Genetic Test Evaluation

understanding how genetic tests impact patient management

Breast Cancer Index (bioTheranostics Inc.)

October 13, 2016

Breast cancer is the most common cancer for American women other than skin cancer.  Although breast cancer is common, if it is identified early (when localized), the 5-year survival rate for women is 98.8%. However, the survival rate is lower (85.2%) if the cancer has spread to the lymph nodes (i.e., node-positive [N+]) and drops dramatically to 26.3% if it has metastasized.  Adjuvant chemotherapy is used in the treatment of many patients with a high risk for breast cancer recurrence to reduce the risk of recurrence following surgical resection. However, not all women who receive adjuvant treatments will benefit from them; therefore, physicians and patients must balance the benefits along with the risks of adjuvant chemotherapy and endocrine therapy, such as toxicities. Due to the potential benefits and risks of adjuvant therapies, a patient-specific approach is recommended. Several gene-based assays are clinically available, including MammaPrint (Agendia Inc.), Prosigna Breast Cancer Prognostic Gene Signature Assay (NanoString Technologies Inc.), Breast Cancer Index (bioTheranostics Inc.) and Oncotype DX (Genomic Health Inc.) to help guide decisions. These assays differ in the intended patient populations, sample requirements, genes evaluated, platforms, results, and validation. The current report focuses on the commercially available version of the Breast Cancer Index (BCI).