Secondary cancer in the lymph nodes is when cancer cells have spread to the lymph nodes from a cancer that began elsewhere in the body.
The lymphatic system
The lymphatic system is one of the body’s natural defenses against infection. It’s made up of organs such as the bone marrow, thymus and spleen, as well as lymph nodes (sometimes called lymph glands). The lymph nodes are all over the body and are connected by a network of lymphatic vessels.
Cancer in the lymph nodes
Cancer can develop in the lymph nodes in two ways. It can start there as a primary cancer, or it can spread into the lymph nodes from a primary cancer elsewhere in the body. Cancer that starts in the lymph nodes is called lymphoma. If cancer spreads into the lymph nodes from another part of the body, this is known as secondary or metastatic cancer.
How cancers can spread
Cancerous tumors are made up of millions of cells. Some of these cells may break away from the primary cancer and travel to other parts of the body. They can travel:
- in the lymphatic system to nearby lymph nodes
- in the bloodstream to another part of the body, where they can grow into secondary tumors.
When cancer spreads to lymph nodes, the cancer cells in the nodes will look like cells from the primary tumor when they’re examined under the microscope. For example, when a lung cancer has spread to the lymph nodes, the cells in the lymph nodes look like lung cancer cells. This affects the way they are treated.
Very often when a primary cancer is operated on, the surgeon will also remove some of the nearby lymph nodes. It’s important to know whether a primary cancer has spread to any nearby lymph nodes, as it helps the doctors assess the risk of the cancer coming back. It also helps them decide whether further treatment is necessary.
Signs and symptoms
The most common sign of cancer cells in the lymph nodes is that one or more of the lymph nodes becomes enlarged or feels hard. However, if there are only a small number of cancer cells in the lymph nodes, they may feel normal. It’s only possible to tell whether a cancer is present by removing part or all of the lymph node and examining the cells in a laboratory. It’s important to remember that lymph nodes can also be enlarged for other reasons, such as infections.
If the enlarged lymph nodes are deep inside the chest or abdomen, they may cause pressure on surrounding organs or structures. This can lead to symptoms like breathlessness or backache.
Sometimes a lymph node, or group of nodes, may appear larger than they should on a scan, such as an ultrasound scan, CT scan or MRI scan. This may be a sign that there is a secondary cancer in the lymph nodes.
How secondary cancer in the lymph nodes is diagnosed
Sometimes a CT scan or MRI scan is all that is needed to make a diagnosis of secondary cancer in the lymph nodes.
CT (computerized tomography) scan
A CT scan takes a series of x-rays that build up a three-dimensional picture of the inside of the body. The scan is painless and takes 10-15 minutes. CT scans use a small amount of radiation, which is very unlikely to harm you or anyone you come into contact with. You’ll be asked to not eat or drink for at least four hours before the scan.
You may be given a drink or injection of a dye, which allows particular areas to be seen more clearly. This may make you feel hot all over for a few minutes. It’s important to let your doctor know if you are allergic to iodine or have asthma, because you could have a more serious reaction to the injection.
MRI (magnetic resonance imaging) scan
This is similar to a CT scan, but uses magnetism instead of x-rays to build up a detailed picture of areas of your body. Before the scan you may be asked to complete and sign a checklist. This is to make sure that it’s safe for you to have an MRI scan.
Before having the scan, you’ll be asked to remove any metal belongings, including jewelry. Some people are given an injection of dye into a vein in the arm. This is called a contrast medium and can help the images from the scan to show up more clearly. During the test you will be asked to lie very still on a couch inside a long cylinder (tube) for about 30 minutes. It is painless but can be slightly uncomfortable, and some people feel a bit claustrophobic during the scan. It’s also noisy, but you’ll be given earplugs or headphones. You’ll be able to hear, and speak to, the person operating the scanner.
PET (positron emission tomography) scan
This uses low-dose radioactive sugar to measure the activity of cells in different parts of the body. A very small amount of a mildly radioactive substance is injected into a vein, usually in your arm. A scan is taken a couple of hours later. Areas of cancer are usually more active than surrounding tissue and show up on the scan.
For some people it may be necessary to carry out further tests, which may include the following:
This involves removing a lymph node, or nodes, under general anesthetic.
A sample of cells may be taken from an enlarged lymph node, using a fine needle attached to a syringe. The needle biopsy is usually done in a clinic and you won’t need a general anesthetic.
The cells will be sent to a laboratory to be examined under the microscope by a pathologist (a doctor who diagnoses illness by looking at cells).
If your doctors feel that the affected lymph nodes are quite clearly linked to the primary cancer, it may not be necessary to remove a node or take a biopsy.
Sentinel lymph node biopsy
This is widely used as part of the treatment of breast cancer and malignant melanoma. It is a way of checking just one or two lymph nodes close to the cancer. Usually it’s done at the same time as an operation to remove the cancer. It involves injecting a tiny amount of radioactive liquid into the area of the primary cancer. The lymph nodes are then scanned to see which have taken up the radioactive liquid first. A blue dye is also injected into the area of the cancer. The dye stains the lymph nodes blue. The nodes that become blue or radioactive first are known as the sentinel nodes. The surgeon removes only the sentinel nodes so that they can be tested for cancer cells.
If the sentinel nodes do not contain cancer cells, no further surgery will be needed. If the nodes do contain cancer cells, either another operation can be done to remove other nearby nodes, or they can be treated with radiotherapy or chemotherapy.
Treatment for cancer in the lymph nodes
The treatment for cancer that has spread to the lymph nodes depends on the individual situation, including the person’s general health and type of primary cancer. It may include chemotherapy, hormonal therapy, radiotherapy, surgery, or a combination of these treatments.
Sometimes lymph nodes close to the primary cancer are removed during surgery to remove the tumor. If cancer cells are found in the lymph nodes, treatment such as chemotherapy may be suggested. This is because if a primary cancer has spread to the nearby lymph nodes, it increases the risk that the cancer may have spread to other parts of the body (even if those nodes have been removed). Chemotherapy and/or hormonal therapy can reduce the chance of the cancer coming back for some people.
Learning that your cancer has spread or come back can be a shock. You may have many different emotions, including anger, resentment, guilt, anxiety and fear. These are all normal reactions, and part of the process many people go through in trying to come to terms with their illness.
Everyone has their own way of coping with difficult situations. Some people find it helpful to talk to family or friends, while others prefer to seek help from people who are not so closely involved with their situation, and some people prefer to keep their feelings to themselves. There is no right or wrong way to cope, but help is available if you need it.
Our cancer support specialists can give you information about counseling services in your area.