Bone metastases occur when breast cancer cells travel from the original tumor in the breast and establish new tumors within the bones. While located in the bones, it is still considered breast cancer and is treated with breast cancer therapies, not bone cancer drugs.
Understanding Bone Metastases
Breast cancer cells can spread to bones through the bloodstream or the lymphatic system. Once these cells reach the bone marrow, they interact with the bone’s microenvironment, which includes various cells and growth factors that support their survival and growth. This interaction can disrupt the natural balance between bone formation and bone breakdown.
The most commonly affected bones include the spine, ribs, pelvis, and the long bones of the arms and legs. Bone metastases can be categorized as osteolytic, osteoblastic, or a mixture of both. Osteolytic lesions involve cancer cells causing the breakdown of old bone without new bone being formed, leading to weaker, less dense areas. In contrast, osteoblastic lesions result from the formation of new, often disorganized bone without the corresponding breakdown of old bone, which can also compromise bone strength.
Identifying Bone Metastases
The presence of bone metastases can manifest through various signs and symptoms, with pain being the most common. This pain is often described as a persistent ache that may worsen with activity or at night, differing from typical muscular strains or arthritis. Other indications include pathological fractures, which are breaks in bones that occur with minimal trauma due to weakened bone structure.
High calcium levels in the blood, known as hypercalcemia, can also develop as bone breakdown releases calcium into the bloodstream. Symptoms of hypercalcemia can include nausea, vomiting, confusion, excessive thirst, and frequent urination.
To diagnose bone metastases, healthcare providers utilize several imaging tests. Bone scans, X-rays, CT scans, MRI, and PET scans are frequently employed to visualize the bones and detect abnormal growths or changes in bone density. Blood tests are also performed to check for elevated calcium levels, which can indicate bone breakdown. Additionally, certain tumor markers in the blood may be monitored, as their levels can correlate with cancer activity.
Treatment Options
Managing bone metastases involves a combination of systemic and local therapies aimed at controlling cancer growth, strengthening bones, and alleviating symptoms. Systemic therapies, which treat cancer cells throughout the body, include chemotherapy, hormone therapy, targeted therapy, and immunotherapy. Chemotherapy uses strong drugs to kill rapidly dividing cancer cells, while hormone therapy blocks the effects of hormones that fuel breast cancer growth. Targeted therapies focus on specific molecules involved in cancer cell growth and survival, and immunotherapy helps the body’s immune system fight the cancer.
Local therapies are directed at specific areas of bone involvement. Radiation therapy is often used to relieve pain, reduce tumor size, and prevent fractures in affected bones. Surgery may be performed to stabilize bones at risk of fracture, repair existing fractures, or decompress the spinal cord if metastases are pressing on it. This can involve inserting metal rods or using bone cement to strengthen weakened areas.
In addition to these therapies, medications that strengthen bones are commonly prescribed. Bisphosphonates, such as zoledronic acid, and denosumab are two types of drugs that help reduce bone breakdown and can decrease the risk of skeletal-related events like fractures and spinal cord compression. Pain management is also a significant aspect of treatment, often involving a combination of pain relievers, nerve blocks, and other supportive measures to improve comfort and quality of life.
Managing Life with Bone Metastases
Living with bone metastases often involves a comprehensive approach focused on supportive care and maintaining overall well-being. A multidisciplinary care team, which may include oncologists, pain specialists, physical therapists, dietitians, and social workers, is often involved in coordinating care.
Physical therapy plays a significant role in maintaining mobility, strength, and independence. Therapists can help design exercise programs that are safe and effective, focusing on gentle movements and strategies to protect bones from injury. Nutritional support is also important, as adequate intake of calcium and vitamin D can help support bone health, although this should be guided by a healthcare professional. Addressing emotional well-being through counseling, support groups, or mindfulness practices can help individuals cope with the psychological impact of the diagnosis and treatment.