Introduction:

High-intensity focused ultrasound (HIFU) is a type of focal therapy that uses magnetic resonance imaging (MRI) and transrectal ultrasound (TRUS) imaging to specifically target areas affected by prostate cancer (PCa), with careful attention to avoid normal tissues. HIFU has been shown in prior studies to have moderate PCa control outcomes with little impact on sexual or urinary side effects. A significant concern limiting widespread adoption of HIFU is inadequate treatment of disease and recurrence. Here we share institutional biopsy-proven recurrence outcomes following HIFU, and identify clinicodemographic factors associated with in-field and overall recurrence.

Methods:

All men who underwent robotic HIFU (FocalOne) at the University of California, San Francisco and underwent 1-year post-procedure MRI-fusion biopsy were included. The primary outcomes were in-field recurrence, defined as biopsy-diagnosed PCa greater than or equal to Gleason Grade 2 (≥GG2) in the same sextant of HIFU treatment, and overall recurrence, defined as ≥GG2 diagnosed anywhere in the prostate. Secondary outcomes were urinary and sexual quality of life (QOL) changes, measured by the International Prostate Symptom Score (IPSS) and Sexual Health Inventory for Men (SHIM) score. Multivariable logistic regression models were used to estimate associations between patient characteristics and risk of recurrence, controlling for age, Gleason grade, number of positive biopsy cores, MRI Prostate Imaging Reporting and Data System (PI-RADS) score, genomic risk score (based on Decipher, Oncotype Dx, and Prolaris scores), and PSA density.

Results:

There were 102 men included in analyses who had 1-year post-HIFU biopsy follow-up. In-field and overall recurrence on 1-year biopsy was 42% and 56%, respectively. IPSS and SHIM scores were not significantly different between pre-HIFU and one-year post-HIFU (p>0.05). GG3 or greater disease was borderline associated with greater risk of in-field recurrence (OR=2.84; 95% CI 1.00-8.07; p=0.05; Table 1), and pre-HIFU PSA was associated with greater risk of overall recurrence (OR=1.19; 95% CI 1.04-1.37 p=0.01; Table 1).

Conclusion:

In-field and overall recurrence rate on biopsy one year after HIFU was found to be 42% and 56%, respectively. GG3 or greater disease trended towards in-field disease recurrence and increased pre-HIFU PSA was associated with overall disease recurrence. No significant changes in sexual or urinary symptoms were observed. These findings emphasize the importance of careful patient selection for HIFU, which has potential for cancer control with minimal side effects in the appropriate PCa patient.  

Funding: UCSF Goldberg-Benioff Program in Translational Cancer Biology