The Future of Treatments for Triple-Negative Breast Cancer

Health Line

4 days ago

This type of breast cancer can be difficult to treat, but advances in therapeutic approaches are promising.
Triple-negative breast cancer (TNBC) is a rare type of breast cancer that doesn't respond to common hormone-based therapies. However, other treatments are available.
'Triple-negative' describes cancer cells that test negative for three types of receptors:
estrogen
progesterone
HER2
Because of its triple-negative status, TNBC doesn't respond to treatments that target estrogen or progesterone receptors. It also doesn't respond to the various HER2 cancer treatments.
However, TNBC is sensitive to chemotherapy and immunotherapy, which can shrink tumors so they're easier to remove surgically.
About 10% to 15% of all breast cancer types are of the triple-negative type. Most instances of TNBC are invasive ductal carcinoma, but ductal carcinoma in situ can also be estrogen-receptor and progesterone-receptor negative. The cell type, not the location, determines whether breast cancer is TNBC.
Black and Latinx people are more likely to develop TNBC than those of other ethnicities. A 2021 study found that Black women were 2.7 times more likely than white women to receive a TNBC diagnosis.
Many Black females don't have access to the insurance or resources they need to manage this type of cancer. They may experience delays between diagnosis and treatment and challenges communicating with doctors.
People with mutations on their BRCA gene, especially on the BRCA1 gene, are also at risk for this type of breast cancer, as are those younger than age 50.
Types of treatment
Even though TBNC is harder to treat compared to other types of breast cancer, treatments continue to evolve.
Chemotherapy
A common TNBC treatment strategy is to begin with chemotherapy, either alone or in combination with an immunotherapy drug. This helps shrink tumors so they're easier to remove with surgery. It can also shrink affected lymph nodes.
Some research suggests that neoadjuvant chemotherapy (chemotherapy that occurs before other treatments) can eliminate invasive breast cancer in about 30% to 50% of cases. Other studies have found that it is effective in over 58% of those with TNBC.
Research has found that when chemo can eliminate TNBC, the 5-year event-free survival rate is 92% and the 10-year event-free survival rate is 87%. Event-free survival includes cancer recurrence and further complications. However, this is dependent upon the stage of the tumor.
Your doctor might prescribe additional chemotherapy treatment after surgery. Chemotherapy after surgery is known as adjuvant chemotherapy and is performed to reduce the likelihood of a cancer recurrence.
Surgery
Surgery can be performed before or after chemotherapy.
When an early stage TNBC tumor is small enough, treatment may begin with surgery. The surgeon will remove the tumor and check your lymph nodes.
Surgery might involve:
a lumpectomy, which removes the tumor while preserving breast tissue
a mastectomy, which removes the entire breast
a sentinel lymph node biopsy, which removes nearby lymph nodes
Additional treatment may be needed after surgery to help improve outcomes.
Immunotherapy
Immunotherapy works by boosting your immune system and teaching it to target cancer cells by controlling the action of protein checkpoints that turn your immune response on or off. It can be used before or after surgery.
Pembrolizumab (Keytruda) is an immunotherapy drug that targets the immune cell protein PD-1. This protein usually stops immune cells from attacking. Pembrolizumab prevents PD-1 from blocking immune system cells so they can attack breast cancer cells. About 1 in 5 instances of TNBC have the PD-1 protein.
Targeted therapy
Targeted therapy works by targeting specific proteins in breast cancer cells to slow or stop the cancer from growing and spreading. This type of treatment can also help you live longer.
Targeted therapy can be used to help other types of treatment work better or in place of other interventions that aren't effective.
One type of targeted therapy is an antibody drug conjugate, such as sacituzumab govitecan (Trodelvy). This attaches itself to a specific protein in the cancer cell to directly deliver chemotherapy to it.
If you have a BRCA mutation, your doctor may recommend taking olaparib (Lynparza) or talazoparib (Talzenna).
Radiation
Radiation treatment is recommended if you elect for breast conservation with a lumpectomy. It can also be used if you've had a mastectomy with positive lymph nodes.
Radiation treatment uses high energy radiation that destroys remaining breast cancer cells. There are two types of radiation treatment: external beam radiation and internal radiation.
During external beam radiation, a machine outside your body will direct radiation to the target area.
For brachytherapy, or internal radiation, a healthcare professional will place radioactive material inside your body, next to the cancer site.
Clinical trials
Clinical trials are research studies using human volunteers. Trials are available for all stages of cancer.
If you're part of a clinical trial, you might have advanced access to new treatments. By participating in a trial, you will also contribute to improving medical knowledge and progress in cancer treatments.
You can discuss the option of a clinical trial with your doctor. You can also find more information through the following online resources:
Treatment considerations
Your unique circumstances determine the approach to TNBC treatment. Your care team will develop a specific treatment plan based on your situation.
In some cases, you'll have surgery first to remove the cancerous tumor, followed by other treatments to reduce the risk of cancer coming back, helping prolong your life.
In other cases, you'll undergo treatment first to help shrink the tumors before having them surgically removed. Follow-up treatment may then also be recommended after surgery.
People diagnosed with stage 4 TNBC rarely undergo surgery or radiation. However, they may be prescribed stronger types of chemotherapy, targeted therapy, or immunotherapy — or different combinations of these treatments — to help improve outcomes.
Personalized treatment approach
Newer treatment options, such as targeted therapy and immunotherapy, have advanced the personalized approach to TNBC treatment.
The BRCA mutation may present an opportunity for a precision treatment approach. It occurs in about 20% to 30% of TNBC cancer instances and responds to treatment using poly (ADP-ribose) polymerase (PARP) inhibitors.
Using pembrolizumab to target PD-1 is another personalized approach for TNBC cancer cells with this protein.
For more advanced TNBC where other treatments aren't effective, using sacituzumab govitecan can be another personalized option.
Research is also ongoing to determine whether the aggressive nature of TNBC in Black women is because of health issues such as obesity or factors like socioeconomic status, healthcare access, or cultural practices. This may lead to much-needed precision treatment approaches for Black women.
However, TNBC can still be challenging to treat. This is mainly due to its aggressive nature and lack of certain protein receptors. There are also few outlook (related to a person's overall outcome, regardless of therapy) and predictive (related specifically to treatment outcomes) biomarkers.
Outlook
The National Cancer Institute (NCI) maintains a database called the Surveillance, Epidemiology, and End Results Program (SEER).
The SEER database tracks 5-year relative survival rates by grouping cancers into categories based on how far they've spread.
A relative survival rate compares a person with cancer against the overall population. For example, if you have breast cancer with a 90% 5-year relative survival rate, you're 90% as likely to live for 5 years as someone without this disease.
According to the American Cancer Society, the SEER 5-year relative survival rates for TNBC are:
92% for localized (cancer is contained within the breast)
67% for regional (cancer is located in the breast and nearby lymph nodes and tissues)
15% for distant (cancer is located in distant areas like the liver, bones, or lungs)
78% for all stages combined
These percentages have increased slightly in recent years, as treatment methods continue to evolve.