Prevalence, Risk Factors, and Interventions for Female Sexual Dysfunction After Radiotherapy for Anal Cancer: A Systematic Review
32 studies found vaginal dryness in up to 98% of women after anal cancer radiotherapy — and it often doesn't resolve
Journal: British Journal of Cancer | Published: 2026-04-09 | Type: Systematic Review | PMID:41957141Authors: Steffensen JH et al. (Aarhus University Hospital, Denmark; Medical University of Vienna)
Funding/COI: Danish Council for Independent Research. No competing interests declared.
Summary
Anal cancer radiotherapy is highly effective — survival rates are strong — but it leaves a substantial proportion of female survivors with lasting sexual dysfunction. This systematic review of 32 studies using modern intensity-modulated techniques (IMRT/VMAT) found that vaginal dryness, dyspareunia, and stenosis are common, often severe, and frequently persist for years. The evidence base is a mess: prevalence estimates range from 0.9% to 85% for overall sexual dysfunction, which tells you more about measurement chaos than about actual rates.
Claims
Overall female sexual dysfunction (FSD) prevalence ranged from 0.9% to 85% across 32 studies using modern radiotherapy techniques
Dyspareunia reported in 0.3–79% of women
Vaginal stenosis in 1–88%
Vaginal dryness in up to 98%
Several symptoms persisted at 3- and 6-year follow-up (e.g., dyspareunia 13% at 3 years, 14% at 6 years in one prospective cohort)
Higher radiation dose to vaginal structures was the most consistent risk factor for worse outcomes; patient factors like age and menopausal status showed inconsistent associations
Two studies linked vaginal dilator use to reduced stenosis risk; nurse-led and multidisciplinary programs showed "promise" in observational data
Only 8 studies evaluated any intervention; only 1 RCT appeared in the prevalence analysis
Study Quality
The search was rigorous — four databases, PROSPERO-registered (CRD42024592088), dual independent screening, 3,764 records assessed — and the domain-specific approach (disaggregating dyspareunia, dryness, stenosis, and orgasmic difficulty rather than treating "sexual dysfunction" as one endpoint) is genuinely useful. The restriction to IMRT/VMAT for prevalence estimates was an appropriate methodological boundary that many similar reviews skip.
But the narrative synthesis instead of meta-analysis is forced by the data, not a choice: heterogeneity across instruments, populations, timepoints, and outcome definitions made pooling impossible. The review is largely a catalog of how badly this literature is designed rather than a summary of what we know. Most validated patient-reported outcome measures only include sexually active women, meaning women who stopped having sex due to pain or dryness are excluded from the very analyses meant to capture that harm — a systematic undercount baked into the measurement tools themselves.
Red Flags
Prevalence ranges are clinically useless: 0.9% to 85% for FSD; 1% to 88% for stenosis. This reflects instrument and population heterogeneity, not true variation. No pooled estimate is possible.
Low and declining response rates: one prospective study saw sexual function item response drop from 34–59% at baseline to 19–27% at one year — precisely the window where dysfunction peaks. Dropout is almost certainly non-random.
Exclusion of sexually inactive women from PRO instruments: women who stopped sex due to dysfunction are systematically excluded from sexual function scores, understating burden.
Inconsistent vaginal contouring and dosimetry reporting: dose-toxicity relationships can't be compared across studies because institutions don't contour the same structures or report the same parameters.
Intervention evidence is thin: 8 studies, only 1 RCT, small samples, low adherence, short follow-up. "Dilator use linked to less stenosis" is an association from observational data, not a causal finding.
EORTC QLQ-ANL27 — the only instrument validated for anal cancer specifically — was used in only 5 of 32 studies.
Strengths
Independent public funding; no industry involvement; no competing interests
PROSPERO-registered with a priori eligibility criteria
Comprehensive four-database search with manual reference screening, completed December 2025
Methodologically appropriate restriction to modern RT techniques (IMRT/VMAT) for prevalence domain
Symptom-disaggregated approach surfaces domain-specific burden that composite scores obscure
Risk of bias assessed with the AXIS tool across all included studies
Highlights a genuine gap: standardized vaginal contouring protocols could enable dose-toxicity modeling that currently doesn't exist
Verdict
This review is more valuable as a diagnosis of a broken literature than as a source of clinical facts. The finding that we can't characterize FSD prevalence better than "somewhere between 1% and 88% depending on how you ask" — after decades of treating anal cancer with radiotherapy — is damning. The review is well-executed within the constraints of its source material, but those constraints are severe: no standardized measurement, no consistent contouring, shrinking response rates, and instruments that exclude the most affected women by design. The intervention evidence is too thin to support conclusions. Read this paper if you want a clear map of what research needs to be done, not if you want numbers you can act on.