Seven questions about triple-negative breast cancer

1. What is triple-negative breast cancer?

Triple-negative breast cancer or TNBC (triple-negative breast cancer) is a subtype of breast cancer with its own characteristics. Triple-negative breast cancer lacks three receptors that are present in the other types. Receptors are locks on the outside of a cell and with which the cell interacts with its environment. TNBC lacks three locks or receptors: estrogen receptors, progesterone receptors and HER2 ("human epidermal growth factor receptor 2").

2. Why is TNBC more difficult to treat?

All types of breast cancer except triple-negative, carry receptors for hormones on their cell surface. This allows them to be treated with hormone therapy or HER2 inhibitors. Because these receptors are missing in TNBC, there are fewer treatment options.

3. Why do some breast cancer patients have TNBC and others do not?

We don't know. Some factors are known to increase the risk of TNBC: being young (not yet menopausal), having black skin color and being a carrier of an inherited breast cancer gene.

4. How is TNBC diagnosed?

Either one feels a lump in the breast or notices some other alarm sign for breast cancer, or the tumor is found in a screening mammogram. To know if it is TNBC, a biopsy must always be taken (piece of tissue from the suspected lesion) and this is examined in a lab for the presence of receptors. Only then can one tell if the cancer is a TNBC.

5. How is TNBC treated?

Treatment depends on the stage at which TNBC is discovered. It usually consists of surgery, chemotherapy and radiation. Sometimes they give immunotherapy, targeted therapy or a combination drug. The latter is specific to TNBC with metastases.

6. What are the survival rates of TNBC?

Survival rates depend on the stage at which the cancer is discovered. If TNBC is detected and treated at an early stage, you can be cured. If the cancer has already spread, healing is no longer possible, but you can survive for several years with specific medication.

7. Is there any research being done on TNBC?

Absolutely. TNBC may be the least common type of breast cancer, but it affects a lot of women and often in the prime of their lives. Several pharmaceutical laboratories are specifically targeting TNBC, which has already led to important drugs that we also have available in Belgium.