HER2/neu testing in primary colorectal carcinoma

Background: Anti-HER2/neu therapy is well-established in breast and gastric carcinoma. The increased understanding of this pathway led to the identification of new promising drugs in addition to trastuzumab, offering further perspectives. The role of HER2/neu in colorectal carcinoma is controversially discussed, as discrepant data has been reported. Methods: Here, we retrospectively assessed the prevalence of HER2/neu positivity in a large series of colorectal carcinoma, testing HER2/neu status according to current recommendations. We correlated the results to clinico-pathological data and patient survival. Results: Overall, in 1645 primary colorectal carcinoma cases, 1.6% of the cases were HER2/neu positive. HER2/neu positivity significantly correlated with higher UICC stages (P = 0.017) and lymph node metastases (P = 0.029). In the subgroup of sigmoideal and rectal carcinomas, positive HER2/neu status was associated with T-category (P = 0.041) and higher UICC stages (P = 0.022). Although statistically not significant, HER2/neu-positive colorectal carcinomas displayed a tendency to poorer overall survival. Conclusions: These results illustrate the importance of testing HER2/neu by approved diagnostic techniques and scoring systems. We assume that although the prevalence of HER2/neu positivity in colorectal carcinoma is low, HER2/neu testing in advanced, nodal-positive colorectal carcinoma is reasonable, offering a potential target in high risk colorectal carcinoma.