Practical and molecular evaluation of colorectal cancer: new roles for the pathologist in the era of targeted therapy.
BACKGROUND
Colorectal cancer is the third most common cancer and the fourth most common cause of cancer death worldwide. Patient cases are discussed in multidisciplinary meetings to decide on the best management on an individual basis. Until recently, the main task of the pathologist in such teams was to provide clinically useful reports comprising staging of colorectal cancer in surgical specimens. The advent of total mesorectal excision and the application of anti-epidermal growth factor receptor (EGFR)-targeted therapies for selected patients with metastasized colorectal cancer have changed the role of the pathologist.


OBJECTIVE
To present the traditional role of the pathologist in the multidisciplinary team treating patients with colorectal cancer, to address the technique of total mesorectal excision and its implications for the evaluation of surgical specimens, to offer background information on the various EGFR-targeted therapies, and to review the currently investigated tissue biomarkers assumed to be predictive for efficacy of such therapies, with a focus on the role of the pathologist in determining the status of such biomarkers in individual tumors.


METHODS
This article is based on selected articles pertaining to biopsy evaluation of colorectal carcinoma and reviews of EGFR-targeted therapies for this cancer. All references are accessible via the PubMed database (US National Library of Medicine and the National Institutes of Health).


CONCLUSIONS
Pathologists play an increasingly important role in the diagnosis and management of colorectal cancer because of the advent of new surgical techniques and of targeted therapies. It is expected that this role will increase further in the near future.
De Hertogh
Gert
G
Department of Pathology, University Hospitals KULeuven, Leuven, Belgium. gert.dehertogh@uz.kuleuven.ac.be
Geboes
Karen Paula
KP
D014408:Biomarkers, Tumor / Q000235:genetics; D001706:Biopsy; D015179:Colorectal Neoplasms / Q000188:drug therapy* / Q000235:genetics* / Q000473:pathology; D016503:Drug Delivery Systems / Q000639:trends*; D066246:ErbB Receptors / Q000037:antagonists & inhibitors / Q000235:genetics; D006801:Humans; D009154:Mutation / Q000235:genetics; D011518:Proto-Oncogene Proteins / Q000235:genetics; D016283:Proto-Oncogene Proteins p21(ras); D018631:ras Proteins / Q000235:genetics
D014408:Biomarkers, Tumor; C117307:KRAS protein, human; D011518:Proto-Oncogene Proteins; C512478:EGFR protein, human; D066246:ErbB Receptors; D016283:Proto-Oncogene Proteins p21(ras); D018631:ras Proteins