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Genetic Tests Predict Breast Cancer Survival

Profile of 70 genes more accurate than any other method

WEDNESDAY, Dec. 18, 2002 (HealthDayNews) -- A sophisticated genetic test can single out breast cancer patients with the best chance of survival and those who need more aggressive treatment because of a poor prognosis, a Dutch medical team reports.

The test uses an array of 70 different genes that has been found to be a good predictor of ultimate outcome, says a report in tomorrow's issue of The New England Journal of Medicine. Over a 10-year period, just 54.6 percent of breast cancer patients found to have a poor prognosis were alive, compared to 94.5 percent of those with a good prognosis.

"The gene-expression profile we studied is a more powerful predictor of the outcome of disease in young patients with breast cancer than standard systems based on clinical and histological [cellular] criteria," the journal report says.

The test could have an important impact on breast cancer treatment, says Dr. Clifford Hudis, chief of the breast cancer medicine service at Memorial Sloan-Kettering Cancer Center in New York, but more work is needed before that happens.

"What will need to happen is for the test to be applied to another patient population by other investigators," Hudis says.

Several laboratories are working to develop such a test, he says. Any test that does show accurately which breast cancer patients need more aggressive treatment would be valuable to doctors, even though it might be technically difficult, Hudis says.

"It is difficult to do now, but that will change," he says. "This is a high-technology approach that is available only in the laboratory at the moment, but if it is judged to be clinically important it would become widely available."

The report came from researchers and physicians at the Netherlands Cancer Institute, who have been following 295 women with breast cancer for more than a decade. They had either a modified radical mastectomy or breast-conserving surgery. After genetic analysis of their cells using the 70-gene profile, 115 were listed as having a good prognosis and 180 as having a poor prognosis.

In addition to the overall survival rate, there was a clear difference between the two groups in development of metastases -- cancer colonies that spread to other parts of the body, which usually are associated with a poor outcome. The incidence of metastases was 49.4 percent in the poor-prognosis group and 14.8 percent in the good-prognosis group.

An accompanying editorial by Dr. Anne Kallioniemi of the University of Tampere in Finland calls the report "an excellent starting point for work aiming to predict the behavior of a tumor." However, like Hudis, Kallioniemi says more trials are needed on patients of different ages and at different stages of the disease. Researchers must also work to determine whether the genetic profile is the last word "or whether there will be a need to refine or expand this list of genes."

"Do we have a test that allows us to predict with certainty who will relapse?" Hudis asks. "Do we have a test that assures us that some patients will not relapse? This test is good, but it is not perfect."

What To Do

You can get more information about the genetics of breast cancer from the National Cancer Institute or the American Cancer Society.

SOURCES: Clifford Hudis, M.D., chief, breast cancer medicine service, Memorial Sloan-Kettering Cancer Center, New York City; Dec. 19, 2002, The New England Journal of Medicine
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