Disease Background:
Total mesorectal excision can be associated with transient post-operative urinary retention
due to surgical disruption of pelvic autonomic nerves during procedure. These patients
receive intra-operative urinary catheter to prevent post-operative urinary retention.
However, the optimal duration for post-operative urinary catheter is not known, and longer
duration of urinary catheter is associated with increased morbidity, such as urinary tract
infection. A previous prospective randomized controlled trial from 1999 looking at this
subject showed an increased rate of postoperative urinary retention in patients who had
shorter duration of urinary catheterization. However, surgical techniques have improved
significantly since then and a newer retrospective study comparing outcomes between patients
who had catheter removal on postoperative day 1 vs catheter removal on day 2 or later
demonstrated lower rates of urinary retention overall and there was no difference in rates of
urinary retention between the two groups. A recent randomized non--inferiority trial
investigating early urinary catheter removal in patients undergoing major colorectal surgery
found that early removal, when combined with an oral alpha- antagonist, is non--inferior to
standard removal and is associated with lower rates of urinary tract infections and shorter
hospital stays.
Rationale:
A current prospective randomized trial is needed to determine the optimal duration of urinary
catheterization in patients who receive total mesorectal excision (TME). Urinary
catheterization is an established part of the intraoperative and postoperative care for this
surgery. There should be minimal urinary dysfunction as total mesorectal excision should
preserve pelvic autonomic nerve function with careful dissection. Current standard of
practice is removal of urinary catheter on postoperative day 3. The study participants would
be exposed to minimal risk as they would already require urinary catheterization as part of
the standard of care. While this study will determine duration of postoperative urinary
catheterization, it will not impact the surgical procedure itself. The control group would
undergo removal of urinary catheter on postoperative day 3 and the experimental group would
undergo removal of urinary catheter on postoperative day 1. The main risk endured by study
participants would be the need to replace the urinary catheter if the patient has urinary
retention following catheter removal. This study will contribute to existing knowledge by
providing a prospective randomized non--inferiority trial investigating the impact of
duration of urinary catheterization following total mesorectal excision on rates of
postoperative urinary retention, urinary tract infections, and length of hospital stay. If
shorter duration of urinary catheterization is shown to be non--inferior to standard duration
of catheterization in terms of postoperative urinary retention, adopting a practice of
catheter removal on postoperative day 1 may result in lower rates of catheter--associated
urinary tract infections and shorter hospital stays. This practice would also adhere to the
Surgical Care Improvement Project (SCIP) measures which recommend removal of urinary catheter
on postoperative day 1 or 2. We hypothesize that postoperative urinary catheters may be
safely removed on postoperative day 1 following total mesorectal excision without increased
urinary retention rates when compared to removal on postoperative day 3.
Study Design:
This study will be conducted as a prospective, randomized, non-inferiority trial. The
investigators will evaluate all patients undergoing total mesorectal excision for study
eligibility. Consent for participation in the study will be obtained perioperatively. All
male patients will be given a survey to assess their international prostate symptom severity
(IPSS) score preoperatively. After surgery, the participant will be randomly assigned to the
control (day 3 catheter removal) or experimental (day 1 catheter removal) group if there were
no intraoperative complications deemed to interfere with the study, such as genitourinary
tract injury requiring prolonged urinary catheterization postoperatively. Randomization will
be performed using Microsoft Excel using a reported simple randomization method. The control
group will have catheter removed at 9AM on postoperative day 3, while the experimental arm
will have catheter removed at 9AM on postoperative day 1. Participants will receive
appropriate maintenance IV fluids depending on their ability to tolerate PO intake
postoperatively.
The primary endpoint of the study will be urinary retention, defined by grade 2 urinary
retention per NCI CTCAE. Clinically, the investigators will identify these patients as those
unable to void within 6 hours of urinary catheter removal with associated signs of suprapubic
fullness and/or tenderness, and bedside ultrasound bladder scan showing more than 250cc of
urine. Bladder scan will only be performed on patients who have signs of urinary retention
and are unable to void within 6 hours of catheter removal. If subjects are unable to void
spontaneously within 6 hours following catheter removal, a one-time straight catheterization
will be performed, as per standard practice. If subjects are still unable to urinate within 6
hours following straight catheterization, an indwelling urinary catheter will be replaced.
Secondary endpoints include urinary tract infection and length of hospital stay
postoperatively. Urinary tract infection is defined as grade 2 or 3 urinary tract infection
per NCI CTCAE. Patients will be evaluated for symptoms and signs of infection such as
suprapubic pain, tenderness, dysuria, hematuria, and urinary frequency in addition to the
presence of >100,000 colony-forming units/mL of bacteria on urine culture. Urinalysis and
urine culture will only be sent in the setting of clinical signs and symptoms of urinary
tract infection. Patients identified with UTI will be treated with pathogen-appropriate
antibiotics as per standard practice. Length of hospital stay will be defined as the number
of admitted days in the hospital from day of surgery to day of discharge. The participants
will remain in the study until discharge from the hospital.
Data Collection:
Data regarding patient's demographic, past medical history, surgical indication, surgical
approach, intraoperative complications, and postoperative outcomes including the mentioned
endpoints will be collected prospectively through the electronic medical record system. The
international prostate symptom severity (IPSS) score will be completed preoperatively for all
male patients. Patient's medical record number will be numerically encoded and stored in a
separate file. All paper documentation, including the original consent form, will be stored
in a secure cabinet in the division office.
Follow up:
There will not be post-discharge follow up for the purpose of the research. Only data related
to patient's history and inpatient hospital stay will be collected. Therefore, the follow up
period for the endpoints is up to day of discharge.
Sample Size and Accrual:
Previous studies have identified rates of urinary retention following rectal surgery to
approximately 20%. Given no expected difference between the two groups, the investigators
therefore anticipate the urinary retention rate of both the study and control group to be
20%. Using a type I error of 5%, a power of 0.8, and a non-inferiority limit of 15% as
reported by literature (3), a sample size of 88 per group will be needed. Given the
anticipated rate of approximately 10 total mesorectal excision procedures per month, the
investigators anticipate needing 18 months to fulfill the required sample size.
Data Analyses Plans:
The two randomized groups will be compared in terms of their preoperative demographics, prior
history of benign prostatic hyperplasia, surgical indication, cancer staging, and neoadjuvant
treatments. Intraoperative and postoperative factors will also be compared between the two
groups. Subgroup analysis may be performed stratifying patients with different surgical
indications and/or cancer staging. Given that the main research question involves patients
following TME, regardless of surgical indication, the study may not be powered to observe
differences when performing subgroup analyses.
Comparisons between groups will be analyzed by the chi square test, the Mann Whitney U test,
or the Student t test for quantitative and qualitative variables, as appropriate. The early
catheter removal will be considered noninferior to standard removal if the upper limit of a
1-sided 95% confidence interval excludes a difference in favor of the standard group of the
standard group of more than 15%. A p-value of <.05 will be considered statistically
significant.