Study Explores Link Between Breast Cancer Recurrence Score and Chemotherapy Use
A genetic test that helps predict whether some women’s breast cancer will recur might influence how chemotherapy is used, according to a study from Duke Medicine. The study found that low-risk patients who had the test appeared to opt for more treatment, and high-risk patients who were tested received less treatment.
The findings indicate that the 21-gene recurrence score test, which was approved for Medicare coverage in 2006, is being used to help guide clinical decisions in what is among the first widespread application of personalized medicine. The results of the study were published by Dinan et al in JAMA Oncology.
“The decision to get chemotherapy is very complex and personal, and it needs to be made between patients and physicians,” said Michaela A. Dinan, PhD, of the Duke Cancer Institute and the Duke Clinical Research Institute. “This shows that the risk score test provides information that appears to affect patients’ selection of treatment options in general clinical practice.”
Study Findings
In their retrospective study, Dr. Dinan and colleagues analyzed data of 44,044 Medicare patients with early-stage, estrogen receptor–positive breast cancer for whom the recurrence score assay is recommended. Of those patients, 24% were classified as low risk using National Comprehensive Cancer Network (NCCN) guidelines; 51.3% were intermediate risk; and 24.6% were high risk (due to lymph node involvement).
Overall, 14.3% of patients received chemotherapy within 12 months after diagnosis. The authors observed no overall association between having the recurrence score test and chemotherapy use.
However, among the different NCCN categories, differences emerged. Recurrence score testing was associated with decreased chemotherapy use among patients designated under NCCN definitions as high risk—particularly the younger Medicare patients between the ages of 66 and 70. Increased chemotherapy treatment was associated with test use among NCCN-designated low-risk patients.
The authors did not know what the recurrence scores were for the patients so could not ascertain whether patients in the NCCN risk categories coincided with recurrence score risk. “This limitation of the study affected the extent to which we could determine how the recurrence score results were being used to guide chemotherapy within individual patients and remains an area of ongoing research,” Dr. Dinan said.
The study received funding from the Agency for Healthcare Research and Quality.
The content in this post has not been reviewed by the American Society of Clinical Oncology, Inc. (ASCO®) and does not necessarily reflect the ideas and opinions of ASCO®.
