Epidermal growth factor receptor (EGFr) as a marker for poor prognosis in node-negative breast cancer patients: Neu and tamoxifen failure

Analysis of EGFr and ER was performed on tumour samples from 231 patients with operable breast cancer followed for up to 6 yr after surgery. The median duration of follow-up in patients still alive at the time of analysis was 45 months.

Thirty-five percent of patients (82) had tumours greater than 10 fmol/mg ¹²⁵I-EGF binding (EGFr⁺) and 47% (109) had cystolic ER concentration >5 fmol/mg (ER⁺), with a marked inverse relationship between EGFr and ER (P<0.00001). EGFr was second only to axillary node status as a prognostic marker for all patients both in terms of relapse-free and overall survival (P<0.001, logrank EGFr⁺ vs EGFr⁻).

For patients with histologically negative axillary nodes EGFr was superior to ER in predicting relapse and survival (P<0.01 and P<0.005, respectively, compared to P<0.1 and P<0.1, logrank). In a multivariate (Cox model) analysis only EGFr, out of EGFr, ER, size and grade, was predictive for either relapse-free or overall survival for patients with node-negative disease (P=0.052 and P=0.026, respectively).

The correlation of neu expression with response to tamoxifen in patients with recurrent disease was assessed immunochemically. Response rate was reduced in the presence of neu from 50 to 17% for ER⁺ cases and from 26 to 0% for ER⁻ cases.