Visceral obesity, muscle mass and outcome in rectal cancer surgery after neo-adjuvant chemo-radiation.

•Visceral obesity is associated with co-morbidity and poor outcome in rectal cancer surgery.•Visceral obesity is associated with more complications and a longer length of stay in rectal cancer surgery.•Different cut-off values for visceral obesity different associations with outcome were found.•Skeletal muscle area increased during chemoradiation, a phenomenon that remains to be explained.