A new study shows that 10 years of hormone therapy reduces the risk of breast-cancer recurrence. (Rui Vieira/Press Association via AP Images)
Extending hormone therapy to 10 years significantly reduces the risk of a recurrence of breast cancer in many older women who have early-stage disease, according to a new study. It also found that prolonging treatment decreases the chance of a new cancer developing in the healthy breast.
The study involved post-menopausal patients who had what's known as hormone-receptor-positive cancer. Those women benefited from taking the drug letrozole, part of a class of hormone therapies called aromatase inhibitors, for 10 years. Currently, that drug typically is taken for just five years, although some women take it longer.
While many women with early-stage breast cancer live for a long time, they “face an indefinite risk of relapse,” said lead study author, Paul Goss, director of breast cancer research at Massachusetts General Hospital. He said the new research "provides direction for many patients and their doctors, confirming that prolonging aromatase inhibitor therapy can further reduce the risk of breast cancer recurrences."
However, there wasn't any difference in length of survival for women who took the drug for 10 years, the data showed. Some researchers suggested that such a survival benefit could emerge in the next several years as more information becomes available.
The results of the study were published online Sunday in the New England Journal of Medicine and released at the annual meeting of the American Society of Clinical Oncology. An accompanying editorial in the journal said the data was "reassuring, and the findings have direct application for clinical practice."
But some experts were cautious about predicting wholescale changes in treatment strategies, in part because letrozole has some side effects. For example, women in the study who got letrozole had significantly more bone fractures than the ones given a placebo.
Because of that, as well as the absence of a survival benefit, "this is not as clear a result as one might like," said J. Leonard Lichtenfeld, deputy chief medical office for the American Cancer Society who wasn't involved in the study.
Claudine Isaacs, a medical oncologist at Georgetown University’s Lombardi Comprehensive Cancer Center, said the results of the study had been eagerly awaited by physicians wondering whether longer treatment with aromatase inhibitors, which block estrogen, would help patients.
“This gives us data to take back to the clinic to talk to our patients about,” she said. “If I had a patient who doesn’t have side effects from this therapy, and has a higher risk of recurrence, I’d consider extending it -- or at least having an informed discussion with her.”
The study enrolled 1,918 postmenopausal women for the randomized Phase 3 trial; half received letrozole and half got a placebo. A total of 165 women had a recurrence of cancer or a new cancer in the opposite breast; of those, 67 were in the letrozole group while 98 were in the placebo group.
The researchers said the risk of disease recurrence and of a new cancer in the opposite breast was 34 percent lower among women who continued the aromatase inhibitor drug for 10 years compared to those who received a placebo after the initial 5 years of treatment. Calculated another way, 95 percent of the women in the letrozole group experienced disease-free survival, compared to 91 percent in the placebo group.
Currently, when older women develop breast cancer, they’re prescribed a variety of regimens to reduce the possibility of recurrence, the researchers wrote in the journal article. Those include the anti-estrogen drug tamoxifen for 5 or 10 years, or some combination of tamoxifen and an aromatase inhibitor, or an aromatase inhibitor without tamoxifen for 5 years.
Clinicians knew from previous studies that using tamoxifen for up to 10 years was better than using it for 5 years, but there wasn’t corresponding data for aromatase inhibitors.
Harold Burstein, an assistant professor of medicine at Harvard Medical School and a medical oncologist at Dana-Farber Medical Institute, acknowledged that “10 years of any therapy is a long time.” But, added Burstein, who wasn’t involved in the study, most of the women tolerated the extended treatment reasonably well.
This is dummy text. It is not meant to be read. Accordingly, it is difficult to figure out when to end it. But then, this is dummy text. It is not meant to be read. Period.
ConversionConversion EmoticonEmoticon