For several years, various research teams have been assessing the potential of focal therapy as a means to treat carefully selected men with localized prostate cancer. However, to date, the ability to identify such men with accuracy prior to such treatment is still in question.
In theory at least, focal therapy offers the opportunity to eliminate cancer in a man’s prostate while minimizing risk for complications such as urinary incontinence and sexual dysfunction. However, prostate cancer is commonly found (after whole gland radical postatectomy) to be a multifocal as opposed to a unifocal disease, even in men who have been given saturation biopsies with only one positive biopsy core.
Katz et al. have carried out a restrospective analysis of data from a series of 599 patients who were given a transrectal ultrasound (TRUS)-guided prostate biopsy followed by radical prostatectomy for localized prostate cancer between 2001 and 2009. They state that they “established very restricted criteria to select patients with very-low-risk disease for whom focal therapy would be suitable (only 1 biopsy core positive, tumor no larger than 80% of a single core, no perineural invasion, PSA serum level < 10 ng/ml, Gleason score < 7 and clinical stage T1c, T2a-b).”
In other words,they divided their 599 patients into two groups based on the pre-surgical biopsy and related data: those who would have been theoretically appropriate for focal therapy based on the criteria above and those who would not. They then used the post-surgical pathology data to assess whether, in fact, the men who were theoretically appropriate for focal therapy would have received effective curative treatment if focal therapy had been given.
Here are their findings:
- Only 56/599 men (9.3 percent) met the pre-surgical criteria for focal therapy.
- The average (mean) age of these men was 59 years.
- The mean number of biopsy cores taken from these men was 14.4.
- 47/56 (83.9 percent) were clinical stage T1c.
- 9/56 (16.1 percent) were clinical stage T2a-b.
- 44/56 patients (78.6 percent) would apparently have been adequately treated by focal therapy.
- 12/56 patients (21.4% percent) would clearly not have been adequately treated by focal therapy.
- All 12 patients had a bilateral, significant secondary tumor.
- 7/12 men (58.3 percent) had a Gleason score ≥ 7.
- 3/12 men (25 percent) were pathologic stage pT3.
Based on this series of 56/599 men, it is evident (yet again) that we do not yet have the tools to accurately identify men who are truly eligible candidates for focal therapy, unless we are willing to carry out extensive imaging and saturation biopsy studies prior to surgery — and even then it is known that some men will still be found to have had multifocal disease that was no evident at the time of initial treatment.
In saying this, we are by no means suggesting that the potential of focal therapy should no longer be explored. We are, however, suggesting that any patient who wants to consider focal therapy should be having it carried out within the context of a well-defined clinical trial conducted by an appropriately experienced research team. That way the patient will likely be getting high quality care (despite the risks) and everyone else in the future will have the opportunity to benefit from the data collected and the skill sets that are being enhanced.