Stages, types and treatment of breast cancer
Breast cancer is a complex collection of many different subtypes, and there is no “one-size-fits-all” treatment. Health professionals may refer to a tumour by its size, grade or spread, as hormone receptive, invasive or metastatic.
“Staging” is a classification tool used by health professionals to describe:
- the size of a breast cancer;
- whether it is limited to one area in the breast or it has spread to healthy tissues inside the breast; and
- whether the cancer has spread to the lymph nodes or to other parts of the body beyond the breast.
Stages of breast cancer are numbered from 0 to 4. Classification helps determine the right treatment plan – and is based on a pathologist’s study of any tumour tissue or lymph nodes removed during biopsy or surgery.
Types of treatment
Breast cancer treatments are based on the specific biological or molecular signature of a tumour. Each tumour is different and requires a personalised approach. The most common treatments include:
The goal of breast cancer surgery is to remove the entire tumour from the breast. A lumpectomy aims to preserve the breast and remove only cancerous tissue. A mastectomy removes the entire breast. Some of the lymph nodes from the underarm area (axillary nodes) may also be removed to see if cancerous cells are present.
Radiation is given to the breast, chest, collarbone and underarm to kill any cancer cells that might remain after surgery.
Chemotherapy is a chemical compound that kills rapidly dividing cells, such as cancer cells. It is usually given to those with early breast cancer after surgery (adjuvant chemotherapy). For large tumours, it can be used before surgery (neoadjuvant chemotherapy) to shrink the tumour.
Some breast cancer cells need estrogen and/or progesterone (female hormones) to grow. Hormone therapy slows or stops their growth by preventing the cancer cells from getting these hormones. It is usually given after surgery as a long-term preventative treatment. High-risk women who have never had breast cancer may take it as a preventive therapy.
A targeted therapy is a drug designed to attack a molecular agent or pathway involved in the development of a particular breast cancer. For example, HER2 positive breast cancer has too many copies of a particular gene known as HER2 which stimulates cell growth. The drug trastuzumab (Herceptin) works by attaching itself to the HER2 receptors on the surface of breast cancer cells, blocking them from receiving growth signals. Unlike chemotherapy drugs, targeted therapies kill cancer cells with little harm to healthy cells.
Personalised therapy and/or precision medicine
Increasingly, research is allowing a combination of personalised treatments to be used. A person’s individual situation, overall health, age, lifestyle risk factors and the molecular make-up of his/her tumour are taken into account to provide the best strategy.