Breast Cancer Genetic Test Refined
Researchers have developed what may be the most accurate method yet for answering a woman’s scariest question about breast cancer: Will it spread and kill me?
By combining such a test with existing techniques, doctors could answer with greater certainty. That, in turn, could ease many women’s fears and enable more of them to skip the grueling ordeal of chemotherapy.
The approach is still experimental, but researchers say a cancer genetic test -- perhaps one that is even more accurate than the newly developed method -- could come into use within the next several years.
And researchers say the technique could, in theory, be adapted for use with other types of cancer. “I think that the era of treating tumors just based on their size, the extent of where they have spread in the body, and how they look under the microscope -- these days are numbered,” said Dr. Carlos Caldas, a cancer specialist at Cambridge University in England.
The test was developed at the Netherlands Cancer Institute, with help from Rosetta Inpharmatics in Kirkland, Wash. The findings are published in today’s issue of the New England Journal of Medicine.
About 200,000 U.S. women are diagnosed with breast cancer and 40,000 die yearly, the American Cancer Society says. Even with tumor-removing surgery, about a quarter of breast cancers that show no sign of spreading will return elsewhere in the body within 10 years.
Standard prediction factors include the tumor’s size, how it looks under a microscope, and the patient’s age, since breast cancer in younger women tends to be more aggressive. But such criteria give only a rough prediction. To be safe, doctors provide chemotherapy to the vast majority of these women, despite such side effects as nausea.
Genetic researchers have begun to study potentially powerful new methods to predict survival chances of patients with breast and other cancers. Even though all human cells, healthy or cancerous, carry virtually identical genes, they differ widely in which ones are turned on or off at a given time. A technology known as gene microarrays, or chips, can show this.
The Dutch researchers used a 1- by 3-inch chip to examine simultaneously which of 25,000 genes were turned on in tumor samples from 295 women all younger than age 53. They discovered 70 genes that, when turned on or off in a certain pattern, predict either that the cancer will spread and kill the patient, or that it won’t.
