Triple negative breast cancer: What to know

Triple negative breast cancer is an invasive cancer that makes up about 15% of all breast cancers. Though its name can seem confusing, triple negative breast cancer (TNBC) refers to the lack of certain receptors on cancer cells:

1. Receptors for the hormone estrogen
2. Receptors for the hormone progesterone
3. The human epidermal growth factor receptor 2, or HER2, protein

Because TNBC does not possess these three receptors, this type of cancer does not respond to some traditional breast cancer treatment options, like hormone therapy, and is usually treated with chemotherapy. TNBC can spread quickly and is more likely to recur than other types of breast cancer. It is more common in women under 50 years of age, Black women and women who inherited a BRCA1 genetic mutation.

Diagnosing triple negative breast cancer

TNBC often shows up like many breast cancers: As a lump you can feel in the breast, a cancer that shows up on mammograms or through changes to the breast size, shape or nipple. This diagnosis is confirmed once the breast is biopsied by removing a small bit of breast tissue and examining it under a microscope. TNBC may be detected during an annual screening mammogram, but it can also develop suddenly between these annual visits.

“Triple negative breast cancer can show up as an ‘interval cancer,’” said Dr. Carla Fisher, surgical oncologist and Director of Breast Surgical Oncology at IU Health. “We perform screening mammograms every year to pick up on any changes, but TNBC can grow quickly. You may have a normal mammogram in January and feel a mass in June.”

Triple negative breast cancer treatment

Because it spreads rapidly, chemotherapy is often the first step in TNBC treatment because it targets fast-dividing cells in the body. Chemotherapy is usually followed by surgery to remove the tumor. But if the tumor is small, the patient may benefit from surgery first. There are national clinical trials working to identify which patients with TNBC may not need surgery after preoperative chemotherapy, but surgery is still the standard of care.

• Radiation therapy and a combination of medications for breast cancer are also common treatment options for TNBC.
• If the cancer stops responding to traditional chemotherapy, patients with a BRCA genetic mutation may be candidates for targeted drugs called PARP inhibitors.
• In recent years, immunotherapy, or drugs that help the immune system attack the cancer cells, have been effective in addressing TNBC.

Preventing recurrence of triple negative breast cancer

TNBC recurrence can be a concern because the disease is aggressive. One advantage of having chemotherapy before surgery is that it allows the physician to assess whether the tumor is resistant to treatment. Patients with TNBC that responds well to chemotherapy often have lower recurrence rates. They’re also less likely to have cancer that spreads to other parts of the body.

Advancement in immunotherapies have offered additional treatment options, in combination with chemotherapy, to address recurring TNBC. Participating in clinical trials can offer patients new treatment possibilities.

Ultimately, the prognosis of recurrent TNBC is often easier to understand in the first few years after initial treatment.

“In these more aggressive forms of triple negative breast cancer, we’re usually most concerned about recurrence in the first two to three years,” Dr. Fisher said. “Once we get past that point, the risk is not zero, but it’s much lower.”

Though TNBC can be difficult to treat, early diagnosis can help patients identify the best treatment options for their specific needs. Annual exams and regular breast self-exams can help ensure abnormalities are identified and addressed as soon as possible.