Serum EGFR and serum HER‐2/ neu are useful predictive and prognostic markers in metastatic breast cancer patients treated with metronomic chemotherapy

BACKGROUND. Metronomic chemotherapy has been demonstrated to be of value in patients with advanced breast cancer. No reliable markers of response are available. In breast tumor, HER‐2/ neu is a prognostic factor, whereas no definite data exist for EGFR. The aim of the study was to evaluate the prognostic and predictive role of serum HER‐2/ neu and serum EGFR in breast cancer patients treated with low‐dose chemotherapy. METHODS. Serum levels of HER‐2/ neu (n = 135) and of EGFR (n = 113) were prospectively determined before the start of chemotherapy, after 2 months of treatment, and when progressive disease was diagnosed. RESULTS. Elevated (>15 ng/mL) serum HER‐2/ neu before the start of chemotherapy was not associated with response rate, whereas elevated serum HER‐2/ neu at 2 months was significantly associated with reduced long‐term clinical benefit (24weeks) ( P < .001), as well as changes in HER‐2/ neu levels between baseline and 2 months ( P < .0001). Multivariate analysis identified a ≥20% increase of serum HER‐2/ neu as an independent factor for progression‐free survival (PFS). Kinetics of serum HER‐2/ neu were significantly associated with PFS ( P < .0001) and overall survival (OS) ( P = .015). Low baseline serum levels of EGFR (<45 ng/mL) were predictive of reduced response rate both at 2 months ( P = .031) and after 24 weeks ( P = .022). Moreover, they were significantly associated with reduced PFS ( P = .016) and OS ( P = .015). CONCLUSIONS. Serum HER‐2/ neu and EGFR may represent useful markers for early prediction of probability of response, PFS, and OS in patients with advanced breast cancer treated with metronomic chemotherapy. Cancer 2007. © 2007 American Cancer Society.