Helpful definitions of terms that guide treatment decisions in early-stage breast cancer.
The language of breast cancer can be baffling. Here’s a short list of terms that guide treatment decisions in early-stage breast cancer.
HER2 status: Breast cancers that overexpress a gene called HER2 are often more aggressive than HER2-negative cancers, but can be targeted with specific drugs, including Herceptin (trastuzumab) and Tykerb (lapatinib).
Hormone status: Breast cancer cells may or may not have receptors for the hormones estrogen and progesterone. Hormone receptor-positive cancers often grow more slowly than hormone-negative cancers, and hormone receptor-positive status means doctors can make use of hormonal therapy.
Invasive: A cancer that has moved beyond its place of origin—usually the milk ducts or lobule lining—to invade surrounding breast tissue.
Lymph node status: Breast fluid drains into lymph nodes, so stray cells from a cancer that is beginning to spread may be caught in the nodes. So-called sentinel nodes are most directly linked to the breast. If these nodes are positive, more lymph nodes are removed and dissected to determine how many nodes the cancer has reached, and help assess recurrence risk and determine treatment.
Oncotype DX and MammaPrint: Genetic tests that measure the levels of a suite of genes expressed by a tumor. Researchers hope these and other tests will help them understand how dangerous a cancer might be and why some cancers respond to certain treatments while others do not.
Stage 1: The tumor measures less than 2 centimeters. Although cancer cells have invaded fatty or connective tissue, the cancer has not spread outside the breast (including lymph nodes).
Stage 2: A stage 2A tumor can be as large as 5 centimeters without lymph node involvement or less than 2 centimeters but has spread to nearby lymph nodes under the arm. A stage 2B tumor is between 2 and 5 centimeters and cancer has invaded one to three nearby nodes; the tumor can be larger than 5 centimeters as long as it has not invaded axillary nodes.
For more breast cancer terminology, visit the National Cancer Institute’s Dictionary of Cancer Terms at www.cancer.gov/dictionary.