Evaluating high-intensity focused ultrasound for prostate cancer

This study investigated the effect of high-intensity focused ultrasound (HIFU) on the function and outcomes of patients with localized prostate cancer (PCa).

The data showed that treatment with HIFU on half of the prostate gland leads to better functional outcomes than the standard treatment.

HIFU is an emerging treatment option for PCa that is limited to the prostate itself (localized). This means it has not yet spread beyond the prostate or to distant organs (metastasis). PCa can be found in half of the prostate gland (hemi-gland PCa) or the whole prostate gland (whole-gland PCa). HIFU destroys the affected cancer cells with local heat application. 

There are several measures to determine, how successful HIFU is for a particular patient. A tissue sample taken after HIFU (biopsy) will show upon microscopic examination if there are still cancer cells present. A blood test can show the value of prostate-specific antigen (PSA) and determine whether the cancer is reducing. The goal is to reach the lowest possible PSA-level (PSA-nadir). 

Functional abilities will also be measured. They include urinary incontinence, impotence, blocked/limited urine flow, a not-fully emptied bladder (retention), and infection. Apart from these functional outcomes, the main goal of any cancer treatment is a long survival. HIFU is known to be less invasive than standard procedures such as radiotherapy and a radical removal surgery of the prostate (radical prostatectomy). There are not yet enough studies observing the effects of HIFU and manifesting the pros and cons. 

This study collected and explored data of 27 articles on HIFU in PCa. Overall, 7393 patients were included. 18 studies covered whole-gland HIFU and 9 studies covered hemi-gland HIFU. 

The follow-up time on patients after whole-gland HIFU was 2 to 168 months for 5695 patients. After the treatment, the average PSA-nadir ranged from 0.4 to 1.95 ng/ml. The average time to reach the PSA-nadir ranged from 2.4 to 5.4 months.

The overall survival (OS) after 5 years was 90-100% in 2 studies. Also, two studies reported a 10-year OS of 80%-88.6%. Biochemical disease-free survival (BDFS; survival without a rise in PSA levels) at 5 years was 77%-88% in 4 studies.

10% of patients reported urinary incontinence (leakage) and 44% had impotence. The rate of urinary obstruction was 15% and infection was 7%.

The follow-up time on patients after hemi-gland HIFU was 1 to 131 months for 1698 patients. After treatment, the average time to reach PSA-nadir was 5.7-7.3 months. The average PSA-nadir ranged from 1.9 to 2.7 ng/ml. Three studies reported an 8-year OS of 97%. BDFS was between 58%-90.3%. 

Urinary incontinence occurred in 2%, impotence in 21%, urinary obstruction in 2%, and infection in 11% of patients.

The authors concluded that while the survival rates are similar, the functional outcomes after HIFU remain better compared to standard procedures. The authors suggest that partial-gland HIFU is similarly effective to whole-gland HIFU and safer for patients with lower risk PCa. 

The study included a wide range of patients from different studies. Every patients’ diagnosis and additional treatment affects the outcome of HIFU and needs to be considered individually.