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When a woman is diagnosed with breast cancer, one of her first questions about treatment may be "Will I have to have chemotherapy?" More than surgery or radiation, the prospect of chemo frightens many women, with its litany of debilitating side effects, ranging from nausea and vomiting to hair loss, fatigue, infections, and premature menopause.
But the chemotherapy of today is not the chemo women underwent even 10 years ago. Many of the drugs are the same, but improvements in scheduling, dosing, and managing side effects, have combined to often make breast cancercancer chemotherapy less arduous and more effective than ever before.
"Over the past decade, there have been changes across the board," in breast cancer chemo, says Clifford Hudis, MD, chief of the Breast Cancer Medicine Service at Memorial Sloan-Kettering Cancer Center in New York City. "There aren't that many new drugs, but there are new ways to use existing drugs to significant advantage."
Chemotherapy Drugs: Who Gets What?
Not long ago, doctors thought of breast cancer as a single disease, and treatment options were often one-size-fits-all. Today, an improved understanding of cancer genetics means that the chemotherapy regimen -- and the option to pursue chemotherapy at all -- is chosen much more carefully and personally.
"Chemotherapy is only offered to women who are likely to benefit from it -- that is, those who are at some significant risk of having a microscopic spread of cancer cells beyond the primary tumor, that's not otherwise detectable," says Marisa Weiss, MD, director of Breast Radiation Oncology at Pennsylvania's Lankenau Hospital, and founder and president of Breastcancer.org. "The big challenge has always been: how do we identify those women?"
Previously, the size of the tumor -- along with whether cancer was found in a selected number of lymph nodes removed -- were the factors dictating whether a woman was advised to undergo chemotherapy.
"Now, we have a whole list of additional cancer personality features and clinical intelligence telling us who is likely to benefit from chemotherapy and who isn't," Weiss says. Among those factors:
Cancer "grade." On a scale of 1 to 3, how much do the cancer cells still resemble the normal cells they once were? Grade 1 means they haven't mutated much, Grade 2 means they're "kind of naughty," says Weiss, and Grade 3 cancer is "rebellious," with cells bearing almost no resemblance to normal cells. Grade 3 cancers are the most aggressive and call for the most aggressive treatment.
Lymphatic-vascular invasion: whether or not the cancer is in the lymphatic or blood channels of the breast.
Her2 status. Cancers that overexpress the Her2 protein are particularly aggressive, and may also respond particularly well to strong chemotherapy, especially in combination with the new drug Herceptin.
The presence or absence of hormone receptors. Women with hormone receptor-negative cancers get the most benefit from chemotherapy, says Weiss. "So, often in those cases a woman and her doctor will want to choose an aggressive chemo regimen.
Meanwhile, "hormone receptor-positive women get the most benefit from hormone therapies [such as tamoxifen or aromatase inhibitors such as Arimidex, Aromasin, and Femara]," says Weiss. "With hormone-positive disease, when do the benefits of chemotherapy make it worth taking on chemo? That's an individual decision you make with your doctor."
And for those women with hormone-positive breast cancer that hasn't spread to the lymph nodes, there's also a new tool that may help them make the decision. Oncotype DX, a new genetic test, analyzes the gene expression of a woman's tumor to predict whether or not her breast cancer is likely to recur.
Right now, this test is only useful for a subset of women with breast cancer, but other, similar genetic tests are on the horizon, says Eric Winer, director of the Breast Oncology Center at Boston's Dana-Farber Cancer Institute. "Oncotype DX isn't the only game in town. There are other ways to predict which women will benefit more or less from chemo. And what we don't know yet is whether there are women who benefit absolutely zero. If there are such women, can we develop a test to identify them?"