The prognostic impact of epidermal growth factor receptor (EGFR) in patients with metastatic gastric cancer.

e14557 Background: The prognostic role of the epidermal growth factor receptor (EGFR) in metastatic gastric cancer has not been established. Methods: EGFR was analyzed by immunohistochemistry (IHC) in a total of 357 patients (formalin-fixed, paraffin-embedded samples) and by real-time quantitative PCR (RTqPCR) in 130 patients with esophagogastric cancer. Staining intensity on IHC was scored in EGFR 0, 1+, 2+ and 3+. Staining intensity (alternatively intensity x % positive cells or the H-Score) and quantitative mRNA expression were correlated with progression-free (PFS) and overall survival (OS) and pathological and clinical characteristics. Results: On IHC, EGFR was negative, 1+, 2+, and 3+ in 205 (57%), 50 (14%), 62 (17%), and 40 (11%) patients, respectively. EGFR 3+ status correlated positively with intestinal type histology (p=.05) but no other correlations between baseline criteria such as age, sex, ECOG, tumor location, type of metastatic sites, and type of sampling and EGFR status were found. PFS and OS were similar in patients with EGFR-positive vs. those with EGFR negative gastric cancer, regardless whether positivity was defined as ≥1+ (PFS, 5.3 vs. 5.7 months, p=.185; OS, 10.6 vs. 10.9 months, p=.463) or as 3+ (PFS, 5.7 vs. 4.9 months, p=.159; OS, 8.6 vs. 10.8 months, p=.377) or when alternative scores were used such as the H-score. The multivariate overall survival analysis indicated that EGFR status is not an independent prognostic factor (hazard ratio 0.84, 0.56 to 1.12, p=.227). There were also no significant differences in progression-free or overall survival when patients were categorized according to median (PFS p=.173, OS p=.116) or quartile (PFS p=.634, OS p=.767) distribution of EGFR mRNA expression or when the cut-off with the highest predictive value was calculated (PFS p=.148, OS p=.189). Conclusions: EGFR status is not prognostic of patient’s outcome in metastatic gastric cancer.