(005) Feasibility of Delineating the Clitourethrovaginal Complex in a Cohort of Female Patients With Pelvic Cancers Who Received Radiotherapy

Abstract Introduction Around 60% of all patients will receive radiation during their treatment journey. Sexual health issues are common among patients with pelvic cancers receiving radiotherapy, surgery, and chemotherapy. Female sexual organs of interest (OOIs), specifically the bulboclitoris (BC), paraurethral glands, inferior hypogastric plexus (IHPs), and anterior vaginal wall (AVW) work together, known as the clitourethrovaginal (CUV) complex. The internal pudendal neurovascular bundles (IPAs) supply blood to the complex. Damage to these structures, including radiation-induced changes in blood flow, may impair orgasm ability, pleasure, and sexual satisfaction. CUV contouring may provide a time-efficient method for capturing functional tissues versus each structure individually. Dose-exposure to the CUV during treatment has not been quantified nor has the relationship between dose-exposure and organ function been evaluated. Objective We aimed to demonstrate the feasibility of delineating female sexual OOIs and evaluate the relationship between dose to the CUV and sexual function and satisfaction. Methods We conducted a cohort study of adult female pelvic cancer survivors who had completed radiotherapy ≥1 year before enrollment. Sexual OOIs (BC, paraurethral glands, AVW, IHPs, IPAs, and CUV) were retrospectively contoured on fused CT/MRI. Sexual function outcomes were assessed using the Patient Reported Outcome Measurement Information System (PROMIS) Sexual Function and Satisfaction Full Profile (Female) for general and erectile tissue function-related domains: sexual activity, interest, clitoral discomfort, lubrication, orgasm-pleasure, and satisfaction. Calibrated T-scores were obtained via the HealthMeasures Scoring Service and compared to sexually active adult female population means for clinically significant dysfunction (≥ or ≤ 3). Cumulative dose-volume indices were extracted for each OOI (CUV, BC, AVW, paraurethral glands: D95%, D50%, D5%; IHP, IPAs: D0.03cc, D0.1cc, D50%) representing minimum dose to the most irradiated reference volume, in equivalent dose in 2Gy fractions (α/β = 3). Dose-volume indices were compared by treatment type and correlated with T-scores using Spearman’s correlation coefficient (Rs) as follows: strong 0.6, moderate 0.4–0.59, weak 0.2–0.39. Results 20 adult female cancer survivors (median age 58, IQR 49-72; months post-treatment, median 24 (IQR 13-32)) completed PROMIS SexSF, including 7 anal cancer (35%), 6 uterine (30%), 5 cervix (25%), and 2 (10%) rectum cases. 17 (85%) received chemotherapy and 13 (65%) underwent surgery. 16 participants received external beam radiotherapy (EBRT) and 4 were treated with EBRT and brachytherapy (BT). 10 (50%) participants reported sexual activity in the past 30 days. Among them, 7 (70%) experienced decreased satisfaction with their sex life (Table 1). OOI dose-exposure varied by treatment type for all dose-volume indices (Table 2). Dose to IHPs differed greatly with D50% 32.6 Gy during EBRT versus D50% 74.1 Gy from EBRT+BT. CUV D50% and D95% indicated a moderate negative correlation with sexual satisfaction. Conclusions This study is the first to demonstrate the feasibility of contouring the CUV and quantify dose to the IHP and IPA neurovascular bundles. A moderate negative correlation between dose to CUV and decreased satisfaction was demonstrated. The CUV may be a time-efficient contouring approach for clinicians. Further research is warranted to establish dose guidance for sexual OOIs, refining radiation planning to mitigate sexual dysfunction in female cancer survivors. Disclosure No.