May 15, 2001 WASHINGTON (AP) - Women who have been treated for breast cancer may reduce the risk of developing new breast tumors by half and the risk of dying from the disease by a third if they start hormone replacement therapy, a new study suggests.
Hormone replacement therapy, in which post-menopausal women take pills to replace female hormones that diminish with age, has been avoided by women with breast cancer because it was known that estrogen was linked to the growth of some breast tumors.
But a new study in the Journal of the National Cancer Institute showed that breast cancer patients may have a lower rate of cancer recurrence if they start hormone replacement therapy, or HRT. The results, however, are not considered the final answer on the issue, experts say.
Two large studies investigating questions about HRT and breast cancer are underway in Sweden and in Britain, but have not been completed. Researchers at the University of Washington and the Group Health Cooperative of Puget Sound analyzed data from a group of 2,755 women who had been diagnosed with invasive breast cancer. Within this group were 174 women who become HRT users after their cancer treatment. HRT is used to relieve post-menopausal symptoms, such as flushing or hot flashes, which can be serious problem with some women.
Each of the HRT users were matched by age, disease and year of diagnosis with four randomly selected nonusers. The researchers then compared the long-term effects on their breast cancer.
The study found that rate of breast cancer recurrence for the HRT users was 17 per 1,000 person-years, while for nonusers the rate was 30 per 1,000 person-years. A person-year is one year of human life.
Death from breast cancer was 5 per 1,000 person-years for HRT users, and 15 per 1,000 person years for nonusers, the study found.
However, the study found some data that suggested HRT might increase the risk of cancer in the previously unaffected breast. Researchers said the risk of developing tumors in the unaffected breast was 12 per 1,000 person years for the HRT users and eight per 1,000 person years for the nonusers.
``This result reinforces the need for caution in assessing the overall impact of HRT after breast cancer,'' the authors said.
An editorial in the journal also advised caution in interpreting the results, noting, ``these results must be considered preliminary.''
Copyright 2001 The Associated Press. All rights reserved.
