S460 Utility of DRE in Cancer Patients: Has It Lost Its Touch?

Introduction: Digital rectal exam (DRE) is highly sensitive in identifying dyssynergic defecation (DD) in patients with constipation. However, its accuracy has not been determined in cancer patients, in whom it is possible that interventions such as pelvic radiation or lower GI surgeries may render DRE less reliable due to potential sensory and anatomic changes. This study aims to investigate the diagnostic yield of DRE in patients receiving care at a tertiary cancer center with a history of pelvic radiation or cancer-related lower abdominal surgeries who have undergone anorectal manometry (ARM). Methods: We conducted a single-center, retrospective review of adult patients referred to the GI motility clinic for bowel complaints between July 2024 and May 2025. Among all the pts referred for constipation (eg: straining, incomplete evacuation, splinting), fecal incontinence, or rectal pain, 33 had relevant abdominopelvic cancer history and were treated with pelvic radiation, lower abdominal surgery, or both as part of their cancer therapy. Results: Thirty-three patients (23F/10M) with mean age of 63 years were included in our analysis. Twenty-five (75%) had constipation and 7 (21%) presented with fecal incontinence. DRE was abnormal in 92% of patients with constipation and 85.7% of patients with fecal incontinence. All 33 were subsequently confirmed to have DD on ARM. DRE demonstrated a sensitivity of 90.9% in detecting DD in this cohort with a positive predictive value (PPV) of 87% and sensitivity of 69.7% for accurately classifying the DD subtype. Sensitivity within subgroups was 71% for those with prior radiation and 67% for those with cancer-related surgery. Conclusion: Our study demonstrates that DRE is 90% sensitive in detecting DD in our cancer patient cohort with decreasing sensitivity in pts with history of radiation (69.7%), any one type of abdominopelvic surgery (67%) and more than 2 different abdominal surgeries (50%). DRE had a PPV of 87% in diagnosis of DD in our study. While DRE should be part of the standard outpatient investigation for bowel complaints in cancer patients, this study supports referring for ARM even when DRE is normal in order to avoid missing the diagnosis of DD especially in those receiving abdominopelvic radiation/surgery. Further research with a larger sample size can further validate these findings and evaluate the utilization of low-cost interventions such as DRE to guide the need for confirmatory testing with ARM.