HIFU Hemiablation Shows Mixed Results
Since the FDA approved high intensity focused ultrasound (HIFU) for treatment of tumors in soft tissue, both physicians and patients have expressed interest and curiosity about HIFU for prostate cancer. HIFU has long been used in Europe, Japan, China, Canada and Latin American countries as an alternative to prostatectomy and radiation. The focusing of soundwaves onto a target generates extreme heat within the target tissue, while causing no damage to intervening tissues. HIFU can be adapted to treat the entire prostate gland, half of it (called hemiablation or unilateral [one side] ablation) and focal ablation. Especially for the last two applications, the side effect profile is lower than that of prostatectomy.
To set a context for the latest data on HIFU hemiablation, here are recently reported 5-year outcomes/side effects on 569 patients who had whole-gland HIFU at a single institution:[i]
| 5-year failure free survival rates | Low-risk 87%, intermediate-risk 63%, high risk 58% (avg. 70%) |
| Need for repeat HIFU | 20% of cases needed a repeat HIFU |
| Post HIFU urinary tract infection | 7.7% |
| Pad-free incontinence | 88% of those who were pad-free before were pad-free after |
| Erectile function | 39% with good function before reported good function after |
Hemiablation, which destroys only one side of the prostate gland, may be offered for patients who a) do not have demonstrated significant cancer on the opposite side of the gland where cancer is found, which is called unilateral prostate cancer, and b) wish to reduce their side effect risks by sparing the neurovascular bundle on the opposite side, and exposing less of the urethra to HIFU.
A 2016 paper by van Velthoven et al.[ii] reports their data on 50 low- to intermediate-risk prostate cancer patients who had demonstrated unilateral prostate cancer (multiparametric MRI and TRUS biopsy agreement) and who were treated by HIFU hemiablation. The mean follow-up was 40 months and included PSA and DRE at 1, 3, 6 and 12 months and every 6 months thereafter. Both the Stuttgart and Phoenix criteria for biochemical failure were used to assess suspicion of biochemical recurrence; using the Phoenix criteria alone (Nadir+2?ng?ml?1))
were used to establish a threshold for offering patients a bilateral biopsy, and treatment failure was defined as positive biopsy on the treated side of the gland. If cancer was found on the non-treated side, it was not considered a treatment failure since that side had not been ablated. Here are the reported results:
| 5-year recurrence free survival | 45% (Stuttgart criteria) and 58% (Phoenix criteria) |
| 5-year estimated cancer-specific survival | 100% |
| 5-year estimated metastasis-free survival | 93% |
| Urinary tract infection (UTI) | Acute 8%; non-acute 6%; lower urinary tract symptoms 18% |
| Incontinence | Transient 14%; persistent 6% |
| Erectile dysfunction | 60% with good function before reported good function after
Post-HIFU ED 20% |
Eight men had a bilateral prostate biopsy as part of their follow-up, based on tracking their PSA using the Phoenix criteria. Of those, two were negative, suggesting the presence of no cancer. Three men were found to have cancer in the non-treated side of the gland, one had cancer in the treated side, and two men had cancer diagnosed on both sides of the gland.
As pointed out by one commentator, the 60% of these patients who had low-risk prostate cancer might as well have chosen to go on Active Surveillance.[iii] They were well monitored, so they might have been spared going through treatment and possible side effects – with the same probability of bilateral disease and recurrence risks.
Patients considering a hemiablation, which is a form of focal therapy, are well-advised to
- Get a thorough diagnosis, including a 3T mpMRI and some form of genomic biomarker analysis before considering treatment options;
- Discuss the track record of each treatment choice with their doctors;
- Do their own diligent search for data on each treatment using resources such as pubmed
- Understand what follow-up protocol will be required and adhere to it faithfully.
Focal treatment is a good choice for the right patient, including those who are not comfortable with the idea of Active Surveillance. Focal laser ablation (FLA) has much lower rates of side effects – in many cases, none – with demonstrated cancer control that surveillance alone cannot offer. As for focal HIFU, in whatever form, more results are needed to determine if cancer control rates can improve while side effects such as urinary tract infections and erectile dysfunction can be reduced.
[i] Dickinson L, Arya M, Afzal N, Cathcart P et al. Medium-term outcomes after whole-gland high-intensity focused ultrasound for the treatment of nonmetastatic prostate cancer from a multicenter registry cohort. Eur Urol. 2016 Mar 4. pii: S0302-2838(16)00244-X. doi: 10.1016/j.eururo.2016.02.054. [Epub ahead of print]
[ii] van Velthoven R, Aoun F, Marcelis Q, et al. A prospective clinical trial of HIFU hemiablation for clinically localized prostate cancer. Prostate Cancer Prostatic Dis. 2016;19:79-83.
[iii]Chodak, G. “More Cons than Pros(tate)?” Medscape News & Perspective, March 11, 2016. http://www.medscape.com/viewarticle/859935?nlid=102124_3521&src=WNL_mdplsfeat_160315_mscpedit_radi&uac=112110MY&spon=35&impID=1023251&faf=1
