Medical Breakthroughs: Breast Cancer

There's a major development in breast cancer research. A drug being tested to stop the cancer from coming back is working so well, researchers have stopped the study early.

Women took Tamoxifen to help keep her cancer from coming back. The estrogen blocking drug is proven to reduce recurrence for five years in women who have tumors that depend on estrogen. Another study tests a newer estrogen stopping drug called Letrozole, sold under the named Femara. Researchers hoped the once a day pill would pick up where Tamoxifen left off.

The drug was showing such remarkable results, the five year study of more than five thousand post-menopausal women was stopped at the halfway point so all the women could take it.

While these early results are promising, cancer experts say its important to note that because the study was stopped early, it's not known if Letrozole increases survival rates. There are also concerns about side effects. Women on Letrozole had higher rates of Osteoporosis, Arthritis, hot flashes, and muscle and bone pain.

Some of the questions will be answered by similar trials underway. For now, researchers note, it will be important for women who are considering the treatment to sort out the risks and benefits with their doctor.

Breast cancer is the most common cancer killer in women across the industrialized world, after lung cancer. The World Health Organization says more than 1.2 million people will be diagnosed with breast cancer this year and it will kill 40,000 Americans this year. The study was conducted in Canada and across the United States and is being released early from the New England Journal of Medicine.