Impact of sarcopenia on outcomes in patients with rectal carcinoma treated with trimodality therapy.

687Background: Sarcopenia has been identified as a negative prognostic factor in several gastrointestinal malignancies. We sought to evaluate whether total psoas area (TPA) was predictive of grade ≥ 3 toxicity, recurrence and overall survival in patients with rectal carcinoma who received tri-modality therapy. Methods: After IRB approval, a retrospective analysis of 112 patients with biopsy-proven rectal cancer treated with neoadjuvant chemoradiation followed by surgery and adjuvant chemotherapy was performed. The L4 vertebra was identified on pre-treatment axial CT and the bilateral psoas muscles were manually contoured to determine the skeletal muscle index, which was normalized by height. Sarcopenia was defined as TPA less than the median of the cohort. (< 1463 mm3/m). Acute toxicity was defined as within 3 months of radiation based on Common Terminology Criteria for Adverse Events version 4. Chi-square was used to assess differences between groups. Time to event analysis was estimated by Kaplan-Meier ...