Test Could Determine Which Breast Cancer Patients Need Chemo

Researchers plan to study the Oncotype DX screen in 10,000 women

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FRIDAY, March 16 (HealthDay News) -- Researchers will study a new test that analyzes a breast tumor's DNA in order to determine its aggressiveness and to identify which patients need chemotherapy.

The trial will involve more than 10,000 breast cancer patients across the United States.

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The majority of postmenopausal women with small breast tumors don't need chemotherapy in order to reduce their risk of cancer recurrence after they've had a lumpectomy, experts explained.

"The dilemma physicians have with these patients is, because they have such small tumors, it's hard to tell who needs chemotherapy," study principal investigator Dr. Thomas A. Samuel, a Medical College of Georgia hematologist/oncologist who specializes in breast cancer, said in a prepared statement.

Of every 100 postmenopausal women who have a small tumor that has estrogen receptors and who have no sign of cancer spread to the lymph nodes, only about 12 to 15 require chemotherapy to reduce the risk of cancer recurrence, Samuel said.

But right now, all 100 women would likely receive chemotherapy because of a lack of tests to definitively identify who needs it and who doesn't, he said.

This study will investigate the Oncotype DX test (DXT), which looks at the DNA of the breast cancer to determine whether it's likely to spread and grow. The test looks at 16 tumor genes and uses five reference genes as controls.

The test, which costs several thousand dollars, has been on the market for more than a year but is not widely used. Participants in this U.S. government-funded Trial Assigning Individualized Options for Treatment (TAILORx) study will be assessed using the DXT.

Those with the lowest recurrence risk scores will receive radiation and hormonal treatment following lumpectomy, while those with the highest scores will also undergo chemotherapy. The patients will be followed for a minimum of five years after treatment.

More information

Breastcancer.org has more about recurrent and metastatic breast cancer.

-- Robert Preidt