Expert Explains USPSTF Breast Cancer Screening Guidelines

Anees B. Chagpar, MD

The controversial final set of guidelines recommended by the US Preventive Services Task Force (USPSTF) recognize “adequate evidence” that mammography screening has reduced breast cancer mortality, but maintain that most of the benefit for women at average risk for breast cancer is derived by those aged 50 to 74 years who undergo screening every 2 years.

The Task Force calls for an individualized approach to routine mammograms for asymptomatic women under aged 50 years and biennial testing for women age 50 to 74 years.

Though the issue has been debated for more than 5 years, since the Task Force drafted similar recommendations in 2009, agencies such as the American College of Radiology (ACR) and the Society of Breast Imaging said in a joint statement that following the recommendations would result in lethal consequences for thousands of women each year.

However, some medical experts say that while mammography early detection of breast cancer, biennial screening is sufficient.

OncLive: What are the key points of the final recommendation?

In an interview with OncLive, Anees B. Chagpar, MD, associate professor of Surgery (Oncology) and director of The Breast Center at Smilow Cancer Hospital at Yale-New Haven, shares her thoughts on the final guidelines and how they change the focus of screening.Chagpar: What is being recommended is average-risk women from the age of 50 to 74 get screened every 2 years. For women between the ages of 40 and 50, they can kind of tailor that to their risk and discuss it with their doctor. In women 75 and older, there’s really more data that’s required. I think people may start to wonder how this varies with the the American Cancer Society (ACS) guidelines.

Now, the two organizations are really coming closer together. The ACS recommendations state that women aged 40 to 44 should really talk to their doctor and have individualized recommendations. Women who are 45 to 55 should get screened annually. In women 55 and older, there is evidence for screening every 2 years. Women who have a life expectancy of less than 10 years, or who are no longer healthy, should stop screening.

I think the main message you can take away from both sets of recommendations is that, for women who are, in the case of the USPSTF, over the age of 50 and, in the ACS, women who are over the age of 55, biennial screening is sufficient.

For ages 50 to 74, biennial screening is a B recommendation. What message is that sending to the public?

Does this raise the question that mammography is potentially harmful?

Both sets of recommendations are beginning to agree that, at some point, women need to start asking themselves whether they still need to be screened when they’re getting older and/or are less healthy.If you look at national trends, and ask women, “Have you had a mammogram this year?” A lot of women forget. Therefore, if you get a mammogram every other year, that’s probably just fine. I think that’s the message that this is sending. It’s not sending the message—and I hope that it doesn’t send the message—that mammograms aren’t important. They still are. It’s the best technique for finding cancers early when they are the most treatable and the advent of screening mammography has truly been critical in the reduction in mortality that we’ve seen over the last several decades.I don’t think that mammography is harmful. Both sets of guidelines make it very clear that there is an abundance of evidence that mammography saves lives. We know this. There have been at least 8 randomized controlled trials that have demonstrated that.

We know that, when we screen women, we can pick up cancers that can be potentially lethal. This is why mammography remains, really, a hallmark of early detection for breast cancer.

However, we are now seeing a balance of that benefit with other potential harms. Mammography does carry a slight risk and exposure to radiation. It does carry a risk of overdiagnosis. It does carry a risk of what we call false-positives, and the more we screen, the more we are going to find false-positives, and the more we are going to find cancers that would potentially never harm anybody. Of course, the more we screen, the more radiation we expose women to.

What protocols should women with dense breasts follow for screening?

The question that I think both sets of guidelines are getting to is, “Where is the sweet spot? Where is the balance between the benefit that mammography clearly has, and the risks?”The issue with dense breast tissue is, on mammography, it looks white and cancers also look white. Therefore, women who have dense breasts often have what is called a false-negative. A small, white cancer may be hiding inside a white, dense breast so the mammography may be read as negative.

Women with dense breasts need to know that. If a woman has dense breasts, there are things that they can do. For example, ultrasound may be an adjunct to mammography in women who have dense breasts. Ultrasound is not a replacement for mammography; it will not pick up all of the cancers and pre-cancers that mammography will. Mammograms are still the mainstay of screening.

In terms of the technology we are using, mammography is increasingly advancing so that it can often times address issues with regard to breast density. For example, many centers, including Yale Cancer Center, offer tomosynthesis, or 3D mammography. This allows radiologists to look through thin slices of the breast as they page through the breast, instead of simply taking a composite of all this breast tissue squished together. If you can kind of leaf through “onion skins” through the breast tissue, it helps you to potentially get over this breast density issue.

For women who have dense breasts, they should talk with their doctor about what kind of mammography to have and if they should have an ultrasound, as well.

Women should know what their risk is. Women who are at high risk, for example, who have a genetic mutation that puts them at higher risk for developing breast cancer and who have a very strong family history of breast cancer, should really be talking to their doctors on when they should be starting mammography, and whether they should be having other tests, as well.

Do you predict we will enter an era of a permanent retreat from the annual mammogram?

If you carry a genetic mutation, such as BRCA1/2, you likely should still be getting an annual MRI because you are at very high risk. These recommendations are for women who are at average risk.As time goes on, we are learning more about the biology of breast cancer, the risks and benefits of the technologies that we use to screen, and that some breast cancers may never harm people. As that knowledge continues to evolve, I think the medical community, as well as the general population, will start to move in the direction the data are taking us, which is that mammography is still really important, but we always need to weigh benefits and risks.

What disconnect have you seen between oncologists, radiologists, and the Task Force guidelines?

Many people make the analogy here with prostate cancer, and how recommendations with regard to prostate cancer have changed as we learn more about that disease.When you start getting disconnect like that, the answer is that both answers are likely correct. It is really a matter of timing when these organizations have their review cycles where they examine all of the data. I think that’s where you start to see convergence, very much like we did this year with the USPSTF and the ACS kind of coming together. Still, there are some differences and slight quibbles in terms of interpretation, but I think you’ll see the same coming out of ACR and medical imaging societies, as well.

No matter which society you ask, I think all will agree that mammography is clearly important in terms of early detection of breast cancer. All will agree that there is slight harm associated with mammography, and it’s really kind of determining where that she sweet spot is, in terms of balancing risks and benefits. For women who are at average risk, these guidelines provide a framework for them to talk to their doctors about what’s right for them, but they should continue to get mammograms on a regular basis as long as they’re healthy. That is really going to help, in terms of finding cancers early when they are the most treatable.