Risks of breast cancer screening

Screening in the dark

I have many issues with how we screen for cancer in this country. Mainly because we tend to overdo it, just like we overdo everything.

We overeat. We over-treat. And we also over-diagnose.

That’s not to say that I’m totally against screening procedures. But I do think we need to apply a modicum of intelligence to their use. And it seems the folks in the UK agree with me.

A new review recently appeared in The Lancet. In it, a team of British researchers concluded that, compared to controls, routine screening cuts relative risk for breast cancer mortality by about 20 percent. And it prevents one breast cancer death for every 235 women screened.

That means that, over the next 20 years, 43 out of every 10,000 women over 50 who receive screening in the UK will survive because of it.

But the news isn’t as good as it sounds.

Researchers also found that roughly one percent of the roughly 307,000 women who are screened annually will suffer from “over-diagnosis” in the same time frame.

Stated another way, for every one death prevented with screening, three women were over diagnosed.

Which means that these women probably underwent radiation therapy and chemotherapy, with unknown long term health risks, for no reason at all.

And don’t forget, these statistics come from the UK. Where women ages 50 to 70 are screened for breast cancer every three years. This is much more reasonable than U.S. protocol. Here, we insist on yearly screening from age of 40 on (30 if you’ve got a family history). So you can imagine how high the “over-diagnosis” rate is in this country.

Not to mention the fact that mammograms use radiation, which can cause problems in and of itself.

If nothing else, safer means of screening are most definitely in order. Maybe it’s time to start looking at options like thermography, ultrasound, and MRI–all of which use no radiation.

It would also be nice to find ways to better identify breast cancers that will cause harm during a woman’s lifetime, as opposed to those that will not. This distinction isn’t possible right now. Our current screening methods only give us so much information…

And what doctors do with that information at this point is still based largely on guesswork.

I don’t expect these tough decisions to get any easier. But something has to change.

Instead of scaring women into so many unnecessary procedures, it’s time we started making recommendations based on what we do know… And designing studies to figure out what we don’t.

In the meantime, keep reading for one surefire way to slash your risk of breast cancer…


“The benefits and harms of breast cancer screening: an independent review.” The Lancet 2012; 380(9,855): 1,778-1,786

“Circulating carotenoids and risk of breast cancer: Pooled analysis of eight prospective studies.” J Natl Cancer Inst 2012; Dec. 6 (epub ahead of print)