Edith A. Perez, MD, deputy director, Mayo Clinic Cancer Center, Florida, director, Breast Program, Serene M. and Frances C. Durling Professor of Medicine, Mayo Medical School, discusses the complexities involved in the decision to optimize adjuvant therapy in patients with early breast cancer.

Multiple factors need to be considered when optimizing adjuvant therapy. The 2 main sets of data that need to be analyzed include clinical pathology and genetic analysis. Pathological concerns include the tumor size and lymph node involvement and genomic tests, such as Oncotype DX and MammaPrint, help determine molecular markers.

Genomic testing promises the most new potential and can be used to discover treatment markers for adjuvant therapy. The Oncotype DX test can be used to predict the benefits of anti-estrogen adjuvant therapy and MammaPrint is best utilized as a prognostic indicator.

As the field of cancer genomics continues to progress these tests will become more sophisticated. The Oncotype DX test currently looks at 16 genes and 5 reference genes and MammaPrint analyzes 70 genes. These tests work in some situations, however since there are over 24000 genes involved in breast cancer they are not perfect yet.