Researchers study breast cancers after pregnancy

• Almost one-third of 25,000 breast-cancer cases in women under 45 are postpartum
• Doctors don't know why breast cancer risk goes up after pregnancy
• Pregnancy hormones likely play a role in postpartum breast cancers

BROOKEVILLE, Md. — Christina Miller had just finished her second chemotherapy treatment when her hair began to fall out.

It was a Saturday morning, half an hour before she had to leave the house to take her son to a birthday party, when she realized, "I couldn't go any longer without doing something about my hair," says Miller, 39, who was diagnosed with breast cancer in January.

So Miller handed her husband the hair clippers and asked him to shave her head. Although the decision had been hard to make, Miller says the process itself felt liberating.

"My little 4-year-old looks up at me and gives me the biggest hug," says Miller, who is from Ellicott City, Md. "And he says, 'You're still the best-lookin' mommy.'"

Thanks to recent advances in therapy — and support from her friends and family — Miller says she's coping relatively well with the dual demands of fighting cancer and raising three kids: Alexandra, 5, Thomas Joseph, or T.J., 4, and Nora, 1½.

Researchers say they are also making progress in understanding what drives tumors in young moms.

While breast cancer is not common in women so young, almost one-third of the 25,000 cases diagnosed in women under age 45 fall into the category of postpartum breast cancer, also called pregnancy-associated breast cancer, says Pepper Schedin, a professor at the University of Colorado in Denver.

For reasons doctors don't completely understand, a woman's risk of breast cancer actually goes up in the five years or so after she has a child, Schedin says.

It's likely that the hormones of pregnancy play a role, says Eric Winer, director of breast oncology at Boston's Dana-Farber Cancer Institute. For example, hormonal surges and fluctuations may speed up the growth of a pre-existing cancer, leading a woman to be diagnosed sooner than she might have been if she had never been pregnant.

But the causes of these tumors are also likely to be complex.

Miller, for example, has a strong family history of breast cancer. Her mother and grandmother both had it; Miller and her mom were even diagnosed at the same age. Her grandmother died from the disease.

Not all postpartum breast cancers are the same.

Miller says she's grateful that her tumor belonged to a specific subtype that responds to a newer, targeted drug called Herceptin, which has dramatically improved the outlook for early cancers like hers.

Yet something about the postpartum body appears to give these tumors some common features, Schedin says. In general, women who develop breast cancer within five years of giving birth tend to do worse than those who have never had kids, or even those whose tumors are diagnosed during pregnancy, she says.

Miller's oncologist, Claudine Isaacs, notes that many factors can affect a patient's outcome. She says she's impressed by Miller's strength and ability to convey a sense of calm and hope in front of her kids.

"There's never a good time to get breast cancer, but the postpartum period is particularly challenging," says Isaacs, a professor at Georgetown University's Lombardi Comprehensive Cancer Center. "With a baby, you're so protective, and you're supposed to be this even, comforting presence. Yet now, you have to wonder about your future."

Miller, who was still breast-feeding Nora when she was diagnosed, says her toddler now has no memory of her mom being anything but bald. And while their lives might be different today, Miller says she tries not to let her disease take over.

Her 5-year-old, Alex, "sees things in terms of the here and now and doesn't seem to worry about the future. She asks, 'How many more treatments until your hair grows back?' I don't sense fear," Miller says. "What I want them to remember is that Mom might have looked different, but she was still involved in our daily lives."

The pregnancy-cancer equation

Pregnancy has a complex relationship with breast cancer risk, Schedin notes.

Having a baby early in life lowers a woman's risk of developing postmenopausal breast cancer, compared with women who have never had kids. Yet having a baby also raises the short-term risk of postpartum cancer, Schedin says.

In the past, scientists assumed that postpartum cancers were mainly fueled by the hormones of pregnancy. Schedin's work suggests that inflammation also plays an important role.

The immune system becomes active in the breast, Schedin says, when women finish nursing and start to wean. The same process begins after delivery if women don't breast-feed.

That's a time of dramatic change, when the breast needs to shrink back to normal size, and the extra cells created during pregnancy and milk production have to go away.

The body choreographs this "remodeling" partly by turning on a process similar to that used in healing wounds, says Patricia Ganz, a professor at UCLA's Jonsson Comprehensive Cancer Center.

Most of the time, the process goes smoothly.

In younger women, these dramatic changes may actually perform a sort of housecleaning, sloughing off any atypical or potentially cancerous cells in the process, Ganz says. That may help explain why early pregnancy reduces a woman's long-term breast cancer risk; the early precancerous cells, which might have become tumors within a couple of decades, get swept away.

Breast-feeding for at least six months also reduces a woman's breast cancer risk, although doctors can't say with certainty how this works, Ganz says.

But inflammation can go awry.

By age 35 or 40, the precancerous changes in a woman's breasts may be too advanced to simply slough off after breast-feeding. Even worse, these abnormal cells may be stimulated by the inflammatory chemicals.

This research is becoming more compelling, Ganz says, as more women delay childbearing.

A woman who has her first child at age 40 or later has about twice the risk of breast cancer as a woman who never has children, she says.

Schedin says she hopes her findings won't add to women's anxieties. And women don't need to rush into pregnancy just to avoid breast cancer, Ganz says. On average, most breast cancers are diagnosed in women in their 60s.

Instead, Schedin says she hopes her research will one day contribute to new prevention strategies.

After all, doctors have a variety of ways to turn down inflammation. In mice, Schedin found that giving anti-inflammatory drugs stopped the growth of postpartum breast cancers.

Researchers have studied the use of anti-inflammatory drugs in cancer prevention for years, looking at aspirin, ibuprofen, Celebrex, statins and other pills.

Schedin cautions that her research hasn't been tested in humans yet, and it's far too early to give women any real prevention advice. Anti-inflammatory drugs can cause severe bleeding and bruising in some people, which can be particularly dangerous in pregnant or postpartum moms.

The dangers of the drug Vioxx — which was pulled from the market because of its increased risk of heart attacks and strokes — were actually exposed while it was being tested as a way to prevent colon cancer.

Still, Schedin says she's hopeful.

"We're not there yet, but we're closer than we've ever been," Schedin says.

Getting lots of support

Miller, who is participating in a clinical trial of a new drug, says she's glad that researchers are making progress. She hopes scientists will be able to offer better guidance to her own daughters about their risk of breast cancer one day.

Miller also feels grateful to have had so much support.

She and her husband sold their house and moved into her parents' home, Miller says, just as she was beginning chemotherapy. Her mother has accompanied her to every appointment and helped take care of the kids. Miller and her husband moved into their new home only after she finished chemotherapy, although she will continue taking Herceptin for a year.

And while Miller says she and her husband weren't sure about having a third child, they can't imagine life without Nora. She cheers them up just by toddling into the room and keeps them too busy to worry.

"Everything is exactly the way it was supposed to be," Miller says. Speaking of Nora, who is taking an afternoon nap in her crib, she adds, "I will always look at her and be so grateful."

Postpartum breast cancer in perspective

Annual pregnancy-associated breast cancers: 7,000*

Annual breast cancers in women younger than 45: 25,000

Annual breast cancers in all women: 227,000

* Defined as occurring within five years of delivering a baby.

Sources: American Cancer Society; Pepper Schedin, University of Colorado

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