After writing for years about how research shows we may be too aggressive in screening for breast cancer, it’s only fair that I acknowledge the newer – and more conservative – recommendations from the USPSTF.
First: The USPSTF recommends screening mammography every two years for women ages 50 to 74 years. This will certainly upset many advocacy groups, which have long advocated for yearly screening to start long before age 50. The ACA also mandates that such yearly mammograms be paid for without co-payments or co-insurance, so following these guidelines means refusing “free” care.
However, this is an acknowledgement of the fact that the harms of yearly screening might outweigh the benefits. The accompanying review and meta-analysis found that if 10,000 women age 50-59 are screened, there will be 8 fewer deaths from breast cancer. In 10,000 women age 60-69, there would be 21 fewer deaths from breast cancer. BUT, about 20% of women who are diagnosed with and treated for breast cancer are getting therapy for something that otherwise would never have caused a health problem or been found. One in five women is overtreated, and the treatment for cancer is not benign.
False positives are common, too. These have costs – financial, emotional, and physical. They happen even more often than overtreatment and overdiagnosis.
The models they used found that using yearly screens instead of every-other year screens had a pretty incremental benefit. But they had a significant increase in harms. So they recommend five, not ten, screens over a decade.
Second: The current evidence is insufficient to assess the balance of benefits and harms of screening mammography in women 75 years and older. There are no RCTs to show a benefit in this age group. The harms are still there, though, so no recommendation is made.
Third: The decision to start screening mammography in women before age 50 years should be an individual one. Women who place a higher value on the potential benefit than the potential harms may choose to begin screening between the ages of 40 and 49 years.
This is a real change for many, too. It’s saying it’s totally fine not to start screening until age 50. Why? There’s a reasonable case to be made here that the harms overwhelm the benefits.
If we screen 1000 women age 50-74 for 10 years, we may prevent 7 breast cancer deaths. If we drop the screening age to 40, then we might prevent 8 breast cancer deaths. One more death. But it’s totally possible that person might die of other causes, meaning there’s no real gain overall.
Plus, there are real problems. Each time we screen 1000 women age 40-49, there are 121 false positives. There are 10 biopsies that didn’t need to happen. There’s also one false negative, or real breast cancer missed.
That’s each time, not the whole 10 years. So multiply those harms by the number of times you screen over a decade. It adds up, and it might overwhelm that benefit.
So the USPSTF hedges. They say each woman should make a personal decision with the help of their physician, and I think that’s the right call. Recommendations should say what we know to be true, and in this case we know the benefits and we know the harms. When they’re overwhelmed in one direction or the other, we should let personal preferences come into play.
Obviously, women at higher than usual risk for breast cancer should be treated differently. That’s how it should be, too. Recommendations should be applied carefully to the populations they are meant for.
