What is TNBC? - Black TNBC Sanctuary

What is Triple Negative Breast Cancer?

Breast cancer is a disease where certain cells in the breast grow abnormally and form a tumor. If left untreated, some tumors will grow larger and may spread to other parts of the body.

There are different subtypes of breast cancer. Breast cancer is classified into these different subtypes based on certain characteristics of the abnormal cells that form the tumor. The cells of some breast tumors express hormone receptor (HR) proteins known as the estrogen receptor (ER) and/or the progesterone receptor (PR). Some breast tumors express high levels of another protein called HER2. If a breast tumor tests negative for all three of these factors, it is called triple negative breast cancer (TNBC). TNBC is often more aggressive than other types of breast cancer.

TNBC can develop in different parts of the breast. If TNBC develops in the milk-producing breast glands, it is called either lobular carcinoma in situ (if only in the glands) or invasive lobular carcinoma (if the tumor has started to invade surrounding tissue). If TNBC develops in the milk ducts, it is called either ductal carcinoma in situ (if only in the duct) or invasive ductal carcinoma (if the tumor has started to invade surrounding tissue). In rare cases, TNBC can also develop in the nipple—these cancers are referred to as Paget’s disease.

In addition to being more aggressive, TNBC has fewer treatment options than other breast cancer subtypes. Historically, TNBC has been difficult to treat because it doesn’t have PR, ER, or HER2 to target with treatment. This left chemotherapy and radiation as the only available treatments for many years.

That has changed in recent years with the development of drugs that target certain features common in TNBC, as well as immunotherapies that help the immune system to fight TNBC. With even more new treatments on the horizon, the prognosis for TNBC continues to improve.

Black TNBC Stats

The statistics that we cite here are just that—statistics. They speak to big trends across populations. This information can help you to make treatment decisions and choices for your future. Knowing what you’re up against is important, but we know women who beat these odds every day.

Black individuals...

Are2X as likely to be diagnosed with TNBC

than their white counterparts, according to federal statistics*

are typically diagnosed at later stages of disease

when treatment is less likely to be effective

face the lowest survival rate

of TNBC, compared to other races

*However, one study suggested the disparity could be even greater and that Black women may be closer to three times more likely to develop TNBC than white women.

Black women with breast cancer are 40% more likely to die of breast cancer than white women. This may be due to the fact that Black women are more likely to be diagnosed with TNBC, which tends to be more aggressive than other subtypes.

While TNBC accounts for around 10% of cases among white women, it represents 19% of all breast cancer cases among Black women. For every 100,000 Black women, 24.8 are diagnosed with TNBC.

TNBC is the most common breast cancer subtype diagnosed in individuals under the age of 45. Black women, who have a higher risk of developing TNBC, also have a higher risk of being diagnosed with breast cancer before age 45. We have specific resources for young people diagnosed with TNBC in our resources section - learn more here.

Triple Negative Breast Cancer: Understanding your diagnosis

When your doctor gives you a diagnosis, it’s based on a lot of factors. While the next sections will explain some of the terminology that goes into the stages and grades of breast cancer, ask your doctor if you have specific questions about the stage or grade of your diagnosis. Learn more about diagnostics and testing in our resources section.

Triple Negative Breast Cancer: Understanding your diagnosis

To stage a cancer is to determine how far the disease has progressed at the time of diagnosis, with higher stage corresponding to more advanced disease.

TNBC stage is determined using the TNM system, which evaluates three components: tumor size and spread (T), spread to lymph nodes (N), and the presence of metastases (M).

T (Tumor)

Tx: The size and spread of the primary tumor cannot be determined.

T0: There is no evidence of a primary tumor.

Tis: Carcinoma in situ or Paget’s disease with no palpable mass; the tumor is confined to a very small area.

T1: The tumor measures 2 cm or less across. View more

T1mi: The tumor is 1 mm or less across.

T1a: The tumor is more than 1mm but not more than 5 mm across.

T1b: The tumor is more than 0.5 cm but not more than 1 cm across.

T1c: The tumor is more than 1 cm but not more than 2 cm across.

T2: The tumor measures more than 2 cm up to 5 cm across.

T3: The tumor is larger than 5 cm across.

T4: The cancer has spread into the skin and/or chest wall. View more

T4a: The cancer has spread into the chest wall.

T4b: The cancer has spread into the skin.

T4c: The cancer has spread into the skin and the chest wall.

T4d: Inflammatory breast cancer, a rare type of breast cancer marked by swelling and redness of the breast.

N (Lymph nodes)

Clinical Staging:

Stages are based on a physical examination and imaging scans. Clinical staging may be less accurate and comprehensive than pathological staging. View more

cNX: It is impossible to assess the lymph nodes.

cN0: There is no evidence of cancer in the lymph nodes.

cN1: Cancer cells are present in nodes of the lower or middle part of the armpit, but the nodes are not stuck to surrounding tissue. View more

cN1mi: The masses in the lymph nodes are larger than 0.2 mm but smaller than 2 mm.

cN2: The cancer has spread further or to more lymph nodes. View more

cN2a: Cancer cells have stuck together in the lymph nodes in the armpit or to other parts of the breast.

cN2b: Cancer cells are present in the lymph nodes behind the breastbone but not in the armpit.

cN3: The cancer has spread extensively through the lymph nodes. View more

cN3a: Cancer cells are present in the lymph nodes below the collarbone.

cN3b: Cancer cells are present in lymph nodes behind the breastbone as well as in the armpit.

cN3c: Cancer cells have spread to the lymph nodes above the collarbone.

Pathological staging:

Stages are based on examining the tissue from surgery or a biopsy. This may provide more information than a clinical exam. View more

pNx: It is impossible to assess the lymph nodes.

pN0: No cancer cells are detected in nearby nodes, or only small clusters measuring less than 0.2 mm.

pN1: The cancer is present in lymph nodes near the tumor. View more

pN1mi: Small clusters of cells exist in the lymph nodes near the armpit, larger than 0.2 mm but smaller than 2 mm.

pN1a: Cancer cells are present in 1 to 3 lymph nodes in the armpit, and the mass in at least one node measures more than 2 mm.

pN1b: Cancer cells are present in the sentinel lymph nodes, the first lymph nodes into which fluid drains from the breast, located behind the breastbone.

pN1c: Cancer cells are present in 1 to 3 lymph nodes in the armpit, including one mass larger than 2 mm, and in the sentinel lymph nodes behind the breastbone.

pN2: The cancer has spread further or to more lymph nodes. View more

pN2a: Cancer cells are present in 4 to 9 lymph nodes in the armpit, and at least one mass is larger than 2 mm.

pN2b: Cancer cells are present in lymph nodes behind the breastbone that lie beyond the sentinel lymph nodes (found by imaging tests), with no evidence of cancer in the lymph nodes in the armpit.

pN3: The cancer has spread extensively through the lymph nodes. View more

pN3a: Cancer cells are present in 10 or more lymph nodes in the armpit with at least one mass larger than 2 mm, or cancer is present in the lymph nodes below the collarbone.

pN2a: Cancer cells are present in 4 to 9 lymph nodes in the armpit with at least one mass larger than 2 mm and in the sentinel lymph nodes behind the breastbone. Alternatively, cancer cells are present in 1 to 9 lymph nodes in the armpit with at least one mass larger than 2 mm and in non-sentinel lymph nodes behind the breastbone.

pN2a: Cancer cells have spread to the lymph nodes above the collarbone on the same side of the body as the primary tumor.

Metastasis (M)

M0: There is no evidence of metastasis.

M1: Metastases have been observed in other organs, or a mass larger than 0.2 mm has been found in a distant lymph node.

Once tumor size and spread, spread to lymph nodes, and the presence of metastasis have been defined, the tumor is assigned a stage as outlined below. The higher the stage, the more advanced the cancer.

Stage 0: Tis, N0, M0

Stage 1A: T1, N0, M0

Stage 1B: T0, N1mi, M0 | T1, N1mi, M0

Stage 2A: T0, N1, M0 | T1, N1, M0 | T2, N0, M0

Stage 3A: T0, N2, M0 | T1, N2, M0 | T2, N2, M0 | T3, N1, M0 | T3, N2, M0

Stage 3B: T4, N0, M0 | T4, N1, M0 | T4, N2, M0

Stage 3C: Any T, N3, M0

Stage 4: Any T, Any N, M1

A note: TNM classification can also be combined with other tumor factors to determine the tumor’s prognostic stage, which incorporates TNM, tumor grade, and the presence of various biomarkers. You can ask your doctor if the stage they have given you is based solely on the TNM system (above) or is a prognostic stage.

Grading TNBC

The extent to which cancer cells differ from healthy cells determines their grade. Grading provides clues to how quickly cancer may grow. TNBC has three grades:

Grade 1: The cancer cells appear somewhat like healthy cells. They usually grow slowly and are less likely to spread.

Grade 2: These cells show more abnormality and grow slightly faster than grade 1 cells.

Grade 3: These cells show marked differences from healthy cells and are often described as “poorly differentiated.” They may grow quickly and are likely to spread if not treated.