Preliminary results of sexual quality of life (QOL) outcome for intermediate-high risk prostate cancers treated by stereotactic radiotherapy (SBRT) and androgen deprivation therapy (ADT): Clinical and dosimetric factors.

e17085 Background: There has been numerous evidence about ADT and radiotherapy on sexual QOL among prostate cancer (Pca) patients. This study analyzed the impact of SBRT on sexual health of Pca treated by SBRT and ADT. This also monitored dosimetry related to penile bulb (PB) and neurovascular bundles (NVB). Methods: Consecutive series of 40 Pca patients of intermediate and high-risk group (NCCN) were included. Baseline sexual function was assessed using Expanded Prostate Cancer Index Composite for Clinical Practice (EPIC‐CP) questionnaire for sexual symptoms score. Patients received ADT as per risk groups. Radical SBRT was 36.25Gy in 5 fractions (Pelvic nodal 25 Gy in 5 fractions for high risk) on alternate days or weekly. Mean Dose to penile bulb and dose received by bilateral NVB were documented. Sexual function by EPIC-CP monitored at baseline and then 6 monthly till last follow up. Results: With median age of 61 years and median follow up of 20 months, 20% (8) patients belong to NCCN intermediate favourable risk category,15% (6) Intermediate unfavourable risk category and 65% (26) High risk category. All high risk Pca received elective pelvic nodal radiotherapy. Mean dose to penile bulb was in range of 9.5-29.4Gy. NVB Dose ranged from V34.4 (83.3% - 91.8%), V32 (94.5-99.16%) V28(99.76-100%). The EPIC‐CP for sexual symptoms score reported (out of 12) median score at baseline of 3 (range2-4), at 6 months 4.5 (range3-6)), at 12 months 5 (range 3-7), at 24 months 5.5 (range 4-7) and at 30 months 7 (range 6-8). The higher score represented worsening sexual function QOL. Till last follow up 38/40 patients were biochemically controlled with acceptable gastro-intestinal and genito-urinary late effects. Both the median and mean score of EPIC-CP sexual domain declined over follow up period representing clinical effect of ADT and dose received to PB and NVB. Sexual function scores declined gradually in both risk groups (High risk > intermediate risk) and vitality/hormonal scores were unchanged from baseline in both groups at 3 and 6 months. Few patients beyond 3 years of follow up reported some degree of recovery in EPIC-CP score in sexual function domain. Conclusions: A substantial group of patients in our study had mild or no erectile dysfunction at base-line but compromised sexual health after ADT and SBRT. The technical challenge of sparing NVB for high risk Pca patients combined with effect of ADT remains a concern. However, PB dosage were in the acceptable range signifying multitude of factors besides only dosimetric features. Late recovery of sexual function to some extent probably a possibility. There are limitations in documentation of sexual QOL by EPIC-CP in our cohort and future prospective documentation and pragmatic sparing of NVB can highlight specific issues related to sexual QOL.