Cancer occurs when abnormal or damaged cells grow out of control and invade other parts of the body. Cancer can occur just about anywhere in the body, but certain kinds of cancer are more likely than others to spread to other areas, invading organs and other kinds of tissue in a process called metastasis. Sometimes, these cancerous cells spread to the lymph nodes, which are small glands that help protect your body against foreign invaders. Metastatic cancer is a serious condition, so it is important to understand what it means when cancer spreads to the lymph nodes.
Lymph nodes, sometimes referred to as lymph glands, are bean-shaped glands that help protect your body against disease and infection. The lymph nodes are a part of the lymphatic system, the system that transports immune cells to areas throughout the body. Lymph nodes store white blood cells, which are released when immune defense is needed to fight infection and other foreign invaders. The lymph nodes are connected to lymphatic vessels, which serve as transportation vessels for your white blood cells. Some common lymph nodes involved in metastatic cancer are located in the neck, under your arms and in the groin area. A swollen lymph node is also an early sign of a bacterial or viral infection. However, a swollen lymph node can also be a sign of different kinds of cancer.
Cancerous tumors are formed from millions of cells, which can break away and travel to other parts of the body. Sometimes, these cells travel to surrounding lymph nodes through the lymphatic system. This is what it means when a physician says that cancer has spread to other areas. Because the lymph system transports white blood cells throughout the whole body, cancerous cells can spread quickly once they reach the lymph nodes.
Once in the lymph system, cancerous cells may break through to the bloodstream, causing cancer cells to grow in other places. However, the cancerous cells in a lymph node are the same cells that can be found in the primary tumor. For example, lung cancer cells that have travelled to a nearby lymph node remain lung cancer cells even though they are found elsewhere in the body. Sometimes, this helps doctors determine where a widespread cancer actually began in the body.
The most common sign that cancerous cells have spread to a lymph node is an enlarged but painless lymph node. However, if only a few cancerous cells have migrated to a lymph node, then you may not have any signs at first. Some lymph nodes are located deep within the chest cavity and abdominal area, so you may notice shortness of breath due to enlarged lymph nodes in the chest and abdominal distension for swollen lymph nodes in the abdominal area.
If cancer has spread to the brain, you may notice difficulty concentrating, confusion and seizures. Cancer that has metastasized to the bones can cause bone pain and increased risk for fractures. Sometimes the enlarged lymph node can be seen on certain diagnostic scans, such as an ultrasound, computerized tomography (CT) scan or a magnetic resonance imaging (MRI) scan of the area in question. With some kinds of cancer, blood tests and bone scans can also help determine whether cancer cells have spread to certain areas of the body. A biopsy of the lymph node is often performed to verify that cancerous cells are present in a specific lymph node.
If you believe that cancerous cells may have spread to a nearby lymph node, talk to a cancer specialist about your concerns. Many other conditions can cause swollen lymph nodes, including various bacterial and viral infections. For example, an upper respiratory infection can cause swollen, enlarged lymph nodes in the neck area. In many cases, the lymph nodes are swollen and tender when the cause of swelling is an infection. In some cases, a swollen lymph node is the first sign that a person has cancer. For this reason, if you have a painless, enlarged lymph node, contact your physician for an examination. Your physician can help guide you on the possible causes of your symptoms, and he/she can also order tests to rule out cancerous conditions that affect the lymph nodes.
- National Cancer Institute: Metastatic Cancer http://www.cancer.gov/cancertopics/factsheet/Sites-Types/metastatic
- Macmillan Cancer Support: Secondary Cancer in the Lymph Nodes http://www.macmillan.org.uk/Cancerinformation/Cancertypes/Lymphnodessecondary/Secondarycancerlymphnodes.aspx