EGFR Linked to Poor Survival in Breast Cancer

Protein Presence Found to Produce Aggressive Disease

Women with advanced breast cancer had significantly poorer outcomes if their tumors had a presence of a protein called the epidermal growth factor receptor (EGFR), according to a recent study by M. D. Anderson researchers.

EGFR is a growth stimulus protein that has been found in other cancers to produce a more aggressive disease. This study is the first to firmly link the presence of EGFR to poor outcomes in breast cancer, say the researchers, who presented their findings at the San Antonio Breast Cancer Symposium. Results of the study were compiled by looking back at 14 years of data.

"This is potentially important news in that new drugs have been developed that block the EGFR pathway," says Thomas Buchholz, M.D., associate professor in M. D. Anderson's Department of Radiation Oncology who conducted the study. "The data provide a rationale for studying these agents in selected patients with breast cancer."

Study results

One such study will combine the EGFR inhibitor drug Iressa with the endocrine therapy drug Arimidex. (Endocrine therapy is a treatment aimed at depriving the tumor of the growth-promoting effects of estrogen.) The clinical trial, to be led by M. D. Anderson, will begin soon at 15 centers nationwide.

In Buchholz's study, researchers evaluated EGFR in preserved tissue involving locally advanced tumors (large tumors or tumors associated with bulky lymph nodes). The study reviewed samples from 82 of these breast cancer patients treated between 1989 and 1996 in clinical trials that tested the use of chemotherapy before surgery.

The presence of EGFR was:

• Positive in 14 cases (16%)
• Negative in 68 cases (84%)

Researchers then examined whether EGFR correlated with the outcome and found that patients with EGFR-positive disease had both a worse disease-free survival rate and a worse overall survival rate than patients with EGFR-negative cancer.

For example, EGFR-positive patients had an overall survival rate of 43% at nine years after treatment, compared to 60% in EGFR-negative patients.

"This is a small study, but we can clearly see that EGFR expression correlated with survival," Buchholz says. "This is relatively surprising, because EGFR has not been widely studied in breast cancer and the data suggests that it may have prognostic significance."