To evaluate feasibility and safety of prostate stereotactic body radiotherapy (SBRT) neoadjuvant to radical prostatectomy (RP) in a phase I trial. Primary endpoint was treatment completion rate without severe acute surgical complications. Secondary endpoints included patient-reported quality-of-life and physician-reported toxicities.
Patients with nonmetastatic high-risk or locally advanced prostate cancer received 24 Gy in 3 fractions to the prostate and seminal vesicles over five days, completed two weeks prior to RP. Patients with pN1 disease were treated following multi-disciplinary discussion and shared decision-making. Patient-reported quality-of-life (I-PSS and EPIC-26 questionnaires) and physician-reported toxicity (CTCAEv4.03) were assessed prior to SBRT, immediately before surgery, and at 3-month intervals for one year.
12 patients enrolled, 11 completed treatment (one had advanced disease on PSMA PET after enrollment, before treatment). There were no significant surgical complications. After RP, two patients underwent additional RT to nodes with androgen suppression for pN1 disease. Median follow-up after completion of treatment was 20.1 months, with 9/11 patients having follow-up greater than 12 months. Two patients had biochemical recurrence (PSA >= 0.05) within the first 12 months, with an additional two patients found to having biochemical recurrence after the 12-month period. Highest CTCAEv4 genitourinary grade was 0/1/2/3 (n=1/4/4/2) and highest gastrointestinal grade was 0/1/2 (n=9/1/1). At 12 months, incontinence was the only grade ≥2 toxicity. One and two of nine patients had grade 2 or 3 incontinence, respectively. On EPIC-26, mean/median changes in scores from baseline to 12 months were -32.8/-31.1 for urinary incontinence, -1.6/-6.2 for urinary irritative/obstructive, -2.1/0 for bowel, -34.4/-37.5 for sexual function, and -10.6/-2.5 for hormonal. Mean/median change in I-PSS score from baseline to 12 months was 0.5/0.5.
RP following neoadjuvant SBRT appears to be feasible and safe at the dose tested. Severity of urinary incontinence may be higher than RP alone.

Published by Elsevier Inc.