Female veterans in Congress are pressing the Pentagon to cover a type of mammogram that increasingly is being accepted as the standard of care for early detection of breast cancer.

Sen. Martha McSally, R-Ariz., and Rep. Chrissy Houlahan, D-Penn., will introduce bills Thursday in their respective chambers that would require Tricare to cover digital breast tomosynthesis, or DBT, also known as 3D mammography.

Currently, Tricare covers traditional two-dimensional mammography for screening exams. The 3D versions are similar to a CT scan, taking pictures from multiple angles and producing dozens of images to build a three-dimensional perspective.

The lawmakers say the technology is available to patients at the Department of Veterans Affairs as well as Medicare beneficiaries and private practice and should be provided to service women, military family members and retirees.

“This is a pretty darn big gap in coverage that we need make sure we are filling,” Houlahan told Military Times.

Use of 3D mammograms has increased from 13 percent of screening examinations in 2015 to 43 percent in 2017. Still, the U.S. Preventive Services Task Force and American Cancer Society have said there isn’t enough evidence to advise women on the benefits of 3D mammograms over traditional screening technology.

A study is underway at the National Cancer Institute to try to answer the question as to whether they are more effective, but Houlahan said 3D mammograms can help detect cancers in women with dense breast tissue, about 40 percent of the female population.

Dense breast tissue, made up of supportive tissue and compact milk glands and milk ducts, can make finding anomalies and tumors more difficult on a 2D scan. “This is not a niche issue … This is the only technology that identifies issues in those with dense breast tissue. People should be able to use the technology that is the most appropriate for them,” Houlahan said.

The Defense Health Agency, DHA, said Wednesday it will begin covering 3D mammography on a provisional basis starting on Jan. 1, with the goal of expanding the policy system-wide by “early 2020.” Prior authorization will be required, and the stipulation that it is provisional means that Tricare will cover the exams for up to five years while studies continue on the technology’s effectiveness.

“Provisional” also means DHA can cancel the benefit at any time.

For the lawmakers, the DHA step is not enough. They hope their legislation will be incorporated into the fiscal 2021 National Defense Authorization Act to ensure that Tricare coverage is made permanent.

“We first tried to use our oversight role to get them to shift, and they re not shifting,” said McSally, who sent a letter in October to Assistant Secretary of Defense for Health Affairs Thomas McCaffery about the issue. “So we are introducing an act of Congress in order to make it happen.”

From 2005 to 2014, 652 female service members were diagnosed with breast cancer, an incidence rate of 31.8 per 100,000 person years of military service. The incidence rate in the U.S. in 2016, according to the Centers for Disease Control and Prevention, was 20 per 100,000 persons.

Breast cancer is the second most diagnosed cancer in women, behind skin cancers. Although death rates from breast cancer have been declining since 1989, the disease is expected to kill 41,760 women in the United States this year, according to the non-profit group Breastcancer.org

In the letter, cosigned by 10 other female senators, McSally said more than 250 clinical studies have shown that 3D mammography detects cancer and reduces the number of callbacks or follow-up tests.

Houlahan sent similar correspondence earlier this year that was signed by 50 House members, men and women from both political parties.

“I hope this is the beginning of a lot of exploration into this kind of thing as we have more women in Congress. … I don’t know that there have been a whole lot of conversations talking about breast tissue in Congress previously," Houlahan said.

McSally received her first mammogram while she was in the Air Force preparing for retirement, a traditional 2D mammogram.

“They said, ‘Oh, you’ve got some anomalies,’ so I personally know that feeling of kind of freaking out [of thinking], ‘Well what does that mean?!’ ” McSally said.

She now receives 3D mammograms at the Phoenix VA Health Care System.

“We have so many active duty women that deserve to have certainty, with the best technology with that first image, so they understand what the risk is and they are able to get a diagnosis as quickly a possible if they do have breast cancer," she said.