Additional studies are under way to define more clearly the role of other risk factors for uterine cancer, such as prior hormone use, in women receiving tamoxifen. Like many cancers, uterine cancer is potentially life threatening. Most of the uterine cancers that have occurred during studies of women taking tamoxifen have been found in the early stages, and treatment was usually effective. However, breast cancer patients who developed uterine cancer while taking tamoxifen have died from the disease. Women on tamoxifen should see their doctor if they experience these symptoms.
Women taking tamoxifen appear to be at increased risk for developing cataracts.
Other eye problems, such as corneal scarring or retinal changes, have been reported in a few patients. There have been a few reports of liver cancer and reports of other liver toxicities that have occurred in women taking tamoxifen. Although tamoxifen can cause liver cancer in particular strains of rats, it is not known to cause liver cancer in humans. It is clear that tamoxifen can sometimes cause other liver toxicities in women, which rarely can be severe or life threatening. Doctors may order blood tests from time to time to check liver function.