Many women receive chemotherapy and a hormonal therapy medicine such as tamoxifen after breast cancer surgery to reduce the risk of the cancer coming back. A study showed that, either alone or in combination, chemotherapy and tamoxifen also reduce the risk that a new cancer will develop in the opposite (contralateral) breast.
Chemotherapy reduced the risk of a new cancer in the other breast by 43% over 10 years. Tamoxifen reduced the risk of a new cancer in the other breast by 34% over 5 years.
These results are important because once a woman is diagnosed with breast cancer, her risk of developing a new, second breast cancer in the other breast is 2 to 6 times higher than the breast cancer risk of a woman who's never been diagnosed.
If you've been diagnosed with breast cancer, you and your doctor will decide whether treatments like chemotherapy and hormonal therapy are right for you. Worrying about recovering from treatment and getting healthy, plus being anxious about the cancer possibly coming back is hard enough without having to think about the possibility of a new, second breast cancer in the other breast. The good news is that the treatments your doctor may recommend to lower the risk of the cancer coming back also can lower your risk of developing a new, second breast cancer.
If you've been treated for breast cancer, visit the Lowering Risk for People with a Personal History area to learn more about steps you can take to lower your risk of developing a new and different breast cancer.