Overview

Even when patients with rectal cancer have an excellent ontological resection with no anastomotic complications, their bowel function may still be quite different than what they had experienced before they became symptomatic from their rectal cancer. Regardless of the method chosen for rectal reconstruction (e.g., end-to-end, side-to-end, colonic J pouch), 25%–60% of patients undergoing proctectomy will develop low anterior resection syndrome (LARS) in varying degrees of severity.[1][2][3][4][5][6] This syndrome of defecatory dysfunction is defined by a constellation of symptoms that may include frequency, urgency, fragmentation (i.e., bowel movement within 1 hour of the last bowel movement), clustering (multiple small evacuations within a short time period), incomplete evacuation, and fecal incontinence. For some patients, LARS decreases quality of life (QoL) because of “toilet dependence” and fear of leaving the home. LARS is associated with loss of the reservoir function of the resected rectum with impaired capacity and compliance of the neorectum,[7] iatrogenic internal sphincter injury,[8] autonomic nerve injury,[9] loss of neorectum compliance due to neoadjuvant chemoradiation,[6][10] anastomotic leak following rectal resection,[11][12] changes in colonic motility following mobilization of the left colon,[13] and pelvic floor disease existing prior to surgery.[14][15] Anastomotic height is also a risk factor. 46% of patients with a rectal remnant < 4 cm experience major LARS compared with 10% with a rectal remnant ≥4 cm.[16] This finding is more than likely a result of patients with a low colorectal/coloanal anastomosis having a lower maximal tolerated volume.[6] Because of frequency of this complication, the surgeon must mention this possibility with the patient when discussing the preoperative risks and benefits of a sphincter sparing surgery. Patients need to be prepared for the possibility of life-long bowel dysfunction that may require diet limitations, fiber/antidiarrheal agents, biofeedback, and pelvic floor rehabilitation.[17][18]