Study: FDA Approved Drugs Could Prevent Cancer Development In Other Breast

NEW YORK (CBSNewYork) -- A new study has come out with important news for women with breast cancer. It shows that there is a way to help prevent cancer in the other breast.

As CBS2's Dr. Max Gomez reported, the class of drugs has already been FDA approved.

One of the greatest fears for women with breast cancer is that they'll also develop cancer in the other breast.

It's partly what leads women to have a preventative mastectomy on the other side.

Fortunately, other sided breast cancer is rare, and there's a way to make it even rarer.

When Paloma Garcia was diagnosed with breast cancer at 25, she made the tough decision to have surgery to remove both breasts even though the cancer was only in one.

"I just pretty much thought, what would keep me here longer for my daughter?" she said.

The actual risk is lower than most women believe. During the 10 years after breast cancer diagnoses, about 5 percent of women develop cancer in their opposite breast. Tightly controlled studies show the risk can be lowered even further with certain medication, however researchers wanted to see more.

"We wanted to evaluate these medications in a general community health care setting to see how well they worked in the real world," Gretchen Gierach, PhD Investigator, National Cancer Institute, said.

Researchers at the National Cancer Institute reviewed the records of more than 7,500 women diagnosed with invasive breast cancer from 1990 to 2008.

They followed the women through 2011 to see which ones developed breast cancer in the opposite breast.

The researchers also recorded who took tamoxifen or aromatase inhibitors, two types of medication that block estrogen.

"So for women who took the drug for four years or longer, we observed reduced risk of contralateral breast cancer for up to 5 years after they stopped taking the medication," Gierach said.

The study -- in JAMA Oncology -- suggested that if women take and stick with the drugs, there are long-term benefits.

"These medications are known to have side effects which might impact or challenge women in being able to complete her full treatment course. The longer they took the drug, the grater the risk reduction, so we know that therapy duration really does make the difference," Gierach said.

The main side effect of the drugs are menopause like symptoms, but the average age for women in the study was 61, past the age of menopause.

There were also uterine issues that had to be monitored, but for most women the side effects were worth the significant reduction in breast cancer.