A series of studies of the Oncotype DX colon cancer test were presented at the 2014 American Society of Clinical Oncology Gastrointestinal Cancer Symposium.
A review of four validation studies of the Oncotype DX colon cancer test, which included a total of 3,315 patients with early stage colon cancer, consistently demonstrated a significant association (p<0.05) between the test results and recurrence risk and cancer-specific survival.
Based on these results, the colon cancer test meets level I evidence criteria, according to the test’s sponsor, Genomic Health Inc., and it underscores the test’s clinical value beyond traditional clinicopathologic variables such as age, tumor size, tumor grade, number of nodes examined or evidence of lymphovascular invasion.
Additionally, three decision impact studies with a total of 502 patients showed that the test changed treatment recommendations in 29 to 45 percent of stage II colon cancer cases, leading to a net reduction in adjuvant chemotherapy use.
This analysis included previously-presented positive results by Partnership for Health Analytic Research, a multi-center study conducted in collaboration with the Mayo Clinic Cancer Research Consortium and a study conducted by Clalit Health Services in Israel.
A separate prospective study, which analyzed physician recommendations and patient treatment preferences before and after receiving the Oncotype DX colon cancer test results, demonstrated that the test greatly increased concordance between physician and patient treatment choice, from 66 percent to 96 percent.
The evaluation showed that the quantitative information provided by the Recurrence Score result influenced a majority of patients’ treatment decisions, 85 percent, and physicians’ treatment recommendations, 69 percent, and it increased 84 percent of physicians’ confidence in their own recommendations. Patients’ anxiety was also significantly reduced.
