For many women diagnosed with breast cancer, the disease doesn't make them feel ill. It's the treatment -- surgery, radiation, and, most of all, chemotherapy. Coping with side effects that range from nausea and fatigue to mouth sores and premature menopause can make four, six, or eight months of treatment seem like a lifetime.
And for many women, side effects can linger long after breast cancer treatment is over. What's more, some, such as low blood counts or nausea and vomiting so extreme they can't be controlled, can delay the next treatment, possibly making it less effective.
As scientists research new treatments for breast cancer, they're also studying new "treatments for the treatments," new ways to prevent or reduce some of the most debilitating side effects of cancer therapies.
New Drug Controls Nausea
One of the most common (and awful) side effects of many types of chemotherapy is nausea and vomiting. It leaves many women exhausted, dehydrated, and sometimes so distressed that they want to stop chemotherapy altogether. Some women are so affected by chemotherapy nausea that, even years later, they find themselves searching for a bathroom or a bucket at the mere sight of their oncologist.
Now, a new drug is helping many more women get through chemotherapy nausea-free. Emend, approved by the FDA in 2003, works differently than many of the other standard anti-nausea medications used with chemotherapy. It blocks "substance P," a chemical substance that transmits nausea and vomiting signals to the brain. It's effective at staving off "delayed-onset" nausea, which hits 24 to 48 hours after a chemotherapy dose and can last as long as five days. In studies, Emend kept about 20% more patients nausea-free for up to five days following chemotherapy.
In late 2004, Memorial Sloan-Kettering Cancer Center in New York made Emend part of its standard regimen of drugs for women undergoing breast cancer chemotherapy. "It's very well tolerated and very effective," says Andrew Seidman, associate attending physician in the Breast Cancer Medicine Service at Sloan-Kettering.
"It doesn't replace other anti-nausea drugs, but rather works well in combination with them. With these other medications alone, patients still had the potential for breakthrough nausea two or three days after treatment. Since we've made the change, I think we're doing an even better job at managing nausea."
Sick and Tired: Tackling Fatigue
Almost everyone undergoing breast cancer treatment feels some fatigue. It often builds up over the course of treatment, so while you start out thinking "This isn't so bad; I still have plenty of energy," by the end of chemotherapy and radiation you may feel lucky if you can get out of bed.
Some treatment-related fatigue, doctors say, is almost inevitable. "Chemotherapy does cause collateral damage to normal tissues, and the broad tissue damage is one source of this fatigue," says Mark Pegram, MD, director of the Women's Cancer Program at the Jonsson Comprehensive Cancer Center at UCLA. "Until we have more targeted therapies that don't damage normal tissues as much as chemotherapy does, we will have to try to manage fatigue as best we can."
Longer-lasting drugs to treat chemotherapy-induced anemia, which can leave patients drained and dragging, are now available, says Pegram. These red blood cell boosters were once only available as weekly injections, but a newer drug in this category, Aranesp, requires fewer injections and office visits.
According to a study presented at the San Antonio Breast Cancer Symposium in 2004, 94% of patients treated with Aranesp reported a significant improvement in their quality of life. "I don't think that anybody has a magic bullet for fatigue, but maintaining an adequate hemoglobin level is definitely an important goal," says Pegram.
Aiming to Protect Bones, Prevent Osteoporosis
Women diagnosed with breast cancer before going through menopause often endure "chemopause." This short-term or permanent menopause is a result of chemotherapy, which interferes with the production of ovarian cells. Research shows this early and harder-hitting form of menopause (which happens all at once, instead of the slower slide of natural menopause) can lead to an increased risk of osteoporosis.
Medications called bisphosphonates, like Fosamax and Actonel, slow the rate of bone breakdown and are commonly prescribed to improve bone density in people who have already developed osteoporosis. But what about women who are at higher risk for bone loss due to "chemopause" but haven't developed osteoporosis yet? Should they take a drug like Fosamax to help prevent bone loss?
Studies are happening now, says Pegram. "We're waiting for clinical trial data to come in to confirm how these drugs work specifically in women who are in menopause as a result of chemotherapy," he says. "From a scientific point of view, it makes sense that they should work. They are known to be highly effective in controlling bone loss in osteoporosis after natural menopause, and in cancers that have metastasized to the bone, so we believe they're likely to be effective in this situation as well."
Some doctors are already prescribing bisphosphonates for women who've experienced menopause as a result of chemotherapy, but Seidman is cautious. "Do we have data telling us that's the right thing to do in these cases? Not yet," he says. "For now, if menopause occurs early, we need to be more attentive to monitoring bone density and making sure that women get sufficient calcium and vitamin D."
New Drugs in the Works for Mouth Sores, Nerve Damage
Doctors call it mucosal toxicity or mucositis, while most patients just call it "mouth sores." Whatever you call it, the damage done by some powerful anticancer agents to the normal cells lining the mouth and throat can make eating dinner an agonizing chore. What's more, says Pegram, "Mouth sores can leave the patient more vulnerable to infection, which is particularly dangerous for people undergoing chemotherapy."
Researchers are now studying a group of compounds called keratinocyte growth factors. These compounds are similar to a protein substance normally made by the body and could prove to be a potential treatment to prevent mouth sores. They encourage the cells lining the mouth and throat to make more cells more quickly to replace the ones destroyed and damaged by chemotherapy.
Late in 2004, the FDA approved one of these drugs, Kepivance, for the treatment of mouth sores caused by high-dose chemotherapy regimens for leukemia, myeloma, and lymphoma. It's "not ready for prime time" in breast cancer treatment yet, says Seidman, but studies are ongoing.
Also in development: a potential remedy for neuropathy (or nerve damage), one of the most debilitating side effects of the commonly used chemotherapy drugs Taxol and Taxotere. "Both drugs can cause nerve damage, which can range from mild numbness to severe pain that can interfere with motor function," says Seidman.
All kinds of remedies have been tried, but none have proven their mettle in clinical trials. Now, researchers are studying a new drug, Tavocept, in the U.S. and abroad for its potential to protect against this neuropathy. The manufacturer, Bionumerik, reports that it's shown promise in phase III clinical trials, and has been granted "fast track" research status by the FDA. "If it works, it would be a real first-in-class drug," Seidman says.
