Prostate cancer screening is getting new support from an unlikely source – the Cochrane group, which historically has been skeptical of population-based screening. Cochrane researchers last week published a new report supporting prostate screening, a sharp change from the group’s previous guidance.
Prostate cancer screening hasn’t achieved the generally accepted status of other cancer screening tests like breast, cervical, colorectal, and lung.
- One of the main sticking points has been overdiagnosis. Prostate cancer can often be slow-growing, and many men live for years with prostate disease before dying of other causes.
But that dynamic has been changing in recent years, in large measure due to the ability of MRI to differentiate aggressive prostate cancer from more indolent disease.
- Clinicians are incorporating MRI into prostate screening protocols, using it to determine which men with elevated PSA levels should be biopsied and which ones can be followed with active surveillance.
For its part, Cochrane is an international non-profit research consortium that periodically analyzes the peer-reviewed evidence behind new medical exams and technologies.
- But Cochrane’s work has occasionally been controversial: The group last month published a negative review of Alzheimer’s drugs that included treatments that never made it to market. Also, a Cochrane research center in Denmark for years was one of the most vociferous opponents of mammography screening.
So that’s why last week’s statement on prostate screening is so surprising, especially given that Cochrane’s 2013 review found no evidence to support the claim that screening reduced prostate cancer mortality.
In the new review, Cochrane analyzed data from six clinical trials in Europe and North America that included 800k men, finding that screening with PSA blood tests…
- Detected 30% more prostate cancers overall, most at an early stage.
- Reduced the relative risk of a metastatic prostate cancer diagnosis by 35%.
- Reduced prostate cancer mortality by 2 deaths for every 1k men screened (for comparison, mammography’s benefit is estimated to be 6-8 deaths).
- For every 1-2 deaths prevented, 36 additional cancers were diagnosed – a possible sign of overdiagnosis.
What changed? Cochrane researchers said that we now have longer-term data that makes it easier to detect screening’s subtle mortality benefit.
- They also cited the success of technologies like MRI in reducing unnecessary biopsies – and the harms of overdiagnosis.
The Takeaway
Last week’s news suggests that the ground is shifting under prostate cancer screening in favor of broader use of the exam, potentially with MRI follow-ups. If you can convince a screening-skeptical group like Cochrane of prostate screening’s value, you can convince anyone.
