Sexual dysfunction outcomes and reporting disparities after multimodal treatment for rectal cancer: A systematic review and narrative synthesis.

Sexual dysfunction is a recognised adverse outcome after rectal cancer treatments, yet reporting is predominantly male-focused, with female sexual dysfunction less consistently assessed or reported. This systematic review aimed to assess sexual health domains studied, examine sex-based reporting disparities, and identify limitations in the current evidence. A systematic review and narrative synthesis were conducted in accordance with PRISMA and registered with PROSPERO (CRD420251178502). PubMed/MEDLINE, EMBASE, Scopus, CINAHL Plus, PsycINFO, and Cochrane Library were searched from March 1995 to March 2025, with an updated search to March 2026. Eligible studies included adults treated for rectal cancer in whom sexual function outcomes were assessed using International Index of Erectile Function (IIEF) and/or Female Sexual Function Index (FSFI), with additional related patient-reported outcome measures (PROMs) accepted where relevant. Risk of bias was assessed using RoB 2 and MINORS. Twenty-five studies involving 4,071 patients were included. Participants were predominantly male (65.8%), while women comprised 34.2%. PROM reporting was inconsistent; only eight studies reported both total and domain-level results. Sexual outcomes were most consistently reported for men, particularly erectile and ejaculatory function, whereas female outcomes were often reduced to overall scores. Five studies restricted sexual outcome assessment and analysis to men. Only six reported response rates, and missing PROM data handling was not described. Key contextual variables, including sexual activity, sexual orientation, sexual practices, and menopausal status, were rarely captured. Sexual function outcomes after rectal cancer treatment are inconsistently reported, with low certainty. Female sexual dysfunction remains under-represented. Standardised, inclusive sex-specific reporting and development of a core outcome set are needed.