Triple-Negative Breast Cancer (TNBC) is an aggressive form of breast cancer, accounting for approximately 15% of all newly diagnosed breast cancer cases.
The term "triple-negative" refers to the absence of three key molecules, known as receptors, on the surface of the cancer cells. These three receptors are:
The HER2 protein
Receptors for the hormone Oestrogen
Receptors for the hormone Progesterone
Most breast cancers have at least one of these three receptors, which can be targeted by specific drugs. However, because TNBC lacks all three, drugs targeting these receptors are ineffective. This necessitates the use of different, non-receptor-targeting treatment approaches. TNBC is also known to grow quickly and has a higher risk of recurrence, underscoring its aggressive nature.
The prognosis for TNBC is unique for every individual and depends on several factors, including the extent of cancer spread at the time of diagnosis and how the tumour responds to treatment. Overall, the five-year survival rate for patients with TNBC is approximately 77%. This figure is a general estimate, and the survival rate for current patients may be higher due to recent advancements in treatment.
TNBC shares many risk factors with other types of breast cancer. However, one key difference is age, as TNBC is more common in women under the age of 50. Black women are also at an increased risk for developing the disease.
Symptoms of breast cancer can vary widely from person to person. It is important to be familiar with the normal feel and look of your breasts and to report any changes to your doctor immediately. Many breast cancers are detected early through routine screening mammograms before any symptoms become apparent.
These symptoms do not definitively mean you have breast cancer, but it is vital to discuss any changes with a healthcare professional as they may also signal other health issues.
If you notice changes to your breasts, experience symptoms, or have an abnormal mammogram result, your doctor will carry out a thorough investigation to confirm a diagnosis. The process typically involves a sequence of exams:
The doctor manually checks the breast and armpit for lumps and abnormalities.
If cancer is suspected, imaging tests are ordered for a detailed evaluation. These most often include a mammogram (X-ray pictures) and an ultrasound (uses high-energy sound waves to create a 'sonogram'). Occasionally, doctors may use Magnetic Resonance Imaging (MRI) or other specialised examinations.
If imaging reveals a suspicious mass or skin thickening, a tissue sample is required for a definitive diagnosis. This is called a biopsy. For breast cancer, an image-guided core needle biopsy is typically performed, often during the initial imaging exam to precisely target the suspected tissue. Additional imaging and biopsies may be performed after cancer confirmation to determine the full extent of the disease, including whether it has spread to nearby lymph nodes.
Once breast cancer is confirmed, the cells are analysed to identify the molecular receptor subtype. This is crucial for developing a personalised treatment plan. TNBC is diagnosed if the cancer cells show no receptors for Oestrogen and Progesterone and do not have high levels of the HER2 protein.
The treatment of breast cancer is highly personalised. It is primarily treated with surgery, often combined with chemotherapy, radiation therapy, or both. Other treatment options may include targeted therapy and angiogenesis inhibitors.
When TNBC is caught before it has spread to distant parts of the body, it is usually treated with chemotherapy, sometimes combined with immune checkpoint inhibitors, followed by surgery. Patients may also receive radiation therapy after surgery. Additional chemotherapy or immunotherapy may be administered after surgery to kill any remaining cancer cells and reduce the risk of recurrence.
If the disease has spread to distant parts of the body (metastatic disease), it can be treated with a variety of cancer drugs, including immune checkpoint inhibitors, chemotherapy, and targeted therapy. In some cases, radiation therapy may also be used.
Many patients undergo some form of surgery as part of their treatment plan. Some may receive chemotherapy or targeted therapy before surgery to shrink the tumour and simplify the procedure. There are two main categories of surgery:
This involves removing the tumour and a small amount of surrounding normal tissue. It is generally appropriate for early-stage breast cancer cases and is usually followed by radiation therapy.
This involves removing the entire breast, with several different types available, including procedures that spare the breast's skin and/or nipple/areola. A mastectomy can often be combined with immediate breast reconstruction. In some high-risk cases, a double mastectomy (removal of both breasts) may be performed to prevent the development of new breast cancer.
Nearby lymph nodes are often removed and studied to determine if cancer cells are present. This information is critical for assessing the risk of disease spread and planning subsequent chemotherapy and radiation therapy. Our breast cancer surgeons and reconstructive surgeons at SSCHRC work together to plan procedures that minimise scarring and achieve the best possible cosmetic outcome and symmetry.
Chemotherapy uses powerful drugs to directly kill cancer cells, control their growth, or relieve pain. It may be given orally or intravenously. It is often administered before surgery to shrink the tumour and simplify the surgical procedure.
Radiation therapy uses powerful energy beams designed to kill breast cancer cells. It can be used before surgery to shrink large tumours or after surgery to eliminate any remaining cancer cells. The duration of treatment varies:
SSCHRC radiation oncologists use various advanced techniques, including 3D conformal radiation therapy, Intensity-Modulated Radiation Therapy (IMRT), Volumetric Arc Therapy (VMAT), and Stereotactic Body Radiation Therapy, to ensure a precise dose of treatment.
Targeted therapies interfere with the specific molecules or genes that cancer cells rely on to survive and multiply. These treatments have become a major weapon against breast cancer subtypes such as hormone receptor-positive and HER2-positive cancers.
Note on TNBC: While targeted therapy is a primary treatment for many breast cancer subtypes, there are currently no targeted therapies specifically for triple-negative breast cancer. Researchers are actively studying the disease to identify potential drug targets.
Angiogenesis is the process by which cancer tumours create new blood vessels to increase their blood supply and grow rapidly, often exploiting a molecule called Vascular Endothelial Growth Factor (VEGF). Angiogenesis inhibitors, or anti-angiogenic therapy, are drugs developed to disrupt this growth process by binding to VEGF molecules or receptor proteins, thereby prohibiting the activation of new blood vessel formation.