A Randomized Trial Comparing Quality of Life After LDR or HDR Prostate Brachytherapy Boost with Pelvic External Beam Radiation Therapy

Purpose/Objectives To compare health-related Quality of Life (QoL) in urinary, bowel and sexual domains after combined external beam radiotherapy (EBRT) and either low dose rate (LDR) or high dose rate (HDR) prostate brachytherapy (BT). Materials/Methods Eligible men with intermediate or high-risk prostate cancer, treated with combined pelvic EBRT and BT were randomly assigned to either HDR (15 Gy) or LDR (110 Gy) boost. International Prostate Symptom Score (IPSS), Index of Erectile Function (IIEF), Expanded Prostate Cancer Composite (EPIC-26) were collected at baseline, 1,3,6 and 12 months, q6 months to 3 years and then annually along with PSA/testosterone. Fisher's exact test compared categorical variables and the Mann Whitney U test EPIC domain scores. Results From 01/2014 to 12/2019, a random number generator assigned 195 men: 108 to HDR and 87 to LDR. Median age was 71 years. Risk group was high in 57% and unfavorable intermediate in 43%. Androgen deprivation (used in 74%) began with 3 months neoadjuvant and continued for median 12 months. Baseline EPIC scores were similar for the LDR/HDR cohorts: 89/88 for GU and 92/93 for GI. EPIC urinary scores decreased at one month for HDR but recovered promptly to a steady state by 6 months. LDR scores reached a nadir at 3 months with slow recovery to 18 months, after which urinary QoL was similar for HDR and LDR. Bowel QOL scores fell in both cohorts reaching respective nadirs at 12 months. HDR patients recovered close to baseline and maintained higher scores than LDR patients to 5 years. The decline for LDR patients remained > the MCID out to 5 years. Conclusions Patient experience for combined EBRT and prostate BT is improved with HDR BT. Urinary QoL improves over time to be equivalent between the 2 modalities after 18 months, but LDR patients report lasting bowel symptoms.