SAN FRANCISCO (AP) -- Many women with early-stage breast cancer might be spared chemotherapy if doctors check tumors for proteins that help reveal whether the disease will spread.
Testing for these proteins is already becoming routine in Europe, but U.S. doctors say they need more evidence that the approach actually works.About 175,000 women will be diagnosed with breast cancer in the United States this year. Most will have small tumors that have not yet spread to the lymph nodes. About 70 percent of these women can be cured with surgery and radiation alone.
However, cancer will come back in the other 30 percent. Giving chemotherapy to these women can reduce this risk by about one-third.
The problem for doctors is trying to identify this minority who need chemotherapy.
In general, doctors recommend treatment with the drug tamoxifen for those whose tumors are fueled by estrogen, and they urge chemotherapy for those who tumors are larger than two centimeters, or about an inch.
On Monday, at a meeting in San Francisco of the American Association for Cancer Research, Dr. Anita Prechtl of Technical University in Munich described the use of two proteins in tumors that might help reveal their likelihood of coming back.
The proteins are uPA -- short for urokinase-type plasminogen activator -- and its natural inhibitor, known as PAI-1. About 45 percent of breast cancer patients have high levels of these proteins. They have a higher risk of cancer spread, even though their lymph nodes seem free of cancer.
Prechtl's study involved 684 women whose breast tumors ranged up to five centimeters in size but had not spread to their lymph nodes. Those with low levels of uPA and PAI-1 were given no further treatment. Those with high levels were randomly assigned to get no more treatment or to receive a combination of three chemotherapy drugs.
After nearly three years of follow-up, cancer had come back in 7 percent of women with low levels of the protein. Among those with high levels, it had returned in 12 percent receiving chemotherapy and in 18 percent in the untreated comparison group.
However, breast cancer can come back after many years, and doctors plan to follow the women for 10 years to see if the proteins continue to help predict women's risk.
By testing for the two proteins, "more than half of all node-negative breast cancer patients can be considered as a low-risk patient group with less than 10 percent probability of disease recurrence," Prechtl said.
The study was financed by the German Research Association and the test's maker, American Diagnostica Inc. of Greenwich, Conn.
Dr. Karen Antman of Columbia-Presbyterian Medical Center in New York City cautioned that the test results need to be confirmed in larger studies before it becomes part of routine care.
While doctors would like to spare the majority of node-negative breast cancer patients from going through chemotherapy, she said, they fear missing those who might benefit.
Dr. Carlos Arteaga of Vanderbilt University said that even if the test proves out, U.S. doctors will still probably want to offer chemotherapy to node-negative patients with tumors larger than two centimeters.
Still, he said, the study's results might eventually apply to many women. "The majority of breast cancer patients are node negative, and a large proportion of them are under two centimeters," he said.
UPA and PAI-1 are also being tested as possible ways to assess the outlook of patients with ovarian, prostate and digestive system cancers, among others. Research suggest these proteins increase the tendency of cancer to spread throughout the body.
On the Net: American Association for Cancer Research: www.aacr.org