Study at AGH finds markers predict response to breast cancer treatment

PITTSBURGH — Allegheny General Hospital and the Mayo Clinic have found that genetic markers will predict how women at a high risk for developing breast cancer will respond to targeted preventive medications, according to data published Thursday.

Twenty years ago, a breast cancer diagnosis resulted in chemotherapy, radiation and drug therapy, said Jane Raymond, AGH's director of medical oncology. Treatment began at detection, but not anymore.

“We've had these two medications, tamoxifen and raloxifene, for a long time and we've given them to a lot of women,” she said, “but too often we don't know who they're going to help. We don't want to prescribe a drug full of side effects to tons of women if only one out of every 50 sees an increased chance at long-term prevention.”

The study, published in Cancer Discovery, a journal of the American Association for Cancer Research, capitalized on breast cancer prevention trials dating back to 1992, when approximately 33,000 healthy, high-risk women donated their time and blood to international research.

In this latest phase, scientists tracked 592 patients who developed breast cancer despite having taken either tamoxifen or raloxifene for the maximum five years and found consistent genetic changes — not mutations, AGH physician LawrenceWickerham said — that help delineate who is best suited genetically for which medications.

The research was led in part by  Wickerham.

“For the women who aren't likely to respond to the drugs, this will allow doctors to identify other options faster,” he said. “Eventually, our hope is that we can make breast cancer a preventable disease.”

Norma Kreutz, now 71, took raloxifene as part of a related blind study between 1999 and 2004 after her older sister died from the disease. Kreutz's grandmother had a single mastectomy in her early 80s and a younger sister, JoAnn Mendys, was diagnosed, too. Mendys will celebrate her seventh year in remission this winter.

“The drug, it really felt like a lifesaver for me,” she said. “JoAnn was never recommended for the study. Maybe she wouldn't have gotten cancer at all if they'd given it to her, too.”

The Centers for Disease Control and Prevention ranks breast cancer as the second most common cancer among U.S. women. Almost 212,000 women were diagnosed in 2009, the most recent year available.

“I have granddaughters and a daughter,” Kreutz said. “I don't want my girls to suffer like I saw my sisters suffer.”

Wickerham compared the new test to the widely used Oncotype DX, a genetic diagnostic tool that, among other uses, assesses how well patients already diagnosed with breast cancer will respond to chemotherapy. In the same way the Oncotype helps physicians direct the course of treatment, he said this new, unnamed test could help direct a course for prevention.

Researchers will present their findings next year at the American Association for Cancer Research convention in Philadelphia. The research, he said, is still in its infancy and years from commercial viability.

“It's a powerful study,” Raymond said, “one I would love to see someone further refine with other trials. The results need to be confirmed, but it's definitely something to watch.”

This article was written by Channel 11’s news exchange partners at TribLIVE.

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