Finding breast cancers that regular mammograms don't catch | St. Louis Public Radio

Finding breast cancers that regular mammograms don't catch

Aug 14, 2013

This article originally appeared in the St. Louis Beacon: Lori Jackson was vigilant about getting yearly mammograms. She had gotten mammograms since the age of 35 because her older sister had been diagnosed with breast cancer at age 37.

In spite of this, Jackson was diagnosed with stage IV breast cancer in 2009. She was 44.

“I followed the health-care protocols, and I thought I was doing everything I was supposed to,” she said in a video posted on her Facebook page.

Following her diagnosis Jackson said that her oncologist told her the reason that the mammograms had missed the cancer: Jackson had dense breast tissue, which can hide cancers because both the cancers and dense tissue show up as white on a mammogram.

Lori Jackson died in 2012.

“It just blew us away that doctors have been taking this measurement [breast density] for years,” said Jackson's widower Jeff Jackson. He believes that knowing that Lori had dense breasts, and might benefit from additional screening (such as MRI or ultrasound), would have armed them to ask and pay for additional testing that would have allowed her to detect her cancer at a much earlier stage, potentially saving her life.

Nancy Cappello, founder of Are You Dense?, had a similar experience. In spite of diet, exercise, and yearly mammograms, she was diagnosed with stage III breast cancer in 2004, at age 51. She learned that she had dense breasts only after her diagnosis.

“In my case, what shocked me was that I had stage III breast cancer with 13 [affected] lymph nodes,” she said. “I could not get out of my head, ‘Oh yeah, because of your dense tissue it’s very hard to find (cancer) on a mammogram,’” she said.

In 2004, Cappello successfully pushed for a law in Connecticut that required insurance companies to cover additional ultrasound screening for women with dense breast tissue.  But, doctors still weren’t sending women to get the ultrasounds, she said. Then she focused on mandatory breast density notification legislation, which passed in Connecticut in 2009.

“People say, ‘why legislation?’ I say, darn it, I wish we didn’t have to,” she said.

Since the passage of legislation in Connecticut in 2009, 11 more states have passed mandatory breast density notification laws, seven in the 2013 legislative session. 

Lori Jackson worked with Cappello and Rep. Sue Allen, R-Ballwin, to introduce mandatory breast density notification legislation in Missouri in 2012. The bill was defeated and has not been reintroduced.

Science behind mammograms, breast density

While many studies have shown that mammograms detect breast cancers in 98 percent of women with fatty breasts, mammograms also find fewer than half of cancers in women with very dense breasts. Forty percent of women have dense breasts, and 10 percent of all women have very dense breasts, so this is a common condition.

Breast density has also been found to be a risk factor for breast cancer. Women whose breasts are over 75 percent dense tissue are four to six times more likely than women with low breast density to develop breast cancer.

Additonal screening has been shown to result in higher detection of breast cancer in women with dense breasts. One study published in 2012 in the Journal for the American Medical Association showed that ultrasound plus mammography increased the detection of breast cancers by 34 percent, while mammogram plus MRI increased cancer detection by 54 percent.

However, the same study found that 5 percent of women receiving ultrasound had biopsies and only 7 percent of those biopsied had breast cancer -- a high rate of false positives.

Some physicians and professional organization are uncomfortable with notifying women about breast density, let alone mandating it.

Why the opposition? The answer, says radiologist Dr. Barbara Monsees, is multi-layered.

Monsees, the chair of the Breast Imaging Commission for the American College of Radiology and the Ronald and Hanna Evens professor of Women’s Health and Diagnostic Radiology at Washington University School of Medicine, worries that the emphasis on other modalities may damage women’s perception of mammograms, which she says are still the best way to detect breast cancer. 

Another concern is false positives.

“Screening breast ultrasound sends a far greater percentage of women for breast biopsy, and the vast majority of those biopsies are for benign disease (not cancer),” she wrote. “In addition, screening breast ultrasound results in many more recommendations for women to return for short interval follow-up (extra testing in six months).”

Monsees favors an individualized approach to breast cancer diagnosis and screening, where a doctor and patient go over all risk factors, including family or personal cancer history, prior breast biopsies, and other factors.

Opposition to legislation

The American College of Radiology is neutral with regard to mandating breast density notification. But other medical organizations such as the Missouri State Medical Association, the American College of Obstetricians and Gynecologists and the Missouri Radiological Society have lobbied against it.

“The best way to deal with issues like this is to let doctors be doctors,” said MSMA lobbyist Jeff Howell.

Harvey Tettlebaum, an attorney for the Missouri Radiological Society, cautioned against legislatures setting a standard of care, and said that such a law could makes physicians vulnerable to malpractice lawsuits.

“If a woman has a ‘dense breast,’ if you don’t run an additional test, are you committing malpractice?” he asked.

Opponents also cite the cost of additional screening as a downside to the legislation.

New technologies

Dr. Carrie Morrison, head of Breast Imaging at St. Luke’s Hospital in Chesterfield, said she was skeptical about the possibility of ultrasound to help detect breast cancers. She didn’t feel she had time to learn a new modality.

But, Morrison became convinced after she participated in a reader’s study of SonoCine, an automated breast ultrasound system (as opposed to the more commonly used handheld screeners).

“I couldn’t believe it,” she said. “Those perfectly normal mammograms were hiding cancer.”

St. Luke’s has offered SonoCine since 2010 at a patient cost of $300 per screen. SonoCine was FDA-approved in 2012 and is one of a host of other screening modalities that imaging centers are using in addition to mammograms.

Morrison says if ultrasound becomes widely used, radiologists will have to add to their skill set, as reading a screening ultrasound is different from reading a mammogram. With experience, she believes that radiologists can lower the rate of false positives.

“As a radiologist, when you read a screening mammogram, you’re looking for something really obvious,” she said. In a diagnostic ultrasound, radiologists are looking for a specific problem that’s already been identified. That's a very different process from looking at everything on a screening ultrasound.

“It takes some experience to have the nerve not to call everything a cancer,” she said.

Resources from the American College of Radiology:

Standards for describing mammogram results

Breast Density Breast Cancer Screening