Who is an appropriate candidate for focal therapy, and how do we know?

Yesterday we posted a commentary on a review by Marberger et al. that addressed the potential of certain techniques as focal therapies for localized forms of prostate cancer. In the following commentary, we shall address an associated review that discusses which patients can or should be considered eligible for such types of therapy.

It will be evident that there are limited data from relatively few patients that can be used to answer the question, “Who is appropriate and eligible for focal therapy?” A recent paper by Sartor et al. has attempted to address this issue, but the authors freely admit that the guidance they can offer at this time is not exactly definitive!

For what it is currently worth, here are what seem to be the key points made by Sartor and his colleagues in this paper:

  • At present the most likely candidates for focal therapy are patients with low-risk, small-volume tumors, located in a single region or sector of the prostate, who would clearly benefit from early intervention.
  • Prostate cancer tends to be multifocal, even in its earliest stages. However, secondary cancers are usually smaller and less aggressive than the “index” cancer (the most clinically significant and largest focus of cancer).
  • When a single focus of cancer is found in a single biopsy core, physicians tend (rightly) to suspect that more foci of cancer are also present in the prostate.
  • Nomograms are available to predict the presence of a very low-risk or “indolent” cancer, based on the patient’s clinical stage, Gleason grade, PSA level, and prostate volume, along with the quantitative analysis of the biopsy results.
  • Imaging techniques, particularly magnetic resonance imaging and magnetic resonance spectroscopic imaging, have been used with some degree of success to evaluate men with early-stage prostate cancer.
  • Large-volume cancers can be seen reasonably well with such techniques, but small lesions have been difficult to detect reliably or measure accurately. Nevertheless, magnetic resonance imaging and magnetic resonance spectroscopic imaging can aid in evaluating patients with prostate cancer being considered for focal therapy by providing additional evidence that the patient does not harbor an otherwise undetected high-risk, aggressive cancer.
  • More work is necessary before staging studies can uniformly characterize a prostate cancer before therapy, much less reliably identify and locate small-volume cancer within the prostate.

Even given these provisos, Sartor et al. go on to argue that exploring the potential role of focal ablation as a therapeutic option for selected men with low-risk, clinically localized prostate cancer does not, in their opinion, need to await the emergence of perfectly accurate staging studies.

In their opinions, modern biopsy strategies, combined with optimal imaging and nomograms to estimate the pathologic stage and risk, taken together, provide a sound basis for the selection of appropriate patients for entry into prospective clinical trials of focal therapy.

2 Responses

  1. Focal therapy (focal HIFU) is now available in the UK. The aim of focal HIFU is to leave untreated as much of the healthy tissue as possible. It is the equivalent treatment for men with prostate cancer as for women with breast cancer, the male lumpectomy.

    Focal HIFU could be suitable for men with low or intermediate risk prostate cancer who have unifocal or unilateral disease. If (following careful prostate mapping) the clinician is confident that the cancer is confined to a specific area in the prostate, they then can just treat these areas with HIFU and monitor the untreated areas.

    All men are followed up after focal HIFU with PSA tests every 3 months. If the PSA rises then further diagnosis is undertaken, but for approximately 90 per cent of men treated, focal HIFU should be the only treatment required. If further treatment is required this is usually a further HIFU treatment, though any of the traditional treatments including surgery and radiotherapy are possible after focal HIFU.

  2. Dear Jessica:

    While we appreciate the fact that focal HIFU is possible, there are no long-term data whatsoever to demonstrate that it is effective and safe. It is the opinion of The “New” Prostate Cancer InfoLink that all focal therapy should currently be carried out in a carefully controlled clinical or registry trial context to collect data sufficient for analysis of effectiveness and safety over a minimum of 5 years. We would also note that the value of HIFU in men with a Gleason score > 6 is still in question, and the value of any treatment for the majority of men with a Gleason score of 6 or less is also questionable (especially if those men are >70 years of age). The availability of a treatment is not by any means the same as proven clinical value in a highly defined set of patients.

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