Long-Term Tamoxifen Use Linked To Rise In Second Breast Cancer, Study Finds

TORONTO -- A new study suggests long-term use of tamoxifen is linked to an increased risk of a second type of breast cancer. U.S. researchers looked at more than 700 women who had been diagnosed with breast cancer and compared them to nearly 400 diagnosed with both a first and second breast cancer. Tamoxifen is an estrogen-blocking drug researchers say has been shown to reduce the risk of dying of breast cancer. Researchers found women who received tamoxifen for five or more years lowered their risk of developing the more common type of breast cancer that responds to estrogen-blocking therapy. But the study found the risk of another rare subtype of the disease increased by more than 400 percent. Lead author Dr. Christopher Li...