Cancer

A new test 10 years in development and available next summer to help physicians zero in on the best possible treatment options — including no chemotherapy at all — for the four known types of breast cancers was announced Monday by a group of researchers in Utah and at several sites nationwide.

Turns out that a set of 50 genes that reliably mark the cancer types can predictably identify the most effective treatment options, including lumpectomy only for some women, the research group reports in the Journal of Clinical Oncology.

Unlike a popular diagnostic gene test for two types of cancer, the new test applies for all women diagnosed with breast cancers, the research report says.

A simple test, which will also identify a fifth so-called “normal-like” type that has an insufficient number of cells to be classified malignant, is set to undergo clinical trials with thousands of breast cancer patients.

Dr. Philip Bernard, an investigator at the Huntsman Cancer Institute, a senior author of the study and co-inventor of the patents-pending test, told the Deseret News that based on the type of tumor, doctors now will be able to prescribe only the treatment that will be most beneficial.

For some patients that could mean no chemotherapy at all, he said. For others it will mean targeted treatments that work best for that patient, and they will no longer have to endure needless chemotherapy.

“This will give women peace of mind knowing that we’re diagnosing more accurately than ever before, plus we can tell them if they are likely to benefit from chemotherapy,” he said. “If chemo isn’t going to be beneficial, we shouldn’t be giving it.”

Breast cancer is the second-leading cause of death among American women, and research is just now applying recent knowledge that there are different breast cancer subtypes that lead to different outcomes, Bernard said.

According to the Centers for Disease Control and Prevention, one in eight women in the United States is diagnosed with breast cancer. The study not only shows that some of them can be cured by lumpectomy, but will determine who will respond to what type of chemo among those with malignant tumors.

Although all breast cancers result from genetic abnormalities in breast tissue, not all abnormalities are identical, according to the research report. By analyzing the gene activity of more than 1,000 breast tumors, thousands of genetic differences were refined to 50, Bernard said.

Researchers then validated the genetic signature of each of the four types of breast cancers: luminal A, luminal B, HER2-enriched and basal-like. (The latter three types usually have the poorest prognosis.)

Basal-like type breast cancers are arguably the most aggressive yet the most sensitive to chemotherapy, according to the report.

Luminal A was not sensitive to the chemotherapy, suggesting that patients with this good-prognosis type can forgo chemotherapy in favor of hormone-based therapy.

Bernard said investigations are under way to determine how each tumor type responds to the more than 20 cancer drugs available. The group plans to study tumor samples from breast cancer cases going back a decade or more. Because the patients in these cases have already been treated, the researchers can relatively quickly discover how well various therapies worked for each breast cancer type.

http://www.deseretnews.com/article/1,5143,705283915,00.html

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