Beginning July 1, women getting mammograms will learn whether they have dense breast tissue that could hide cancer. This is due to recent legislation that addresses the test’s failure to detect certain cancers in women with dense breast tissue.

Under the new law, if radiologists conducting mammograms find dense breast tissue, they must send the patient a letter noting that fact – and that dense breast tissue can hide cancer. The letter will urge women to talk to their physicians about the matter.

The new “patient inform” law resulted from efforts by a breast cancer survivor, Cathryn Tatusko of Fairfax County, with support from an aptly named national awareness organization called Are You Dense.

JoAnn Pushkin, co-founder of Are You Dense, said she was pleased that Virginia has enacted the new law.

“I am thrilled that women of Virginia will join those in Connecticut and Texas in receiving this life-saving information about their breast health,” Pushkin said.

During its 2012 session, the General Assembly approved two identical measures addressing the issue: Senate Bill 544, sponsored by Sen. John Edwards, D-Roanoke; and House Bill 83, introduced by Delegate Robert Orrock, R-Thornburg. Both bills passed unanimously, and Gov. Bob McDonnell signed them into law.

Currently, after a woman gets a mammogram, her referring physician receives a report from her radiologist with a statement on her breast density. However, the patient receives a letter without medical jargon that simply says whether abnormalities were detected. Women can ask for the more detailed report, but most don’t.

Studies also show that only one in 10 women learn about breast density from their doctors.

Most women have a combination of dense and fatty breast tissue. On a mammogram, dense tissue appears white and fatty tissue appears gray.

Cancers also show up as white on a mammogram. As a result, they can be hidden by dense tissue. In contrast, against fatty tissue, cancers stand out and can be more readily spotted.

Thus, women who have very dense breast tissue have a greater risk that their cancer could be overlooked. According to many studies, cancers can be obscured more than 40 percent of the time, depending on the degree of breast density.

Tatusko approached Orrock and asked him to propose the legislation. She did so after her own ordeal with breast cancer.

Tatusko’s dense breast tissue had masked the large tumor on the yearly mammogram she had just five months before being diagnosed with breast cancer. Even a mammogram she received the day of her diagnosis failed to show the advanced-stage cancer. As of February, Tatusko is considered cancer-free.

Are You Dense was founded by another breast cancer survivor, Nancy Cappello of Connecticut. Cappello persuaded her home state to pass a “patient inform” law in 2009, and she helped women in Texas pass legislation that same year. Fourteen states besides Virginia considered such proposals this year. A federal bill is also pending.