Diagnostic Tool Oncotype DX Associated with Reduction in Chemotherapy Rates Post-Surgery in Younger Patients

The gist: New research shows interesting results for a test that’s used to determine whether early-stage breast cancer patients need chemotherapy after tumor-removal surgery. The test, called Oncotype DX, is linked with lower chemotherapy use in younger patients, but not in patients 66 years old or older. The test is used for patients with lymph node-negative, hormone receptor (HR)-positive and HER2-negative breast cancer. It looks at a patient’s tumor genes to determine how likely a return of cancer later on (recurrence) might be.

“In what’s believed to be one of the largest population-based studies of Oncotype DX ever conducted, researchers at The University of Texas MD Anderson Cancer Center have found that the commercial diagnostic tool, Oncotype DX, was associated with a decrease in chemotherapy use in younger patients, but not in those over 66 years of age.

“Mariana Chavez Mac Gregor, M.D., assistant professor, health services research and breast medical oncology, will present the findings at a poster session of the 2014 San Antonio Breast Cancer Symposium.

“Oncotype DX is a 21-gene assay used to help estimate the likelihood of recurrence in women with early-stage breast cancer and, thus, determine those who may or may not benefit from adjuvant chemotherapy. The National Comprehensive Cancer Network includes its use for women with lymph node-negative, hormone receptor (HR)-positive and HER2-negative disease…

” ‘In the younger group of breast cancer patients for whom the test is appropriate, and when used in this setting, we’re finding an important reduction in chemotherapy use. The contrast between older and younger patients’ results did surprise us. However, generally, older breast cancer patients receive much less chemotherapy because of their age and because they often have additional co-morbidities. Perhaps we will see that impact with time,’ said Chavez Mac Gregor.”