A MULTI-part series on this topic
Today, we we will review this 2012 paper by
Archie Bleyer, a fellow OHSU faculty member, and.... H. Gilbert Welch
Sit down, It's a doozy.
Here we take a CLOSE LOOK at what mammography screening has brought us over the last 30 years in the USA
In order for mammograms to deliver benefit, they must
1. Find more early cancers (confined to breast)
2. Leading to fewer advanced cancers (in the lymph-nodes or distant organs) among women over time
For screening to work: you gotta detect cancers that would otherwise spread, before they do. By acting upon them (surgery, radiation, chemo) you have to keep them from spreading-- that's the theory
Early goes up
Distant goes down
Nothing controversial here.
Clear and steady uptake.
It rose from 112 to 234. Quite a jump!
More mammograms means more detection of early breast cancer.
That is how it is supposed to work.
What should then happen is for distant/ advanced/ late stage cancers to...
But instead of noting a fall, Bleyer and Welch found this
The massive rise in the detection of early breast cancer did not result in a commensurate decrease in advanced/ late cancers, in fact, late cancers have barely budged. (102 per 100k to 94)
Well, the goal of this entire thing is to catch and treat cancer before it spreads to distant sites, and to treat it SO IT DOESN"T SPREAD.
But Bleyer and Welch find no evidence that this has happened.
They also make this good point:
What if 2 trends are occurring that cancel each other out?
What if more cancer occurs for biology reasons, & screening is keeping it at bay?
Without mammograms, distant cancer would rise, you may contend
They find no evidence for the canceling trends theory.
They are suggesting that decades of mammographic screening has resulted in MANY MANY women given the cancer label, subjected to a battery of invasive interventions, which did not benefit them.
Like much of the work I do (estimating things people don't want estimated), they use CONSERVATIVE assumptions
(when we estimated use of cancer molecular therapy we used assumptions that likely overestimate it)
Scientists use conservative assumptions to move people from the position they are entrenched in closer to truth
Anyway Bleyer and Welch sliced it, over 1,000,000 women had been over-diagnosed.
At least 50k per year.
This is what the conclusion they authors reach:
Not just offered, but persuaded, badgered and pushed.
There are many classic papers that proponents cannot read because of the anger they feel.
That's the anger inherent in questioning the status quo.