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David Katz, M.D.

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Omission, Commission & Medical Outcomes: PSA And Sin Selection

Posted: 10/11/11 09:31 AM ET

There are, as you know, sins of omission -- and sins of commission. Which do we tend to think is worse?

That seems to depend on context, but it should depend on consequences.

In this week's New York Times magazine, the tale is told of Dr. Otis Brawley, the chief medical officer for the American Cancer Society. The American Cancer Society tends to promote all that can be done to combat cancer, and thus is far more likely to encourage than discourage screening. Dr. Brawley, however -- whom I have the privilege to know -- is devoted to the scientific evidence, and has thus long had serious reservations about use of the prostate-specific antigen (PSA) test to screen for prostate cancer. The New York Times' piece makes clear that Dr. Brawley supports the recommendation of the U.S. Preventive Services Task Force against PSA screening, as do I.

But, of course, many people feel differently about the PSA test -- and passionately so.

We'll come back to this disagreement, but first I want to tell a story. Quite a few years ago, when I was a medical resident in my second or third year of training, I was serving as the senior resident on call for the Intensive Care Unit (ICU).

My beeper went off around 1 a.m. or so, and when I called in it was my counterpart -- the resident on call that night responsible for the regular medical floors. She was telling me about a female patient in her late 50s with advanced kidney disease who was suddenly having desperate difficulty breathing and needed to be transferred to the ICU and probably placed on a ventilator. I said something along the lines of: Do that thing we do (save the patient!) and I'll be right there.

When I got to the patient's bedside, it was quite clear the patient was just moments from death. It was equally clear -- and rather horrifyingly so -- that my fellow resident wasn't doing much about it. She acknowledged this, saying she wasn't sure what was causing the patient's respiratory distress. Although she suspected pulmonary edema (fluid filling the lungs due to pumping failure of the heart -- which was, in fact, the case) -- she wasn't sure, and besides, she was afraid of the potential harms of injecting medication into a patient whose kidneys didn't work (the patient received dialysis several times a week).

My assessment was entirely different. It seemed likely the patient was in pulmonary edema. Other diagnoses were possible, but the main contenders, such as pulmonary embolism, were less treatable. If the patient had something we couldn't fix quickly, she was going to die. So best to assume she had something we could fix quickly and give it a shot. As for the potential harms of injecting dangerous drugs, the patient was about to die! She couldn't be much worse off.

So inject dangerous drugs, I did. I injected, among other things, a hefty dose of morphine into the patient's vein -- morphine being the single most effective, rapid treatment for pulmonary edema in most cases. I made preparations to intubate the patient (put her on a ventilator) when we got to the ICU, but that never proved necessary. In response to the cocktail of potent (and yes, dangerous) drugs I injected, by the time we got to the ICU, she was breathing comfortably and never needed the ventilator. In fact, she was transferred back to the general medical floor the next morning.

Then, as now, it seemed to me that my fellow resident was placing far too great an emphasis on the distinction between the sin of commission, and the sin of omission. She was so afraid of hurting the patient by doing something that she very nearly killed the patient by doing nothing. The "bad" thing -- the "sin," if you will -- was neither action nor inaction, but a dead patient!

I have seen this same pattern many times. Doctors, I find, often favor omission over commission when the stakes are very high (with the possible exception of surgeons, who may tend to go the other way), because it feels less like it's your fault if a patient dies when you haven't done anything. If a bad outcome immediately follows an action you do take (and we've all been there, alas), it's harder not to feel entirely to blame for the cause-and-effect sequence. I have had patients die literally in my hands as I was taking action, and frankly, a long span of nightmares and flashbacks tends to ensue. It's hard to shake.

So in the context of high-stakes medical decisions by doctors, sins of omission may be favored.

In the case of the PSA, however, and cancer screening in general, the prevailing preference runs the other way. Cancer is the enemy we want to chase down and dispatch -- before it dispatches us. Some people may prefer the bliss of ignorance, but most, it seems, want to know -- convinced that knowledge is power. By extension, lack of knowledge is lack of power, so failure to go looking for a cancer feels like disempowerment and helplessness.

And so, there is vigorous -- even vitriolic -- opposition to the Task Force position on PSA, to Dr. Brawleys' opinion and, as I suspect comments here will show, to mine. But if the Task Force, Dr. Brawley and I are called unpleasant names, I don't plan to take it personally. It is really just opposition to helplessness in disguise. And frankly, I can relate; I don't like being helpless either.

But if taking action leads to more bad outcomes than good, it is not empowerment. It is, if you will, the sin of commission. Similarly, if inaction leads to bad outcomes, it does not exonerate us. It is the sin of omission.

What all this means, of course, is that the propriety of given means must be linked to the likely ends. Treating patients with potentially toxic drugs is bad if it hurts them -- but good if it saves their lives. Screening for cancer is good if it reliably improves outcomes and quality of life -- bad if it does the opposite far more often.

We should not favor omission, or commission. We should favor good outcomes and prioritize whatever medicine most reliably gets us there.

-fin

Dr. David Katz; www.davidkatzmd.com
www.turnthetidefoundation.org

 

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There are, as you know, sins of omission -- and sins of commission. Which do we tend to think is worse? That seems to depend on context, but it should depend on consequences. In this week's New...
There are, as you know, sins of omission -- and sins of commission. Which do we tend to think is worse? That seems to depend on context, but it should depend on consequences. In this week's New...
 
 
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03:28 PM on 10/13/2011
Knowledge is power! The more knowledge we have about this disease the better chance we have of finding a cure. Dr. Katz if you prefer to keep your head in the sand, more power to you! This woman will NOT be joining your ranks. LET"S PUT AN END TO PROSTATE CANCER!!!
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euthman
11:55 PM on 10/14/2011
I agree we should seek to put an end to prostate cancer, but mass screening using PSA is not an effective way to do it.
02:15 PM on 10/12/2011
Once again, this is medicine by commission. In this instance it is the task force headed by a pediatrician???? who added 2+2 and decided it equalled 0. The PSA is far from perfect and needs a skilled clinician to evaluate the result properly. That said, it is still the best screen we have to detect early prostate cancer. Should be stop doing mammograms because it often shows lesions that are needlessly biopsied? My father died of prostate cancer. Should I stop screening myself because the test is not infallible? You may be willing to bet your life and not screen but I am not willing to bet mine. And yes, I am an MD with 2 board certifications.
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euthman
11:08 AM on 10/13/2011
I am board-certified in pathology, 30 years' practice experience in hospital and outpatient markets, and run a large professional listserv with 800 subscribers. I can tell you that few pathologists defend PSA screening programs, unless they are involved in commercial enterprises that cater exclusively to the prostate biopsy clientele.
04:35 PM on 10/14/2011
So what is your alternative? Denigrating the value of the PSA is one thing, but then you have to offer a better option. IMO, there is none at this time.
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euthman
06:33 AM on 10/12/2011
Having been involved on the pathology side of PSA screening for the last quarter century, I have seen a questionable but promising program balloon into a veritable axis of excess, driven less by good epidemiology and public health policy than pure profit. Biopsies are reimbursed by Medicare and other insurers on a per-core basis. If a urologist collects 2 cores of tissue from two different sites in the prostate, he or she is paid a certain figure times two. The result has been that what used to be a two-core case has now grown into a case with 12 or more cores. There is so much potential profit involved that many urology groups have built their own pathology labs and hire salaried pathologists to read the biopsies, pocketing not only the technical component for processing each core, but a healthy margin between what they pay they the pathologist and what they collect from the professional component. More cores also means the pathologist is more likely to stumble on a microscopic focus of inconsequential adenocarcinoma, which puts the patient on an even more intensive/expensive track of repeat biopsies, follow-up office visits, and even radical treatment. I am glad that the new recommendations will accelerate the swinging of the pendulum away from such an aggressive approach.
10:10 PM on 10/11/2011
Of course we should favor good outcomes. The question is whether PSA screening overall has net benefits. The Task Force says No. But I think their position rests on a misreading of the evidence.

The net benefits and costs of prostate cancer screening are largely determined by the "Number Needed to Treat" (NNT) to reduce one prostate cancer death. Most of the benefits and costs of prostate cancer screening are associated with treatment, in particular the life-savings of treatment versus the potential large side effects..

The best study, the European study, says the NNT is 48 to 1 as of 9 years after the PSA screening trial was initiated.. Dr. Katz in his previous post linked to an article in the Journal of Clinical Oncology that says the European study shows that the NNT is 18 as of 12 years after the trial was begun.

If the NNT is 48, the basic issue is this: do you think that treatment that leads to a 2% reduced chance of death after 9 years is worth a large probability (over 50%?) for the other 98% of serious side-effects? If the NNT is 18, do you think that treatment that leads to a 5% reduced chance of death after 12 years is worth a high probability of serious side-effects for the other 95%? My answer is Yes, but others may differ. .
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Charles Queen
I am a disabled nam vet
07:38 PM on 10/11/2011
They don't feel that a healthy male 50 and up should have to take the blood testing for prostate cancer and or other prostate problems?The blood test is extremly reliable along with the scoping method which is the best way to determine if one has any need to worry.I'm having the scoping done this winter at the VA.I'm all for it too.At least they can see whats what in there and can test polps to see if their cancerous or not.Like they say,prostate cancer is known as the silent kiler.You might have it and never know it until it's to late to do anything about it.I'm getting tested and they can take all of the biopsy's they wish to test and make sure that I do not have it hopefully.Only the tests wil confirm it though and I'm just not in any hurry to die yet