Sarcopenia in Patients With Rectal Adenocarcinoma: An Opportunity for Preoperative Rehabilitation

Background Sarcopenia, defined as low skeletal muscle mass, affects up to 60% of rectal adenocarcinoma patients receiving neoadjuvant chemoradiation (NACRT), with negative impact on patient outcomes. Identifying modifiable risk factors may decrease morbidity and mortality. Methods A retrospective review of rectal cancer patients from a single academic center from 2006 to 2020 was performed. Sixty-nine patients with pre- and post-NACRT CT imaging were included. Skeletal muscle index (SMI) was calculated as total L3 skeletal muscle divided by height squared. Sarcopenia thresholds were 52.4 cm 2 /m 2 for men and 38.5 cm 2 /m 2 for women. Student T-test, chi-square test, multivariable regression, and multivariable Cox hazard analysis were performed. Results 62.3% of patients lost SMI from pre- to post-NACRT imaging, with a mean change of −7.8% (±19.9%). Eleven (15.9%) patients were sarcopenic at presentation, increasing to 20 (29.0%) following NACRT. Mean SMI decreased from 49.0 cm 2 /m 2 (95% CI: 42.0 cm 2 /m 2 -56.0 cm 2 /m 2 ) to 38.2 cm 2 /m 2 (95% CI: 33.6 cm 2 /m 2 -42.9 cm 2 /m 2 ) (P = .003). Pre-NACRT sarcopenia correlated with post-NACRT sarcopenia (OR 20.6, P = .002). Percent decrease in SMI was associated with a 5% increased mortality risk. Conclusion The presence of sarcopenia at diagnosis and its association with post-NACRT sarcopenia suggests an opportunity for a high-impact intervention.