Data from a prospective trial of HIFU-based hemiablation for localized prostate cancer

A new report provides data from a prospective, single-center, Phase II trial of high-intensity focused ultrasound (HIFU) in prostate cancer hemiablation as a form of focal therapy. The study was carried out in Belgium.

The new paper by van Velthoven et al. describes the outcomes of a cohort of 50 patients, all treated with prostate cancer hemiablation as first-line therapy using the Ablatherm HIFU technology, starting in 2007 and with a maximum follow-up of 8 years at the time of publication. For interested readers, the entire text of the paper is currently available on line.

The selected patients were all initially diagnosed with biopsy-proven, clinically localized, low- or intermediate-risk prostate cancer. The patients all appeared to have cancer confined to a single lobe of the prostate (i.e., unilateral prostate cancer) at time of diagnosis and work-up, in complete concordance with the lesions identified by magnetic resonance imaging (MRI). Post-treatment follow-up included regular serial measurement of the patients’ PSA levels. Biochemical recurrence was reported using both the Stuttgart and the Phoenix criteria. Complete follow-up data were available for all patients.

Here are the key results reported by the authors:

  • Average (median) follow-up was 39.5 months (range. 6 to 94 months).
  • Average (mean) nadir PSA level after first-line treatment was 1.6 ng/ml (a 72 percent reduction from pre-treatment PSA levels; P < 0.001).
  • Average (median time) from treatment to nadir PSA level was 3 months.
  • Biochemical recurrences occurred in
    • 14/50 patients (28 percent) according to the Phoenix criteria
    • 18/50 patients (36 percent) according to the Stuttgart criteria
  • Patients with intermediate-risk disease at diagnosis were much more likely to exhibit biochemical recurrence than the patients with low-risk disease (see Figure 2 and Figure 3).
  • The overall 5-year actuarial survival rates were
    • Metastases-free survival — 93 percent
    • Prostate cancer-specific survival — 100 percent
    • Overall (all-cause) survival — 87 percent
  • 8/50 patients received post-treatment biopsies after biochemical recurrence according to the Phoenix criteria.
    • 3/8 patients had a positive biopsy evident in the untreated, contralateral lobe
    • 1/8 patients had a positive biopsy evident in the treated, ipsilateral lobe
    • 2/8 patients had a positive biopsy with cancer evident bilaterally (i.e., in both lobes).
  • Two patients had Clavien–Dindo grade 3b complications related to their treatment (urethral strictures).
  • Complete continence (with no pads) was documented in 47/50 patients (94 percent).
  • Erections sufficient for intercourse were documented in 80 percent of the 30 patients who had erectile function sufficient for intercourse prior to treatment.

van Velthoven et al. conclude that:

Hemiablation HIFU therapy, delivered with intention to treat, for carefully selected patients affords mid-term promising functional and oncological outcomes. The effectiveness of this technique should be now compared with whole-gland radical therapy.

There is no doubt at this time that various forms of hemiablative treatment (HIFU-based hemiablation included) offer an appropriate option for the management of carefully selected patients with localized prostate cancer. The question is, which patients both need and will benefit from this treatment (or any other form of appropriate focal therapy) and can we identify these patients with accuracy?

Table 1 of the current paper suggest that

  • 30/50 patients (60 percent) had low-risk prostate cancer (and therefore might have done equally well on active surveillance).
  • 14/50 patients (28 percent) had favorable intermediate-risk prostate cancer.
  • 6/50 patients (12 percent) had unfavorable intermediate-risk prostate cancer.

One therefore needs to be very clear that — arguably — only 6/50 patients actually required immediate treatment and that all of the others could have been monitored on active surveillance for at least a while before any treatment was required. It is also relevant that these patients were relatively elderly, with an average age at treatment of 74 years. In addition all 50 patients seem to have had relatively small prostates.

The “New” Prostate Cancer InfoLink finds these data to be rather less than compelling. If one is going to get treated for low-risk prostate cancer, one should reasonably expect to be cured. (Otherwise, why get what may well be unnecessary treatment?) Indeed, if one is treated for a small amount of intermediate-risk cancer, one could also, reasonably, expect to get cured. On the other hand, because these 50 patients were all treated by HIFU, we have no idea whether their pathological Gleason scores would have corresponded to their clinical Gleason scores.

We would disagree with van Velthoven et al. that their data justify comparison of this technique to whole gland radical prostatectomy in patients like these — for the simple reason that 60 percent of their patients should, almost certainly, have most appropriately been managed initially on active surveillance.

One Response

  1. Well said.

    Thanks for the update.

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