Test Shows Risk of Metastatic Breast Cancer

An experimental prognostic assay identifies at the time of diagnosis those breast cancer patients who are at greatest risk for metastatic disease with more than 90% sensitivity, according to a study published in the February 19, 2005, issue of The Lancet.

The test can be used with all lymph-node-negative (LNN) breast cancer patients, regardless of age, tumor size, and grade, or estrogen receptor/progesterone receptor (ER/PR) status. The assay will give oncologists access to information not previously available with this level of sensitivity, which will enable them to assess individual risk in a broad range of LNN breast cancer patients. The information will also help doctors make effective decisions on post-surgical therapy. In particular, the 76-gene signature on which the assay is based could help identify those patients who may not require adjuvant chemotherapy or those who could undertake a less-aggressive course of treatment. This prognostic signature has been independently validated in about 320 patients, but investigators are pursuing further clinical evaluation.

The assay is the result of a collaboration between researchers at Erasmus Medical Center-Daniel den Hoed Cancer Center (Rotterdam, The Netherlands; www.erasmusmc.nl) and Veridex, LLC (Warren, NJ, USA; www.veridex.com). They analyzed tumor samples of 286 breast cancer patients, all of whom were LNN and did not receive adjuvant chemotherapy. The samples represented patients from routine practice, from all age groups, and who were both ER/PR-positive and ER/PR-negative.

A genomic signature was constructed using gene expression data of 76 genes derived from extensive tumor profiling. This signature showed 93% sensitivity and 48% specificity in subsequent independent testing of 177 LNN patients. The gene profile was highly informative in identifying patients who developed metastatic disease within five years, in both premenopausal and postmenopausal women and in patients whose tumors measured 10-20 mm, for whom prediction of prognosis is difficult.

"These findings could one day profoundly change treatment standards for lymph-node-negative breast cancer patients by more precisely determining who is at risk for metastases,” remarked David Atkins, Ph.D., general manager, molecular diagnostics, Veridex.



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Erasmus Medical Center
Veridex