Preventing Ovarian Cancer Through Oportunistic Salpingectomy at the Time of Colorectal Surgery

Research design:

120 eligible participants will be enrolled and consented to undergo OS at the time of colorectal surgery. As a control group, 120 participants undergoing colorectal surgery without OS will be included. When eligible participants decline OS, they will be approached to participate as a control, and once 120 participants have consented to OS, participants will be enrolled as controls until there are 120 patients in the control group.

Methods and analysis:

The research coordinator will contact participants to consent them to undergo OS or to participate as a control participant at a preoperative visit prior to their colorectal surgery. The research coordinator will walk them through the informed consent form and answer any questions about the study. This will occur either at St Paul's Hospital, or over the phone or via telehealth video conference.

Information will be collected regarding all participants who were approached to consent for OS. For those who agree to participate in the study, a short questionnaire will be applied to collect some additional information that would not be available in the chart. Those who decline OS will be asked about their reasons for not participating to better understand the patient perspective, inform future research and develop lay communication materials around OS. The percentage of participants who consented to OS will be calculated, as well as those who successfully had both fallopian tubes removed during their colorectal surgery.

To calculate how much additional operating room (OR) time is required when OS is performed concurrently with colorectal surgery, the research coordinator will attend the OR and record the amount of time taken for both fallopian tubes to be removed or for the attempt to be abandoned (in rare cases where both tubes are not removed).

To assess the safety of providing OS at the time of colorectal surgery, postoperative complications will be addressed, including duration of hospital stay and 30-day hospital readmission rate, blood transfusion and surgical site infection. All participants will receive standard post-operative care. All data on perioperative complications are available in the participant's medical chart. The research coordinator will access this information for the research team. Perioperative complications will be graded according to the Clavien-Dindo classification of surgical complications, which uses a grading approach. Grade 1 represents any deviation from the normal postoperative course that does not require the need for additional treatment beyond the use of antiemetics, antipyretics, analgesics, diuretics, electrolytes and physiotherapy. Grade 2 represents complications that require pharmacologic treatment beyond what is included for grade 1 complications and includes blood transfusions. Grade 3 includes complications that require surgical, endoscopic, or radiological intervention, Grade 4 includes life threatening complications requiring admission to intensive care and Grade 5 is death of the patient.

To determine the cost effectiveness of OS at the time of colorectal surgery, the data generated regarding additional OR time and any additional complications will be used to conduct Markov Monte Carlo simulation models. Monte Carlo simulations will estimate the number of people who will be diagnosed with HGSC in the future after OS compared to those not having this procedure, based on the effectiveness data generated from OS at the time of hysterectomy and tubal ligation. Direct and indirect health care costs will be derived from previously existing sources, including patient cost estimators from the Canadian Institute for Health Information that includes provincial cost estimates for colorectal surgeries by province. Lifetime risks of HGSC will be modeled from the Canadian Cancer Statistics. Competing mortality risks that are age and sex dependent will be derived from Canadian Life Tables. The researchers will use published costs for treatment of HGSC and compare the direct HGSC-related costs (costs associated with either prevention or treatment of HGSC) across the groups.

Reporting for adverse events:

All potential side effects related to study interventions will be recorded. Adverse events will be monitored on an ongoing basis by the research coordinator, and frequencies will be reported to investigators bimonthly.

Any Clavien-Dindo complication of 3, 4, or 5 (more serious) will be immediately reviewed. The rate of Clavien-Dindo grade 1 and 2 complications will be reviewed at interim analyses, which will be conducted when 1/3 of participants have been recruited and again when 2/3rd have been recruited.

If the study shows that adverse events, serious or not, are occurring at a higher rate for people undergoing OS compared to baseline expected rates the study may be stopped early. If unanticipated adverse events are discovered, the study may be stopped early. In either case, there would be no further recruitment.

In the case of study stoppage, all colorectal surgeons at St Paul hospital will be immediately notified in writing. The research coordinator will no longer recruit and consent patients at St Paul's hospital.