TAMPA — When Jenna Johnson went for her annual mammogram in November, she was also offered a newer screening test that would take three-dimensional images. It would take a few extra minutes, but Johnson didn't mind.
Like a lot of women, she has received those nerve-wracking phone calls after a mammogram to tell her that something didn't look quite right.
"I've been called back before," said Johnson, 51, an executive assistant who lives in Tampa. "It's always been nothing, so I thought maybe with 3-D they'd get a better view of what's in there."
Doctors at the Shimberg Breast Center at St. Joseph's Women's Hospital did get a better view. They found a small, flat but aggressive cancer in Johnson's left breast, something that didn't show up on the digital 2-D images.
"The (3-D view) allows you to see distortions around the cancer that you wouldn't normally see," said Dr. Mia Jackson, a breast radiologist and medical director of imaging at the Shimberg Center who reviewed Johnson's scans. "It draws your eyes to those changes, so you find cancers smaller and earlier."
A study in the Journal of the American Medical Association late last month added to the evidence for the still-young technology, known as tomosynthesis. It found that tomosynthesis appears to be better than standard mammography both at finding cancer earlier and at reducing those frightening false alarms.
The new results are promising but not definitive, according to experts not associated with the study. Tomosynthesis was approved by the Food and Drug Administration in 2011, so it is too soon to know whether its use will translate into fewer deaths from breast cancer.
But the promise of finding cancers earlier and reducing false alarms is enough to get more doctors and patients on board. Two years ago, St. Joseph's was the first to adopt the technology in the bay area. Moffitt Cancer Center added it five weeks ago (see list).
Jim Culley, a spokesman for Hologic, which makes the only tomosynthesis equipment approved by the FDA, estimated that more than 6 million American women will undergo tomosynthesis this year. More than 38 million mammograms are performed each year in the U.S.
Tomosynthesis is more expensive than a digital mammogram — some centers charge an extra $100 — and not all insurance covers it. Some experts say it might be most appropriate for women with a genetic risk of breast cancer or who have dense breasts, meaning they have a higher ratio of connective to fatty tissue. Dense breast tissue looks white on a mammogram, and so do tumors, making them harder to see.
"I have very dense breasts and have been called back once or twice for something that didn't look right," Johnson said. "So when it happened (in November), I was thinking, no big deal."
After a lumpectomy followed by seven weeks of radiation, her prognosis is good.
"I tell everybody about (tomosynthesis) now and am glad to have the opportunity to get the word out. 3-D really saved me."
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Mammography, considered the gold standard for breast screening, provides a flat, two-dimensional picture of a three-dimensional breast. When a breast is squeezed between plates during screening, all its internal structures — blood vessels, milk ducts, fat, ligaments — are pressed together, causing them to overlap on one another and possibly hide small, early cancers.
Overlap can also make normal tissue appear abnormal and result in a woman being recalled for additional screening or for more invasive testing, such as a biopsy.
The breasts are still compressed in tomosynthesis, but the device moves around the breast, capturing a series of images that look like slices. Because each structure within the breast becomes visible, small cancers that might have been concealed in a standard mammogram are visible.
"Five major studies prove 3-D finds more cancers, about 40 percent more invasive cancers than standard mammography, and there are fewer recalls," said Dr. Jennifer Drukteinis, a breast radiologist and director of breast imaging research at Moffitt Cancer Center.
Recalls, which happen in about 10 percent of all mammograms, are inconvenient, produce anxiety and expose women to more radiation. And some women who are called back do not return.
Several studies found 3-D imaging reduces recalls by 15 to 37 percent, Drukteinis said.
"It makes me much more confident to look at the films and say, 'You're fine. We'll see you next year,' " she said. "It gives radiologists greater confidence in diagnosing or ruling out cancer."
The 3-D test requires a higher dose of radiation than the 2-D scan. Some centers, such as Moffitt, have technology that creates a 2-D image from the 3-D images, so women get the benefits of both technologies in one exam, without additional exposure.
It takes longer to read a 3-D mammogram because there are more images to review. Instead of four pictures, two of each breast, the radiologist reviews dozens of each breast. If a mammogram is diagnostic — ordered because an earlier test looked suspicious — there could be several hundred images to read.
So it's not yet an option that all women will choose.
Carolyn Lastoria, 50, has been getting regular mammograms for a decade. She has never had cancer, but she has had some scares.
"They are very reassuring on the phone, they tell you it doesn't mean anything's wrong, but I was a little scared, worried," the Brandon resident said.
She had read about the latest tomography study and was happy to learn that every woman screened at Moffitt Screening and Prevention gets a 3-D mammogram.
Lastoria, whose test showed no problems, wishes it had been available sooner. "I probably wouldn't have had to go back those other times. It would have shown a more comprehensive picture."
Information from the New York Times was used in this report. Contact Irene Maher at firstname.lastname@example.org.