Triple-negative breast cancer – What do we know ?

This paper reviewed triple negative breast cancer. 

Triple-negative breast cancer refers to cancer in the absence of the estrogen receptor, progesterone receptor and human epidermal growth factor receptor 2 (HER2). These receptors are proteins that can be found on cells, and are often used as targets by breast cancer treatments. 

Triple-negative breast cancer has been associated with the breast cancer gene (known as BRCA). A mutation of BRCA increases the risk of breast cancer and this gene can be passed down generations. Patients diagnosed with triple-negative breast cancer aged 60 years and below should receive genetic counselling.

Triple-negative breast cancer is more likely to spread to the brain and lungs compared to other types of breast cancer. The tumors tend to be larger and more aggressive than other types of breast cancer. Both breast density and obesity increase the risk of triple-negative breast cancer.

Studies have found that approximately 40% of patients with triple-negative breast cancer benefit from chemotherapy. Compared to other types of breast cancer, there can be an increased rate of triple-negative breast cancer returning to the original site after breast conserving therapy (part of breast removed) or mastectomy (whole breast removal). However, in a study the local recurrence (return of breast cancer to the original site) after 5 years was only 4.2% among those who had breast conserving therapy and 5.4% among those who had mastectomy. Thus, excellent outcomes can be achieved in triple negative breast cancer.

Recent studies suggested patients who have small tumors with no spread to the lymph nodes do well. For such patients with triple-negative breast cancer, the overall survival after 5 years exceeds 90% without therapy.

Studies show that chemotherapy alongside surgery with conventional anthracyclines (chemotherapy drugs) or taxanes (chemotherapy drugs) treatment gives high rates of complete disappearance of tumors. Small studies have suggested that patients with BRCA1 mutation may be sensitive to effects of platinums (form of chemotherapy) or ionizing radiation (technique to kills cells). 

The authors concluded that though triple negative breast cancer may be associated with some adverse characteristics, it is treatable and good outcomes may be achieved, particularly with the addition of chemotherapy to surgery.