Like all forms of cancer, breast cancer can potentially spread (metastasize) beyond the breast tissue where it initially developed to other areas of the body. In order for breast cancer metastasis to occur, cancerous cells must break away from the original tumor and attach themselves to the outer wall of a lymph vessel or a blood vessel. Then, the cancer must penetrate the vessel wall so that it can flow with the blood or lymphatic fluid to reach a lymph node or organ.
The sentinel lymph node
When cancer spreads, the lymph node located closest to the original tumor (the sentinel node) is usually affected first. In breast cancer cases, the sentinel lymph node is often located in the underarm area. An important part of the body’s immune system, lymph nodes are small structures that fight infection by attacking and destroying harmful substances carried in the lymphatic fluid. As a tumor drains into the sentinel lymph node, the immune system works hard to filter and destroy the cancerous cells, but the cancer may become trapped within the node.
Distant organs and tissues
Once breast cancer cells enter the bloodstream or lymphatic system, the cancer can spread to distant organs and tissues. The parts of the body most often affected by breast cancer metastasis are the:
- Lymph nodes
After the lymph nodes, the bones are the second most common site of breast cancer metastasis. Although breast cancer can spread to any bone, it most often affects the ribs, spine, pelvis and long bones in the arms and legs.
Talk with a specialist
If you would like to learn more about breast cancer metastasis, you are welcome to consult with a breast cancer specialist in the Don & Erika Wallace Comprehensive Breast Program at Moffitt Cancer Center. Request an appointment by calling 1-888-663-3488 or completing a new patient registration form online. We do not require referrals.