Mediterranean diet, active surveillance, and low-risk prostate cancer

The abstract of a newly published study on the use of the Mediterranean diet (MD) by men on active surveillance (AS) for management of low-risk, localized prostate cancer states that

The MD is associated with a lower risk of GG progression in men on AS, and this is consistent with prior reports about the MD and reduced cancer morbidity and mortality.

Further information is available in a media release from the M. D. Anderson Cancer Center. However, we have asked the authors for a copy of the full text of this paper so that we can assess the details of the study. For example, the media release tells us that:

For every one-point increase in the Mediterranean diet score, researchers observed a >10% lower risk of progression. After a median follow-up of 36 months, 76 men saw their cancer progress.

What the abstract and the media release do not tell us are almost any other details about the actual outcomes of this study, especially among the men who were on AS for longer periods of time.

4 Responses

  1. Thanks for posting this.

    It is good news, of course, but it did need taking with a small pinch of salt. It’s small, as retrospective questionnaire studies go, but more worrying is that the follow-up is only 36 months, far to short a time to “prove” anything about early prostate cancer, so it really isn’t possible to fully address the benefits of the diet.

    I’d also like to see the full text, but like so much scientific knowledge, that come at a price.

    But don’t get me wrong; it is good news, for sure. But we really can’t tell how good.

  2. Dear heenan73:

    Respectfully, you need to read the follow-up report with the details.

  3. Thank you; I have, since writing my original post.

    I am still not convinced by this small questionnaire study with a very short life. I am further concerned that other factors are poorly controlled for. And, of course, without access to the full text, no way to assess the article based on sponsorship and author details.

    I have no quibble with the MD — but I do have a quibble with mutton dressed as lamb research. Prostate cancer is a marathon, not a sprint, and research that fails to recognise that should not be taken too seriously. If the authors wish to promote the MD, then I’d a expect at least a a 10-year study (preferably 20), with some hard facts on outcome.

  4. Dear heenan73:

    Again, respectfully, NO ONE is suggesting that this study “proves” anything. All that it shows, based on the available data, is that if one is already eating an MD at the time one is diagnosed with low-risk forms of prostate cancer and one goes on AS, there is a better chance of longer time to disease progression. This was not “mutton dressed as lamb” at all. It was simply mutton, but one did have to read the whole paper. Ask your urologist whether he can provide you with a copy.

    Similarly, EVERYONE, would like to see a prospective, 20-year-long, highly structured study, with perhaps 15,000 patients enrolled (similar to the Prostate Cancer Prevention Trial in the 1990s), which could give us much better long-term data on the effects of diet related to prostate cancer. Alas, the costs associated with such a trial today run into the tens (if not hundreds) of millions of dollars. Such trials are incredibly complicated to conduct in ways that one can accurately track patient behaviors over time. And then there is the other problem, which is that … by the time the study is completed (in say 2050) it may be out of date because (for example) we have discovered much better ways to select patients for specific forms of management. Your sitemaster will have a low probability of being around to read the results, but that doesn’t mean it isn’t worth doing.

    There was no external commercial support for this trial or any other form of “sponsorship”. The authors were, at the time of the study, all full-time employees of the M. D. Anderson Cancer Center. One of the authors, Dr. Kim, does appear to have joined Merck & Co. as a clinical research scientist by the time the paper was published. Dr. Davis reports having received grants or fees from Janssen, and GenomeDx and Intuitive Surgical unrelated to this research.

    Here is the information about how the staff at M. D. Anderson were being funded in relation to this study:

    “Justin R. Gregg is funded (in part) by an early career award from the Prostate Cancer Research Program of the US Department of Defense (grant W81XWH-18-1-0173; principal investigator Justin R. Gregg) and by an MD Anderson Cancer Center Specialized Program of Research Excellence career enhancement award from the National Cancer Institute (grant P50 CA140388; principal investigator Christopher J. Logothetis). Xiaotao Zhang is funded (in part) by a research training award from the Cancer Prevention Post-Graduate Training Program in Integrative Epidemiology of the Cancer Prevention and Research Institute of Texas (grant RP160097; principal investigator Margaret R. Spitz). Carrie R. Daniel is funded (in part) by a National Cancer Institute Cancer Center Support Grant (CCSG 5P30 CA016672-37) to MD Anderson (principal investigator Peter W. T. Pisters).”

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