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The paradox of the Prostate-Specific Antigen (PSA) test (mitpress.mit.edu)
32 points by anarbadalov on Nov 3, 2021 | hide | past | favorite | 47 comments



This article isn't very good IMHO because it focuses on emotional considerations rather than the underlying math. The core problems with the PSA test is that it has relatively low statistical specificity and it hasn't been shown to have any statistically significant effect on mortality in aggregate, and the resulting treatment options do have statistically significant morbidity. Hence all the debate about when, how often, and for whom. All the arguments about increased anxiety are pretty unhelpful and obscure the underlying statistical challenges.


My understanding was that the article was specifically meant to be about the emotional considerations, which are a result of the statistical challenges.

BTW: one flipside of the high sensitivity is that if you have your prostate removed the PSA becomes a fantastic test. I get it once a year and if it's anything other than zero I know I have a problem


Indeed. My father had prostate removed (due to a tumor) and does PSA screening regularly. A while after the surgery his PSA showed up again and started raising - slowly. Unfortunately, it took _years_ before doctors were able to locate source of it and remove it. I suspect you can imagine the impact it had on his mental well-being. Each test was bringing him closer to potentially grim diagnosis. He knew he had it, but he didn't know where and how serious it was going to be.

I was shocked by it. So many times I've heard that people get diagnosed too late, and here was my father with as early as possible confirmation of spread of his cancer and he was told to wait.

Edit: clarification on the cause of prostate removal.


If you don’t mind me asking, how did they find it and remove it years later?


PET scan, the tumors where in lymph nodes. They got rid of them with surgery.


>> if it's anything other than zero I know I have a problem

Is that actually factually always true?

At least two of the men I know have had prostate removed and show occasional PSA spikes, that have stumped their doctor for a decade but has never led to any specific issues concerns problems or actions (other than, yes, anxiety...)


That is concerning. I've heard that PSA can be produced in other parts of your body but at very low level, not enough to pass the threshold of concern. If the spikes are high and the test is reliable then there could be something lurking in the body somewhere. The other answer also suggests it's difficult to diagnose where the cancer (or tumor, etc.) is located.


Here's an authoritative source on Protein Specific Antigen ( aka KLK3, Kallikrein related peptidase 3 ): https://www.proteinatlas.org/ENSG00000142515-KLK3/tissue


I don't understand this thinking at all. Most prostate cancers are a non-issue if caught and treated early. As my father's doctor told him - prostate cancer, if caught early, is largely a disease you die with, not a disease you die from. The PSA is the best tool we have for early diagnosis and treatment. I have the test done as part of my annual checkup and have done so for the past 15 years. Let me put it this way - it's a heckuva lot less invasive than a colonoscopy!


Get your colonoscopy. Period. Don't let people tell you fables about "the prep" or be afraid of something going up your butt.

"The prep" is a bit unpleasant for a couple of hours, but no big deal. The actual procedure is done under propofol. Consider that part the best nap you will ever get.

You will either get a clean bill of health, or the doctors will find something that is easily treated right then and there. The stigma (especially of men) about this procedure will lead to countless numbers of them to die from something that doesn't have to be.

Get the procedure when your doctor says. Just do it. Please.


I just had mine a couple days ago and opted for no sedation because I wanted to see what's going on. It was a bit unpleasant, at a couple spots the doc snakes the scope around some sharp bends and you can feel that inside of you. It totally paid off, though, I had a clear view of the monitor and could watch everything going on. I've done a fair amount of optical engineering so I was really curious about the whole thing and it's really fabulous.

Unfortunately, they found quite a few polyps and one was large enough that a) the doc marked the spot with some dye and b) they cauterized it. The puff of smoke inside my gut was definitely the highlight for me.


Similar experience here.

In my case, I didn't want to be administered a powerful substance (and experience any lasting effects) unless absolutely necessary. My understanding is that adverse reactions are very rare, but if the only upside is avoidance of minor discomfort for 30-60 minutes, I don't see the point.


I cannot imagine why you’d possibly want to be awake for it… especially to the point of calling it fabulous? I’m sure they could have given you a video afterwards without the discomfort.


My original goal was to avoid the extra time and having to organize a ride but also the aftereffects - the last time I felt weird a day or two later (could have been a red herring).

I just found it totally fascinating to see my own insides live in in high res and listen to the doctor and nurses talk about what was going on.


Well, I guess everyone has their own interests. I'm glad you got so much out of it. Personally I have no desire to see and feel myself be rotorootered and am very happy to knocked out, but it would be nice not to have the sedation after effects. The last two times I got one I ended up taking like a 4h nap afterwards. I'd imagine you also wouldn't have the same restrictions around drinking water cutoff times without sedation.


That's an interesting idea, asking for no sedation. Next time....


I should have also mentioned that my colonoscopy was done under a sedative, I wasn't knocked out - so I got to see the whole thing! The doctor provided a narrative as we went along. At one point they were having issues making a turn and I could feel it and let them know so the nurse squoze my guts in some way to allow them to get around it. They even showed me the polyp when they found it (I was laying on my left side with the monitors right in front of me - so I could watch the whole thing.) Except for that one turn I didn't feel a thing.


I've had my colonoscopy - I speak from experience when I say the PSA test is a heckuva lot less invasive! With that said, the colonoscopy wasn't bad at all - not nearly as bad as people make it out to be. They found a polyp, extracted it and did a biopsy, and found it to be benign. Now I have to have a colonoscopy every 5 years instead of every 10. Yay!!! :)


The prep for my second colonoscopy had me passed out on the bathroom floor. More than "unpleasant".


There are multiple protocols for the prep. Check with your doctor for an alternative and mention the passing-out bit.


i believe (from experience) that propofol is massive overkill for what can be done easily with versed, making an even easier total win, to your point!


Yeah, didn't like the aftereffects of Propofol the first time I had it so I did it without sedation the second time. Saves time as well.


The problem is twofold: the test is notoriously flakey, and the cancer is frequently not an issue. You're also absolutely right that many more men die with prostate cancer than from it — but that's most commonly _without_ treatment or even knowledge of it!

The trouble is exactly that it _can_ manifest early and it can become aggressive and that's when it's crucial to catch and treat.


For decades the cancer treatment industry has beat the drum of early diagnosis and treatment. I looked into statistics a few years ago, and the drum beat appears correct for skin cancer.

I couldnt find statistical benefits of early diagnosis for internal cancers. The statisticians remove people from the counts if they die during treatment. So the 'early diagnosis' numbers were meaningless because they stop considering all the people in the original group.


Early diagnosis can give a false impression by increasing the time between when you're diagnosed and when you die, simply by bringing forward the former without changing the latter.

However, for diseases like Hodgkins where we have what is in effect just a cure, albeit a fairly drastic one (I had Hodgkins in my mid-20s, I'm now in my 40s) clearly early diagnosis isn't just playing with the statistics. If I hadn't been diagnosed, they couldn't cure it, and then I'd almost certainly just be dead.

So the answer is it's complicated.


The cynic would say it's a scam to transfer wealth from the cancer-afflicted to the medical industrial complex. After seeing how both my parents' cancers played out, I can see the appeal of that idea. Years of discomfort, hundreds of hours spent in medical facilities (mostly waiting around) and expensive medicines and fees, and in the end you're still just as dead.


But that simply isn’t true for many types of cancer if you catch early.


>I don't understand this thinking at all.

Which thinking do you not understand?


And I recommend both! No matter how invasive the test, cancer is worse.


Malignant cancer is certainly worse, but many prostate cancers that are exposed by this test are totally benign.


And not discovering early might very well mean the cancer becomes a lot more serious. Never understood the fear of medical exams.


Over treatment is a real issue and can create more serious issues that the original problem.


There absolutely are things worse than cancer.


Depends on the cancer, doesn't it?


The trouble with preventative medicine is that it is creating artificial anxiety on the basis of the possibility of illness. Thus, we the people are constantly in a state of "possible sickness" and instead of thinking of illness as what it has always been (a state of lack of health which manifests in lack of well-being), we are made to think of illness as "having a wrong parameter".

The acceptance of mortality (or its lack) is key to this.

Or, on the other hand, we can think of health as "public health", and forget about the individual. But I reject this proposition.


We are always possibly sick at all times, getting a test done will not prevent or change that. The fact that we don’t get anxiety daily is because we forget about it and move on with life. But what is worse? Getting anxiety over being sick for a couple days or living in regret because you didn’t get a simple test to discover something potentially treatable early on?

If you “accept mortality” in the way you seem to imply then there’s no need to worry about health anyway. Should I just “accept” that if it wasn’t prostate cancer something else would’ve killed me anyway, so why check?


> The trouble with preventative medicine is that it is creating artificial anxiety on the basis of the possibility of illness.

I don't see it this way. Regardless of the existence of preventative care, what brings anxiety is the knowledge of the existence of the illness and the possibility of being sick. The preventative care (assuming we mean test/monitoring and not constant medication) is what shows me that the anxiety is unfounded.


I honestly have no idea what you're trying to say. Are you against preventative medicine? Are you against public health initiatives?


I am against preventative medicine in the case where it has not been shown to have benefits worth the costs.


> The trouble with preventative medicine is that it is creating artificial anxiety on the basis of the possibility of illness

The possibility of illness exists with or without preventative medicine. Preventative medicine decreases that possibility, and reduces anxiety.

> The acceptance of mortality (or its lack) is key to this.

Whether or not you accept mortality has no effect on whether it is a condition we all share. Though it's unclear to me if you wish for everyone to accept mortality, or reject it.

> Or, on the other hand, we can think of health as "public health", and forget about the individual.

I'm trying not to read something into this, but it's hard not to. In general, health is personal/individual, even if the way it affects you can then affect others. Of course, in the case of infectious disease, individual infection leads to transmission and public spread, so it should be thought of at more than just an individual level. (That isn't really relevant for the PSA, though. That's quite individual.)


I'm one data point pro PSA: at 43 I had elevated levels, biopsy, detected cancer, prostatectomy followed by full recovery. I can also attest to the anxiety about the two big Is: incontinence and impotence. Luckily I had a great surgeon who'd done hundreds of prostatectomies and everything turned out well.

The urologist who originally treated me gave me one good piece of advice, he said "statistically you're not likely to die of this but the problem with statistics is that they may not apply to you". When the surgeon removed my prostate he said that I would have developed symptoms sooner or later even if it hadn't metastasized.


> "statistically you're not likely to die of this but the problem with statistics is that they may not apply to you"

I like that. A lot. Thanks for the quote.


I think I'm well versed in statistics, but I don't understand the problem. Why not test everybody, and then adjust the threshold of intervention to reduce overall mortality? (Or maximize quality of life * years, or some other metric taking patient well-being into account.)


This video does a good job also of covering the topic of over-testing/over-treating potential cancer (or creating "Fake Disease" as it terms it):

https://www.youtube.com/watch?v=yNzQ_sLGIuA


I had a positive PSA test 11 years ago. Followed by a confirming biopsy. Followed a couple days later by a robotic surgery.

Problem solved, obviously, I'm still here. <g>


I wonder if in the book the author explores the relationship between prostate testing and breast cancer testing. I can (vaguely) remember when the big push for more and more regular of the latter variety---with similar emotional considerations---started, and also when the FDA (?) reduced the amount of testing after a given age (because it empirically did not lead to better outcomes) and caused a significant furor.


I decline PSA tests. That said, there's no family history.




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