Gene Expression Test Targets Cancer Recurrence

A multigene expression assay of tumor tissue will help doctors decide the prognosis and treatment of breast cancer.

The test measures the expression or activity level of 21 specific genes within a tumor sample and based on that pattern assigns a recurrence score of anywhere from 0 to 100. Earlier trials have shown that the higher the recurrence score, the more likely the patient's cancer will recur.

Scientists, specializing in cancer, have launched a clinical trial that could keep thousands of breast cancer patients from getting chemotherapy that is unlikely to do them any good. The trial will reveal whether chemotherapy benefits patients with node positive breast cancer who have low to intermediate Oncotype DX recurrence scores. The trial also seeks to determine whether there is an optimal recurrence score cut-point for these patients, above which chemotherapy should be recommended.

The scientists plan to enroll 4,000 women with recurrence scores of 25 or less who have early stage, hormone receptor-positive, HER2-negative breast cancer that has been found to involve one to three lymph nodes. They expect to screen about 9,000 breast cancer patients in order to register these 4,000, who will be randomized to receive either chemotherapy with endocrine therapy or endocrine therapy alone.

The Oncotype DX assay is a product of Genomic Health Inc. (Redwood City, CA, USA), and is only one of several gene expression profile tests oncologists now use to help them judge how likely it is a patient's cancer will return or to inform treatment decisions. The investigators plan to evaluate other tests as well, including the PAM50 test, which measures the expression level of a set of 50 genes to determine a patient's "risk of recurrence" score. The PAM50 (ARUP Laboratories, Salt Lake City, UT, USA) uses a reverse transcription/quantitative polymerase chain reaction on formalin fixed paraffin embedded tissue.

Ana M. Gonzalez-Angulo, MD, the study coordinator from the MD Anderson Cancer Center (Houston, TX, USA), said, "If the treatment (Rx) for Positive Node, Endocrine Responsive Breast Cancer (RxPONDER) trial confirms findings from earlier studies, it will mean that we know more precisely how to use a genomic-based test to spare thousands of women whose breast cancer has spread to as many as three lymph nodes, the grueling side effects and staggering costs of chemotherapy they do not need."

Related Links:
Genomic Health Inc.
ARUP Laboratories
MD Anderson Cancer Center