Trajectory of change of low anterior resection syndrome over time after restorative proctectomy for rectal adenocarcinoma

Background Restorative proctectomy for rectal cancer is associated with a high incidence of low anterior resection syndrome (LARS), but few studies report longitudinal results for bowel function. The aim of our study was to examine the trajectory of change of LARS over the first 18 months after restorative proctectomy for rectal cancer. Methods A prospective database measuring functional outcomes in rectal cancer patients from a single university-affiliated specialist colorectal referral center from 10/2018 to 03/2020 was queried. Patients were included in this study if they underwent restorative proctectomy for rectal cancer and had at least three assessments in the first 18 months after primary surgery or after closure of proximal diversion. Bowel function was assessed using the LARS score, administered at every surveillance follow-up after restoration of bowel continuity. Latent-class growth curve (trajectory) analysis was used to identify different trajectories of LARS changes over the first 18 months and group patients into these trajectory groups. These groups were then compared to identify predictors for each trajectory. Results A total of 95 patients were included (63 males, mean age. 61.3 +/- 12.5 years). Trajectory analysis identified three distinct trajectory groups. Group 1 had stable minimal LARS over time (26%). Group 2 had early LARS scores consistent with the minor LARS category and improved with time (28%). Group 3 had persistently high LARS scores (45%). Neoadjuvant therapy, intersphincteric resection, and proximal diversion were more common in group 3. Conclusions We identified three main trajectories of change of LARS in the 18 months after restorative proctectomy. These data may be used to better inform patients of their expected postoperative bowel function.