Testosterone Recovery Following Short Course Androgen Deprivation Therapy And Stereotactic Body Radiotherapy Correlates Closely With Improvements In Patient-Reported Hormonal And Sexual Domain Scores

Androgen deprivation therapy (ADT) causes fatigue and sexual dysfunction. The time to testosterone recovery following ADT is variable and depends on both patient and treatment-specific characteristics. The kinetics of testosterone recovery in men treated with neoadjuvant ADT and stereotactic body radiotherapy (SBRT) is not well established. The current study seeks to characterize the timeline for testosterone recovery and evaluate its relationship with the return in patient-reported hormonal and sexual function. Institutional IRB approval was obtained for retrospective review of data that was prospectively collected. All patients with localized prostate cancer treated with short course ADT (3-6 months of Leuprolide) and SBRT at a single institution were included in this analysis. All patients were treated to 35-36.25 Gy in 5 fractions delivered with robotic SBRT. Testosterone levels were measured at the start of radiation, every 3 months for the first year, and every 6 months thereafter. Sexual and hormonal function was recorded using the Expanded Prostate Index Composite (EPIC)-26 prior to ADT initiation, the first day of SBRT and at each follow-up. The subdomain scores were transformed to a 0-100 scale with higher scores reflecting less bother. Total testosterone recovery was defined as reaching a serum level of 230 ng/dL. Between January 2009 and May 2018, 129 men with a median age of 72 years (range: 55 – 89 years) received ADT along with SBRT. Thirty percent were black and 35% were obese (BMI > 30). Median pre-radiotherapy testosterone level was 15 ng/dL (range: 3-89 ng/dL). 63% of patients received 3 months of ADT. The median pre-treatment EPIC-26 Hormone and Sexual Domain Scores were 87.5 and 39.5, respectively. At 12 months post-SBRT, 70% of patients recovered to a eugonadal state with a mean time to recovery of 4 months. Hormonal and sexual bother subdomain scores declined significantly following ADT but recovered to within 5 points of pre-treatment values in 71% and 57% of patients by 12 months post-SBRT, respectively. Testosterone recovery following short term ADT and SBRT occurs rapidly in the majority of patients within 1 year after treatment. Hormonal and sexual quality of life domain improvements followed the testosterone recovery trend closely.