Metastatic Breast Cancer Disease - MBC

What is metastatic breast cancer?

Metastatic breast cancer is a condition wherein cancer cells from the primary disease in the breast travel to different organs. Once this happens, the cancer is said to have “metastasized” to other sites in the body. Usually, the presence of metastasis (plural: metastases) indicates a Stage IV breast cancer.

How does metastatic breast cancer develop?

Cancer cells are different from normal cells in the sense that they grow very rapidly and are outside the control of the body. Some cancer cells may break away from the primary tumor and travel to different organs through the blood vessels or lymphatic system. The most common organs affected are the lungs, brain, bones, and liver.

When breast cancer metastasizes to another organ, for instance the lungs, it is called metastatic breast cancer and not lung cancer.

What are the symptoms of metastatic breast cancer?

Symptoms may vary for different patients and will depend on where the metastatic lesions develop. For example, metastatic breast cancer in the lungs will produce respiratory symptoms such as dry cough, difficulty of breathing, shortness of breath, or chest pain. Since the most common organs affected aside from the lungs are the bones, brain, and liver, the following symptoms may also appear:

• Constant joint, bone, or low back pain
• Abdominal pain or bloating
• Lack of appetite (anorexia), nausea, or vomiting
• Jaundice
• Headaches
• Blurring of vision
• Seizures
• Loss of balance

How is metastatic breast cancer diagnosed?

A thorough physical examination is performed to determine the possible causes of the presenting symptoms. This will also guide your doctor in deciding what diagnostic tests are needed to investigate the condition further. These tests may include, but are not limited to:

• Blood tests, including tumor markers
• X-rays of the chest and abdomen
• Abdominal ultrasound
• Whole-body bone scan
• Computerized tomography (CT) scan of the chest and abdomen (cranial CT scan if brain metastasis is suspected)

Can metastatic breast cancer be treated?

Metastatic breast cancer represents an advanced stage of the disease and is difficult to treat. This stage of cancer is generally incurable but treatments may be given to control the disease and improve the patient’s quality of life. Since cure is not a likely option anymore, the goals of therapy for metastatic breast cancer are:

• Decrease the number or the size of the metastatic cancer lesions
• Relieve the symptoms
• Slow the disease progression
• Prolong the patient’s survival

As with primary breast cancer, early detection of metastatic breast cancer is critical in order to initiate early therapy and improve the chances for longer survival.

How is metastatic breast cancer treated?

Metastatic breast cancer is generally treated with systemic therapies – drugs that are given orally or through intravenous infusion. Given that the cancer cells have spread to other parts of the body, local treatments such as surgery or radiation treatment have limited use. For example, if a metastatic lesion in the spine compresses a spinal nerve and causes significant pain, surgery may be indicated to relieve the pressure and the pain. However, the patient will still need to take systemic treatments.

Treatment will vary according to the patient, and a multitude of factors must be taken into account. The number of metastatic lesions, the hormone receptor status of the patient, and the HER2/neu status must all be taken into consideration. The following drugs, given alone or in combination, are used for metastatic breast cancer treatment:

• Hormone therapy for estrogen receptor positive patients: tamoxifen, aromatase inhibitors such as letrozole or anastrozole
• Targeted therapies for HER2/neu positive patients such as trastuzumab, pertuzumab, lapatinib
• Other targeted treatments such as CDK4/6 inhibitors, an example of which is everolimus
• Immunotherapy to improve the patient’s immune response against the cancer, an example of which is atezolizumab
• Chemotherapy, consisting of several classes of drugs
  • Anthracyclines such as doxorubicin and epirubicin
  • Antimetabolites such as capecitabine and gemcitabine
  • Antimicrotubule agents such as vinorelbine, vincristine, ixabepilone, and eribulin
  • Platinum-based agents such as cisplatin, oxaliplatin, and carboplatin
  • Taxanes such as paclitaxel and docetaxel

What is the prognosis of a patient with metastatic breast cancer?

Data from the American Cancer Society spanning from 2009-2015 show a 5-year survival rate of 27% for women with distant metastasis. However, treatments for metastatic breast cancer are continuously improving and this figure may be different for different types of patients. Other factors such as receptor positivity, HER2/neu status, the size and number of lesions, and the tumor grade may also affect the prognosis.

What is the prognosis of a patient with metastatic breast cancer?

As with most diseases, a reliable support system is essential for women with this disease. Close relationships with family and friends can provide the patient with much-needed emotional support. Counseling provided by a healthcare professional can help the patient understand and deal with her condition. Support groups, whether physical or online, can help the patient feel less alone and encourage a more optimistic outlook.

For more information on metastatic breast cancer, consult your physician.