Breast Cancer

Breast cancer is the most commonly diagnosed cancer in American women and the second leading cause of cancer death. This year, the American Cancer Society estimates 192,370 new cases of invasive breast cancer will be diagnosed in the U.S. In addition, 62,280 cases of carcinoma in situ (the earliest form of breast cancer) will be diagnosed. Roughly 40,610 women will die from the cancer in 2009.

Screening Mammography

The earlier breast cancer can be detected, the greater the likelihood of successful treatment. The gold standard for breast cancer screening is mammography, or X-rays of the breast. The American Cancer Society currently recommends an annual screening mammogram for all women starting at age 40.

Mammograms can detect very small breast tumors before they can be felt by the physician or patient. But they aren’t perfect and can miss some cancers. In addition, X-rays can’t tell the difference between cancer and other types of abnormal tissue (like calcifications or cysts), so patients may need further screening or a breast biopsy. The American College of Radiology estimates up to 15 percent of screening mammograms lead to further testing. Most of these tests show the questionable areas are not cancer (called a false-positive screening result). Radiologists say women 40 to 49 who get annual mammograms have a 30 percent chance of a false-positive mammogram and a 7 to 8 percent chance of needing a breast biopsy.

Looking for Better Techniques

A false-positive mammogram can lead to a great deal of anxiety for a woman and the need to undergo unnecessary surgery. So, researchers are looking for better ways to detect breast cancer while reducing the risk for false-positive results. One of the newer techniques is dynamic contrast-enhanced MRI (DCE-MRI). An MRI uses magnets and radiowaves to produce detailed cross-images of the body. In DCE, a contrast dye is injected into a vein. MRI images are taken before, during and after the injection. The technique enables doctors to follow the passage of the dye as it moves through the tissues.

Charles Springer, Ph.D., Imaging Researcher with Oregon Health & Science University, says DCE-MRI avoids exposure to radiation from diagnostic mammography, but is only a little less likely to produce false-positive readings. He says that’s because the model used to interpret the signal intensity during a DCE-MRI is flawed. So, Springer and his colleagues developed a new mathematical formula, called the shutter speed model, to correct for the flaw.

The researchers tested the new model on a group of 22 women scheduled for breast biopsy. Before the biopsy, all the women had a DCE-MRI scan, using the new model to interpret the results. Then, after the biopsy, the information from the pathology report was compared to the results of the scan.

The investigators found the information from the scan correlated 100 percent with the biopsy in all cases: 15 cases were benign and 7 were malignant tumors. If the scan would have been used to make the decision for a biopsy, 15 women could have avoided the surgery. In a larger study of 77 breast tumors, the DCE-MRI scan with the shutter speed model correctly identified 75 of the tumors (more than 97 percent).

Springer doesn’t expect the shutter speed model will replace standard mammography because mammography is still much cheaper and more widely available. However, one day doctors may be able to use the new technique as a second screening step, before referring women with a positive mammogram for biopsy.

Springer says the DCE-MRI shutter speed model is also being tested for other types of cancers. Researchers are also looking at the technique to study multiple sclerosis, Alzheimer’s disease and stroke.

For information on breast cancer or screening: American Cancer SocietyNational Cancer InstituteSusan G. Komen for the Cure®