Prognostic value of epidermal growth factor receptor in node-positive breast cancer

Abstract

The prognostic significance of EGFR (epidermal growth factor receptor) was studied in a cohort of 68 node-positive patients with breast cancer, who entered a controlled protocol of adjuvant therapy between February 1980 and June 1984. EGFR radioligand binding assay was carried out on frozen stored samples. Twenty five (37%) of 68 primary sites and 9 (41%) of 19 lymph node metastases assayed were EGFR-positive with a cut off value of 5 fmol/mg membrane protein; there is no statistical difference between the two distributions. EGFR was significantly correlated to ER and histological grade. EGFR-positive tumors and high levels of EGFR were mainly found in the ER-negative group of tumors (p = 0.008) and in histological grade III (p = 0.007). Fifty five patients could be followed for 40 to 92 months. EGFR was an independent prognostic factor for survival after 40 months (p = 0.05). EGFR+/ER- patients had the lowest survival probability, but statistical significance was not reached (p = 0.06). The EGFR phenotype appeared as a patients with different early outcome, with potential therapeutic implication especially in the group of ER-negative patients. These results emphasize the need for a standardized assay methodology and for further clinical studies, particularly in protocols where adjuvant hormonal therapy is prescribed on the basis of steroid hormone receptor status, in order to assess the respective prognostic worth of EGFR and ER (or PR).