yearly mammography for average-risk women starting at age 40,” according to the statement from the American College of Radiology and the Society of Breast Imaging.
The groups worry about the cancers that could be missed with biennial screening, and that minority women would be disproportionately affected.
The American Cancer Society also recommends yearly screening, but is more flexible on age — advising women to start by age 45 and at least consider it in their early 40s. (Dahut says the ACS is in the process of updating its advice, however.)
Wong says the task force recommendation is based on a weighing of the benefits versus risks of screening. Cancer screening, by definition, is done when people are ostensibly healthy, and the main “harm” is that it can generate false-positive results. That leads to needless follow-up testing, sometimes with an invasive biopsy — not to mention anxiety, Wong notes.
According to the panel’s calculations, annual mammography leads to 50 percent more false positives over a lifetime of screening, compared with screening every other year.
When should you stop screening?
As for when to stop screening, Wong says there was not enough evidence to recommend for or against screening after age 74.
A central issue is that cancer screening needs to not only detect more early-stage tumors — but also make people’s lives “healthier and longer,” Wong notes.
Back in 2016, there had not been enough evidence that screening women in their 40s achieved that, according to the task force. That kind of evidence is still lacking for women aged 75 and up.
So those women should speak to their doctors about whether they want to continue screening, Wong advises.
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What if you have dense breasts?
The task force also took on the question of whether women with dense breasts should have supplemental screening — with ultrasound or MRI — in addition to regular mammograms. Again, it says, there is not enough evidence to make a call.
Nearly half of women over 40 have dense breasts, which means they have more fibrous or glandular tissue than fat.
Those women have a relatively greater risk of developing breast cancer, Dahut says, and the dense tissue makes it harder to detect tiny tumors on a mammogram. So following up with an ultrasound or MRI scan may spot abnormalities that were initially missed.
Like the task force, the cancer society has no specific screening recommendation for women with dense breasts. But, Dahut notes, many U.S. women with dense breasts, after talking to their doctors, are already getting supplemental screening.
“And it’s certainly reasonable for them to do so,” he adds.
Where everyone agrees, Wong and Dahut says, is that women in their 40s should start screening, and then continue at regular intervals.