659 - Baseline CEA serum levels predict the efficacy of bevacizumab-based treatment in advanced colorectal cancer

Date 28 September 2012
Event ESMO Congress 2012
Session Publication Only
Topics Anti-Cancer Agents & Biologic Therapy
Colon Cancer
Rectal Cancer
Presenter Gerald Prager
Authors G. Prager1, C. Zielinski2
  • 1Medical University of Vienna, 1090 - Vienna/AT
  • 2Department Of Medicine I, Medical University of Vienna, 1090 - Vienna/AT

Abstract

Background

Carcinoembryonic antigen (CEA) has been shown to affect tumorigenesis by enhancing tumor cell survival as well as to paracrine induce tumor angiogenesis. Thereby, CEA induces angiogenesis independent of VEGF/VEGFR-2. The aim of this study was to evaluate baseline CEA serum levels as response predictor to bevacizumab-based therapies in patients with metastatic colorectal cancer (mCRC).

Methods

169 patients with mCRC receiving anti-angiogenic therapy by administration of bevacizumab plus chemotherapy (FOLFOX6 or FOLFIRI) were analyzed in a retrospective study. Disease control (DC), progression-free survival (PFS) as well as overall survival (OS) were assessed and related to baseline CEA serum levels. Patients with basal CEA serum levels below the statistical median of 26.8 ng/ml were compared with patients with higher basal serum CEA levels.

Results

Baseline CEA serum levels inversely correlated with therapeutic response in patients receiving bevacizumab-based treatment (Chi square i < 0.005: OR = 0.579, 95% C.I. 0.422, 0.795; p < 0.001). Median PFS for bevacizumab-treated patients correlated with baseline CEA serum levels leading to a median PFS benefit of 2.1 month for patients in the CEA ≤ 26.8 ng/ml group when compared to high CEA group (p < 0.05). Furthermore, CEA levels correlated with median OS for bevacizumab-based therapies (37.5 month vs. 21.4 month, p < 0.05). In an independent cohort of 129 patients treated with cetuximab-based therapy, no association of therapeutic response or PFS with CEA serum levels was found (p > 0.05), while CEA levels correlated with OS.

Conclusions

We conclude that baseline serum CEA levels might constitute an important predictor for the efficacy of first-line bevacizumab-based therapy in patients with mCRC. Thus, determining baseline CEA serum levels might represent a first step in optimizing and individualizing anti-angiogenic therapeutic approaches with bevacizumab-based treatment in mCRC to maximize patient benefit.

Disclosure

G. Prager: Payments for lectures including service on speakers bureaus: Roche, Amgen.

C. Zielinski: Consultany: Merck-Serono, Roche Payment for lectures including service on speakers bureaus: Roche