Side effects force women off 'safe' cancer pills
WASHINGTON (Reuters Life!) - Side effects are causing women to stop taking pills that can help keep breast cancer from returning, and women who stop taking the pills risk early death, according to several reports released on Thursday.
One study found that women in Scotland were not taking the breast cancer pill tamoxifen as directed, and a second one found that a new type of breast cancer pill was causing mysterious aches and pains in women.
The women who did not take tamoxifen as directed were 16 percent more likely to die, researchers told a meeting of breast cancer experts in San Francisco.
"We need to acknowledge that this is something that is truly affecting our patients," Dr. Julie Gralow of the University of Washington School of Medicine told reporters in a telephone briefing.
Tamoxifen transformed breast cancer therapy when it was shown to reduce the risk of cancer coming back by close to 50 percent. But the pill, sold by AstraZeneca under the brand name Nolvadex and also available generically, raises the risk of death from strokes and endometrial cancer.
A newer class of drugs, the aromatase inhibitors, appear to be safer, but they cannot be taken by women who are not yet through menopause.
Dr. Alastair Thompson of the University of Dundee in Scotland and colleagues looked at the records of 2,080 women treated for breast cancer between 1993 and 2002.
Ten percent of the women failed to fill 30 percent or more of their tamoxifen prescriptions. These women were 16 percent more likely to die over the study period than women who took the pills as directed.
STOPPING EARLY
Although tamoxifen is shown to work best when taken for five years, the women in the study took the drug for an average of just under 2 1/2 years.
"It could well be a question of side effects," Thompson told reporters. "I think most women who take tamoxifen know that it does have very substantial and life-affecting side effects, even if just hot flashes, which can make life a misery."
In another study, Dr. Lynn Henry of the University of Michigan Comprehensive Cancer Center found that 13 percent of women taking an aromatase inhibitor asked to stop because of muscle aches.
Overall, 23 percent of 100 women enrolled in a trial comparing two different aromatase inhibitors dropped out because of side effects, Henry told the Breast Cancer Symposium, sponsored by five cancer care societies, including the American Society of Clinical Oncology.
"The vast majority of patients are switching to something else. They understand that they still need to have their breast cancer treated," Henry told reporters.
They may need to switch to another aromatase inhibitor or tamoxifen, she said.
Aromatase inhibitors include anastrozole, made by AstraZeneca under the brand name Arimidex, and exemestane, made by Pfizer Inc. under the brand name Aromasin.
Breast cancer is the second-leading cause of cancer death among U.S. women, after lung cancer. It kills 500,000 people globally every year.
What breastcancer.org says about this article…
Side effects force women off 'safe' cancer pills
After surgery, women diagnosed with breast cancer face the risk of the breast cancer coming back (recurrence). Recurrence can happen at any time. But the risk of recurrence is highest during the first 3 years after treatment. To lower the risk of recurrence in post-menopausal women diagnosed with hormone-receptor-positive early breast cancer, hormonal therapy usually is prescribed for 5 years after the initial treatment. Treatment that comes after surgery or another initial treatment is called adjuvant therapy.
For years, tamoxifen was the hormonal therapy of choice for women diagnosed with hormone-receptor-positive early breast cancer. But in 2005, large clinical studies showed that aromatase inhibitors worked better than tamoxifen to reduce the risk of the cancer coming back in post-menopausal women diagnosed with hormone-receptor-positive breast cancer. So aromatase inhibitors — Arimidex (chemical name: anastrozole), Aromasin (chemical name: exemestane), and Femara (chemical name: letrozole) — now are used more often than tamoxifen.
Both tamoxifen and aromatase inhibitors can cause side effects. Tamoxifen may cause hot flashes. Aromatase inhibitors may cause muscle and joint aches and pains. The study reviewed here reports on the results of several different studies looking at how often side effects made women stop taking hormonal therapy. The study also looked at how stopping hormonal therapy affected the women's risk of dying.
The researchers found that side effects are causing a large number of women to stop taking hormonal therapy early instead of taking it as prescribed for 5 years. These women have a higher risk of recurrence and a higher risk of dying from breast cancer.
It's likely that other factors besides side effects play a role in the risky decision to stop hormonal therapy early. Some women may need to put everything related to cancer behind them after initial diagnosis and treatment. Lingering depression also may play a role. For other women, the cost of hormonal therapy may be a reason. Some women just may not understand the importance of adjuvant hormonal therapy or don't have good communication with their doctors.
Still, all these reasons are overshadowed by the reality that breast cancer can come back. Adjuvant hormonal therapy reduces that risk. Anyone prescribed adjuvant hormonal therapy must remember this.
There are good ways to get rid of any obstacles stopping you from doing all you can to lower your recurrence risk. If side effects are a major problem for you, talk to your doctor about ways to manage them. You may also be able to switch to a different hormonal therapy.
For more information, visit the Breastcancer.org section Staying on Track with Treatment. You can read about why it's so important to stick to your treatment plan, as well as ways to manage side effects after radiation, chemotherapy, and hormonal therapy. If you're taking adjuvant hormonal therapy medicine now, stick with it as prescribed. If you're thinking of stopping early, talk to your doctor first. Together, you can find a solution that is best for YOU.
