Tamoxifen trial should prompt breast cancer patients to reconsider treatment options

The trial is called ATLAS (Adjuvant Tamoxifen Longer Against Shorter). It included women with estrogen receptor-positive breast cancer that had not spread to distant organs. Women who took tamoxifen for 10 years had a lower risk of recurrence and lower mortality rate than women who took the drug for 5 years, which is the current standard of care.

"I think this is going to create a need for women with this type of breast cancer to readdress their treatment options," Albain said.

Dr. Richard Gray, on behalf of the ATLAS trial investigators, announced results Dec. 5 during the San Antonio Breast Cancer Symposium. Albain moderated the opening oral session in which the results were announced and discussed.

A worldwide team of investigators enrolled 6,846 women with estrogen receptor-positive breast cancer who had been taking tamoxifen for five years and were free of recurrence of their breast cancer. Women were randomly assigned to either stop taking tamoxifen, or to continue taking the drug for another five years.

During the second decade following diagnosis, women who continued taking tamoxifen had a 25 percent lower recurrence rate and a 29 percent lower breast cancer mortality rate, compared with women who stopped after five years. Overall, taking tamoxifen for 10 years cut the risk of dying of breast cancer in half.

Albain noted there are risks to taking tamoxifen, including a higher risk of endometrial cancer in postmenopausal patients and an increased risk of blood clots. But endometrial cancer generally is curable, and in certain women, the benefits of taking tamoxifen for longer periods may outweigh the risks, Albain said.

Premenopausal women may benefit by taking tamoxifen for 10 years rather than 5 years, Albain said. The picture is more complicated for postmenopausal women. Depending on the patient, a regimen could involve taking tamoxifen for a period of time and an aromatase inhibitor for a period of time.

"Each woman's situation is different, which is why she should consult her doctor on the best course of action in light of these exciting and significant new findings," Albain said.

Provided by Loyola University Health System