title: Biomarker testing for treatment of metastatic colorectal cancer: role of the pathologist in community practice.
abstract: The past decade has been marked by significant advancements in the treatment of patients with metastatic colorectal cancer (mCRC), including the approval of novel biologic agents such as the angiogenesis inhibitors bevacizumab and afibercept and the epidermal growth factor receptor monoclonal antibodies (mAbs) cetuximab and panitumumab. Cetuximab was recently approved by the US Food and Drug Administration in combination with FOLFIRI (irinotecan, 5-fuorouracil, leucovorin) for the first-line treatment of patients with KRAS mutation-negative (wild-type) tumors as determined by an FDA-approved companion diagnostic. It was the first FDA approval in mCRC requiring use of a diagnostic test that is predictive of response prior to initiation of frontline therapy. The approval highlights the need for reflexive KRAS mutation testing at diagnosis to accurately determine all available treatment options. Although KRAS testing has been used by pathologists in mCRC for several years, accurate and timely reporting of test results and open communication with medical oncologists is even more essential to ensure appropriate first-line treatment selection and avoid any treatment delays. Consequently, it is critical that pathologists are highly trained and educated on KRAS testing methodology and the pros and cons of the various methods available. In this review, we discuss the development of KRAS as a biomarker in mCRC and key topics of concern to the pathologist who works with the oncologist in the community setting, including specimen preparation, KRAS testing methods, and reporting of test results. In this era of personalized medicine, pathologist education and communication with oncologists on biomarkers is paramount for optimal patient care.
authors: PathLogic, West Sacramento, CA USA Email: Rafael.Rodriguez@pathlogic.com.
authors: Rafael
authors: R
authors: Rodriguez