At 19:19 13/02/01 -0000, Shapiro wrote:
>The original comments about screening was in relation to gender differences
>in attitude to health which might be psycho-social.
It was indeed, but then Jim Slattery asked, in relation to the screening
issue, how long women had outlived men - the implication being that he was
considering (if only so as to be able to dismiss it) the possibile
suggestion that the beneficial consequences of introducing screening
programmes (more in women than men), per se, might explain the
existance/appearance of gender difference in longevity.
I did not intend to be 'discouraging' in relation to screening, but was
merely indicating some of the limitations, as I see them, at the present
time. It goes without saying that early detection and treatment of
disease, particularly cancers, is intuitively a good idea - and will,
eventually, presumably reap its benefits when we have treatments which are
able to arrest, or even cure, the early disease process effectively in the
majority of patients. In other words, any current limitations of the
'outcome effectiveness' of screening programmes is not any indictment of
the screening, per se, but is rather a reflection on the limitations of
currently available treatments.
I still think, however, that it remains the case that, at least in the UK,
the effects of introduction of breast (and probably also cervical)
screening programmes on morbidity and mortality asociated with the disease
has been pretty disappointing so far - but, again, that is a reflection on
available treatments rather than the screening process.
As for prostatic screening, I certainly cannot claim to be any sort of
expert, but was reflecting views I have heard expressed by a number of (UK)
urologists. I am aware of a transatlantic divide in relation to these
issues, and the view being expressed by Ray seems to me to be closer to the
more 'Western' of the two.
One of the difficulties as I see it is that if (intuitively not
unreasonably) one seeks to detect ever earlier prostatic cancer (associated
with increasing low PSA levels), one then ends up having to undertake an
increasing number of prostatic biopsies (not without their morbidity, and
presumably at least occasional consequent mortality) on a group that will
have an increasing proportion without histologically demonstrable cancers.
In terms of a young age group (for this disease), say 40-60, I can
certainly see that quite a strong argument for screening could be put
forward, but the argument seems to weaken as age increases.
Particularly as we move into the older age groups, says from 60 onwards,
the view that has been expressed to me by (UK) urologists is that we do not
yet really know enough about the natural history of very early
(histologically diagnosed, as a result of PSA screening) asymptomatic
prostatic cancer in the absence of any therapeutic intervention to be able
to judge whether therapeutic intervention (with its attendant risks) is,
overall, either beneficial or justified. As Ray has pointed out, more men
die 'with' prostatic cancer than 'from' it - and in those who die 'with
it', it has to start (and be 'early') at some point in time! One imagines
that such information might be limited, in as much as once one has detected
early prostatic cancer (involving the 'risks' of biopsy etc.) it might be a
'bit much' (and maybe ethically questionable) to randomise a proportion of
such patients to a 'do nothing' arm of a trial, particularly for the
younger patients. However, if Ray can point me to some studies that have
done this, or to any other published material which sheds light on the
natural history of very early (histologically diagnosed) asymptomatic
prostatic cancer in the absence of treatment, I would be very interested.
Those are my thoughts, anyway!
Kind Regards,
John
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