According to new research presented at the European Breast Cancer Conference in Barcelona, a set of four biochemical markers may be a better indicator than tumor size and grade for indicating whether or not cancer is likely to spread to other parts of the body-and thus which patients will most benefit from post-surgical chemotherapy.

Dr. Ruth Heimann of the University of Chicago told attendees that patients with early stage breast cancer that has not spread to the lymph nodes (node-negative) are usually offered chemotherapy as a safety precaution, even though they have a 70-80% chance of being cured of the disease by just having the tumor surgically removed. (It is important to note that these odds improve even further with adjuvant radiation therapy.)

However, Heimann reported the discovery of four biochemical markers that appear to be significant in predicting a patient's likelihood of developing metastatic disease (disease that has spread to other parts of the body), and thus her need for additional chemotherapy.

Heimann studied tissue taken from women with node-negative breast cancer who had been treated by surgery alone up to an average of 14 years ago. She looked for the markers which are already known to play a role in cancer metastasis, and found that four specific markers were detectable in the tissue and could be used to predict the outcome of node-negative breast cancer: p53 (the tumor suppressor gene which is involved in many cancers); E-cadherin (the gene involved in making cells stick together); and nm23H1 and MMP-2 (two genes involved in cell invasion).

"These markers were independent predictors of outcome, whereas the traditional indicators of tumor size and grade, were not independent," she said. "With these markers we can, on one hand, identify node-negative patients with very low likelihood of metastasis, and on the other hand, identify those with a very high likelihood of metastasis."

She added that such an accurate predictor of the risk of metastasis in patients could enable physicians to individually tailor treatments, and to give chemotherapy only to the women who would most benefit from it.

"However, despite the fact that we can identify women with a low probability of metastasis, as well as those with a high probability," she cautioned, "there is still a middle group of women in whom further work needs to be done."

SOURCE:
3rd Annual European Breast Cancer Conference, March 23, 2002, Barcelona, Spain