U. PENN (US)—Many women being treated for breast cancer stop taking a medication proven effective—even at the risk of the cancer returning—because the pain associated with it is too much to bear, researchers say.
A protein on the surface of breast cancer tumors called the estrogen receptor allows the tumors to use estrogen to grow. Aromatase inhibitors, or AIs, are useful in treating postmenopausal women with curable breast cancer by lowering the amount of estrogen in the body.
The most prominent side effects associated with AIs are joint pain, stiffness, and achiness.
“Women feel like they all of a sudden have arthritis,” says Angela DeMichele, an assistant professor in medicine and epidemiology at the Abramson Cancer Center at the University of Pennsylvania.
“It’s really hard when they get up in the morning, to try to walk, and to type on keyboards. It’s hard for them to do the things that they need to do because their hands are really, really sore.”
In a study published in the journal Cancer, DeMichele and colleagues have identified patterns and risk factors associated with AI-related pain among breast cancer survivors.
The researchers discovered that estrogen withdrawal might play a role in the onset of joint pain during AI treatment.
Women who experienced menopause fewer than five years before starting AI treatment were three times more likely to experience these pains than those who went through menopause more than a decade earlier.
These women cannot be given estrogen to treat estrogen withdrawal because estrogen feeds breast cancer tumors.
The study involved a cross-sectional survey of patients with breast cancer who were receiving care at the Rowan Breast Cancer Center between April and October 2007.
Among 300 survey respondents, 47 percent attributed AI as a cause of their joint pain. Of those patients, 74 percent recognized the onset of pain within three months of starting medication, and 67 percent rated joint pain as moderate or severe in the previous seven days.
In a separate study, published in the journal Integrative Cancer Therapies, the researchers determined if patients would be open to undergoing acupuncture to treat their pain. Fifty percent of participants in the study said they were very interested.
Study coauthor Jun Mao, an assistant professor in Family Medicine and Community Health at the Abramson Center, who is also an acupuncturist, says acupuncture can help the brain produce more endorphins, which may help individuals change their pain perceptions and decrease pain.
DeMichele says the main rationale for the use of the traditional Chinese treatment is that it has been used to treat inflammation.
“You want to try to modulate pain receptors because all our cells have these receptors for pain and acupuncture can really help make those receptors less responsive to the pain,” she says.
DeMichele and Mao have embarked on a third study, a comprehensive Wellness After Breast Cancer review, which expands on the original Cancer study and focuses on a more detailed assessment of symptoms and some of the mechanisms that might underlie the symptoms, such as hormone levels or genetics.
Mao says the issues surrounding AI treatment are twofold. One group of women is suffering intense joint pain because of AI treatment, he says. But they are determined to complete the full five-year dose, so it is important that these women are given pain relief and an improved quality of life.
The second group, the non-optimal adherence patients, are not taking their medication the way it was intended, so part of the research is looking at what factors are related to a women’s decision to switch, stop or even restart AI medication.
“All of those things really need to be looked at from a research prospective. That way we can really tell patients what is the best strategy to deal with AI-related symptoms and how to optimize the quality of life while they’re on AI,” he says.
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