The latest generation of genomic tests for breast cancer can improve physicians’ ability to diagnose the disease and more precisely tailor each patient’s treatment. This study examined the first commercially available genomic tests to determine the molecular subtype of a breast cancer tumor.

Genomic testing is part of the revolution in personalized medicine. It uses a patient’s tumor genomic profile and other information to individualize treatment with the goal of better clinical results and overall cost savings. Genomic tests examine tumor tissue and the activity of groups of genes within the tumor, to provide a more comprehensive view of the cancer and treatment options.

This study compared the accuracy of immunochemistry and fluorescent in-situ hybridization results to two genomic tests, MammaPrint and BluePrint, which are part of the Symphony panel of genomic tests. A retrospective analysis was conducted of 208 tumor samples from breast cancer patients whose age, survival, and cancer pathology findings were known. The median follow-up time for these 208 patients was 11.3 years.

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Researchers concluded that these relatively new genomic tests can more accurately classify breast cancer tumors by their disease subtype. In turn, that can help doctors to better predict what type of treatment is best for that cancer subtype. Further, the study findings also suggest that some breast cancer patients who are currently prescribed chemotherapy after surgery may be able to avoid that therapy and its risks.

The risks of chemotherapy include immediate side effects, discomfort, and long-term damage, including a possible second cancer. Several studies have concluded that chemotherapy provides no real benefit for many breast cancer patients because of their cancer subtype and low risk of recurrence.

“We now have a better tool for determining which patients do not need to undergo treatments such as chemotherapy, when that treatment would be expensive and would not be useful to that particular patient,” said medical oncologist Massimo Cristofanilli, MD, FACP, lead author of the study and chief of the breast service line at Fox Chase Cancer Center, in Philadelphia.

The new genomic tests will enable physicians to more precisely employ the sophisticated treatments that have been developed for breast cancer, according to Cristofanilli. He said, “Our sophisticated therapies mean nothing if we cannot apply them to patients appropriately. This newer panel of genomic tests enables us to better classify patients. That will help improve outcomes, because we will be more precisely applying the right treatment to the right patient.”

“One message is that we cannot any longer afford to use the older methods alone for breast cancer prognosis and treatment planning,” said Cristofanilli.

This study was presented at the 2012 CTRC-ACCR San Antonio Breast Cancer Symposium, held on December 4-8, 2012.