An NEJM Editorial last week, discussing long-term follow-up from the European Randomized Trial of Screening for Prostate Cancer (ERSPC), addressed itself to a lack of consensus on PSA screening which [it is claimed] contrasts markedly with general consensus around screening for other cancers. Remarkably, the article cited only a relative risk reduction in this context.
The NNT (or here, NNS) that one would read off the abstract of the accompanying report [2] is pretty large. I know NN_’s are ‘canceled’ on Datamethods 
, but it seems to me that even an NNS would have made a reasonable addition to this piece.
- Vickers A. Early Detection of Prostate Cancer — Time to Fish or Cut Bait. N Engl J Med. 2025;393(17):1742-1743. doi:10.1056/NEJMe2509793
- Roobol MJ, De Vos II, Månsson M, et al. European Study of Prostate Cancer Screening — 23-Year Follow-up. N Engl J Med. 2025;393(17):1669-1680. doi:10.1056/NEJMoa2503223
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It’s an absolute reduction in risk of prostate cancer death of 0.002. That’s not far from the reduction of mortality from wearing seat belts or not wearing a large metal belt buckle in an electrical storm. Worth it? We’d need patient utilities to figure that out.
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Agree. Although mammo and PSA similar RR, can’t just compare based on RR, need to consider adverse effects (and what they mean to individual patients*). Mammogram → core biopsy, which is relatively well tolerated (#) → even mastectomy is relatively well tolerated. PSA → biopsy itself can cause incontinence, impotence → prostatectomy even higher risk.
I cringe as I write this (and I value the editorial), because PSA useful information to have. The lesion is in its interpretation. There is CAPRA, but don’t see much else.
*This is not to say screening decision should be abdicated to patient. Some more discussion on this here.
(#) Hope not making generalizations here with respect to tolerability.
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I liked your essay on ‘Kindness of Decision Analysis’, Sam! But it brought to mind the “indignity of proof” of this passage from A. N. Whitehead’s Modes of Thought
There is very little large-scale understanding, even among mathematicians. There are snippets of understanding, and there are snippets of connections between those snippets. These details of connection are also understood. But these fragments of intelligence succeed each other. They do not stand together as one large self-evident coordination. At the best, there is a vague memory of details that have recently been attended to.
This succession of details is termed proof. But the large self-evidence of mathematical science is denied to humans.
To give an example, the snippet of knowledge that the addition of 1 and 4 produces the same multiplicity as the addition of 2 and 3, seems to me self-evident. It is a humble bit of knowledge; but, unless I deceive myself, it stands before me with a clarity of insight. I hesitate to claim any such self-evidence when larger numbers are involved. I have recourse to the indignity of proof. Other people have wider powers.
For example, consider Ramanujan, the great Indian mathematician, whose early death was a loss to science analogous to that of Galois. It was said of him that each of the first hundred integers was a personal friend. In other words, his insights of self-evidence, and his delight in such insights, were of the same character as most of us feel for the integers up to the number 5.
Compare Whitehead’s sentiment here with the “relinquishing of control” acknowledged in your post.
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Thank you—I enjoyed this quote. While unpacking it, I wanted to also expand.
Note the last line of the editorial, “we have to do better than abdicate the responsibility for PSA decisions to individual patients and instead formulate policies that maximize benefits and minimize harms.”
Especially for difficult decisions like PSA screening, there is a disturbing trend where—sometimes under the guise of “shared decision making”—decisions are almost completely offloaded to the patient. I think that the editorial reacts to this trend, but it may go too far in the other direction. In particular, the last line of the editorial seems to sort of separate “individual patients” from (“instead”) “benefits” and “harms.”
The individual patient plays a key role in decision making, always—they define the benefits and harms. As I argued in my post, the better we characterize the patient’s role, and distinguish it from the other roles in a decision (which involve probabilities and optimization), the better things will be. This leads to true “shared decision making,” where the patient, provider (referencing randomized trials), and optimization all play a role. This just a framework, but it serves as a guide.
For example, it helps to define the words “benefits,” “harms,” etc. It shows us how to systematically compare tests—e.g., PSA and mammogram—by taking probability (relative risk) into account, but also forcing adverse effects and individual patient preferences into the conversation.
It is difficult sometimes (for me) to see the details of all the possible scenarios and how decision analysis might apply (especially when we get into complex cases, eg the higher integers), but an overarching framework (a sort of indignity to which we have recourse) in this case is helpful.
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Beautiful point. It has long been true that very knowledgeable patients choose not to engage in PSA screening because the supporting data have long been quite weak and the consequences of excessive invasive testing and treatment are substantial. It’s not just that tiny benefit from screening but also all the associated biopsies, hormonal treatment, surgery, and anxiety.
We do not “abdicate” decisions that we have no right, or even definitive evidence, to make.
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