US health officials approved a genetic test on Tuesday that can give women with early breast cancer an estimate of whether the disease is likely to return in five to 10 years.
Officials cautioned, however, that the test was not perfect and should be used with other information to help doctors and patients decide how aggressively to treat an early tumor.

Called MammaPrint and made by Dutch company Agendia, the test is the first with US Food and Drug Administration approval that relies on a complicated computer analysis of several genes. Cancer recurrence depends partly on the activation and suppression of certain genes in a tumor.

The MammaPrint test measures the activity of 70 genes using a sample from a breast cancer tumor that has been removed. Women will be told if they have a high or low risk of their disease returning in five to 10 years.

Women at high risk have about twice the chance of breast cancer returning and spreading than low-risk women.

The test accurately picked which women were at low risk at least 90 per cent of the time, FDA officials said.

But for women who were told they were at high risk for a recurrence within five years, just 23 per cent actually had their cancer come back.

Doctors and patients should use the findings with other information - such as medical history, other test results and available treatment options - to choose a course of therapy, FDA officials said.

"You can't go all the way to the bank with this test," said Dr. Steven Gutman, head of the FDA's Office of In Vitro Diagnostic Device Evaluation and Safety.

But he said the information was an important step toward personalizing treatment for individual patients.

"I think it's better than having no information at all. It does provide a risk profile for patients," he said.

The test is not yet sold in the United States. Agendia Chief Executive Bernhard Sixt said in a statement the company was "exploring ways to make this product available in the U.S." It has been on the market in the Netherlands since 2005.

Similar tests already are being offered to U.S. patients under FDA rules that allow some lab tests to be sold without agency approval. One, made by Genomic Health Inc. and called Oncotype DX, helps predict if a woman will benefit from chemotherapy.

The agency is debating if tests that use the complicated computer technology to analyze multiple genes need more oversight before they can be used on patients. A public meeting on the topic is scheduled for Thursday.

In Agendia's case, the company approached the FDA and asked for an official approval, Gutman said.

The FDA said it based the MammaPrint clearance on a study of 302 women in Europe, who were under age 61, and had either of the two earliest stages of the disease.