Women Still Misunderstand Risks of Breast Screening

We’ve regularly blogged about the confusion about breast screening procedures – the risks, the rewards and which women should be screened regularly – and recent research shows that a lot of women still don’t understand the risk-benefit balance.

Researchers writing in the British Journal of Cancer (BJC) said that in a survey of about 2,200 women in that country’s National Health Service (NHS) who were given information about the changes of “overdiagnosis” when they got a mammogram, 1 in 3 didn’t fully understand the risks.

Although 2 in 3 did indicate that they understood that the procedure could detect tumors that would never develop to the point they caused harm, the rest are especially vulnerable to the harm caused by such overdiagnosis; that is, when something suspicious is detected, leading to additional tests that have their own risks, such as infection from a biopsy, radiation exposure, unnecessary anxiety, cost and the wasteful use of resources.

Like previous efforts to clarify the risk-reward balance of mammography, the British study explained overdiagnosis as cancers that grow so slowly that it would take more than a lifetime for them to threaten the host’s health; that for every life saved through screening, approximately three women would undergo all of the additional tests that leave them open to complications.

But even informed women who understand that screenings can find things that aren’t necessarily problems are vulnerable – only 7 in 100 of the women in this study said they would be less likely to get a mammogram despite the risks of overdiagnosis.

Dr. Jo Waller, the study’s author, said, “[T]he study found that many women still struggle to understand the balance of benefits and harms linked to breast screening, so we need to find better ways to communicate the risks as well as the benefits.”

Even though this study was limited to British women, we’re sure U.S. women also live in this climate of confusion. And the media can be responsible for much of it, as we blogged in April, citing examples of news outlets that completely misconstrued the results of a JAMA study concluding that the harms of screening might outweigh the benefits for some people. One TV news headline about it, for example, read “”Mammogram benefits outweighs risks, new study says.”

Although many medical organizations are moving toward a greater appreciation of overdiagnosis, and although there’s a better understanding of it by consumers, progress can be undermined by well-meaning but misguided efforts by the government. For example, under the Affordable Care Act, among the “preventive” medical procedures insurance plans are required to perform at no cost to their covered patients are mammograms for women older than 40 every 1 to 2 years.

So exactly who should get screened regularly?

If you don’t have a higher than normal risk for breast cancer, you generally don’t need regular mammograms. Women at higher risk:

• have a family history of breast cancer;
• have genetic mutations known as BRCA1/BRCA2 ;
• have dense breast tissue (which makes it more difficult to detect masses).

And if women who aren’t considered high risk have a screening that detects a small tumor, many of them would benefit more from “watchful waiting” than aggressive, premature treatment. “Watchful waiting” means monitoring without invasive procedures something identified on a screening test that may or may not become dangerous.

Women and their doctors must discuss what’s best for them, individually, because breast screening is not like a tetanus shot – not everybody needs one.