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Dr. Bethany Niell reviews a patient's breast scans prior to treatment

Also known as stage 4 breast cancer, metastatic breast cancer occurs when cancerous cells break away from the original breast tumor and enter the bloodstream or lymphatic system. The rogue cancer cells then circulate throughout the body to reach distant tissues and organs, such as the bones, liver, lungs or brain. Once established in a new location, the cancer cells may grow and form secondary tumors.

The signs of stage 4 breast cancer can vary based on the site of metastasis. Possible symptoms include bone pain, difficulty breathing, neurological symptoms and liver dysfunction. While this advanced stage of breast cancer is considered incurable, it is often treatable.

Metastatic breast cancer treatment focuses on slowing the progression of the tumor, managing the symptoms and improving the patient’s quality of life. In addition to localized treatments for specific metastasis sites, such as radiation therapy and surgery, other options include systemic therapies for widespread cancer cells, such as chemotherapy, hormone therapy, targeted therapy and immunotherapy.

What does immunotherapy for metastatic breast cancer involve?

Checkpoint blockade immunotherapy can be used to treat metastatic breast cancer by enhancing the body’s natural immune response to cancer cells. The treatment involves the use of a class of drugs known as checkpoint inhibitors, which are designed to block certain proteins found on the surface of immune cells, such as PD-1 or CTLA-4. These proteins serve as natural checkpoints, or “brakes,” on the immune system, helping to prevent an overly robust immune response. However, by exploiting these proteins, breast cancer cells can avoid detection by the immune system. To counteract this unique characteristic of cancer cells, checkpoint inhibitors can reactivate the immune cells so they will recognize and destroy cancer cells more effectively.

Checkpoint blockade immunotherapy medications are administered intravenously in cycles. The frequency and duration of the cycles can vary depending on the patient’s tolerance of—and response to—the therapy. Regular monitoring is necessary to assess the effectiveness of treatment and manage any side effects.

What are the risks and possible complications of immunotherapy for metastatic breast cancer?

Possible side effects of immunotherapy for metastatic breast cancer include:

  • Weakness and fatigue
  • Muscle pain
  • Loss of appetite
  • Skin itching and rash
  • Nausea
  • Diarrhea or constipation

Complications of checkpoint blockade immunotherapy can include inflammation of the intestines (colitis), liver (hepatitis) and lungs (pneumonitis). If the patient experiences shortness of breath or other breathing problems while receiving immunotherapy for metastatic breast cancer, they should seek immediate medical attention.

What to expect during recovery from immunotherapy for metastatic breast cancer

During recovery from immunotherapy for metastatic breast cancer, the patient can expect regular follow-up appointments to monitor their response to treatment and manage any side effects, such as persistent fatigue. Immune-related side effects require careful monitoring and may necessitate additional treatments, such as corticosteroids, to reduce inflammation. A gradual return to normal activities, a balanced diet and a healthy lifestyle can aid in overall recovery and improve the patient’s quality of life.

If you have received a breast cancer diagnosis or test results indicative of breast cancer, the experts at Moffitt can help. You can submit a new patient appointment request - no referral needed.
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How effective is immunotherapy for metastatic breast cancer?

Immunotherapy for metastatic breast cancer has shown promise, particularly for specific subtypes, such as triple-negative breast cancer, that express high levels of PD-L1, a protein that interacts with PD-1. Checkpoint inhibitors such as pembrolizumab (Keytruda) and atezolizumab (Tecentriq) have demonstrated effectiveness in improving progression-free survival and treatment response rates in some patients. However, the overall effectiveness of immunotherapy varies widely, and not all individuals respond to this treatment approach.

Combining immunotherapy with other treatments, such as chemotherapy, can enhance its effectiveness. Through ongoing research and clinical trials, scientists continue to explore the potential of immunotherapy in treating metastatic breast cancer, aiming to develop more effective treatment strategies and identify which patients are most likely to benefit.

Benefit from world-class care at Moffitt Cancer Center

If you would like to learn more about immunotherapy for metastatic breast cancer, you can request an appointment with a specialist in our Don & Erika Wallace Comprehensive Breast Program by calling 1-888-663-3488 or submitting a new patient registration form online. We do not require referrals.