The main topic of the week on the wires is the US preventative
task for recommendation (USPTF) against PSA screening for prostate cancer. Timely given this sites discussion on
overscreening a week previous overscreening
- a new public health risk. DPHealth
takes no credit for the wisdom of the USPTF.
prostate
screening recommendations . The Canadian
task force came under similar scrutiny for its enlightened view of breast
cancer screening CTF
breast cancer screening , CTF has
yet to comment on prostate cancer screening.
The USPTF short version – PSA screening may benefit the
reduction in death from prostate cancer by 0-1 men per 1000 screened.
80% of PSA positive tests are false positive - that is they do not reflect cancer, but they will likely result in at least a discomforting biopsy.
Screening leads to an upwards 50% increase in detection of
what otherwise would have been clinically non-relevant cancers (ie asymptomatic
and would not contribute to the individual’s subsequent health)
1/3rd of men who have prostate surgery develop significant
post surgical discomfort, 5 in 1000 die post surgery, and 10-70 will have significant
complications.
On the balance sheet the harms are roughly the same, or slightly
more than the benefit.
As Hippocrates wrote into the oath taken by physicians – "first,
do no harm". One of the four pillars of modern medical ethics is this principle of non-maleficence. Kudos to the USPTF for staying true to the Hippocratic oath.
To celebrate the Canadian contribution, the Canadian Task
Force on the periodic health examination was founded in 1976 and formed the model
for the USPTF that followed in 1984. The CTF developed
the methodology that has been emulated numerous times in assessing quality of
evidence review and the synthesis into grading of recommendations. Both bodies as well as other national bodies
modelled after the CTF are designed to look carefully at the evidence for
applying population level interventions.
The current iteration of the task force was revived in 2010 after a 5
year disbanding and one only hopes survives the scythe which is swinging in
Ottawa these days.
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