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.
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.
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).
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.