New Danish Study Raises Questions Regarding Need for Mammograms

Findings show that one-third of lumps detected by procedure may never cause a health problem

New Danish Study Raises Questions Regarding Need for Mammograms
Image: Pixabay
January 10, 2017

If you're a woman at least 40 years old, chances are that your doctor has recommended a procedure called a mammogram, which can reduce your risk of dying of breast cancer by detecting tumors at an early stage, when they are most treatable.

However, scientists have recently begun to question the need for this procedure, as shown in a new Danish study. In this study, researchers monitored thousands of women in Denmark for more than 10 years. They discovered that about one third of the lumps that a mammogram finds might never actually cause a health problem.

"Breast screening can have some very substantial harms," says study leader Karsten Jorgensen, the deputy director of the Nordic Cochrane Centre in Denmark. "And the most important one of those is the overdiagnosis of breast cancers that would never have developed into something life-threatening."

These findings add to a growing pile of evidence that screening for breast cancer can result in unnecessary treatment.

Otis Brawley is the chief medical officer at the American Cancer Society (ACS). He wrote an editorial that accompanies the study. "There's a tendency in the United States to think that screening is better than it actually is," he says. "It's important that we learn the limitations of screening so that we can apply that tool as best we possibly can to save as many lives as possible."

According to Brawley, the real problem is that doctors are not currently able to tell which tumors need treatment and which they can just monitor. For the time being, he says, women should keep following guidelines for getting a mammogram and get treatment if they are diagnosed.

"One of my nightmares is people will read this paper," Brawley says, and "elect to not get treated."

The guidelines set by the ACS say that women should have the option of getting a mammogram beginning at the age of 40 and that they should start getting one annually at 45. At 55, the guidelines say, they can go back to once every two years. The U.S. Preventive Services Task Force, meanwhile, recommends regular mammograms every two years beginning at age 50.

Others believe that the findings should encourage women to re-consider whether or not they actually need a mammogram.

"Women should understand all of these issues and make their own decision if they want to have a mammogram," says Fran Visco of the advocacy group National Breast Cancer Coalition. "They should really think very carefully before getting a mammogram."

Furthermore, not every scientist agrees with the findings. Some claim that the Danish study is flawed and argue that there is clear evidence that the procedure is a life-saving one.

"It's giving women the wrong idea that half of all cancers maybe are nothing to worry about," says Debra Monticciolo, chairwoman of the American College of Radiology's Breast Imaging Commission. "Nothing could be further from the truth."

Because Denmark made mammography for breast cancer screening available to every woman at different times in different locations throughout the country, the researchers were able to compare the occurrence of both early- and late-stage breast cancer in different places. They compared the women who received a mammogram with those who did not.

"We wanted to look at whether breast screening led to fewer advanced-stage cancers because screening is really based on the premise that you detect cancer earlier so you should have less advanced cancers over time," Jorgensen says.

Their analysis found no "reduction in the frequency of late-stage tumors in the screened areas compared to the non-screened areas," according to Jorgensen. "But we did see a huge increase in the occurrence of early-stage cancers," he said.

The results of the study suggest that mammograms often detect lumps that would never actually turn into a health problem. It is possible that, like many types of prostate cancer, they will never grow and may even go away on their own in part or completely.

"That means that these essentially healthy women get a breast cancer diagnosis that they otherwise would never have gotten," says Jorgensen. "It's really a life-changing event to get a cancer diagnosis."

A diagnosis of breast cancer often leads to many things: not only stress and anxiety, but also a treatment that may include surgery, radiation, and/or chemotherapy. These treatments are hard to get through, and patients can suffer serious side effects from them.