KRAS G>A mutation favors poor tumor differentiation but may not be associated with prognosis in patients with curatively resected duodenal adenocarcinoma

KRAS mutations have been found in duodenal adenocarcinomas and may have prognostic significance. The purpose of this study was to classify clinicopathological characteristics, microsatellite instability and KRAS mutations and identify possible prognostic role of KRAS mutations in duodenal adenocarcinomas. Demographics, tumor characteristics and survival were recorded for 78 patients with duodenal adenocarcinomas (Stages I-III). KRAS mutations were detected in 27 (34.6%) cases, of which the majority (74.1%) were G>A transitions. Multivariate logistic regression analysis showed that KRAS G>A mutation was significantly associated with late stage (p = 0.025) and poor tumor differentiation (p = 0.035), when compared with wild-type and other than G>A mutations. KRAS G>A mutation carriers were at increased risk for distant relapse (p = 0.022) and had significantly shorter overall survival (OS; log-rank p = 0.045) and a trend toward shorter relapse-free survival (RFS; log-rank p = 0.062) when compared with those who did not carry the KRAS G>A mutation. In multivariate analyses, there was a significant correlation between ≥ 3 positive lymph nodes and poor OS (p < 0.001) and RFS (p = 0.001) and KRAS G>A mutation carriers demonstrated no effect on clinical outcome. In conclusion, KRAS G>A mutation correlates significantly with late stage and poor tumor differentiation in duodenal adenocarcinoma. Among patients who undergo a curative resection of duodenal adenocarcinoma, KRAS G>A mutation carriers will more likely experience distant relapse but may not exhibit a poor prognosis. The number of positive lymph nodes should be incorporated in future staging systems.