The two halves of the human colon have different embryonic origins and gene expression patterns, and these differences may also play a role in cancer biology, according to a study published in the JNCI: Journal of the National Cancer Institute.
To determine if there is an association between right or left colon primary tumor location and prognosis in metastatic colorectal cancer (CRC), as well as efficacy of the antiangiogenic agent bevacizumab, Fotios Loupakis, M.D., Ph.D. of the University of Southern California Norris Comprehensive Cancer Center, Los Angeles, and U.O. Oncologia Medica, Azienda Ospedaliero-Universitaria Pisana, Istituto Toscano Tumori, Pisa, Italy, and colleagues, used data from a prospective pharmacogenetic study and two randomized phase III trials. Overall survival (OS) and progression-free survival (PFS) were assessed in 2027 patients with metastatic CRC according to tumor location. Given the prognostic impact of BRAF mutational status and mucinous histology and their association to right-sided CRC, the prognostic impact of primary tumor location was also assessed in a subgroup of 200 patients from the prospective PROVETTA study, with full information on BRAF status and details on histology.