One method of treating breast cancer involves the use of treatments that affect the actions of hormones. One such treatment is tamoxifen. However, because tamoxifen has effects throughout the body, this form of treatment is not without its side effects and risks. One of these side effects is a result of tamoxifen's effects on the endometrium (lining of the uterus), where it can increase the likelihood of developing endometrial cancer.
Identification
Tamoxifen is a medication that is commonly given to women who have had breast cancer. According to the American Association of Family Physicians, when tamoxifen is given to women who have been treated for breast cancer, it reduces the risk of developing breast cancer a second time (in the other breast) by 50 percent. Consequently, it is also used as a preventive measure in women who have a high risk of developing breast cancer.
Tamoxifen Mechanism
Tamoxifen works by blocking the effects of estrogen on breast tissue. Because many breast cancers grow in response to estrogen, it can help inhibit their growth. However, in other tissues throughout the body, tamoxifen mimics the effects of estrogen. This can cause a condition known as endometrial hyperplasia.
Endometrial Hyperplasia
Endometrial hyperplasia is when the endometrium grows abnormally. This is known as a pre-malignant condition, because the abnormal growths of the endometrium are not cancerous. However, abnormal tissue growth can lead to an increased risk of cancer. Consequently, tamoxifen-induced endometrial hyperplasia puts women at an increased risk of developing endometrial cancer.
Symptoms
Endometrial hyperplasia typically causes abnormal uterine bleeding. It also causes abnormal cells to appear in the endometrium, which can be detected on a Pap smear. Endometrial hyperplasia can also be identified on a trans-vaginal ultrasound, as it causes the uterine lining to be abnormally thick.
Screening
Because of the risks of tamoxifen, women who have received this treatment for breast cancer need to be monitored to ensure that they do not have endometrial cancer. A study headed by Dr. Bertelli in Genova, Italy, found that endometrial screening (whether via a pelvic ultrasound or through a biopsy of the endometrial tissue) was unnecessary for women with no other signs of uterine cancer. However, women who have received tamoxifen therapy should be screened for uterine cancer in the event that they experience abnormal vaginal bleeding or have abnormal cells detected on a Pap smear.
