Advances in precision medicine can improve breast cancer treatment

Precision medicine

In a new study, researchers examine how one early example of precision medicine–tumor genome testing–is being used in women with breast cancer to reduce overtreatment and maximize the benefits of chemotherapy.

Researchers find that genome testing can help physicians identify which patients can most benefit from chemotherapy and patients for whom chemotherapy can be safely omitted.

The finding is published early online in CANCER, a peer-reviewed journal of the American Cancer Society.

Currently, most precision medicine studies in cancer have been confined to patients enrolled in clinical trials.

However, few have examined how physicians in everyday practice use biomarker tests to recommend chemotherapy or have assessed patient experiences with testing and decision-making.

To investigate, researchers from the University of Michigan in Ann Arbor surveyed 3,880 women who were treated for breast cancer in 2013 and 2014 in Los Angeles County, CA or the state of Georgia.

A total of 1527 patients with early stage breast cancer responded to the survey, and 778 had received the 21-gene recurrence score assay (RS), which estimates the risk of disease recurrence and the estimated benefit of chemotherapy in breast cancer.

The result showed that overall, 47.2% of patients with RS scores received a recommendation against chemotherapy and 40.6% received a recommendation for it.

In addition, RS results correlated with recommendations: nearly all patients with high scores received a chemotherapy recommendation, whereas the majority of patients with low-risk results received a recommendation against it.

Also, most patients with high RS received chemotherapy, whereas few patients with low scores received it.

Finally, there were no substantial racial/ethnic differences in testing and treatment. Women were largely satisfied with RS and chemotherapy decisions.

The researchers also noted that although most women were highly satisfied with their experience, only 60 percent of tested women accurately recalled their test results.

This suggests that while precision medicine for breast cancer has left the station, it has also left some women behind.

The oncology community needs to do a better job explaining to women the purpose of these tests, how to interpret the results, and what the results mean for their breast cancer treatment.

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Citation: Friese CR, et al. (2016). Chemotherapy Decisions and Patient Experience with the Recurrence Score Assay for Early-Stage Breast Cancer. CANCER; Published Online. DOI: 10.1002/cncr.30324.
Figure legend: This image is credited to National Cancer Institute.