Triple-negative breast cancer presents unique treatment challenges, but in many cases it can be managed effectively. Dr. Bonnie Sun, a breast cancer surgeon, provides insight into the nature of triple-negative breast cancer, the outlook for patients, and reasons to remain hopeful.

What does “triple-negative” mean in breast cancer?

Under normal circumstances, breast cells have receptors that respond to hormones like estrogen and progesterone, helping them grow and shrink depending on hormone levels. Cancerous breast cells may or may not have these receptors. About two-thirds of breast cancers are classified as “positive” because they possess these hormone receptors, similar to normal cells. These tend to be less aggressive, and treatments focus more on hormone therapies, surgery, and sometimes radiation, rather than chemotherapy.

Another factor is HER2/neu, a protein that promotes cell growth. In some breast cancers, excessive HER2 production leads to “HER2-positive” cancers. For these cases, specific medications are available that directly target this protein.

Triple-negative breast cancers, however, lack estrogen, progesterone, and HER2 receptors. As Dr. Sun points out, “Because these markers aren’t present in triple-negative cases, chemotherapy becomes necessary.” She explains that, even though chemotherapy can have serious side effects, triple-negative cancers tend to respond well to it, making it a vital treatment option. Given the aggressive nature of this type of cancer, the treatment approach must also be aggressive. But as Sun highlights, there are various strategies available to tackle the disease.

Who is at risk of triple-negative breast cancer?

While anyone can develop triple-negative breast cancer, certain groups are at a higher risk:

• Individuals under 50 years old (most hormone-receptor positive cancers typically occur in those 60 or older).
• Black or Latinx individuals.
• People carrying BRCA mutations, which increase the likelihood of breast and other cancers. Most BRCA1-related breast cancers tend to be triple-negative.

How is triple-negative breast cancer treated?

Chemotherapy remains the cornerstone of treatment. “Chemo is almost always part of the solution,” states Dr. Sun. “Chemotherapy can reduce the size or aggressiveness of the tumor, a process known as downstaging.” While the intensity of chemotherapy for triple-negative breast cancer can be demanding, it can be tailored carefully, especially for older or more vulnerable individuals. Sun adds, “When we achieve a complete response, it signals that the chosen treatment was effective, and the prognosis looks favorable.”

Surgery follows chemo to remove any remaining tumor. Contrary to popular belief, not all surgeries for triple-negative breast cancer require a mastectomy. Dr. Sun explains, “With successful chemotherapy, less invasive surgical options may become available, such as breast-conserving surgeries like lumpectomies. This can significantly reduce recovery time and offer a better overall experience for the patient.” Furthermore, samples taken during surgery help specialists gain more insight into the cancer’s characteristics, allowing them to refine post-surgery chemotherapy if needed.

Radiation therapy is another option, using targeted beams to eliminate cancer cells while trying to minimize harm to surrounding healthy tissues.

New medical advancements are also offering fresh options for treating triple-negative tumors:

• PARP inhibitors (poly ADP-ribose polymerase inhibitors), which can destroy cancer cells, are now FDA-approved for this form of breast cancer.
• Immunotherapy helps the immune system recognize and combat cancer cells, though it is only used for certain cases of triple-negative breast cancer, depending on specific circumstances.

“There’s exciting ongoing research into immunotherapy and PARP inhibitors,” says Sun. “We’re making advances, even here at Johns Hopkins.”

What is the outlook for triple-negative breast cancer?

The prognosis hinges on various factors. “Chemotherapy plays a critical role in improving outcomes,” says Dr. Sun. Other key factors include the tumor size and whether any lymph nodes are involved. However, if the cancer has spread to other areas (metastasized), predicting outcomes becomes more complex.

Despite the potential seriousness of the diagnosis, Dr. Sun emphasizes that hope remains. "It’s important to stay positive, even during challenging treatments like chemotherapy. Maintaining optimism really can make a difference, as many patients do see its benefits in the long run.”