Focal Ultrasound Ablation Demonstrates Utility as Primary Therapy in Prostate Cancer

Andre Abreu, MD

Hemigland high-intensity focused ultrasound (HIFU) ablation of the prostate was found to be a safe and effective primary treatment for men with localized prostate cancer, leading to continence preservation and suitable short-term disease control, according to study findings that were published in the Journal of Urology.1,2

At a median follow-up of 18 months, the 2-year freedom from treatment failure, clinically significant prostate cancer (Grade Group 2 or greater recurrence), repeat focal HIFU, and radical treatment rates were 73%, 76%, 90%, and 91%, respectively.

“This positive data empowers urologists to use focal HIFU ablation to effectively address prostate cancer without the intrinsic side effects of radical treatments,” Andre Abreu, MD, lead study author and assistant professor of clinical urology and radiology at the University of Southern California Keck School of Medicine, stated in a press release. “We hope this study encourages prostate cancer patients to talk to their doctor about all potential treatment options to ensure that they receive a personalized care plan that addresses their individual needs.”

Radical treatment with surgery or radiation, though treatment standards, can cause adverse effects, such as urinary incontinence or impotency.

In 2015, the FDA approved HIFU ablation for prostate tissue ablation. Hemigland HIFU ablation is an outpatient procedure that uses a focused ultrasound beam to heat and eradicate prostate cancer cells. The noninvasive procedure takes approximately 2 hours.

In order to evaluate the utility of hemigland HIFU ablation as an alternative to surgery or radiation, investigators retrospectively followed 100 men who underwent hemigland HIFU from December 2015 to December 2019. Treatment failure, defined as Grade Group 2 or greater on follow-up prostate biopsy, radical treatment, systemic therapy, metastases or prostate cancer–specific mortality, served as the primary end point of the study. International Index of Erectile Function (IIEF), International Prostate Symptom Score (I-PSS), and 90-day complications were also evaluated.

At baseline, patients had very low (8%), low (20%), intermediate favorable (50%), intermediate unfavorable (17%) and high risk (5%) prostate cancer.

Additional results demonstrated that the median times to prostate-specific antigen (PSA) nadir, PSA at nadir, and percent PSA reduction at nadir were 3 months, 1.3 ng/ml, and 75%, respectively.

Notably, bilateral prostate cancer at diagnosis was the sole predictor for Grade Group 2 or greater recurrence (P = .03). No predictors for failure were identified

Of men who underwent posttreatment biopsy (65%; n = 58), 18 had clinically significant prostate cancer. A total of 8 and 10 men had in-field versus out-of-field Grade Group 2 or greater positive biopsy results, respectively. The 31 patients who were eligible for but did not undergo posttreatment biopsy had fewer positive cores (3 versus 5; P = .04) at diagnosis and shorter follow-up (18 versus 25 months; P = .03) compared with patients with clinically significant prostate cancer on posttreatment biopsy.

Follow-up multiparametric MRI was performed in 61 (69%) eligible patients. No suspicious lesions were identified in the majority of patients (n = 43).

Continence, defined as 0 pad, was maintained in 100% of patients. Among 47 evaluable patients with baseline and post-treatment questionnaires, the median IIIEF-5 score was 22 before HIFU versus 21 after (P = .99). The median I-PSS was 9 versus 6, respectively (P = .005).

Minor 90-day complications, including difficulties with urination and urinary tract infection, and major complications occurred in 13% versus 0% of patients, respectively. No patient had rectal fistula or died.

“Throughout screening, diagnosis and treatment, it is important to balance accuracy and efficacy. Our physicians will continue working toward better methods to personalize that balance for every prostate cancer patient,” Inderbir S. Gill, MD, senior study author and Distinguished Professor and chair of the Catherine and Joseph Aresty Department of Urology at the University of Southern California Keck School of Medicine, concluded in the press release.

References

1. Abreu AL, Peretsman S, Iwata A, et al. High intensity focused ultrasound hemigland ablation for prostate cancer: initial outcomes of a United States series. Jour of Urol. 2020;204:741-747. doi:10.1097/JU.0000000000001126

2. Innovative, minimally invasive treatment can help maintain prostate cancer patients’ quality of life. University of Southern California, Health Sciences. September 8, 2020. Accessed September 14, 2020. https://bit.ly/3bZnT5s.