Vaginal Dose and Tumor Location Predict Post-Radiotherapy Sexual Dysfunction, Suggests Study

Pelvic irradiation for rectal cancer often causes vaginal toxicity, yet vaginal dose-volume relationships are rarely studied compared to gynecological malignancies. To address this gap, Dr. Gul Kanyilmaz and colleagues from Necmettin Erbakan University in Konya, Turkey, evaluated how vaginal radiation parameters affect self-reported sexual quality of life.

Therefore, the Turkish retrospective study (2012–2019) evaluated forty-five disease-free female rectal cancer patients with a two-year follow-up, excluding minors, $T_4$ tumors, and abdominoperitoneal resections. Using Radiation Therapy Oncology Group guidelines and European Organisation for Research and Treatment of Cancer questionnaires, investigators analyzed how vaginal radiation dose volumes affected post-treatment sexual quality of life.

Key Clinical Findings of the Study Includes:

• Tumor Location: Investigators reported closer tumor proximity to the anal verge was linked to worse sexual function, with a mean distance of eight centimeters in the low-scoring group versus eleven centimeters in the high-scoring group (p = 0.002).

• Age Factor: Investigators observed older patient age significantly correlated with worse sexual outcomes, with a mean age of fifty-seven years in the low-scoring cohort compared to forty-nine years in the high-scoring cohort (p = 0.001).

• Radiation Hotspots: Investigators identified mean vaginal dose (42.25 Gray), minimum dose (24.18 Gray), and vaginal volumes receiving thirty-five to fifty Gray as key predictors of poorer sexual QOL.

• Independent Drivers: Investigators confirmed via multivariate regression analysis that only tumor distance to the anal verge (p = 0.01) and vaginal volume receiving fifty Gray independently predicted sexual function.

• Treatment Tolerability: Investigators found no significant differences in sexual QOL based on radiotherapy sequence neoadjuvant 18.90 versus adjuvant 19.92; (p = 0.6) or technique conformal 19.90 versus intensity-modulated 18.53; (p = 0.5).

The results suggest that treatment-induced sexual dysfunction is highly prevalent, with forty-two percent of patients experiencing worse sexual functioning (total score below the 19.44-point cut-off) and fifty-eight percent reporting better outcomes. This highlights a clear relationship between vaginal radiation exposure and impaired female sexual function.

Thus, the study concludes that clinicians should implement vaginal dose-reduction strategies during radiotherapy planning to preserve long-term sexual quality of life in female rectal cancer patients.

Although limited by its retrospective design and the lack of baseline pre-treatment data, this study highlights a pressing need for prospective trials to validate vaginal-sparing protocols and optimize survivorship care.

Reference

Kanyilmaz G, Halis H, Ay O, Temelli O, Erkal EY, Etiz D, et al. Evaluation of sexual life quality and vaginal dose‑volume relationship in female rectal cancer patients treated with pelvic radiotherapy. Indian J Cancer 2026;63:76‑81.