Thursday, 24 May 2012
Prostate screening recommendations - First, do no harm
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.