The study authors concluded that the benefits of estrogen alone outweigh its risks. For each case of breast cancer in women due to long-term estrogen use, more than six deaths from heart disease are prevented, they write. Similar data to balance the benefits and risks of combined therapy are unavailable. In the U.S., recent population statistics show that 110 of every 100,000 women develop breast cancer annually. This is five times greater than the rate of endometrial cancer, which is 21 cases in every 100,000 women.
Women also are more likely to die from breast cancer than from endometrial cancer.
Ross said the researchers hope to look into how breast cancer risk differs among women on hormone replacement therapy with different characteristics, such as family history of breast cancer, history of benign breast disease and exercise. The authors concluded that doctors should provide women with information about the possible effects of hormone replacement therapy, and women should be told where uncertainty still remains in weighing risks against benefits.