In honor of March being Triple-Negative Breast Cancer (TNBC) Awareness Month and our own Paint the Town Pink Ambassador Jessie Meyer being a TNBC survivor, let's look more into what TNBC is and how far we’ve come in treating it.
What is triple-negative breast cancer (TNBC)?
In the world of breast cancer, the term "triple negative" carries a weight that extends beyond its name. TNBC is an aggressive form of breast cancer that accounts for 10-20% of all breast cancers.
Breast cancer cells commonly have any of three receptors for estrogen, progesterone, or HER2. However, if the breast cancer cells don’t have any of these three receptors, this is what’s known as “triple-negative.”
TNBC is considered aggressive because it is more likely to have spread to other parts of the body by the time it’s diagnosed, more likely to resist treatment, and more likely to return after treatment compared with other kinds of breast cancer.
What are the signs of TNBC?
TNBC can show signs and symptoms seen with other types of breast cancer, including:
- Breast swelling (even if a lump isn’t felt)
- Lump felt in breast
- Breast or nipple pain
- Change in breast shape
- Nipple discharge (not breast milk)
- Nipple inversion
- Nipple or breast skin is red, dry, flaking, or thickened
- Swollen lymph nodes
While these symptoms alone may not necessarily mean a person has cancer, having a qualified health professional evaluate symptoms can ease anxieties and allow their causes to be identified and treated as early as possible. Regular health screenings like mammograms are also important for detecting breast cancer early — especially for those facing higher breast cancer risk.
Who is at risk for TNBC?
Age, race and ethnicity, and genetic mutations are several factors that can play a role in a person’s risk for developing TNBC.
Women who are African American, Hispanic, or of Indian descent experience higher rates of TNBC, as do women who are under age 50 or have inherited a BRCA1 gene mutation. Ashkenazi Jewish women also have higher risk of inheriting BRCA gene mutations, which can increase the risk for all breast cancers, including TNBC.
You can view a more extensive list of general breast cancer risk factors on the Centers for Disease Control and Prevention (CDC) website.
Why is TNBC so hard to treat?
What makes TNBC hard to treat is that it lacks the three receptors — estrogen, progesterone, and HER2/neu — that are most commonly targeted by medications to fight breast cancer.
Without these receptors, finding ways to slow or stop the growth of TNBC has been challenging.
Traditional hormone therapies prevent hormones like estrogen and progesterone from attaching to cancer cells and therefore starve the cancer of what it needs to grow. Unfortunately, these methods, which work well to treat other types of breast cancer, are ineffective for TNBC.
Over the years, these characteristics have posed a significant challenge for oncologists and patients alike.
Early on, chemotherapy emerged as the primary weapon against TNBC. Unlike hormone therapies that starve the cancer, chemotherapy aims to attack rapidly dividing cancer cells and eliminate them.
However, while chemotherapy is effective in some cases, in others, it may only provide temporary relief and brings its own set of side effects like hair loss, nausea/vomiting, weight loss, mouth sores, and diarrhea.
More research leads to more TNBC treatments
The need for more targeted and personalized therapies became evident as researchers delved deeper into the intricacies of TNBC. Recent years have seen a shift in TNBC treatment with the advent of immunotherapy and targeted therapies.
Immune checkpoint inhibitors, such as pembrolizumab, have shown promising results in certain cases by using the body's own immune system to target cancer cells.
Normally, your body’s immune cells called T-cells would attack and eliminate cancer cells, but some TNBC cells have found ways around this by “hiding” from the T-cells. Essentially, the cancer cells put out a receptor that tells the T-cells to leave them alone. Pembrolizumab allows T-cells to find the hiding cancer cells and get rid of them.
Additionally, researchers have identified specific molecular targets within TNBC cells, leading to the development of targeted therapies that aim to disrupt the pathways that contribute to cancer growth.
How clinical trials have expanded TNBC treatment options
Clinical trials have played a crucial role in advancing TNBC treatment options. The exploration of new drugs and treatment combinations has allowed oncologists to tailor therapies based on the specific characteristics of an individual's cancer. Personalized medicine, guided by genetic and molecular profiling, holds great promise in enhancing treatment efficacy and minimizing side effects.
As treatments evolve, so do the survival rates for TNBC patients. Early-stage TNBC may respond well to standard treatments like surgery, chemotherapy, and radiation, and advancements in targeted therapies and immunotherapy continue to improve outcomes for some individuals. However, challenges persist, especially in metastatic TNBC where the disease has spread beyond the breast.
Lingering challenges need more research
Despite significant progress, challenges remain. TNBC is a heterogeneous disease, meaning that it has several different causes, and has been even further broken down into six subtypes — and not all patients respond uniformly to existing treatments.
Researchers are actively exploring new avenues, including combination therapies, biomarker identification, and further unraveling the genetic structure of TNBC to uncover more effective and less toxic treatments.
A lot of progress is being made for both early-stage and metastatic spread TNBC treatments. The earlier it can be detected, the better, but social determinants of health, like health insurance coverage, access to quality health care options, and access to nutritious food options, can further increase many women’s TNBC risk — and make it more difficult to detect and prevent TNBC early on. This is why healthcare accessibility is also essential for improving TNBC health outcomes.
More solutions are waiting
The history of triple-negative breast cancer treatment is one marked by resilience, innovation, and progress. The journey from limited options to the emergence of targeted therapies and immunotherapy shows the relentless pursuit of improving outcomes for TNBC patients.
As research continues to unfold, the hope is that the strides made in recent years will pave the way for even more effective and personalized treatments, ultimately elevating survival rates and transforming the landscape of TNBC care.