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/m for men and 38.5 cm/m 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/m (95% CI: 42.0 cm/m-56.0 cm/m) to 38.2 cm/m (95% CI: 33.6 cm/m-42.9 cm/m) (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.