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Women with 'dense breasts' could need specialized tests to detect cancer

 
Above, the MRI, or magnetic resonance image, clearly shows tumors in Nikki Lucas’ left breast (the image perspective is reversed so the left breast is on the right side of the screen). In the standard mammogram, below, a mass of dense tissue appears white, obscuring the tumors (a white dot marks location). Fatty tissue appears black.
Above, the MRI, or magnetic resonance image, clearly shows tumors in Nikki Lucas’ left breast (the image perspective is reversed so the left breast is on the right side of the screen). In the standard mammogram, below, a mass of dense tissue appears white, obscuring the tumors (a white dot marks location). Fatty tissue appears black.
Published Oct. 19, 2012

TAMPA

Nearly 20 years ago, Nikki Lucas went to the doctor complaining of breast pain. A mammogram and an ultrasound were ordered up, but the doctors found no problems.

In fact, breast pain can happen for benign reasons like normal hormone fluctuations — it's not a common symptom of cancer.

Doctors did mention that Lucas had "dense breasts,'' but they never explained what it meant, nor did they seem worried, so she didn't inquire further.

Flash forward to a Saturday morning back in March. Lucas decided to do a breast self-exam, because, well, that's what she'd always heard women are supposed to do.

She's 43, and figured she ought to get a mammogram one of these days. In the meantime, a self-exam just seemed like a good idea, even though some experts say they're of little value since lumps really need to be found when they're too small to be detected in a self-exam.

Lucas had no trouble detecting a lump in her left breast.

"It was enormous," the Brandon resident remembers.

"Four days later, I'm at Moffitt Cancer Center and learn I have Stage 3 breast cancer that has spread to my lymph nodes on the left side."

• • •

Experts disagree on when to begin regular mammograms. The American Cancer Society calls for most women without symptoms to start regular screening at age 40; the U.S. Preventive Services Task Force recommends waiting until age 50 unless a woman is in a high-risk group.

As a busy wife, mother and grandmother with a job outside the home, she knew about the debate.

"I was so caught up taking care of family that I wasn't taking care of me," she said. "I would have been dead if I had waited until 50. Period."

What Lucas didn't know was that having dense breasts is a well-known risk factor for breast cancer. Dense tissue also makes it more difficult for doctors to detect tumors on mammogram images.

The good news is that women like Lucas do not have a higher risk of death from cancer than do comparable cancer patients with less dense breasts. That was the finding in a study of over 9,000 women with breast cancer, published Aug. 20 in the Journal of the National Cancer Institute.

Still, the key to treating breast cancer is finding it, and that's the challenge of dense breasts.

"If you have dense breasts, there's a lot of white tissue on the image. But breast cancer is white, too. That makes diagnosing breast cancer really difficult," said Dr. Tracy Halme, director of mammography at the Shimberg Breast Center at St. Joseph's Women's Hospital in Tampa.

"It's like looking for a white cotton ball in a white cloud," she said.

Breast tissue is made up of fatty as well as connective — or dense — tissue. Every woman is different and has a different ratio of fatty to dense tissue. For most women, density decreases as part of the normal aging process.

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But it's impossible to tell what kind of breasts you have just by feeling or looking at your breasts.

It takes a mammogram, an X-ray of the breast, to tell for certain. On a mammogram, dense tissue looks white and fat looks dark; tumors appear like dense tissue or solid white areas. That's due to the fact that X-rays are blocked to a greater extent by fibrous tissue than by fatty tissue.

So women with dense breasts may need specialized tests such as breast MRI or ultrasound as part of their screening. Both can be helpful when trying to distinguish between fatty tissue and dense breast tissue.

This year, the FDA approved tomosynthesis, also known as 3-D mammography, another imaging system that may do a better job of detecting cancer than conventional mammography.

Tomosynthesis produces dozens of images from the top and side of each breast — 50 to 60 from each viewpoint, so the breast is seen as a series of thin slices. St. Joseph's just started using Tomosynthesis this month on all its mammography patients.

"This allows us to see all the way through the breast and to reconstruct the sections as a 3-D image. Because we can see within the breast, we can more accurately tell if we are looking at normal tissue or a real (cancerous) mass," said Halme.

• • •

Cathy Readinger, 54, was one of the first patients to receive the screening. The Tampa woman has known for years that she has dense breasts and that this could make it more difficult to find a tumor. So she has been diligent about self-examinations, annual clinical exams and screenings.

"I was excited to know I was getting a more detailed screening and that if there was a mass, it would be more likely to be detected," said Readinger.

The chief drawback of tomosynthesis is that patients get a higher dose of radiation — about double the dose associated with standard mammography, according to manufacturer Hologic Inc.

"And, the resolution of calcifications is somewhat lower," said Dr. Blaise Mooney, director of breast imaging at Moffitt Cancer Center. Moffitt considered purchasing the technology but decided to wait until the next generation is released.

"It's neat technology and it will be helpful," said Mooney, the radiologist at Moffitt who read Lucas's imaging studies after she came to Moffitt. "The doctor gets more information about the breast and that pro may outweigh the cons."

Given her increased risk of cancer and potential difficulty of finding it, Readinger said she's willing to accept the higher radiation dose.

"I was very happy to see that finally there is a new tool to screen for breast cancer," she said.

Irene Maher can be reached at imaher@tampabay.com