IMRT alone vs. HDR brachytherapy + IMRT — short-term outcomes are similar


There have been strong suggestions over the years (at least from some physician groups) that the combination of brachytherapy with external beam radiotherapy (EBRT) was associated with superior outcomes compared to the use of EBRT alone in treatment of localized prostate cancer.

Wilder et al. have now analyzed the short-term outcomes of  284 patients with early stage prostate cancer treated between October 2003 and August 2008 with either high-dose-rate (HDR) brachytherapy and intensity modulated radiation therapy (IMRT) or IMRT alone. A total of 240 of the patients underwent HDR brachytherapy to 2200 cGy and IMRT to 5040 cGy; the remaining 44 patients received IMRT alone to 7920-8100 cGy. The median followup was 2.2 years.

The results of this analysis show the following:

  • The proportions of patients who had diabetes mellitus  or who received hormonal therapy did not differ significantly by radiotherapy technique.
  • The 3-year biochemical disease-free survival rates in low-risk, intermediate-risk, and high-risk patients treated with HDR brachytherapy and IMRT were 100, 98, and 93 percent, respectively.
  • The 3-year biochemical disease-free survival rates in low-risk, intermediate-risk, and high-risk patients treated with IMRT alone were 100, 100, and 67 percent, respectively.
  • There was no significant difference in biochemical disease-free survival or toxicity between treatment groups.
  • The similarity in outcomes between treatment groups remained unchanged when we examined only hormone-naive patients.

According to the authors of this study, “HDR brachytherapy and IMRT yielded similar biochemical disease-free survival and toxicity to IMRT alone.” They acknowledge, however, that,  “Longer followup will help to determine the role of HDR brachytherapy and IMRT in the treatment of early stage prostate cancer, particularly because a number of patients received androgen deprivation therapy and we delivered a higher biologically effective dose with combined modality therapy.”

Until such long-term data are available, however, the authors also suggest that it would appear reasonable to base the form of radiation treatment used on a specific patient on physician and patient preference, since there is no conclusive evidence that one form of treatment is any better than the other for localized prostate cancer.

4 Responses

  1. It would appear from the data that high-risk patients would benefit significantly from combined radiation treatment (93% vs 67%).

  2. Dear Curt:

    While that would seem to be true numerically, I suspect that, based on the numbers of high-risk patients included in this study, that difference is not statistically significant.

  3. I agree with Sitemaster. I remain amazed that in countless studies important information is often omitted. In this example, just how many patients were in each category of risk? And of course, how many patients had undergone ADT? Did any patients undergo HDR only? It appears not — and why not (this is considered an important standalone treatment option). As noted, 3-year biochemical survival rates are extremely short times in the treatment of prostate cancer. As is often reported, 5-year prostate cancer-specific survival rates are almost 100 percent in those men who are diagnosed as a result of PSA screening. In fact is often suggested that PSA screening gives a 5- to 10-year “jump” on the diagnoses of this disease cvompared to the pre-PSA days. One would think that in designing a time-consuming and possibly expensive study, more thought would go in to the design of same. This is not to belittle the effort, just a suggestion that a bit more thought might produce a more important outcome.

    Roger

  4. Dear Roger:

    Please note that some of the data you ask about may be available in the full paper as opposed to just the abstract. Also, since this is a retrospective analysis, the “study design” was dependent upon the available data, and not on a prospective trial. Such retrospective analyses are commonly not able to provide insight into data that one might like to know about because the data may either not be available or they may be too difficult (or too expensive) to obtain.

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