Is There Currently an Established Role for the Use of Predictive or Prognostic Molecular Markers in the Management of Colorectal Cancer? A Point/Counterpoint

Abstract

The term "personalized oncology" means different things to the oncologist than to the patient. But fundamentally, the phrase creates the expectation that decisions can be informed by the unique features of the patient and patient's cancer. Much like determining antibiotic sensitivities in urinary tract infections, the oncologist is expected to choose the right treatment(s), for each individual patient. Numerous methods can be used to "personalize" management decisions, although truly useful biomarkers continue to escape our grasp. Positron Emission Tomography in patients with GI stromal tumors or genotyping of c-kit in chronic myelogenous leukemia cells can guide the use of imatinib, these scenarios represent a minority of patients. The promise of individualized therapy, however, has led to the commercialization of numerous assays to probe patient's genetic make-up and that of the tumor. Breast cancer management has benefitted from the analysis of gene recurrence scores. More recently the analysis of germline or tumor-associated mutations in non-small cell lung cancer and melanoma has led to clinically meaningful molecular subsets of these diseases, guiding the successful targeting of such cancers with small-molecule inhibitors. Despite the high incidence of colorectal cancer and our relatively long-standing grasp of the molecular pathways in colorectal carcinogenesis, the management of these patients remains mostly empiric and movement toward "personalization" has been slow and incremental. Now, however, molecular imaging and commercial assays for genetic makeup of tumor specimens has put the oncologist and oncologic surgeon in the crossfire with patients and families who believe the era of "personalization" is here.