For the first time in several years, I am writing about
prostate cancer screening. I had hoped that this was sufficiently covered in
2009, with PSA
Screening: What is the value? (March 21) and the excellent guest piece by
Robert Ferrer, PSA
Screening: “One of Medicine's Great Success Stories"? (October 27),
and finally a bit of celebration in 2011 with PSA
redux: The USPSTF finally recommends NOT getting it! (October 14). However,
like the proverbial bad penny (or to use a more au courant analogy, zombie), this issue continues to return from
the dead. The most recent effort is “Bring
Back Prostate Screening”, a NY Times op-ed
piece by Deepak A. Kapoor on July 6, 2015.
What Dr. Kapoor is suggesting is obvious from the title, but
the question is “is there some new information, some new research, that now
makes such screening more reasonable or appropriate?" The answer, unfortunately
(because it makes more work for the zombie hunters) is “no”. Dr. Kapoor
suggests that there is. He notes research is this field is “... now paying off.” He says that the decision to
recommend against prostate screening
by the US Preventive Services Task Force “…didn’t take into account adaptations
that urologists have made to help better identify patients likely to develop deadly
prostate cancers.” He cites the increased sensitivity of PSA screening, the
individualization of it to the risks of different men, and the use of PSA
trajectory (its rate of increase, or not), as well as new methods of assessing
cancer like MRI. However, his assertion is incorrect; all of this information
was available to the USPSTF when it made its recommendations, and was taken
into account. It is not new.
“At the time,” Dr. Kapoor notes, “I and many other
urologists warned of public health repercussions. Our fears have materialized.
Since 2010, fewer biopsies have been performed and fewer prostate cancers
found. But studies show an increase in the risk that a cancer, when found, will
be more aggressive.” This sounds scary, but it is to be expected; when you stop
screening everyone you won’t find the cancers early. A big part of recommending
against PSA screening was that so many of the cancers it identified were
indolent and not going anywhere; the aggressive cancers will be the ones that
eventually show up. Indeed, he actually acknowledges that “No increase in
cancer mortality has been observed,” but continues to raise the alarm with
“…that may be a matter of time; aggressive cancers are less treatable.” So
maybe we should be scared.
Well, in fact all prostate cancer is treatable. All cancer is; in fact all conditions are. The question
is how effective is the treatment? Does it cure? Does it prolong life? Does it
improve the quality of remaining life? This is the area that Dr. Kapoor and his
colleagues do not address, because, for prostate cancer, the answer is
basically no. If you have the more common kind of prostate cancer, it is
slow-growing (indolent) and may even disappear itself; you will die with it,
rather than from it. If you have the less-common aggressive form, you may well
die from it, and unpleasantly; prostate cancer metastases go to bone and cause
a lot of pain. Sadly, however, treatment does not seem to impact this. The
“cures” from treatment of prostate cancer are of the ones that would have
“cured” themselves, or at least not have manifested with symptoms. The
mortality from aggressive deadly cancers is not changed by treatment. This is
the critical point that discussions of the sensitivity and specificity of PSA
or any other kind of screening often ignores. Not only can they not reliably
distinguish between the indolent and aggressive types of cancer well, even if
they could and we had a test to reliably tell which one you had, it is only of
importance if treatment can make a difference. And in terms of mortality, it
doesn’t. What about the other results from treatment? Improved quality of life?
Well, here even Dr. Kapoor notes that “cancer treatment can reduce quality of life.” If you consider impotence,
urinary incontinence, and the many unpleasant and painful effects of radiation
on the rectum to lower quality of life, you betcha.
We can dismiss Dr. Kapoor’s comments by saying he is a
urologist, and they make their money treating prostate cancer; can you imagine
the impact on their income if we didn’t treat it? But this misses the far
bigger issue, which is that we are enamored with – and, more important, spend
huge amounts of money on-- high-technology interventions rather than the
prosaic, low-tech interventions that have actually been demonstrated to improve
the public’s health. Screening for prostate cancer, and overuse and reliance on
mammographic screening for breast cancer, are huge industries which (even in
breast cancer) have had relatively little impact on mortality. Providing good
prenatal care and preventing unwanted pregnancy, ensuring treatment of common
diseases like hypertension and diabetes, ensuring that children are not only
immunized against infectious disease but are well-fed, well-housed, and
well-educated, and free from poisoning by environmental toxins (including
bullets) – the basic components of public health and primary care -- may seem
less sexy and stimulate our collective psyches less, but they are the things
that actually increase population health.
One of the newer fascinations is genomics, the
identification of each person’s sequence of DNA. The promise of “precision
medicine” is that we will find out who has the risk gene for which disease, and
treat it directly and appropriately; treatment for cancer will be based on the
genes you have just as treatment for bacterial infections is based on the
organism identified by culturing it in a microbiology laboratory. It is so
exciting! It is so “sci-fi today”! The American Board of Family Medicine, for
example, is planning to create a new self-assessment module (“SAM”, tests that
family doctors have to complete one of each year to maintain their Board
certification) on genomics. On the other hand, it doesn’t think we need one on
contraception, which is too small an area (isn’t it just part of “women’s
health”? Oh, do men have a role in contraception also?), unlike genomics, which
could affect EVERYTHING!
Except, so far, it hasn’t and there is little evidence to
suggest that it will anytime soon. I wrote a blog on the topic on February 1,
2015 (“Precision
medicine, trade policy and the cost of drugs: benefiting people or profit for
business?) after the appearance of a Times
op-ed by Mayo Clinic cancer expert Michael Joyner (“’Moonshot’
medicine will let us down”, January 15, 2015); Dr. Joyner has more recently
contributed more comprehensive articles on the topic to JAMA (“Seven questions for personalized medicine[1])
and The Lancet (“Is precision
medicine the route to a healthy world?”[2])
in which he makes the important point that most disease is not the result of a
single gene, but rather the result of a complex interplay of different genes
and the environment. Indeed, the only cancer-specific genes that have been
identified so far are the breast cancer genes BRCA1 and BRCA2, and no
treatment has emerged; we simply say “get mammograms more often and consider
prophylactic mastectomy”.
Spending all this money on precision medicine, on high-tech
interventions, expensive drugs and devices is like blowing your house budget on
art for the walls before you have built it. Some art is great, some is
mediocre, and some is poor, but none will hang well on a jerry-rigged house
made poorly of shoddy materials because there was no money left. Some
high-tech, expensive interventions are worthwhile but what we really need to
increase the population’s health is public health nurses making home visits to
pregnant and recently delivered women, and their children; public health nurses
or community health workers or even doctors making visits to people’s homes to
assess the real risk factors to their health and reasons that they might not be
able to comply with treatment plans. We need more primary care, not more
interventionalists. But most important, we need to apply what we know works,
what we know how to do, to everyone.
That is how we move the needle on population health.
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