Researchers mixed on the merits of breast cancer screening
As researchers debate the merits of mammograms, doctors and patients may be hesitant to stop them
An author of a recent study said researchers "do not find any benefit from mammography," prompting some strong reactions in the medical community.Juice Images / Alamy
It may be getting harder for women to know exactly what they should and shouldn't be doing when it comes to breast cancer screening with mammograms. The medical recommendations seem to be universal, but now and then — including in a new study released last month — the need for regular mammograms is called into question, prompting strong arguments from both sides of the discussion.
For years, “mammograms save lives” has been the message of breast cancer awareness campaigns, and public health officials have worked hard to spread that message far and wide. But in recent years, the message has become muddled, as some studies and public health decision makers have seemingly reversed course, noting that excess screening can have diminishing benefits and negative consequences — whether that is the anxiety from false positive tests or treating cancers that might otherwise not have had a significant impact on the otherwise healthy woman who has, as a result of screening, become a breast cancer patient.
It remains the opinion of many physicians that mammograms do save lives.
In 2009, the U.S. Preventive Services Task Force (USPSTF) issued new guidelines on mammography recommending, based on its reading of the scientific evidence, that mammograms no longer be the default routine for women at their annual physical once they reach 40, and the result was condemnation of the new guidelines as a death sentence for women or a real-life instance of the “death panel” myth.
The reaction was perhaps the strongest evidence for the success of efforts to publicize screening programs created with the aim of saving women from dying of breast cancer. But while the guidelines were met with opposition, with many hospitals and physicians saying they would ignore them and other professional societies keeping their guidelines, the issue had been pushed to the forefront.
That debate was reignited last month, as a study with a 25-year follow-up from Canada was published in the British Medical Journal. That study compared women who received an annual mammogram with women who had been instructed in breast self-exams, and showed that women who underwent the mammograms were no more likely to survive a breast cancer diagnosis.
While there was a wide-reaching backlash against the recommendations of the 2009 USPSTF guidelines, the change involved was a small one. In calling for women to discuss mammograms with their physicians rather than getting them by default, it put decision making in the hands of the patient and her physician. But there was an immediate fear that this would lead insurance companies to not cover the cost of mammograms for women in their 40s. This has not come to pass, as health care legislation has ensured continued coverage and Kathleen Sebelius, secretary for health and human services, had instructed people to ignore the USPSTF’s guidelines.
The USPSTF is currently re-evaluating its guidelines and will be issuing new ones in the near future. It’s still not clear what effect the recent BMJ study may have, but it has already caused some consternation among medical professionals who view mammography as an important tool in their arsenal against breast cancer.
“They measured one thing, which is a very important thing, but that’s not the only purpose in the United States, which is why we recommend mammograms,” said Lillie Shockney, an associate professor of nursing and administrative director of the Johns Hopkins Breast Center and Johns Hopkins Cancer Survivorship Programs, and herself a former breast cancer patient.
A better quality of life during and after treatment is a goal as well, she said, adding, “Hopefully, her treatment will be far less physically and emotionally traumatic than if she was a late-stage-diagnosed individual.”
Shockney said that despite the guidelines, she has not seen a decrease in women asking for mammograms, an experience that appears to be fairly standard. In a study from Harvard Medical School and Brigham and Women’s Hospital in Boston published in July, researchers said there was no decrease in mammography rates following the publication of the USPSTF guidelines.
But while quality of life after recovering from breast cancer is an important issue, it remains poorly understood. A complicated aspect of the mammogram debate is a personal one. While the downside of excess screening is unnecessary treatment for a tumor that would not have harmed the woman, in that case she would see it differently — that she is a breast cancer survivor.
Following the publication of papers like the BMJ study or the 2009 USPSTF guidelines on mammography, a number of women shared their personal stories of breast cancer diagnosis, treatment and recovery, and as a general rule they have said mammograms saved their lives. While this is their belief and that of medical professionals who have treated them, studies like the recent BMJ one tell a different and unsettling story — that in many cases these cancers may not have been a threat to the degree thought, and earlier detection simply means more time taking unpleasant treatments and more women being treated for tumors that would not have been a threat. These studies have proved unsettling in part because they raise the possibility that the cause of illness was a false positive diagnosis and the treatment that followed.
“Doctors are just as prone to those (errors) as well,” said Dr. David Gorski, chief of the division of breast surgery at Wayne State University and managing editor of Science-Based Medicine, a blog covering medical issues and controversies. “We feel good we find the tumor early; we think we saved a life. Maybe we did, but we don’t know for sure.”
Another reason the Canadian study has been met with some skepticism is that rather than just implying that screening should be cut back, it implies that screening should be done away with altogether, as it compared a group with annual screens with women who monitored themselves in other ways.
“We do not find any benefit from mammography; instead we find a hazard in the sense that there are breast cancers detected which never would have caused problems in that person’s lifetime,” study author Dr. Anthony B. Miller, a professor emeritus of epidemiology at the University of Toronto, told Al Jazeera.
Dr. Daniel Kopans, director of breast imaging at Massachusetts General Hospital and a member of the American College of Radiology Commission on Breast Imaging, has been a longtime critic of the Canadian group’s methodology.
“There’s no credible person who takes care of women with breast cancer who won’t say we save lives with our therapy by treating when it’s early,” he said.
Other large-scale studies have shown a benefit for mammography, such as one conducted in Sweden that screened women at intervals of 24 to 33 months. But if screening is to be reduced in guidelines, Kopans said, it would require studies comparing different intervals, which haven’t yet been done.
Over time, physicians may be less adamant about screening younger women as frequently as they have in the past, although that may take a while.
“It is one study that didn’t really show a benefit; however, there are others that do,” Gorski said. “The key, I think, is trying to find the sweet spot, and I think we might be beyond the sweet spot in terms of aggressive screening.”
In terms of whether he would advise any change in screening, “I have a hard time doing anything that much differently until a consensus is reached.”
Changing the conversation
But that change in consensus is likely to take some time.
“We have sort of this belief that early detection is the most important thing,” said Dr. Aaron Carroll, director of the Center for Health Policy and Professionalism Research at Indiana University. With more technology, he said, we seem to be doing more universal screening, and “there’s a growing body of evidence that may be overkill, picking up cancer, disease that doesn’t need to be treated,” leading to chemotherapy, surgery and radiation therapy that in the end isn’t being shown to save lives in some studies.
“It should be forcing us to really reconsider our stance, especially in the United States, where we are on the forefront of declaring everybody needs to be screened as much as possible,” Carroll said.
While mammograms still appear to convey some benefit, it’s also becoming clearer that screening has some downsides. What remains less clear is how to overcome years of messaging that screening saves lives and more is better, and to add in that there may be some negative effects from screening.
“Overtreatment is particularly hard because it seems like people’s lives are being saved,” said Brendan Nyhan, an assistant professor in the department of government at Dartmouth College who studies misconceptions about health care.
“Breast cancer has become a cause, and everyone is in favor of fighting breast cancer, and so when you’re told the way we’ve been fighting breast cancer is ineffective, it’s not surprising that people aren’t receptive to that information,” he said, suggesting it may take legislation or other measures at the policy level to actually implement a different program. “I don’t think we know how to change the conversation on the effectiveness of mammograms.”