Patient-reported quality-of-life after pelvic irradiation and SBRT boost with hydrogel spacer for high risk prostate cancer

Summary: The ASCENDE-RT trial revealed brachytherapy boost after pelvic IMRT to offer superior PSA control than standard fractionation boost for high risk prostate cancer (HPRC) at a cost of worse toxicity. An alternative approach to high BED boost is stereotactic body radiation therapy (SBRT). Hydrogel spacer reduces GU and GI toxicity with SBRT alone, though less is known about its benefit on pelvic IMRT with SBRT boost. We therefore prospectively acquired patient-reported quality-of-life (QoL) in HRPC patients treated with pelvic IMRT and SBRT boost with hydrogel spacer and long-term ADT. A total of 50 patients were accrued from 2017-2020 in a single-institution IRB-approved prospective pilot study assessing QoL using EPIC-26 prior to treatment, and at 1, 3, 6, 9, 12, 18, and 24 months post-treatment. Patients were treated with pelvic IMRT to 45 Gy in 25 fractions, followed by a prostate-only SBRT boost of 19.5 Gy in 3 fractions. Incidence of minimally important difference (MID) in the urinary-incontinence, urinary irritative/obstructive, and bowel EPIC domains were assessed. Sexual and hormonal EPIC domains were unreliable given variable timing of ADT. MIDs were defined as a clinically significant decline of 6, 5, and 4 points for urinary incontinence, urinary irritative/obstructive and bowel domains compared to baseline. Early and late periods were defined as ≤ 12 and > 12 months post-treatment respectively. Of the 50 patients enrolled, 5 declined surveys after consent, 1 was treated with standard fractionation due to prostate size, 11 did not complete a pre-treatment survey, and 15 completed only 1 survey. Eighteen patients were evaluable with pre-treatment and post-treatment surveys. Early urinary incontinence, urinary irritative/obstructive, and bowel MID was experienced by 2/16 (12.5%), 6/14 (43%), and 7/11 (64%) of patients, respectively. Late urinary incontinence, urinary irritative/obstructive, and bowel MID was experienced by 1/8 (12.5%), 3/8 (37.5%), and 1/4 (25%) of patients, respectively. However, mean EPIC domain scores remained stable throughout follow-up. Almost half of patients analyzed experienced an early MID in urinary irritative/obstructive and bowel symptoms, but this proportion was reduced in the late period. Fewer patients experienced a MID in urinary incontinence domains. However despite select individual decrease in QoL domains, the collective mean QoL was not detectably different after SBRT boost with hydrogel spacer. Tomas Patrich, MD (Presenting Author) - Yale School of Medicine; David Wallington, MD (Co-Author) - Yale School of Medicine; Jacqueline Kelly, MD (Co-Author) - Cancer Partners of Nebraska; Henry Park, MD, MPH (Co-Author) - Yale School of Medicine; James Yu, MD, MHS, FASTRO (Co-Author) - Yale School of Medicine; Kimberly Johung, MD, PHD (Co-Author) - Yale School of Medicine; Vikram Jairam, MD (Co-Author) - Yale School of Medicine; Preston Sprenkle, MD (Co-Author) - Yale School of Medicine; Michael Leapman, MD, MHS (Co-Author) - Yale School of Medicine; Sanjay Aneja, MD (Co-Author) - Yale School of Medicine; Yi An, MD (Co-Author) - Yale School of Medicine