Cross-sectional areas of rectus abdominis and psoas muscles reduces following surgery in rectal cancer patients.

To evaluate the trophic changes in rectus abdominis and psoas muscles in patients who underwent open or laparoscopic rectum resection for rectal cancer. We retrospectively analyzed preoperative staging computerized tomographies (CT) and postoperative first oncological follow-up CTs of the patients who underwent low anterior resection (LAR) for rectal cancer from 2010 through 2015. We measured cross-sectional area of left and right rectus abdominis muscles from two levels (above and below umbilicus) where they are widest and psoas muscle at mid-level of the fourth lumbar vertebral body in axial CT images and compared preoperative and postoperative measurements. We investigated the effects of age, sex, administration of preoperative chemoradiotherapy (CRT), type of surgery (open or laparoscopic), or construction of a diverting ileostomy on cross-sectional muscle area changes. After applying inclusion and exclusion criteria 60 patients found to be eligible for the study. Muscle areas of all measurement sites were reduced postoperatively compared to paired preoperative values. There was no significant effect of age, sex, administration of preoperative CRT, type of surgery (open or laparoscopic), or construction of a diverting ileostomy to muscle cross-sectional area reductions. Cross-sectional areas of the rectus abdominis and the psoas muscles of rectal cancer patients reduces following rectum resection which indicates atrophy of these muscles. Clinicians should be aware of this problem and focus on prevention of muscle atrophy during the treatment of rectal cancer patients.