The drug anastrozole reduced the risk of breast cancer recurrence among postmenopausal women who took it for three years following treatment with tamoxifen.
A previous clinical trial showed that breast cancer patients who were still disease-free after taking tamoxifen for five years had their risk of recurrence further reduced if they received five additional years of treatment with the drug letrozole. Both anastrozole and letrozole are in the same class of drugs, known as aromatase inhibitors.
Raimund Jakesz, M.D., of Vienna Medical University and colleagues conducted a similar trial—the Austrian Breast and Colorectal Cancer Study Group trial—by randomly assigning breast cancer patients who had taken five years of tamoxifen to receive either three years of anastrozole or no further treatment.
After more than five years of follow-up, women who received anastrozole had a 38 percent reduction in the risk of recurrence compared with women who received no further treatment, but there was no difference in overall survival between the two groups. No unexpected side effects occurred in these women.
“The more manageable side effect profile of anastrozole compared with tamoxifen may allow the duration of adjuvant treatment to extend beyond the 5-year period recommended for tamoxifen,” the authors write.
In an accompanying editorial, Tatiana Prowell, M.D., and Vered Stearns, M.D., of Johns Hopkins University School of Medicine in Baltimore compare this trial with similar breast cancer trials of aromatase inhibitors and discuss the factors that are important for deciding which drugs to give patients and for how long.
“Results from both completed and ongoing studies should not only help to identify women who can safely forego adjuvant therapy as well as those who are best treated with short-term and long-term adjuvant hormone therapy but also provide a rationale for the selection of the most appropriate drug or drugs to incorporate in adjuvant therapy,” the editorialists write.
SOURCE:
Journal of the National Cancer Institute, December 11, 2007
