The American Cancer Society (ACS) states that bone metastasis occurs when part of the breast cancer detaches and travels through the bloodstream. When the cancerous cells from the breast reach the bones, a secondary cancer forms, resulting in symptoms similar to a primary cancer in the bones. The ACS adds that the most common location for a bone metastasis is the spine, although bone metastases may also occur in the skull, pelvis, femur, ribs and humerus.
Bone Pain
The Mayo Clinic states the one of the most noticeable symptoms of a bone metastasis is bone pain; the pain is deep compared with pain located in the muscle. The ACS adds that bone pain is the most common source of pain for cancer patients. The pain can limit the patient's mobility and can be difficult to live with; severe bone pain may require anti-inflammatory medication to control.
Swelling and Tenderness
Another sign that the breast cancer has spread to the bone is swelling and tenderness, according to the Mayo Clinic. The symptoms are localized to where the metastasis is; for example, if the bone metastasis is in the pelvis, the swelling and tenderness would only be located there. The swelling and tenderness can also affect the patient's ability to move.
Weakened Bones
The Mayo Clinic states that secondary bone cancer can also weaken the patient's bones. The decreased strength in the bones may result in fractures, even if the patient is not participating in strenuous physical activity. Another problem with weakened bones, according to the ACS, is the release of calcium from the damaged cells. The excess calcium in the blood can lead to hypercalcemia, or high blood calcium levels; the Mayo Clinic states that hypercalcemia can cause osteoporosis, arrhythmia, kidney stones, kidney failure and nervous system dysfunction.
