Researchers at the University of Regensburg in Germany have just reported progression-free survival data from their 14-year experience of using high-intensity focused ultrasound (HIFU) in the treatment of localized prostate cancer. This research group was one of the first to start testing the use of HIFU in the treatment of prostate cancer.
According to this new paper by Ganzer et al., their report is based on data from 538 consecutive patients who received HIFU as first-line treatment for clinically localized prostate cancer between November 1997 and September 2009. The report provides information about biochemical progression-free survival (bPFS) according to the Phoenix criteria (a PSA nadir + 2 ng/mL); metastasis-free, overall, and prostate cancer-specific survival; salvage treatment; side effects; potency; and continence status. It is our understanding that most if not all of the patients treated at Regensburg have, in fact, been treated with the Ablatherm HIFU technology, which has been through a series of evolutionary improvements over that 12-year period.
Here are the core results reported by Ganzer et al.:
- The average (mean) follow-up was 8.1 ± 2.9 years (range, 2.1 to 14.0 years).
- The overall actuarial rates of bPFS rates are
- 81 percent at 5 years
- 61 percent at 10 years
- For men with low-risk prostate cancer, the actuarial bPFS rates are
- 88 percent at 5 years
- 71 percent at 10 years
- For men with intermediate-risk prostate cancer, the actuarial bPFS rates are
- 83 percent at 5 years
- 63 percent at 10 years
- For men with high-risk prostate cancer, the actuarial bPFS rates are
- 48 percent at 5 years
- 32 percent at 10 years
- Rates of actual metastasis-free survival were
- 99.6 percent in men with low-risk prostate cancer
- 94.3 percent in men with intermediate-risk prostate cancer
- 84.6 percent in men with high-risk prostate cancer
- 18 percent of the patients required salvage treatment
- 75/538 patients (13.9 percent) died from all causes during follow-up.
- Prostate cancer-specific deaths were recorded among
- 18/538 (3.3 percent) of all patients
- 0 percent of men with low-risk prostate cancer
- 3.3 percent of men with intermediate-risk prostate cancer
- 11.0 percent of men with high-risk prostate cancer
- Side effects reported include
- Bladder outlet obstruction ( in 28.3 percent of patients)
- Stress urinary incontinence (of grades I, II and III in 13.8, 2.4, and 0.7 percent of patients, respectively)
- Recto-urethral fistula (in 0.7 percent of patients).
- 25.4 percent of patients who were potent prior to their treatment were able to preserved potency.
Ganzer et al. conclude that their study “demonstrates the efficacy and safety of HIFU for localized prostate cancer” and that “HIFU is a therapeutic option for patients of advanced age, in the low- or intermediate-risk groups, and with a life expectancy of ∼10 years.”
While this conclusion is certainly a reasonable one, there are also some problems with it (in the opinion of The “New” Prostate Cancer InfoLink):
- In the first place we have no idea what percentage of the men with low- and intermediate-risk prostate cancer may not have needed treatment at all within 10 years of diagnosis. In other words, what percentage of these patients would have had a similar therapeutic outcome on active surveillance?
- Secondly, a 37 percent biochemical progression-free failure rate among the men with intermediate-risk disease is hardly an outstanding success rate (although we acknowledge that at least a proportion of these men could probably have been — and maybe were — successfully re-treated with HIFU).
- Third, only 25 percent of the men who were potent prior to treatment were able to recover potency post-treatment (which is similar to the rates of recovery of potency post-surgery).
The authors are careful to point out that there are still “conflicting recommendations for HIFU among urological societies, which can be explained by the lack of prospective controlled studies, reports on preselected patient populations and limited follow-up providing little information on overall and cancer-specific survival.” This is a fair comment.
We should also point out that since the Regensburg patients series extends back to use of the earliest types of Ablatherm technology, outcomes of men treated in the recent past may well be better than those of men treated early on. As an example of this, we believe that occurrence of recto-urethral fistualae among men treated with HIFU today is almost unheard of, and that the four cases in the Regensberg series all occurred very early in the application of this technology.
The things that we feel need to be made very clear to patients considering HIFU is that even for those men with good potency prior to treatment, HIFU is associated with a significant risk for post-treatment erectile dysfunction and, in addition, about 25 to 30 percent of HIFU patients will have significant bladder outlet obstruction post-treatment as prostate tissue dies off.
We have said this before and we will say it again for emphasis … Like every other form of treatment for localized prostate cancer, HIFU is associated with a significant level of risk for complications and side effects.
We would also make one other, final comment. … It does seem odd to us that in 14 years the physicians at Regensburg have only been treating an average of about 38 patients per year since they started using HIFU to treat prostate cancer in 1997. One does wonder whether such numbers represent a high level of confidence in the applicability of this technique to most men with low- and intermediate-risk prostate cancer at Regensberg itself.