When breast cancerspreads to the spine, it's known as bone metastasis. And unfortunately yes, breast cancer that has spread to the bones may spread to other areas such as the brain as well. This happens when cancer cells break away from the primary tumor and travel through the circulatory system. The most common areas for breast cancer to spread are the bones, lung, liver, and brain. However, just because breast cancer has spread to the spine doesn't mean that it will spread to other areas. Doctors can treat the new tumors with radiation and new medications called bisphosphonates can block the progression of tumor cells in the bone and prevent the cancer from spreading to other organs.