It was just another routine mammogram for Marlo Rockwell.

“I do it every year, I’m pretty diligent,” Rockwell said, sitting next to Dr. Anna Wilson in the Yellowstone Breast Center at St. Vincent Healthcare. “I follow the rules.”

It was late June and the first time Rockwell had undergone 3D digital mammography at the center, the latest technology for detecting suspicious masses within the breast.

“Then I got called for additional imaging, which I’ve had before so I wasn’t too freaked out,” she said.

Nothing was seen on an ultrasound, so a biopsy was ordered, and Wilson called Rockwell with the results. Rockwell had cancer.

“My husband was sitting next to me while I was on the phone saying ‘uh, uh, OK’ as she was telling me the next steps,” Rockwell said. “She was very calming, and I remained calm. But after, when my husband said ‘that seemed to go very well,’ I said ‘no it didn’t’ and I lost it.”

After she got over the initial shock, Rockwell was ready to move on to the next step. A patient navigator helped steer her through the process, including meeting with Dr. Kathryn Hatch, the St. Vincent surgeon who would perform the lumpectomy.

While at Hatch's office for the consult, the physician’s nurse looked at the calendar and mentioned a tentative date for the lumpectomy: June 19.

“She said, ‘It’s your birthday, are you sure you want to do it then?'” Rockwell said. “To me there was no better way to celebrate life. It was an honor and a privilege to have that on my birthday. I’ll never forget it.”

The lump was discovered early enough that after the outpatient surgery, there was no need for radiation or chemotherapy, said Wilson, a radiologist and medical director of the Breast Center.

“The options depend on how early you find it,” she said. “The outcome is much better when we find it early.”

With October Breast Cancer Awareness Month, Wilson gave a little history of mammography. Widespread 2D mammography started in the 1970s and ’80s when a lot more women were starting to get screened and more cancer was detected.

Wilson cited an article published by the American Cancer Society that said from the late 1980s to 2015, the death rate for breast cancer dropped by 40 percent.

“They estimated over 300,000 women’s lives were saved through mammography, so 2D mammography has done a great job screening and detecting early breast cancers,” Wilson said.

3D mammography, which is available at both Billings hospitals, has already shown a great increase in the number of breast cancers that are being detected, she said.

“We started about February of this year and we have seen cancers we cannot see with 2D, with 3D,” Wilson said. “We know it’s much, much superior.”

With that in mind, St. Vincent is only offering 3D mammograms to its patients, with the exception of the hospital's mobile mammography coach that doesn’t yet have it. At this point, 80 to 85 percent of insurance companies cover 3D, but the hospital is willing to work with patients and their insurance companies that don’t cover it.

Though there still remains some controversy on when and how often mammograms should be done and their efficacy, the American Cancer Society suggests that for women at average risk for breast cancer, all women should begin having yearly mammograms by age 45 and can change to having mammograms every other year beginning at age 55.

The ACS also believes that women should have the choice to start screening with yearly mammograms as early as age 40, if they prefer. Both the American College of Radiology and the Society of Breast Imaging agree that screenings should start at 40.

“Mainly why they’re supportive of that is we have lots of data on imaging and mortality about where we save the most lives,” Wilson said. “All the data shows that when we start at 40 and do them annually, that’s when we save the most lives.”

Rockwell will undergo screening mammograms every six months for the next two years, to make sure she remains cancer-free. It's something she's glad to do and she encourages other women, including those who never have done it before, to take the step.

"Especially for someone who has never had a mammogram you hear war stories," she said, alluding to the discomfort connected to the test. "It's a little pain for a few seconds, but it's so quick, it's not enough to worry about."