Complications of Tamoxifen Therapy

Tamoxifen blocks estrogen in breast tissue. It also stimulates estrogen in the uterine lining, bone and lipids. Although it may be effective in the treatment and prevention of some breast cancers, it also may be associated with more serious, although rare, complications.

Blood Clots

• Women taking tamoxifen have a slightly higher risk of blood clots, including deep vein thrombosis, pulmonary embolism and stroke. Blood clots are more likely to occur in women taking tamoxifen and chemotherapy together. Clots in the veins of the eye also may develop.

Secondary Cancer

• Tamoxifen has been associated with increased rates of cancer of the uterus and endometrium. Evidence is conflicting as to whether or not tamoxifen can cause liver cancer.

Effects on the Eye

• Eye problems, including cataracts and the need for cataract surgery, have been associated with tamoxifen therapy. Vision changes also may develop.

Other Complications

• Increased levels of calcium in the bood have been found in women with metastatic breast cancer. Endometrial thickening and polyps, uterine fibroids and ovarian cysts also have been reported.

Warnings

• Women taking tamoxifen should notify their physican if they experience new symptoms while on tamoxifen therapy. This includes changes in menstruation or vaginal bleeding, pelvic pressure or discomfort, calf swelling or pain, shortness of breath, chest pain or vision changes. These findings may be indicative of a serious complication of tamoxifen therapy.