Metastatic Bone Disease (MBD) and Breast Cancer

What is Metastatic Bone Disease?

The bones are one of the most common sites for breast cancer to spread, and when the cancer spreads to the bones, it’s called Metastatic Bone Disease (MBD), or bone metastases.3 Although cancer has spread to the bones, it is not considered bone cancer since the cancer didn’t originate in the bones. Breast cancer can spread to any bone, but the most common sites are the ribs, spine, pelvis, and long bones in the arms and legs.4

MBD is considered a common, but very serious complication of breast cancer that puts patients at risk for skeletal complications called skeletal-related events (SREs). These events can reduce quality of life and increase medical costs and risk of death.

What are the Risk Factors for MBD? Researchers have discovered risk factors that contribute to MBD, including:

  • Gender: MBD occurs in both men and women but is particularly common in women with breast cancer.
  • Age: MBD does not typically occur until after the age of 40.
  • Cancer History: A person living with cancer, or with a family history of cancer, is at higher risk for developing MBD. However, MBD can be diagnosed in people without personal or familial history of cancer.

Symptoms of MBD

People who have MBD often experience pain as their first symptom, but there are other associated symptoms, including:

  • Fractures (pathological bone fractures): Weakened bones can cause fractures resulting from a fall or injury, but also from everyday activities. Pathological bone fractures, however, are caused by disease. Typically occurring in the long bones of the arms and legs, they can cause severe pain.
  • Constipation, nausea, loss of appetite: When calcium from the bones is released into the bloodstream, it can cause constipation, nausea, loss of appetite, confused or altered mental state and severe thirst.9 High blood calcium levels, also called hypercalcemia, can increase urine production, leading to dehydration, weakness and fatigue.6
  • Spinal cord compression: Increased growth of cancer in the spine can press against the spinal cord and cause compression of the nerves, leading to numbness and weakness in the lower area of the body, pain or stiffness in the neck, back or lower back, paralysis, trouble with urinating and a lack of bowel movements.

Diagnosing MBD

Depending on the location and severity of the pain, MBD can be diagnosed by:

  • X-Ray or Radiography
  • Bone scans
  • Bone biopsies
  • CT (computer tomography) scans
  • MRI (magnetic resonance imaging)
  • PET (positron emission tomography)
  • Blood tests measuring elevated levels of alkaline phosphatase (an enzyme that originates in the bone) and calcium levels to confirm hypercalcemia

Treatment Options for MBD6

If you are diagnosed with MBD, the primary goal of treatment is preventing SRE’s as they can significantly impact quality of life. Treatment options that are clinically proven include:

  • Bone therapies, which involve using a bone-targeting agent, a class of drugs that prevent the loss of bone density by reducing the turnover of bone. There are various types of agents or medications (e.g. pills, intravenously) that can reduce fractures and slow the spread of cancer, which is dependent on the individual disease.12
  • Anti-cancer therapies, such as chemotherapy, immunotherapy and hormone therapy, are systemic treatments that affect the whole body. While they are not specifically aimed at MBD, they may be used as a part of a treatment plan.
  • Local treatments can be targeted to one specific area of the body. These types of local treatments can include:
  • Radiation, a nonsurgical option which kills the cancer cells, helps to relieve pain, slow tumor growth and prevent bone breakage.
  • Surgery, which is performed to remove the tumor and fix the broken or weakened bone in place using instruments such as wires, plates, rods or bone cement, which is used to strengthen or stabilize the bone.

MBD Infographic
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References:

  1. Coleman, Robert. Skeletal Complications of Malignancy. Suppl Cancer. American Cancer Society Journal. https://acsjournals.onlinelibrary.wiley.com/doi/pdf/10.1002/%28SICI%291097-0142%2819971015%2980%3A8%2B%3C1588%3A%3AAID-CNCR9%3E3.0.CO%3B2-G. Accessed October 19, 2020.
  2. National Institutes of Health. Osteoporosis and African American Women. https://www.bones.nih.gov/health-info/bone/osteoporosis/background/african-american-women. Accessed October 19, 2020.
  3. Susan G Komen. Bone Metastases and Metastatic Breast Cancer. https://ww5.komen.org/BreastCancer/BoneMetastasesAndMetastaticBC.html. Accessed October 19, 2020.
  4. BreastCancer.org. Bone Metastasis: Symptoms and Diagnosis. https://www.breastcancer.org/symptoms/types/recur_metast/metastic/bone. Accessed October 19, 2020.
  5. So, Alan et al. Management of skeletal-related events in patients with advanced prostate cancer and bone metastases: Incorporating new agents into clinical practice. Can Urol Assoc J. 2012 Dec; 6(6): 465–470. PMID: 23282666.
  6. American Academy of Orthapaedic Surgeons. OrthoInfo: Metastatic Bone Disease. https://orthoinfo.aaos.org/en/diseases–conditions/metastatic-bone-disease/ Accessed October 19, 2020.
  7. Wisanuyotin, T et al. Prognostic and risk factors in patients with metastatic bone disease of an upper extremity. Journal of Bone Oncology. 2018 Nov; (13): 71-75. https://doi.org/10.1016/j.jbo.2018.09.007.
  8. Janjan, Nora et al. Pathological Fracture. Science Direct. https://www.sciencedirect.com/topics/medicine-and-dentistry/pathologic-fracture. Accessed October 19, 2020.
  9. American Cancer Society. Bone Metastases. https://www.cancer.org/treatment/understanding-your-diagnosis/advanced-cancer/bone-metastases.html. Accessed October 6, 2020.
  10. John Hopkins Medicine. Conditions and Diseases: Spinal Cord Compression. https://www.hopkinsmedicine.org/health/conditions-and-diseases/spinal-cord-compression. Accessed October 6, 2020.
  11. Gralow, Julie et al. National Comprehensive Cancer Network. NCCN Task Force Report: Bone Health in Cancer Care. Journal of National Comprehensive Care Network. https://www.nccn.org/JNCCN/PDF/2009_Bone_Health_TF.pdf. Accessed October 6, 2020.
  12. Mayo Clinic. Osteoporosis treatment: Medications Can Help. https://www.mayoclinic.org/diseases-conditions/osteoporosis/in-depth/osteoporosis-treatment/art-20046869. Accessed October 6, 2020.