If what the journal Radiology says is true that the lifetime risk of dying from radiation-induced cancer associated with getting just one breast-specific gamma imaging (BSGD test is equal to the risk of getting mammograms every year from age 40 to 80-that is a pretty alarming notion. While mammography increases a woman's risk only for cancer of the breast, BSGI also increases her risk for cancer of the uterus, ovaries, intestines, colon, kidneys and bladder. With so many risks, why would anyone be getting this test?
Rachel F. Brem, MD, is director of the Breast Imaging and Intervention Center at the George Washington University Medical Center. When asked if the potential dangers of BSGI overshadowed its benefits, she said, "The answer is no. While BSGI should not be used for routine screening for everyone, it is a lifesaver for certain women because it spots cancers that mammograms miss. For high-risk patients, the opportunity to detect early, curable breast cancer is so advantageous that it far outweighs the risks from BSGI."
While the risks certainly should not be ignored, the study statistics ought to be considered in context.
Consider this: Digital mammography carries an average lifetime risk of inducing 1.3 fatal breast cancers per 100,000 women who are age 40 at the time of exposure. The risk from one BSGI exam is about 20 to 30 times greater—about 30 per 100,000, or roughly 0.03%.
How BSGI works: A small amount of a radioactive compound called a radiotracer is injected into your arm and absorbed by your cells, which then give off radiation in the form of gamma rays. Due to their increased rate of metabolic activity, cancerous cells absorb more radiotracer than normal cells do. Breast images are taken with a special camera that detects the gamma rays. (The camera itself does not put out radiation) When the images are displayed on a computer monitor, cancer cells appear as visible "hot spots." BSGI does not require breast compression. Typically four to eight images are taken during the 30-to 45-minute procedure.
Your doctor may recommend getting BSGI if you have…
- An "equivocal mammogram" (in which results are inconclusive and merit clarification). BSGI not only detects cancers that mammograms miss, it also is more accurate than mammography or MRI in ascertaining that a suspicious area is, in fact, free of cancer-and thus it reduces the number of unnecessary breast biopsies. This is significant because currently, in about 80% of breast biopsies, results are negative.
Women who have breasts that are dense (meaning that they contain more glandular or connective tissue than fatty tissue) especially benefit in this regard because they often have equivocal mammograms. Dr. Brem explained, "Cancerous tissue and dense areas both appear white on a mammogram, so identifying cancer is like trying to pick out a particular cloud in a cloud-filled sky. That's why mammography detects only about one-third of cancers in dense breasts. But BSGI accuracy is not affected by breast density—so that is a distinct advantage."
- A recent breast cancer diagnosis. In more than 10% of newly diagnosed patients, BSGI detects second, unsuspected areas of cancer-which, of course, impacts the treatment plan. BSGI also helps determine whether tumors are responding to chemotherapy, allowing doctors to customize treatment.
- A strong family history of breast cancer—meaning that multiple family members have had breast cancer, particularly if it was premenopausal or in both breasts...or if your father had breast cancer...or if genetic testing has revealed that you carry a breast cancer gene.
- A history of Hodgkin disease for which you received radiation during adolescence—because this treatment significantly increases the risk for breast cancer.
Good news: The amount of radiation used for BSGI is continually being reduced in an effort to find the lowest possible effective dose, "The dose we use today is much lower than the dose used just one year ago," Dr. Brem noted. So while the statistics cited in the Radiology study mentioned earlier should not be disregarded, the actual risks associated with getting BSGI today are significantly lower than when the study data was collected.
Mammogram May Help Detect Other Health Problems
When 71 women with advanced kidney disease had routine mammograms, the images from 63% of them showed signs of calcification in breast artery tissue. This is a marker of vascular disease, which is common in people with kidney disease. By comparison, only 17% of a matched group of women without kidney disease showed calcification.
When having a mammogram: Ask the radiologist to look for breast artery calcification. If spotted, talk to your doctor about screening for undetected vascular disease and kidney disease.