Pisano to U.S. women: Don't change mammography schedules

Another negative study on the effectiveness of mammography was recently published in Health Affairs, picking up mainstream media coverage everywhere from CNBC and NPR to the Daily Mail.

The study, written by Mei-Sing Ong, PhD, and Kenneth D. Mandl, MD, estimated that false-positive mammograms and breast cancer overdiagnosis cost the United States $4 billion a year and “must be considered in the debate about the appropriate populations for screening.”

Etta Pisano, MD, radiologist, breast cancer researcher and former dean of the MUSC College of Medicine, told RadiologyBusiness.com she had major issues with the study.

“I’m very unhappy with this paper,” Pisano said in a phone interview.

What concerned Pisano the most were some "sloppy" assumptions the researchers made about the overdiagnosis of DCIS. Ong and Mandl wrote that they estimated the overdiagnosis rate of DCIS to be 86%, deriving that number from looking at “patients previously misdiagnosed with benign breast disease who did not receive treatment, but were subsequently diagnosed with DCIS … 14% of these women went on to develop invasive cancer. In other words, 86% of DCIS cases were likely to be overdiagnosed.”

This floored Pisano, causing her to question the rest of the paper.

“The assumption of an over 80% overdiagnosis is completely unjustified,” she said. “Those were women who did not receive treatment. To me, that’s a key point; who are the women who are not receiving treatment? Those are the women with the lowest-grade tumors, almost certainly.”

Dangerous implications

The authors also estimated the overdiagnosis of screen-tested invasive breast cancer to be 22%. Pisano said the most common numbers she hears for this statistic are closer to 10%, and some of her colleagues even believe it to be closer to 1% or 2%.

On the other hand, Pisano takes no exception with the study’s estimates about the cost and regularity of false-positive mammograms. But she does not see these statistics as a reason to consider moving away from the current ACR recommendation of annual mammograms for women over the age of 40.

The most commonly mentioned alternative to the ACR’s recommendation for annual mamograms is moving to a biannual schedule, which Pisano sees as potentially disastrous.

“Studies show a reduction in mortality for women in their 40s when they have annual screenings, so I don’t think we should go to biannual,” she said. “We know breast cancers tends to be more aggressive in younger women—they grow faster—so the more we cut back on screenings for younger women, we’ll lose more women. They will die.”

The other alternative people often hear about is that women should wait until they are older than 40 to begin getting mammograms—perhaps 45, or even 50. But Pisano doesn’t see selecting an arbitrary cut-off age as a legitimate solution. It’s not clear which age makes the most sense, she says, and fact that breast cancers are more aggressive in younger woman once again comes into play.

Culture a factor

Pisano points out that one reason for the higher number of false positives within the United States is the country’s culture.

“Women want to know what’s in their breasts in the United States. So if they have a cyst, in the United States, women expect to be called back and told, ‘you have a cyst.’ They want to know for sure they have a cyst. Most women want that ... They want to know what’s there. The patient drives the screening process here.”

Pisano compares this with other countries, such as those in Europe.

“In Europe, there’s this more paternalistic attitude that if there’s something there and it looks benign, the radiologist can make the call, patients don’t need to hear about it and nothing needs to happen,” she said. “False positives are a problem in this country ... but I think it’s because of our attitude about women as decision makers, and that’s a good thing,”

Ultimately, Pisano thinks the long-term answer to cutting down on false-positives may be conducting screening based on individual risk profiles. But we’re many years, and a lot of research, away from that becoming a reality, she said.

“Screening is a topic that has been understudied in the last 40 years. In my opinion, more money needs to be invested in this before we make these sweeping generalizations about cutting back on screening. I think women would benefit from those studies.”