New breast cancer screening tool shows promise

| September 9, 2008

News story of study findings from my institution using molecular breast imaging to detect breast cancers, particularly in patients with dense breast tissue to see small tumors.

By Will Dunham

WASHINGTON (Reuters) – A new screening tool works three times better than mammography at finding tumors in women who have dense breast tissue, which can confound mammograms, U.S. researchers said on Wednesday.

Mammography, an X-ray of the breasts, detected fewer than a third of the tumors found using a new technique called molecular breast imaging, or MBI, the researchers said ahead of a breast cancer meeting sponsored by the American Society of Clinical Oncology and other groups.

Mammography is used commonly to screen for breast cancer, but about a quarter of women have dense breast tissue — and mammogram X-rays may not see through this to spot small tumors. Doctors are eager for other methods that perform better.

The study, involving 940 women, is the largest to date to compare MBI to mammography. MBI is still experimental and is not commonly available to women.

The women, considered at high risk for breast cancer due to a family history of the disease, genetic susceptibility or other factors, underwent both screening methods.

With MBI, patients are injected with a radioactive agent that gets absorbed by breast tissue. Cancer cells tend to absorb more of it than healthy cells, and specialized cameras that detect gamma rays from the agent then differentiate tumors from healthy tissue.

"We’re certainly not advocating replacing mammography in any way. But we think it (MBI) would have a role as an additional test for those women that aren’t served as well by mammography as we would like," Carrie Hruska of the Mayo Clinic in Rochester, Minnesota, who led the study, told reporters.

Using MBI, the ability to see a tumor is not affected by the density of the surrounding breast tissue, so it offers great promise for women whose mammograms may not provide an accurate assessment, Hruska said.

Among the 940 women, 13 tumors were found in 12 women. MBI found 10 and mammography found three, the researchers said.

Dr. Eric Winer of Harvard Medical School and Dana-Farber Cancer Institute in Boston, commenting for the American Society of Clinical Oncology, said between 10 percent and 15 percent of breast cancers cannot be detected using mammograms.

"More and more we may be getting away from one-size-fits-all in terms of screening approaches, and instead think about screening approaches that are directed more to an individual women based on her risk and on the characteristics of her breasts," Winer told reporters in a conference call.

There has been increasing use of costly MRI exams on some women with dense breasts or with high risk for breast cancer.

Hruska said MBI may be a lower-cost alternative. She estimated it would cost about $500 to perform, and expressed hope its availability would increase in the next year.

The technology used special cameras developed by GE Medical Systems and privately held Gamma Medica-Ideas, Hruska said. The study was funded in part by Bristol-Myers Squibb, which provided the radioactive agent, Hruska added.

The radioactive agent typically exits the body in a day.

Hruska said MBI as currently used presents a very low risk of radiation if a woman has it a few times in a lifetime, but the researchers must lower the radiation if the technology begins to be used as a screening test every year or two.

Category: Radiology

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