Early data on targeted focal therapy in treatment of localized prostate cancer

The potential role of targeted focal therapy in the management of localized prostate cancer is yet to be well-defined, so a paper just published on line in the Journal of Urology is of value in helping us to set our expectations.
Barqawi et al. report data from a series of 62 patients treated with targeted focal cryotherapy (TFC) over a period 3 or 4 years, between 2006 and 2009, and followed for a median of just over 2 years since initial treatment. The authors defined this treatment as the

complete ablation of all clinically detected cancer foci within the prostate using minimally invasive technique with preservation of the sphincter, normal gland tissue, and the neurovascular bundle.

To be considered for treatment with TFC, all patients had to

• Have a diagnosis of low-risk, organ-confined prostate cancer (defined by a clinical stage of T1c to T2b, a Gleason score of ≤ 3 + 4= 7 on TRUS-guided biopsy, a tumor burden of ≤ 50 percent, and a PSA of < 10 ng/ml).
• Show no evidence of metastasis
• Have a life expectancy of at least 1 year
• Undergo  a three-dimensional mapping biopsy, after which patients also had to have
  • < 20 percent positive overall involvement of the prostate based on volume
  • An index lesion volume of < 5 cm³
  • ≤ 4 zones involved with cancer
  • A cancer-free periurethral zone > 5 mm

Here are the core results reported by Barqawi et al.:

• Patients ranged between 40 and 85 years of age (mean, 60.5 ± 6.8 years).
• The average (median) duration of follow-up was 28 months (range, 26 to 31 months).
• At baseline
  • Mean prostate mass was 39.3 ± 12.8 g.
  • Mean AUA symptom score was 6.0 ± 5.6.
  • Mean  sexual health (SHIM) score was 16.9 ± 8.3.
  • Mean PSA was 5.1 ± 2.2 ng/dl.
  • Mean number of positive cores found in 12-core TRUS biopsy was 1.41 ± 0.93.
  • Mean number of positive cores from the mapping biopsy was 1.74 ± 1.13.
• At 1 year of follow-up,
  • 50/62 patients (81 percent) had a negative biopsy
  • 12/62 patients (19 percent) had a positive biopsy.
  • The 12 patients who had a positive biopsy all had 1 or 2 positive biopsy cores exhibiting Gleason 3 + 3 = 6 disease.
• The average decrease in PSA level over 2 years of follow-up was 3.0 ng/ml.
• Over the full course of follow-up
  • 18/62 patients (29 percent) had a rise in their PSA over the course of follow-up.
  • The average decrease in AUA symptom score was 1.5 points.
  • There was no significant decrease in the patients’ sexual health (SHIM) score.
  • There were no episodes of incontinence or other severe side effects of treatment.

Barqawi et al. report that TFC “provides a feasible and practical option for the treatment of low-risk prostate cancer with minimal impact on” quality of life in this series of carefully selected patients.
The “New” Prostate Cancer InfoLink thinks it is hard to know what to make of these data, but here are some general observations:

• The follow-up period is very short.
• The failure rate is probably higher than the treating physicians were hoping for.
• One has to ask how many of these patients needed treatment at all (particularly considering a man of 85 with low-risk disease!).
• The fact that the treatment was “feasible and practical” (which it certainly seems to have been) doesn’t necessarily imply that it was either appropriate or necessary.

Having said that, there are always going to be some patients diagnosed with low-risk prostate cancer who are unable to “deal with” the idea of short- or long-term active surveillance. The idea that one might use something like TFC to treat a 40- or 50-year-old man diagnosed with low-risk disease is probably a better one than the idea that one would give him an (almost literally) “full-blooded” radical prostatectomy. But doesn’t one then need to be able to carry out that TFC or other form of targeted focal treatment with something like 95 percent effectiveness at 2 years of follow-up?
The “New” Prostate Cancer InfoLink is going to need to see more compelling data than these before we would start to consider that the value of targeted focal therapy was demonstrably “proven” for men with low-risk disease who are unable to handle the idea of active surveillance.