overall (OS) and disease free survival (DFS). Also, that pts with accelerated skeletal muscle loss at their 2-year surveillance computed tomography (CT) scan will have higher recurrence rates. Methods: This is a retrospective cohort study of early stage (I-III) CRC from 2007-09. We excluded any pt without analyzable or preoperative CT scan or if a prior diagnosis of CRC. Routine CT imaging was used to measure skeletal muscle (SMA). Total body SMA was normalized for height (skeletal muscle index, SMI). An SMI <52.4 cm2/m2 and<38.5 cm2/m2 was used as a cutoff for sarcopenia in men and women, respectively. Mean muscle radiodensity inHU was obtained as a measure of myosteatosis. Results: A total of 2049 pts were identified, of which 1455 had available, analyzable imaging. The cohort was 59% male. The median age was 67 yrs with over 50% older than 65. Most pts presented with stage II-III disease (39%, 50%, respectively). The prevalence of sarcopenia was 45.0% in females and 56.2% in males, with an average SMI of 40 and 51 cm2/m2, respectively. Average SMD was 31.5 HU for females and 33.2 HU for males. Pts with disease recurrence had a significantly lower SMI (49 vs. 42 cm2/ m2, p<0.001). Pts with recurrence also had lower HU (33.3 vs. 30.3 HU, p=0.001). The median time to recurrence was 538 days and average length of follow up was 5 yrs. Data collection and analysis is currently ongoing.We anticipate that pts with disease recurrence within 5 yrs of diagnosis will have a significantly faster rate of muscle loss. Conclusions: Our study demonstrates for the first-time body composition's ability to predict recurrence of a solid tumor after curative surgery. Pts with reduced overall SMI and SMD had increased risks of disease recurrence. These findings if validated may allow better stratification of treatment and surveillance of CRC pts.