Effect of partial preservation versus complete preservation of Denonvilliers' fascia on postoperative urogenital function in male patients with low rectal cancer (PREDICTION): protocol of a multicentre, prospective, randomised controlled clinical trial.

Introduction: Total mesorectal excision (TME) has been the gold standard for the surgical treatment of mid-low rectal cancer, but traditional TME removal of Denonvilliers' fascia (DVF) is too low and is prone to damage the connecting branches of the bilateral neurovascular bundles, which can lead to posturogenital dysfunction. A recently published multicenter randomised controlled trial revealed that TME with complete preservation of DVF (CP-DVF) has protective effects on postoperative urogenital function for male patients with rectal cancer with specific staging and location (preoperative staging T1-4N0-2M0, but T1-2 for anterior rectal wall). Our previous studies have confirmed that TME with partial preservation of DVF (PP-DVF) could also achieve satisfactory results regardless of the circumferential location of the tumour. However, there is a lack of randomised controlled trials to prove that the efficacy of TME with PP-DVF is equivalent to that with CP-DVF with respect to postoperative urogenital function.

Methods And Analysis: This study is a prospective, multicentre, equivalent design, open-label randomised clinical trial in which 278 male patients with low rectal cancer will be recruited from 11 large-scale gastrointestinal medical centres in China. Patients will be randomly assigned to undergo PP-DVF or CP-DVF. We will test the hypothesis that PP-DVF is similar to CP-DVF with respect to sexual function at postoperative month 12 (5-item version of the International Erectile Function Index Questionnaire and ejaculation function classification). The secondary outcomes include the assessment of urinary function, surgical safety and oncological outcomes.

Ethics And Dissemination: This trial has been approved by the Institutional Review Board of Fujian Medical University Union Hospital (2020YF016-01) and is filed on record by all other centres. Written informed consent will be obtained from all eligible participants before enrolment. The trial's results will be disseminated via peer-reviewed scientific journals and conference presentations.

Trial Registration Number: ChiCTR2000034892.