Breast Cancer Controversy Lives in the Data

December 24, 2015

CHICAGO-Breast imaging experts look at the same data, but see different results, as explained at RSNA 2015.

“I’m confused and I spend my life thinking about [breast cancer screening guidelines],” Etta D. Pisano, MD, professor of radiology, Medical University of South Carolina, said at RSNA 2015.

Pisano was referring specifically to the three different sets of guidelines set forth by the American Cancer Society (ACS), US Preventive Services Task Force (USPSTF) (currently in draft recommendations), and the American College of Radiology/Society of Breast Imaging (ACR/SBI). As they stand today, the guidelines are as follows:

American Cancer SocietyWomen aged 40-44: Women should have the choice to start annual breast cancer screening with mammograms if they choose to do so. The risks of screening as well as the potential benefits should be considered.

Women aged 45-54: Women should get mammograms every year.

Women aged 55 and older: Women should switch to mammograms every two years, or have the choice to continue yearly screening.

Screening should continue as long as a woman is in good health and is expected to live 10 more years or younger.

USPSTF Draft RecommendationsWomen aged 40-49: The decision to start screening mammography should be an individual one. Women who place a higher value on the potential benefit than the potential harms may choose to begin biennial screening between the ages of 40 and 49.

Women aged 50-74: Women should receive biennial screening mammography.

Women age 75 and older: Current evidence is insufficient to assess balance of benefits and harms of screening mammography.

ACR/SBIWomen beginning at age 40: Screening mammography should be performed annually.

“The ACR and SBI suggest that screening with mammography should continue as long as a woman has a life expectancy of ≥5 to 7 years on the basis of age and health status, is willing to undergo additional testing including biopsy, if indicated by findings on mammography, and would be treated for breast cancer if diagnosed.”

“The confusion is really out there,” Pisano said. “I think it’s inappropriate and we’ve really created a lot of problems for ourselves and for our patients.”[[{"type":"media","view_mode":"media_crop","fid":"44517","attributes":{"alt":"Etta D. Pisano, MD","class":"media-image media-image-right","id":"media_crop_7807120136885","media_crop_h":"0","media_crop_image_style":"-1","media_crop_instance":"4991","media_crop_rotate":"0","media_crop_scale_h":"0","media_crop_scale_w":"0","media_crop_w":"0","media_crop_x":"0","media_crop_y":"0","style":"float: right;","title":"Etta D. Pisano, MD","typeof":"foaf:Image"}}]]

Screening saves lives, she said. She cited the seven randomized trials, all performed before 1990 with none of the modern screening technology, that showed it saves lives.

“We know there is a bigger mortality reduction in older women than younger women,” Pisano said. Factors that affect this include older women having lower and less aggressive breast cancer, leaving more time until the cancer will kill the woman, giving the physician more time to find it, and a higher likelihood of it being found when its intervenable.

“The range of mortality reductions, depending on the study, depending on how you analyze the data, is very large,” she said. “The people who are most pessimistic about screening will always reach the 15% figure of mortality reduction, the people who are most optimistic will always reach the 50% reduction.”

There is also overdiagnosis, or finding things that will never kill the woman, which Pisano said is more of a worry now than ever in the history of the profession.

“Our technology has become so sensitive, so it’s possible that we are finding things that will never kill women,” she said.

More important than the actual finding is how the findings are treated.

“Overtreatment is the real issue, in my view,” Pisano said. “It’s essentially giving a woman a mastectomy that doesn’t need one, or giving a woman radiation and chemo that doesn’t need that.”

Pisano said there is almost nothing published on how often overtreatment occurs. She referred to a 2004 paper that showed only 20% of women got the recommended therapy, most of the women were overtreated.

“If we have a problem with overdiagnosis, it is because we have been overtreating these women,” she said.

“In 2015, in the US and the world, we cannot tell which cancers are not going to kill the woman,” Pisano said. She cited advancements in technology that allow physicians to look at genetics or types of breast cancer, but radiologists “cannot tell an individual that they do not need to treat their breast cancer, so we’ve got to treat everyone equally.”

Treating everyone equally can be difficult to do when three leading organizations are providing different guidelines on how to screen for breast cancer.

Pisano believes the recommendations differ because they are weighing the risk-benefit ratio differently.

The ACS knows that breast cancer is less common in the early 40s, but women can have the screening if they want it, she said. “This goes for support for biennial mammography for older women because, again, the rate of breast cancer on average is lower in older women, so you are more likely to intervene and have a benefit to those women.”

ACS decided to go to less frequent mammography because the harms will be less because the women tend do have less and slower growing cancers, Pisano said.

The USPSTF, Pisano said, made the respective calculation for women and said they should not have mammography. They know it saves lives, she said, but the risks are so high that women should not be screened in their 40s. Risks include false positives, overdiagnosis, and overtreatment.

“ACR/SBI want to find all of the cancers out there,” she said.

With no randomized trials in the modern treatment and diagnostic error, organizations like USPSTF can cite that there is a lack of evidence of a mortality benefit for new, more sensitive systems, like tomosynthesis. It becomes even more important when considering that USPSTF recommendations suggest whether these services should be paid for, and how often.

 “Radiologists have to be aware of this group of critics that are not going to be satisfied with us saying, look we proved the mortality benefit in the 1970s and 1980s and now we have better tools,” she said. “They really wonder if everything we find right is now helping women.”

“I hope we can clean up a lot of this confusion. I’m personally sick of this conversation I think we just need the data to help us make the right decision,” Pisano said.