Prognostic Test for Breast Cancer Recurrence Validated

A prognostic test indicates a patient's risk for another breast cancer tumor after diagnosis and surgical removal of a tumor. The test helps physicians make more personalized treatment decisions for breast cancer patients regarding postsurgical therapy, which can have significant impact on a patient's quality of life.

The test, called MammaPrint, is a U.S. Food and Drug Administration (FDA; Rockville, MD, USA)-cleared DNA microarray-based in-vitro diagnostic multivariate index assay (IVDMIA). It measures the activity of 70 genes, providing information about the likelihood of tumor recurrence. The MammaPrint test measures the level of expression of each of these genes in a sample of a woman's surgically-removed breast cancer tumor and then uses a specific formula or algorithm to produce a score that determines whether the patient is deemed at low- or at high-risk for the spread of the cancer to another site.

Data from two studies involving the breast cancer prognosis test were presented at the American Society of Clinical Oncology's (ASCO) annual meeting, held May 30-June 3, 2008, in Orlando, FL, USA. Collectively, the findings showed that MammaPrint 70-gene signature provided important information for more effective patient management.

In the first study conducted at the University of Texas M.D. Anderson Cancer Center (Houston, TX, USA), tumor samples from 198 patients with early stage, lymph-node-negative breast cancer were analyzed with multiple gene-expression assays, including MammaPrint, to determine whether both prognostic and treatment prediction data could be generated from a single specimen.

Among 32% of patients (64 of 198) predicted to be at low risk for breast cancer recurrence with MammaPrint, 31% (20 of 64) were predicted to be highly sensitive to endocrine therapy while 88% (56 of 64) were predicted to be insensitive to chemotherapy. The remaining 134 patients, who were considered to be at high risk for cancer recurrence, were predominantly predicted chemo-sensitive (> 51%).

The second study was a prospective trial to assess the clinical implementation of MammaPrint in 15 community hospitals in The Netherlands. Of 427 MammaPrint gene profiles obtained from 812 patients with node-negative breast cancer, 30% of the results were discordant with the Dutch treatment guidelines. For example, some patients categorized as high risk for cancer recurrence using MammaPrint had been previously identified as low risk using the guidelines. In 54% of the discordant cases, the course of treatment was changed.

"These studies demonstrate the clinical utility of MammaPrint in helping physicians make more informed decisions about the course of care for their patients with breast cancer,” said Laura van't Veer, Ph.D., head of molecular pathology at the Netherlands Cancer Institute (Amsterdam, The Netherlands) who participated in both studies. "Prognostic tests such as MammaPrint have ushered in a new era in personalized medicine, helping us to determine the most appropriate care based on an individual patient's risk and treatment preferences. This might mean, in some cases, avoiding harsh therapies that may otherwise not be effective.”

All MammaPrint tests are conducted in Agendia's (Amsterdam, The Netherlands) central service laboratory. Agendia was the first company to commercialize the prognostic test that predicts the risk of breast cancer recurrence.


Related Links:
University of Texas M.D. Anderson Cancer Center
Netherlands Cancer Institute
Agendia