How MRI Scans Find Breast Cancers Like Christina Applegate's

When I first heard that actress Christina Applegate had breast cancer, I wondered how the 36-year-old's tumor was detected. Did she find the lump herself, or did her doctor feel it during a regular checkup? Perhaps Applegate was diagnosed via a screening mammogram, like my 37-year-old friend, Panina. Turns out, Applegate's tumor was detected through magnetic resonance imaging, which was ordered by her doctor, according to her publicist. That decision could prove lifesaving because the cancer was caught early—when it's most likely to be cured.

The exquisitely sensitive MRI is very good at detecting tumors in young women whose dense breast tissue often hides tumors on mammogram X-rays. But it's very expensive and all-too-frequently detects false abnormalities that necessitate biopsies. For this reason, the test is recommended only for those at increased risk of breast cancer. (Breast cancer is very uncommon in those under 50, so it would be foolhardy to screen all women in their 30s.) News reports disclosed that Applegate's mother had previously battled breast cancer, but that by itself isn't usually enough to justify an MRI in a woman so young. Last year, the American Cancer Society issued recommendations for the use of MRI screening for women at increased risk of breast cancer, as my colleague Katherine Hobson previously reported. You should have an annual test if you fall into one of these categories:

1. You have a BRCA1 or BRCA2 gene mutation.

2. Your mother, sister, or daughter has a gene mutation, and you haven't been tested.

3. You have a lifetime risk of breast cancer of at least 20 percent using this widely accepted risk assessment tool.

4. You received radiation treatment to the chest between ages 10 and 30 for conditions such as Hodgkin's disease.

5. You carry or have a first-degree relative (parent, sibling, child) who carries a genetic mutation in the TP53 or PTEN genes responsible for these conditions: Li-Fraumeni syndrome; Cowden syndrome; Bannayan-Riley-Ruvalcaba syndrome.

Other women who have a personal history of breast cancer or precancers or who have extremely dense breasts, says the ACS, could also benefit from screening MRIs and should talk to their doctor about whether they should get screening.