New methods to detect breast cancer show promise

1.00pm

WASHINGTON - New tests that measure water, oxygen and other breast tissue properties could be more effective than mammograms in diagnosing breast cancer, scientists said on Monday.

Researchers at Dartmouth Medical School used several types of electromagnetic waves to also gauge how normal breast tissue absorbed or scattered light.

By first measuring healthy breasts, the new techniques can eventually help researchers better understand and detect changes that could signal cancer, said the study's lead author, Steven Poplack.

"It's very important to know what normal is before you can begin to characterise what abnormal is," Poplack, a radiology professor at Hanover, New Hampshire-based Dartmouth, said in an interview.

The three types of energy waves tested included infrared light, microwaves and low-level electrical currents, according to the study published in the May issue of the journal Radiology.

Mammograms, the standard test for breast abnormalities, use X-rays to take pictures of breast tissue.

Experts say mammograms do not work as well on dense breasts and can make it easy for doctors to miss very early-stage cancer in some women. Mammograms can also fail to distinguish between cancerous tumours and other thick matter, raising the risk of false positives, they say.

The new techniques measured normal tissue levels of oxygen and haemoglobin, which carries oxygen in the blood. Breast cancer tissue is "more active" Poplack said, and uses more oxygen and blood to survive.

Scientists also measured cell membrane structure and the tissue's ability to conduct and store electrical charges.

Poplack's team used the alternative technologies on 23 white women ages 40 to 79 who had a history of normal mammograms, the study said.

The five-year, US$7 million ($11.30 million) study funded by the National Institutes of Health's National Cancer Institute is part of a larger effort to find alternative ways to create images of the breast, principal investigator Keith Paulsen said.

The researchers, who are seeking another US$10 million in National Cancer Institute grants, are working on a second study using the new techniques on women who have had abnormal mammograms.

Poplack said another 5 years of intensive study was needed before broader studies could be done with more women, including those of different races. Commercial versions of the tests are at least 10 years away, he said.

Barbara Croft, head of the cancer institute's Cancer Imaging Programme, said there was "a big need" to find alternative ways to look inside the breast.

A number of breast cancer groups also said the limitations of mammogram technology can lead to unnecessary biopsies and missed cases of breast cancer.

"We tend to overdiagnose or overtreat women because it is just not very specific," said National Breast Cancer Coalition Vice President Carolina Hinestrosa, who was diagnosed with the disease in 1996. "Clearly we could do better."

"Any test that is easier, more available, less invasive (and) more comfortable would always be welcome," said Susan Braun, president and CEO of the Susan G Komen Breast Cancer Foundation.

But until new methods are perfected, women should check their breasts themselves each month and continue to get annual mammograms. "It is certainly the best available screening tool," Braun said.

- REUTERS