Today is Triple Negative Breast Cancer (TNBC) Day – a day dedicated to raising funds and awareness for TNBC. You might be wondering why a specific type of breast cancer needs its own day. Well, TNBC is an aggressive form of breast cancer that can be difficult to treat and targets specific populations. Read on to find out more about what you need to know.
1. Triple Negative Breast Cancer (TNBC) is not hormonally fuelled
Triple-negative breast cancer (TNBC) are tumours that test negative for estrogen receptors, progesterone receptors, and excess HER2 protein. These results mean the growth of the cancer is not fueled by the hormones estrogen and progesterone, or by the HER2 protein. About 10-20 percent of breast cancers are triple-negative breast cancers.
2. TNBC has a different treatment pathway
TNBC does not respond to hormonal therapy medicines or medicines that target HER2 protein receptors. Treatment often includes systemic therapy (such as chemotherapy and sometimes immunotherapy), along with surgery and radiation depending on the stage and individual circumstances. The following are typical treatment pathways:
Neoadjuvant chemotherapy
Research has shown that when TNBC is treated with chemotherapy before surgery — what doctors call neoadjuvant chemotherapy — and there is a pathologic complete response, disease-free survival and overall survival improve. Disease-free survival is how long a person lives without the cancer recurring. Overall survival is how long a person lives whether or not the cancer recurs.
One way for oncologists to determine the effectiveness of neoadjuvant therapy is to look at the tissue removed during surgery to see if there are any active cancer cells. If no active cancer cells are present, doctors call it a “pathologic complete response” or pCR.
Today, some patients may also receive immunotherapy as part of their treatment plan, particularly for higher-risk early-stage disease.
PARP inhibitors for hereditary TNBC
Poly ADP-ribose polymerase (PARP) inhibitors, enzymes that fix DNA damage in both healthy and cancer cells, have been approved to treat advanced-stage HER2-negative breast cancer in people with a BRCA1 or BRCA2 hereditary mutation. This is important because 70 percent of breast cancers diagnosed in people with an inherited BRCA1 mutation are triple-negative.
Research has shown that medicines that interfere or inhibit the PARP enzyme make it even harder for cancer cells with a BRCA1 or BRCA2 mutation to fix DNA damage. In other words, a PARP inhibitor makes some cancer cells less likely to survive.
PARP inhibitors may also be used in certain early-stage, high-risk patients with inherited BRCA mutations to help reduce the risk of recurrence.
Immunotherapy
Research also suggests that the immunotherapy medicines combined with chemotherapy may improve outcomes for metastatic TNBC patients, compared to chemotherapy alone. Immunotherapy medicines work by helping your immune system work harder or smarter to attack cancer cells.
Immunotherapy is now part of treatment for some early-stage and metastatic TNBC patients, depending on tumour features and individual factors.
This is still an emerging field in breast cancer and we are hoping to see more immunotherapies developed and approved for use in treating breast cancer.
Surgery
Most TNBC patients undergo a mastectomy to reduce their chance of recurrence for breast cancer. Depending on your diagnosis (stage, grade of cancer), a unilateral or bilateral mastectomy may be recommended to reduce your risk.
In some cases, breast-conserving surgery (lumpectomy) may also be an option, depending on tumour size, response to treatment, genetics, and patient preference.
3. TNBC targets specific populations
While TNBC can show up in anyone, researchers have found that it is more prevalent in the following populations:
- Younger people. TNBC is more likely to be diagnosed in people younger than 50. Other types of breast cancer are more commonly diagnosed in people age 60 or older.
- African-American and Hispanic women. TNBC is more likely to be diagnosed in African-Canadian and African-American women and Hispanic women. Asian women and non-Hispanic white women are less likely to be diagnosed with TNBC.
- People with a BRCA1 genetic mutation. About 70 percent of breast cancers diagnosed in people with an inherited BRCA1 mutation are triple negative.
4. TNBC has unique features
Triple negative breast cancer is considered a more aggressive type of breast cancer, mainly because there are fewer targeted medicines that treat TNBC. Studies have shown that TNBC is more likely to spread beyond the breast and more likely to recur (come back) after treatment. That being said, when patients do have a complete response to treatment beyond five years, they have longer periods of NED (no evidence of disease).
TNBC tends to be a higher grade than other types of breast cancer. The higher the grade, the less the cancer cells resemble normal, healthy breast cells in their appearance and growth patterns. On a scale of 1 to 3, TNBC is usually grade 3.
TNBC is “basal-like.” “Basal-like” means that the cells resemble the basal cells that line the breast ducts. Basal-like cancers tend to be more aggressive, higher grade cancers — just like TNBC. Most but not all basal-like breast cancers are triple negative, and most but not all TNBC are basal-like.
Researchers now understand that TNBC is not one single disease but includes several subtypes, and research is ongoing to develop more personalized treatments.
5. TNBC can feel scary, but you can take an active role in your care
Being diagnosed with cancer is terrifying but a TNBC diagnosis can be exceptionally scary because it tends to be more aggressive with a poorer prognosis. Also, unlike other breast cancers, when you are done treatment there is no adjuvant therapies like Tamoxifen for estrogen receptive breast cancer or Herceptin for HER2 positive breast cancer. This means there is nothing left to take or “do” to reduce your risk of a recurrence and some people may feel powerless.
While TNBC remains an aggressive subtype, treatment advances in recent years have improved outcomes for many patients.
Keep in mind that everyone is different and a complete response to TNBC treatment can produce an excellent prognosis.
Asking questions and understanding your treatment options can help you feel more confident and informed throughout your care.
For more information on TNBC check out the Triple Negative Breast Cancer Foundation.
Source: BreastCancer.Org