Is a Mammogram Enough?
Do You Need Further Screening?
For many women the answer is no. But if you have dense breasts or risk factors such as a personal history of breast cancer or a previous abnormal biopsy, talk to your doctor about whether you might benefit from additional testing for cancer that mammograms can miss. There are two options -- MRI or ultrasound -- and a lot of debate about who really needs them. The good news? Neither exposes you to harmful radiation.
MRI: A "must" for a few. Of the two tests, MRIs find more cancers than ultrasounds. The American Cancer Society (ACS) recommends a screening MRI in addition to mammography only for women with a high personal lifetime risk of breast cancer (doctors evaluate this according to specific criteria), the BRCA1 or BRCA2 breast-cancer genes, a strong family history of breast or ovarian cancer, or a personal history of chest radiation therapy.
During an MRI you lie on a table that slides into the center of a cylindrical tube where a powerful magnetic field and radio waves produce a detailed computer picture of the breast tissue. You may also get a contrast agent through an IV to improve the image. The procedure is otherwise painless but costly: a low average of $1,072 for both breasts. Insurance may not cover the cost, especially if you don't fit ACS guidelines. Some women get claustrophobic in the machine or say it's hard to lie still for 30 to 60 minutes as it thumps and hums around them.
Ultrasound: An Alternative? Early results from a three-year study of more than 2,800 women nationwide found that adding an ultrasound (low average cost: $87) to a screening mammogram was better than a mammogram alone at finding cancer in those with a higher-than-average risk of it.
The reason? Both cancer and breast tissue show up as white on a mammogram if you have dense breasts. "It's like trying to see a polar bear in a snowstorm," says Wendie Berg, MD, PhD, a radiologist at an outpatient center affiliated with Johns Hopkins Medicine and the study's lead author. But on ultrasound, cancers are usually darker than surrounding tissue.
There's a drawback, though. Adding ultrasound to mammography notably increases the rate of false-positives, when the test red-flags something that turns out not to be cancer. One in 10 women in the study had a biopsy that didn't find cancer. "That's a lot," says Dr. Berg. Some women find these odds unacceptable, while others tolerate the risk because the test ups the chances of finding cancer. Doctors are also divided on this issue. "The evidence so far suggests that for women at highest risk for breast cancer, MRI is superior to ultrasound," says Carol H. Lee, MD, chair of the American College of Radiology's Commission on Breast Imaging, who also prefers it for those at lesser but still higher-than-average risk.