Metformin + ADT in treatment of advanced prostate cancer

Yet another study, just published in the Journal of Urology, has indicated a clear association between the use of metformin along with androgen deprivation therapy (ADT) in the treatment of advanced forms of prostate cancer.

The study by Richards et al. reports findings from a retrospective analysis of data from > 87,000 US Veterans, all treated with ADT for advanced forms of prostate cancer between 2000 and 2008. The study cohort was divided into three groups:

    • Group A: Men treated with ADT who did not have diabetes (61 percent of the cohort)
    • Group B: Men treated with ADT who also had diabetes but who did not receive metformin (22 percent of the cohort)
    • Group C: Men treated with ADT who also had diabetes and who did receive metformin (17 percent of the cohort)

The study excluded patients who were on ADT for < 6 months or who only received ADT in combination with radiotherapy for treatment of localized prostate cancer.

The research team found the following results:

  • Compared to the men in Group A
    • Men in Group C had better overall survival (OS) (hazard ratio [HR] = 0.82) than men in Group B  (HR = 1.03)
    • Men in Group C had better cancer-specific survival (CSS) (hazard ratio [HR] = 0.70) than men in Group B (HR = 0.93)
    • Men in Group C had a noticeable reduction in risk for skeletal-related events (SREs)

Richards et al. conclude that:

Metformin use in Veterans with [prostate cancer] receiving ADT is associated with improved oncologic outcomes. This association should be evaluated in a prospective clinical trial.

Given that this was a study based on VA data, and would therefore have included a relatively high percentage of non-Caucasian patients, it might have been interesting to know whether similar results were identified in the different racial/ethnic groups of patients (even if these data groups were not large enough to demonstrate statistical significance).

The “New” Prostate Cancer InfoLink agrees with Richards et al. It is high time that a large, prospective clinical trial studied the combination of metformin + ADT in first-line treatment of advanced prostate cancer among men who do and do not have diabetes.


6 Responses

  1. Any form of ADT? I’m getting ready to make life choices: 66 years old, Gleason score 4 + 3 = 7 (grade group 3); tumor in transition zone; already take metformin 1000 mg per day.

    Just adding ADT sounds better than what I’m about to do: RT or RP.


  2. Dear Ed:

    You may be ignoring two things.

    The first is that long-term ADT can also come with a whole series of adverse effects that can vary enormously (and unpredictably) from person to person.

    The second is that ADT is not a curative form of treatment. Sooner or later, everyone progresses on ADT, and then you are on to a whole series of other drugs that all come with their own lists of complications and side effects. Starting ADT early is not usually a recommended therapeutic strategy here in the US.

    Futhermore, it doesn’t sound to me as the RT and RP are your only options in the first place. However, they may be the only ones your insurance provider is willing to pay for.

  3. OK. Thanks. My insurance is the VA. Trying to get OK right now to do BBT at UC Davis or Stanford.


  4. Hi. Waited a week to post this as I know about the down time. Anyway, wanted to ask what other treatments may be available, as you stated in your reply. Maybe proton or …?

    Thanks, Ed

  5. Dear Ed:

    If you join our social network we can offer you that sort of guidance there.

    To do this we are going to need some very specific information about you and your diagnosis.

  6. Hi Ed,

    I trust by now you may have found some of that guidance on the social network. Here is something to consider about ADT: it often works for either about 10 years or indefinitely long, based on using the older drugs for ADT (not Xtandi, Erleada or Zytiga, which might lead to even longer success in intermediate-risk men without hormone resistance or metastases, but none approved for that yet); metformin appears to substantially reduce side effects of ADT. However, it is not clear how much of the benefit was due to metformin and how much to the associated exercise program.

    These days, with the excellent radiation now available (including imaging and targeting technology), it makes sense to use radiation now plus ADT for intermediate-risk patients, with metformin in support. (I’m a layman who had radiation in 2013 with my fourth round of ADT in support; I have had no enrolled medical education.)

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