General Information About Breast Cancer
If cancer is found, tests are done to study the cancer cells.
Decisions about the best treatment are based on the results of these tests. The tests give information about:
- how quickly the cancer may grow.
- how likely it is that the cancer will spread through the body.
- how well certain treatments might work.
- how likely the cancer is to recur (come back).
Tests include the following:
- Estrogen and progesterone receptor test: A test to measure the amount of estrogen and progesterone (hormones) receptors in cancer tissue. If there are more estrogen and progesterone receptors than normal, the cancer may grow more quickly. The test results show whether treatment to block estrogen and progesterone may stop the cancer from growing.
- Human epidermal growth factor type 2 receptor (HER2/neu) test: A laboratory test to measure how many HER2/neu genes there are and how much HER2/neu protein is made in a sample of tissue. If there are more HER2/neu genes or higher levels of HER2/neu protein than normal, the cancer may grow more quickly and is more likely to spread to other parts of the body. The cancer may be treated with drugs that target the HER2/neu protein, such as trastuzumab (Herceptin) and lapatinib (Tykerb).
- Multigene tests: Tests in which samples of tissue are studied to look at the activity of many genes at the same time. These tests may help predict whether cancer will spread to other parts of the body or recur (come back).
- Oncotype DX: This test helps predict whether stage I or stage II breast cancer that is estrogen receptor positive and node-negative will spread to other parts of the body. If the risk of the cancer spreading is high, chemotherapy may be given to lower the risk.
- MammaPrint: This test helps predict whether stage I or stage II breast cancer that is node-negative will spread to other parts of the body. If the risk of the cancer spreading is high, chemotherapy may be given to lower the risk.
Certain factors affect prognosis (chance of recovery) and treatment options.
The prognosis (chance of recovery) and treatment options depend on the following:
- The stage of the cancer (the size of the tumor and whether it is in the breast only or has spread to lymph nodes or other places in the body).
- The type of breast cancer.
- Estrogen receptor and progesterone receptor levels in the tumor tissue.
- Human epidermal growth factor type 2 receptor (HER2/neu) levels in the tumor tissue.
- Whether the tumor tissue is triple-negative (cells that do not have estrogen receptors, progesterone receptors, or high levels of HER2/neu).
- How fast the tumor is growing.
- How likely the tumor is to recur (come back).
- A woman's age, general health, and menopausal status (whether a woman is still having menstrual periods).
- Whether the cancer has just been diagnosed or has recurred (come back).