“The PSA clock” by Dr. Michael Glodé


Dr. Michael Glodé is a medical oncologist who practices in Colorado, and who has extensive experience in the management of prostate cancer. He also blogs on a regular basis at prost8blog. Your sitemaster tries to remember to check in on that blog site from time to time because it has long been very clear that Dr. Glodé takes the needs of his patients very seriously.

This morning, your sitemaster found out that he had missed a blog post by Dr. Glodé from late December.

In his post from December 21, entitled “The PSA clock“, which you can read for yourself, Dr. Glodé talks about how the constant monitoring of PSA levels can come to rule the lives of many patients — and many of Dr. Glodé patients included. He makes the point that letting a single test come to take over one’s life may not be the best idea when it comes to the quality of one’s life — even for men with advanced forms of prostate cancer.

He is, of course, not suggesting that the PSA test is an unimportant test. But he is suggesting that, under appropriate circumstances, the obsessive need to have one’s PSA measured every 3 months, as if the small variations that may be observed are critically important to everything one is going to do over the next 3 months, can actually become debilitating for many patients, and that “letting go” of that obsessive need may be something a lot of patients need to think about.

Of course, it’s easy to say this, and probably much, much harder for many patients to do, but Dr. Glodé has been treating certainly hundreds and probably thousands of men with progressive and advanced prostate cancer for the best part of the past 30 years. He offers his comments with relevant background information and with sincerity. We recommend this blog post to all our readers.

And how did your sitemaster find out about Dr. Glodé’s post after missing it? Because when he got up this morning, there it was in an e-mail that told him about the content of this month’s ASCO Connection, which is a publication circulated to members of the American Society for Clinical Oncology (ASCO). Clearly the editors of ASCO Connection thought that this was an article that should be placed under the noses of all of ASCO’s members around the world.

9 Responses

  1. I have great respect for Dr. Glodé, but I couldn’t disagree with him more in his apparent assumption that his values are valid for most of his patients.

    For example, he finds the PSA clock “dehumanizing”; I find it as useful a reminder as a gas gauge or weather forecast. He says “it provides a second hand when we should be looking at the hour hand, the calendar, or the seasons.” I understand his allusion to the granularity of metric, but in the absence of an hour hand or calendar, the recommendation should be to look at aggregate of 3600 ticks, or 86400, rather than to look away altogether. (That would be the right recommendation for me, anyway. I also know many men who fit Dr. Glodé’s description; and while I provide them support and encouragement, I can’t help wishing someone had taught them better tools for assessing risk than using their feelings of anxiety as the sole measure.)

    What I find completely baffling are the following questions, which I think he intends rhetorically:

    “Imagine if your cardiologist could measure the thickening of your coronary artery year by year in microns as plaque builds up. Would you want that test? Would it change how you lived if you knew for certain that you will die from a stroke in 8 years?”

    My answer to both questions would be “Of course!” I always want the best possible information about the future. If I knew I were certain to die in 8 years, it would change my plans for retirement, my relationship with my grandchildren, and my priorities in daily life. If none of my behaviors served to hasten or postpone death or disease, I’d spend no time at all at the gym (which I detest) and I’d indulge my love for food even more than I do.

  2. Dear Paul:

    I don’t think Dr. Glode is talking about people like you as much as he is talking about the large numbers of men who you so precisely describe:

    “I also know many men who fit Dr. Glodé’s description; and while I provide them support and encouragement, I can’t help wishing someone had taught them better tools for assessing risk than using their feelings of anxiety as the sole measure.”

    And as a patient who has had a heart attack, yes there are tests I get done every 12 months or so to monitor all sorts of things, but I don’t rush out to get them done every 3 months or so.

  3. Dear Paul and Mike,

    Thanks for your insights regarding the PSA Clock. To expand just a bit on the overall issue, the truth is that many (and in some studies most) men with prostate cancer, even high-risk prostate cancer, die of something else. I will be presenting such a study at the upcoming ASCO Genitourinary Cancers conference.

    The attempt to compare the PSA to a micron sensitive evaluation of the coronary arteries was made to try and get the perspective off of the PSA. I should have used lung cancer instead of a stroke as the terminal event for the hypothetical. (Actually that is a fairly common cause of death in prostate cancer patients.) The point is that we will all die of something, often cardiovascular or cancer. When we have a PSA clock, we can watch ourselves headed down one slope, even though that may well not be the slope that ends up in the lake for us. The psychological issue is important. We (physicians and patients alike — but especially engineers, by the way…I have had engineering guys bring in graphs with second and third derivatives of their curves and proceed to tell me that the math proves they have two — not three, not four — clones of cancer cells) are all addicted to the PSA. I use it all the time in my patients to assess whether a given treatment is working. However, in the 75-year-old guy with a doubling time of 2+ years, I am now encouraging them to consider not ever following it. If they happen to show up with painful metastases in 10 years, I don’t think they have lost much and my thesis is that they will have enjoyed their life much more than visiting with me every 3 months.

    I appreciate your insights and thank you for referring patients who follow this blog to prost8blog.com. I try (somewhat unsuccessfully) to do a post about once/month on a topic that my patients have brought to my attention, and some seem to find it helpful. I am still philosophically attracted to the “Time in a Bottle” mentality when it comes to thinking about PSA.

  4. Dear Dr. Glode:

    I shall make sure I get to your presentation in Orlando in February. Thanks for taking the time to “stop by” and comment.

  5. This is near nonsense. And “habituation” is a much better word than “addiction.” Once cancer had been diagnosed, PSA should become a routine vital sign, no matter how “indolent” the cancer or how “successful” the treatment. Its an easy, inexpensive test, and for now its all we really have. Give us the facts first, please, then let us decide together how much we should worry.

  6. You are certainly welcome to look at your PSA as often as you wish, and I support my patients doing that as well, although as my essay points out, I don’t think it is healthy to become obsessive about it. I would be happy to learn from anyone who has data supporting the fact that some interval (weekly, monthly, quarterly, etc.) is superior for monitoring versus some other interval in terms of outcomes. In the majority of my patients I recommend monitoring quarterly and often monthly if we are monitoring a new treatment.

    I would point out that the PSA has not met Prentice criteria for valid surrogacy in a variety of studies and is not accepted by the FDA as a surrogate for that reason. I could go on, but there are significant differences between the PSA and the vital signs, not least of which is an old medical axiom, “We call them vital signs because they are vital”. Please don’t take it wrong, but I don’t think an essay pointing out some issues regarding quality of life and PSA obsession is “nonsense”, however you are entitled to your opinion, as am I. I have seen too many men ruin a lot of good days needlessly and I hope the essay helps a few avoid that, but it is definitely a personal choice that should be discussed between each patient and his physician.

  7. It often seems to me we’re all sailing aboard the Nina, Pinta, or Santa Maria. Some are non-swimmers, frightened by the water. Others, ignorant and superstitious, worry about sailing off the end of the earth. More than a few believe the captain is loco, and wonder how they were talked into this voyage in the first place. Scattered among us, the old salts. Nothing, save an empty flagon, bothers them.

  8. Rob:

    I really like that analogy. … You may be on to something. … :O)

  9. Fair winds and following seas, Dr. G. I’ll crew for you anytime, but if our cruise lasts a year I’ll want four PSA checks, and daily grog of course. (~) — your new recruit before his mustache turned white with worry

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