M103 - TEMPOUR - A Double-blind, Randomized, Placebo Controlled Trial Assessing the Use of alpha-1-bockers to Reduce Urinary Retention Following TEM Procedures

Purpose/Background: Transanal endoscopic microsurgery (TEM) is a treatment option for a wide range of rectal lesions. With overall low complication rates, postoperative urinary retention (POUR) is among the most frequent ones following TEM. It is associated with increased hospitalization rates and greater healthcare costs. Overall data is still inconsistent, but some studies have suggested that the use of alpha-1-blockers may reduce the risk of POUR after hernia and colorectal surgery. No data exists on its prophylactic use for TEM procedures.

Methods/Interventions: TEMPOUR was a double-blind RCT conducted in a single high-volume Canadian colorectal center, from October 2017 to July 2022. Adult patients awaiting TEM, not already on alpha-1-blocking medication were eligible. Patients were randomly allocated to either Tamsulosin (TAM) or placebo (PLAC) for 5 days prior to surgery and 2 days postoperatively. The primary outcome was the rate of POUR, defined as incapacity of spontaneous voiding within the first 6 hours after surgery, requiring instrumentation. Secondary outcomes were rates of side effects from tested medication, urinary retention-related hospitalization rates, time to removal of Foley catheter and IPSS Score, before and after 7-day treatment. Intention-to-treat analyses were conducted.

Results/Outcomes: 157 patients were randomized, 78 in the control group and 79 in the TAM group. Baseline demographics and surgical features were similar between groups, including operative time, blood loss and specimen volume. Almost all patients had successful same-day discharge (PLAC 94.9% vs TAM 93.7%, p=1.00), with very rare complications, including bleeding, suture dehiscence, fistula, infection or any medical complications. Compliance was good with 90% of patients taking at least 6/7 doses in both groups. Overall, there was no significant difference in postoperative urinary retention, (14.1% vs 22.8 % p= 0.16) in the PLAC and TAM group respectively. All Foley catheters were removed without retention recurrence in the TAM group, compared to three recurrences in the PLAC group, but this was not significant (p=0.25). Urinary retention appeared longer with placebo, although not statistically significant (mean of 8.56 vs 4.75 days, p=0.26). There were no failure of same-day discharge nor readmissions specifically related to urinary retention, in neither group. IPSS scores were not significantly different at the time of surgery (5.37 vs 3.82 p= 0.11) Reported side effects did not differ between treatment groups.

Patients were also analyzed according to POUR occurence (128 patients with vs 29 without). There was a trend towards longer operative time among patients with POUR (45.38 vs 56.79 minutes, p=0.11). More patients who experienced POUR had diabetes (10.9% vs 31%, p=0.01), hypertension (41.4% vs 79.3%, p=0.0003), obstructive sleep apnea (4.7% vs. 17.2%, p=0.03) and worse ASA score (ASA score 3 6.3% vs 24.1%, p=0.007). Their mean age was slightly higher (64.13 vs 69.93, p=0.008) and IPSS scores at the time of surgery were significantly higher in patients with POUR (4.06 vs 7.07, p=0.04).

Conclusion/Discussion: Prophylactic use of alpha-1 receptor blockers for patients undergoing TEM was not associated with a reduction in POUR. Diabetes, hypertension, obstructive sleep apnea and ASA score 3 appear to be associated with POUR. Tamsulosin should not be used systematically, and further dedicated research would be required before claiming effectiveness in such specific subgroups of patients at higher risk.