Predictors of pre- and post-treatment bowel dysfunction severity in patients with rectal cancer

Treatment of rectal cancer is frequently associated with low anterior resection syndrome. However, data concerning the contribution rectal tumors have on pretreatment bowel-dysfunction is scarce. We sought to evaluate the impact of the untreated rectal cancer on bowel-dysfunction and the relationship of pretreatment and post-treatment function.

A prospective database of adults with rectal cancer at a single university-affiliated colorectal referral center from August 2018 to March 2022 was queried. Bowel-dysfunction was measured using the low anterior resection syndrome score questionnaire (categorized as no, minor, or major low anterior resection syndrome) which was provided to patients at their primary visit, and after treatment. Patients were included if they underwent rectal cancer treatment and had pre- and post-treatment low anterior resection syndrome measurements. Observed low anterior resection syndrome scores were compared to normative low anterior resection syndrome data for age and sex-specific distributions from published data. Multiple multinomial regression compared pre- and post-treatment low anterior resection syndrome scores.

Overall, 121 patients were included with mean age 62.0 years (standard deviation 12.3), 74% male, and mean tumor height 8.7 cm (standard deviation 5.72). The proportion of pretreatment observed low anterior resection syndrome were 48% no low anterior resection syndrome, 28% minor, and 24% major. Male and older patients were more likely to have worse than predicted low anterior resection syndrome categories (P < .05). On average, low anterior resection syndrome category did not change after treatment (P = .618) and pretreatment low anterior resection syndrome category was a significant independent predictor of post-treatment category (P = .037).

Pretreatment bowel-dysfunction in rectal cancer patients is common and significantly worse than predicted for older and male patients. Importantly, pretreatment bowel-dysfunction predicted postoperative function. These results may better inform the shared decision-making process.