A first-of-its-kind genetic test will soon be available to help women with breast cancer make one of their most crucial decisions--whether to undergo the rigors of chemotherapy. Genomic Health, a Silicon Valley biotech company, said it has identified nearly two dozen genes that, taken together, can predict with a high degree of accuracy the likelihood that tumors will return in women whose breast cancer was caught at an early stage. Currently, doctors predict the chances of a relapse in pretty much the same way they have been doing it for almost a century--by looking at the patient's age, the size of the tumor, and the tumor's aggressiveness. If the chances of recurrence are seen as very low based on the gene test, a woman may opt to not endure the vomiting, hair loss, and high cost of chemotherapy. But if the odds of the cancer coming back are high, she may view chemotherapy as the difference between life and death. "For the women in that highest group, it makes their decision so much easier," said Melody Cobleigh, a breast cancer researcher at Rush-Presbyterian-St. Luke's Medical Center in Chicago. "For women in the lowest group, they'll still agonize."
The biotechnology company's research--done with the National Surgical Adjuvant Breast and Bowel Project--was outlined Thursday at a breast cancer conference in San Antonio. Genomic Health researchers analyzed tumor samples from nearly 700 women involved in a 1980s cancer study to develop the genetic screening method. The researchers used their findings to create a point system to express escalating chances of recurrence within 10 years. Genomic Health found that by using their screening method, just over half of the women in its sample group fell into the low-risk category. Their determination was supported by the medical records of these patients: the average recurrence rate among these women following surgery and treatment with tamoxifen was about 7%. At the other end of the scale, 27% of the sample was determined to be at high risk of recurrence based on the genetic test. The medical records of these women showed that about 30% developed new breast cancer within 10 years of treatment. In the intermediate-risk group, the 10-year recurrence rate averaged about 14%.
Genomic Health chief executive Randy Scott says that by using a scoring system, his company's test could give women a more individualized prognosis. "What we'll be able to provide is not just that you are low-risk, medium-risk, or high-risk," he said. " Scott said his company plans to make the test available to newly diagnosed cancer patients in early 2004.