Focal (hemiablative) HIFU in the treatment of localized prostate cancer
Posted Feb 21 2011 12:00am
To date there have been few data from well-documented, prospective series of patients receiving any form of focal therapy as treatment for localized prostate cancer, and the criteria for the appropriate clinical use of focal therapy are still a matter of considerable debate.
Ahmed et al. have now reported 12-month follow-up data from a prospective, Phase I/II clinical trial of focal therapy in a series of 20 patients, all diagnosed with low-risk or intermediate-risk prostate cancer and all treated with hemiablative, high-intensity focused ultrasound (HIFU). In hemiablative therapy, only one lobe of the prostate is actually treated; the other lobe is left untreated because it is believed to be cancer-free at the time of diagnosis and treatment. As far as we are aware, these are the first data reported from a prospective clinical trial of focal therapy.
All patients in this study received an initial TRUS-guided biopsy (to establish the diagnosis of cancer) and a subsequent transperineal mapping biopsy (to establish that the cancer was localized to a single lobe of the prostate). All patients also received multi-parametric magnetic resonance imaging (mp-MRI) prior to treatment. In other words, significant efforts were made to establish that the patients did, in fact, have localized prostate cancer confined to a single lobe of the prostate.
The patients were all treated using Sonablate 500 HIFU equipment, and a suprapubic catheter was placed prior to treatment. All patients were also followed intensively for oncologic and quality of life outcomes over 12 months post-treatment. The primary objective of this study was only to establish whether hemiablative HIFU was feasible and safe for treatment of carefully selected patients in an ambulatory setting.
Her are the results reported by Ahmed et al.:
8/20 men (40 percent) had intermediate-risk prostate cancer (according to the D’Amico criteria) based on the results of their initial TRUS biopsy and other factors.
15/20 men (75 percent) had intermediate-risk prostate cancer based on the results of their mapping biopsy and other factors.
The average (mean) age of the patients was 60.4 ± 5.4 years (range, 50 to 70 years)
The average PSA level of the patients pre-treatment was 7.3 ± 2.8 ng/ml (range, 3.4 to 11.8 ng/ml).
18/20 patients were discharged within 24 hours post-treatment
All patients were able to urinate on post-surgical day 2 with the suprapubic catheter clamped but a significant number of men had mild to moderate problems with urination over the following week and blood and other debris in their urine for about 2 weeks.
1 man (5 percent) developed a stricture that required dilation.
19/20 men (95 percent) had recovery of erections sufficient for penetrative intercourse at 12 months (although it is unclear whether this ability was with or without the use of PDE-5 inhibitors like Viagra).
18/20 men (90 percent) were pad-free and leak-free at 12 months.
Mean PSA level had deceased to 1.5 ± 1.3 ng/ml at 3 months (a reduction of 80 percent compared to the mean baseline PSA level); this reduction in PSA level was still evident at 12 months of follow-up.
17/19 men (89 percent) showed no histologic evidence of cancer on re-biopsy. (One patient refused re-biopsy.)
Of the 2 men who showed continuing evidence of cancer post-treatment, one opted for a second session of HIFU and the other opted for active surveillance.
It would be inappropriate to conclude from this study that hemiablative HIFU is effective in the treatment of unilateral, localized prostate cancer, but it certainly appears to be feasible, and the side effects reported appear to be limited. We will require extended follow-up of these patients (out to at least 10 years) before the effectiveness of this treatment can be established.
It is interesting that in an editorial comment on this paper, Eggener questions the inclusion of men with intermediate-risk prostate cancer in this study. Our interpretation is very different. Our view would be that it is the men with intermediate-risk prostate cancer who have the greatest to gain from a demonstration that hemiablative HIFU is effective and safe in the treatment of unilateral prostate cancer (if this does indeed turn out to be the case). Men with low-risk disease already have the option of active surveillance, whereas men with intermediate-risk disease and a life expectancy of 15+ years could benefit greatly from a relatively benign form of treatment that left them continent and with reasonable sexual functionality.
Ahmed and his colleagues are to be commended for their thorough approach to the investigation of the potential of focal therapy with HIFU … regardless of the ultimate, long-term outcomes. It is this type of thoughtful and careful approach that will allow the urology community to develop optimal treatments for localized disease over time as opposed to simply promoting new forms of treatment without this type of careful patient assessment and follow-up.