Benefit of brachytherapy in patients with early-stage prostate cancer is still unclear

It remains an unresolved issue as to whether interstitial brachytherapy has advantages compared to other therapy options in men with localized prostate cancer, nor do newer studies provide proof in this respect. This is the result of a report published by the Institute for Quality and Efficiency in Health Care (IQWiG) on 11 January 2011. In this report IQWiG examined whether newer studies challenged the findings of research already completed in 2007. However, it was shown that no relevant new evidence could be obtained from the recent studies. The conclusions of the final report of 2007 therefore remain unchanged.

Comparison of therapy alternatives

Prostate cancer is potentially curable as long as the tumour is still confined to the prostate gland. Several options are available for the treatment of such a localized tumour: besides complete surgical removal of the prostate (prostatectomy) or radiation with an external radiation source (external beam radiotherapy), low-dose-rate (LDR) permanent interstitial brachytherapy offers another therapy option. In this treatment, small radioactive particles are permanently implanted in the prostate via specific needles; these particles enable a local and targeted radiation of the tumour. As prostate tumours either stop growing or grow very slowly in many patients, the fourth option to be considered is a specific form of watchful waiting called active surveillance.

Evidence base is still insufficient

In the research now available, prepared as a rapid report, IQWiG was able to include 20 additional studies, which for the first time also included results of a randomized controlled trial (RCT).

However, overall IQWiG still rates the evidence base as insufficient. On the one hand, this is due to the fact that many studies showed deficiencies, so that the results cannot be reliably interpreted. On the other, the studies in part included too few participants and did not last long enough to demonstrate differences between therapies. As the course of early-stage prostate cancer is favourable in most patients (particularly in older ones), differences between therapies in respect of disease progression and survival may only become noticeable after several years.

No robust statements on survival possible

As in the final report of 2007, IQWiG therefore concludes that it has so far not been proven that, compared to the alternative treatment options, brachytherapy is at least equivalent in respect of the (disease-free) survival of patients. This is also due to the fact that PSA-based recurrence-free survival was often analysed as an outcome in the studies. However, this is a non-validated surrogate and in particular is not designed as a surrogate for a comparison between different treatment groups. Therefore no sufficiently robust conclusions can be drawn with regard to advantages or disadvantages of brachytherapy compared to other treatment options. It cannot therefore be definitely precluded that patients who undergo brachytherapy die earlier or have a shorter disease-free survival period.