I have some empathy for those who are suspicious of recent recommendations pushing back screening ages for breast and cervical cancer.
Nothing, for example, can stop my pre-flight anxiety. And try as my boyfriend may, he will never convince me to go skydiving. It may be a “calculated risk,” as he says, but it just feels unnatural and, well, “risky.”
So I can sympathize with women who say, ‘that one person saved from breast cancer out of 2,000 others could have been me.’
Highly, highly unlikely. But however unluckily so, it could have been.
Humans tend to see things in 50-50 odds, in terms of this outcome or that. Either my plane lands safely or it doesn’t. My chute opens, or I pummel into the earth. It takes a lot more to think in terms of numbers, odds, risk.
That’s why public health experts do it for us. They’re trained to pit the risks of screening (radiation exposure and anxiety from false-positives for breast cancer, for example) against its benefits (how many lives does it really save?) and calculate sound advice.
It’s called evidence-based medicine, and it’s what doctors like to practice best.
But we don’t see the epidemiologists’ thought processes, their methodology, or their rationale, which could explain why there’s so much skepticism in the general public. As Paul Raeburn jokes in a recent Knight Science Journalism Tracker item, we can’t just consult our healthcare epidemiologist to tell us what to do and why.
But we can try to think like one. It’s as simple as searching the New York Times. These numbers are from a fantastic news analysis by reporter Kevin Sack:
According to their review, the U.S. Preventive Services Task Force found that one cancer death is prevented for about every 2,000 women ages 40 to 49 who are screened for 10 years.
For women ages 50 to 59, one death is prevented for every 1,300 women screened.
Looking very broadly at those numbers, your risk almost doubles when you hit 50. Starting to see their thought process?
The screen works even more efficiently for women ages 60 to 69, preventing one death for every 377 ladies. Based on those numbers, no one would deny screening at that age. That’s a huge difference from 1 in 2,000 — your risk is increased almost five times from when you were 40.
I don’t know the exact statistics, but it would also be worthwhile to factor in your risk of cancer from being exposed to radiation once a year from 40 to 49.
I surely wouldn’t be able to calculate that. As a rookie health reporter, I’m just beginning to understand risk. If I’m around it every day and am still no expert, I can imagine how challenging it must be for the lay reader.
And your doctor may not be able to offer much help, either, as Raeburn notes in his commentary. Physicians learned of the recommendations at the same time we readers did. And they are certainly not epidemiologists. Their last statistics course may have been during their undergraduate training.
So what can you do? Well, know your risks. Know that the new guidelines exempt women who have genetic risks for breast cancer. (And bear in mind that the new guidelines are only one set of recommendations. Other medical organizations, like the American Cancer Society, have not changed their policies yet.)
And do a bit of rationalizing on your own. If you’re not in the at-risk population, but you’re not comfortable relying on the numbers, then compromise. Get screened every three or five years during your 40s if that puts your concerns at ease. It may be statistically unnecessary, but at least you will have peace of mind.
Just like I do when I pray to the deity of statistics before takeoff.