Aug. 4, 2008 -- Actress Christina Applegate, 36, is being treated for early-stage breast cancer and is expected to recover fully. Her publicist announced the diagnosis on Saturday, according to media reports.

Applegate's breast cancer, which was found early through a doctor-ordered MRI, isn't life-threatening, her publicist said.

No other details about Applegate's breast cancer, including its specific stage and treatment, have been made public. Applegate, star of the ABC comedy Samantha Who?, has a family history of cancer -- her mother has had breast cancer and cervical cancer.

How common is breast cancer in young women. If Applegate got an MRI, should other women do the same? And what might her treatment involve?

For answers, WebMD spoke with Neil Friedman, MD, FACS, medical director of the Hoffberger Breast Center at Mercy Medical Center in Baltimore. Friedman isn't treating Applegate.

Friedman says breast cancer is "relatively uncommon" in young women. The American Cancer Society's records for 2000-2004 show that 95% of new cases and 97% of breast cancer deaths happened in women age 40 and older and the median age at diagnosis was 61.

What might Applegate's treatment involve?

I don't know what [early stage] means. Early stage can mean different things to different people. Is it noninvasive, invasive? It's hard to talk about things when you don't know specifics, so let's talk about both.

Intraductal cancer, also known as DCIS [ductal carcinoma in situ], is stage 0 breast cancer. It's a noninvasive breast cancer. Many times, you'll do a lumpectomy. If it's really extensive, you might do a mastectomy, but they don't need chemotherapy. And if you have a lumpectomy, more than likely you'll get radiation; sometimes you wouldn't.

If it's truly an invasive cancer, usually the most common is infiltrating ductal cancer. I would call an early stage something that we call stage 1, which means that the tumor is less than 2 centimeters and the lymph nodes are negative [contain no cancer].

The problem with that terminology is that there are still patients with early-stage breast cancer, depending on exactly how you use the terms, where you would end up giving chemotherapy to [them]. And most of us would not consider somebody who needs chemotherapy an early-stage breast cancer. And that's the problem with using those sorts of semantics.