DEAR DOCTOR K:
I’m at high risk for breast cancer. Should I have screening mammograms, MRIs or both?
Many factors can put a woman at high risk for breast cancer. The most common and important are these: (1) inheriting certain high-risk genes from one of your parents; (2) having a parent, sibling or child with breast cancer; and (3) having received radiation treatment to the chest (usually for some type of cancer) before age 30.
Some women at high risk for breast cancer — Angelina Jolie is a very public example — choose to have both breasts surgically removed. For women at high risk, this choice offers the best prevention.
However, most women at high risk opt for a less drastic option: regular screening tests to detect early breast cancer. That’s the easy part of the answer to your question: Nearly every expert would agree that women at high risk for breast cancer should have regular screening tests.
The harder part of the answer is to decide which screening tests should be ordered, and how often they should be done. That’s because there isn’t a lot of evidence comparing the various screening tests, and also because the technology used to perform screening is improving over time. So an answer that’s right today may not be right a year from now.
I think it is reasonable for high-risk women to get yearly magnetic resonance imaging (MRI) exams starting by age 30. Based on today’s technology, there’s little question that MRI is better than mammograms for screening high-risk women. Yearly mammograms are optional.
MRI uses magnetic fields to create an image of the breast, providing more detail than mammograms. And it detects small cancers that mammograms can miss.
What’s more, mammograms expose women to a small amount of radiation. So, is there any reason for high-risk women to have a mammogram in addition to an MRI?
A recent study helps answer that question. It included 2,207 high-risk women, ages 30 to 69. All were screened with digital mammograms and breast MRI scans.
The results were as expected. In the first year, the screening found 35 breast cancers. Of those, MRI detected all 35. Mammograms found only 12. No cancers were detected by mammogram but not by MRI.
Does this mean mammograms are unwarranted? It’s not that simple. Breast MRIs show many more false positives than mammograms. False positives are spots that could be cancers. But after further testing (usually an invasive biopsy), they are found not to be cancers.
Many breast cancer specialists recommend that women at high risk for breast cancer and who have an abnormal result on the MRI should then get a mammogram. If the mammogram is normal, then they assume the MRI result was falsely positive and spare the woman a biopsy.
If you are at high risk for breast cancer, have a breast MRI every year. You and your doctor can decide if you should also have a yearly mammogram.