Arimidex Better Than Tamoxifen Long Term
New Option for Some Women With Early Breast Cancer
This means that women taking Arimidex are 18% less likely to suffer a recurrence of their disease compared with women taking tamoxifen, says study head Aman Buzdar, MD, an oncologist at the University of Texas M.D. Anderson Cancer Center in Houston.
"Compared with placebo, tamoxifen reduces the risk of recurrence by about 50%. Compared with tamoxifen, Arimidex reduces that risk another 20%. That's a 70% reduction in relative risk," says Buzdar.
As for side effects, unlike tamoxifen, Arimidex is not associated with an increase in the risk of uterine cancer or dangerous blood clots. But patients taking Arimidex are more susceptible to bone fractures than those taking tamoxifen, an indication that the new drug accelerates bone loss. A bone-building supplement could prevent many aromatase inhibitor-related fractures, Buzdar says.
The bottom line: "Arimidex should be considered a better choice of therapy for postmenopausal women with hormone-sensitive early breast cancer."
Nevertheless, he stressed, the ultimate choice should be the patient's. "I sit down with each woman and explain the options and that there is some risk of a bone-related event. Nine in 10 women will want the newer drug. But some will want the drug that's been around 30 years."
Winer says the new data will be considered when ACOG convenes its annual expert panel on breast cancer treatment in a few months.
"Though the figures don't seem that different from a year ago [when the panel voted to keep tamoxifen as standard therapy], we have four years of experience instead of three. That means something," he said. "But will we change our recommendations? That's up to the whole panel."
In the meantime, Winer agreed. "It all comes down to sitting down with a woman, telling her everything we know about both drugs and making the decision together."