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Watch VideoNew research: Strong link between hormone replacement therapy and breast cancer
Story By: Bea Karnes
Source: NBC
Doctors have known for years that hormone replacement therapy increases the risk of breast cancer. Now, there's new research suggesting for certain types of cancer, that link may happen sooner, rather than later.
All breast cancers aren't the same. Most develop in the ducts or pathways of the breast. But a few, about 15%, occur in the lobes.Small holding cells deeper in the breast tissue. These lobular cancers are harder to detect and, scientists say, more often triggered by hormones.
Dr. Christopher Li, Fred Hutchinson Cancer Research Center says "We found that women who use the combined hormone therapy, estrogen plus progestin, had almost a 300% increase in their risk of the lobular type of breast cancer but only a 40% increase in their risk of the more common type of breast cancer, the ductal breast cancer."
And it can happen fairly quickly. After just three years of combined therapy not five as previously thought. Interestingly, estrogen alone doesn't seem to have the same effect. Dr. Li said, "We didn't find that women who used the unopposed estrogen -- estrogen by itself-- had any increased risk of breast cancer, even if they used it for more than 10 years." But estrogen has been linked to other cancers, so experts say women considering or currently using it should get good medical advice.
Christine Brunswick, National Breast Cancer Coalition, said "Evidence, evidence, evidence is what we need before we make those really important decisions because it does affect our lives."
It's one more piece of evidence as scientists try to better understand what causes breast cancer and how hormones affect your risk. The National Cancer Institute paid for this study. It was conducted by the Fred Hutchinson Cancer Research Center, and the University of Washington.
