Overexpression of epidermal growth factor receptor as a prognostic factor in colorectal cancer on the basis of the Allred scoring system

Marta Rokita,¹ Rafal Stec,¹ Lubomir Bodnar,¹ Radoslaw Charkiewicz,² Jan Korniluk,¹ Marta Smoter,¹ Marzena Cichowicz,³ Lech Chyczewski,⁴ Jacek Nikliński,² Wojciech Kozłowski,³ Cezary Szczylik<sup>1

1</sup>Department of Oncology, Military Institute of Medicine, Central Teaching Hospital, Warsaw, Poland; ²Department of Clinical Molecular Biology, Medical University of Bialystok, Bialystok, Poland; ³Department of Pathology, Military Institute of the Health Services in Warsaw, Warsaw, Poland; ⁴Department of Clinical Pathology, Medical University of Bialystok, Bialystok, Poland

Background: Overexpression of epidermal growth factor receptor (EGFR) is found in many types of neoplasms. The aim of the study was to evaluate EGFR expression in colorectal cancer (CRC) specimens and to determine whether EGFR expression correlates with clinicopathological data and overall survival.
Patients and methods: Tissue specimens from 181 consecutive CRC patients treated at the Military Institute of Medicine in 2006–2010 were collected and examined for EGFR expression, by immunohistochemistry staining. The staining intensity and percentage of cells with membranous EGFR expression were scored and then grouped according to the parameters of the Allred Scoring system. Cutoff values were subjected to further statistical analysis. Univariate tests and a multivariate Cox proportional hazards model were used in data analysis.
Results: EGFR was overexpressed in 96 of 181 CRC specimens (53%). EGFR expression was not correlated with other clinicopathological variables. On univariate analysis, overexpression of EGFR, determined by PS (percentage score) (>3) and total score (sum of PS and intensity score) (>4), was associated with poor overall survival. On multivariate analysis, EGFR overexpression (PS > 3) was an independent adverse prognostic factor (hazard ratio [HR] 1.62; 95% confidence interval [CI]: 1.03–2.53). Elevated carcinoembryonic antigen (CEA) serum concentration before treatment, performance status (Word Health Organization [WHO]-2), and tumor localized in colon and liver metastases were also independent unfavorable prognostic factors.
Conclusion: EGFR overexpression (PS > 3) in a CRC patient population was an independent adverse prognostic factor. Implementation of the Allred Scoring system criteria into clinical practice might facilitate treatment decisions in CRC patients.

Keywords: expression, receptor, prognosis, cancer