Bowel Function in Survivors of Rectal Cancer Managed with Watch-and-Wait Versus Surgery

Background: Sphincter-preserving surgery for rectal cancer is associated with long-term bowel dysfunction, yet data on outcomes in patients managed with watch-and-wait is limited. This study compared bowel function in rectal cancer survivors managed with watch-and-wait versus sphincter-preserving surgery and evaluated the performance of two instruments: the Memorial Sloan Kettering Bowel Function Instrument (MSK-BFI) and the Low Anterior Resection Syndrome (LARS) score within each cohort. 

Patients and Methods: In this cross-sectional study, rectal cancer survivors treated with long-course chemoradiotherapy between 2011 and 2019 at Flinders Medical Centre were recruited. Participants without stomas completed the MSK-BFI, LARS, and comorbidity questionnaires. Demographics and clinical data were obtained from medical records. Outcomes were compared between the sustained watch-and-wait (WW) and surgical (SURG) cohorts. Associations were examined using regression models. Instrument comparisons were performed in each cohort using factor analysis. 

Results: Of the 190 eligible survivors, 67 participants were included (WW, n=33; SURG, n=34). Surgery was associated with significantly worse bowel function across MSK-BFI domains and higher rates of Any LARS (91% vs. 67%) and Major LARS (70% vs. 36%). Female sex was independently associated with poorer bowel function. Factor analysis revealed that one factor accounted for bowel function in the SURG cohort, whereas two factors were required in the WW cohort, indicating greater complexity. 

Conclusion: Surgery and female sex are associated with significantly worse bowel function in rectal cancer survivors. The WW cohort demonstrated more complex symptom patterns, supporting concurrent use of MSK-BFI and LARS until a WW-specific tool is developed. A larger, prospective study is underway to investigate the findings further.