Cancer can start in and spread to almost any part of the body. When you receive a cancer diagnosis, you may hear discussions about lymph nodes, which are essential to the immune system. Lymph nodes can swell when fighting an infection and usually return to their normal size afterwards. However, if they remain swollen for an extended period, it could signal a more serious condition, such as cancer. If cancer is found in your lymph nodes, it raises the question: Is it lymphoma, a cancer that begins in the lymphatic system, or is it another type of cancer that has spread to the lymph nodes?

The Role Of the Lymphatic System and Lymph Nodes

The lymphatic system is a network of vessels, tissues, and organs, including the spleen, thymus, tonsils, and bone marrow. It plays an essential role in assisting the immune system in defending the body against infections. The lymphatic system's primary function is to transport lymph, a clear, watery fluid that contains infection-fighting white blood cells, throughout the body.

Lymph nodes are small, bean-shaped glands primarily composed of lymphocytes, a kind of white blood cell in the immune system. They are located throughout the body, with clusters found in areas such as the neck, armpit, chest, abdomen, and groin. Lymph nodes act as filters for foreign substances found in lymph fluid.

Typically, lymph nodes can't be felt until an infection occurs. You might notice swollen lumps or tenderness in areas like your neck or armpit when you are sick. These are your lymph nodes working to protect the immune system by filtering out waste products like viruses and bacteria detected by the lymphatic system. 

What Is Lymphoma?

Lymphoma is a group of blood cancers that begins in the lymphatic system and affects lymphocytes. This type of cancer occurs when healthy cells in the lymphatic system change and grow out of control. Because cancer cells can trick the immune system, the lymphatic system doesn't recognize them as threats and fails to fight them off. There are two main categories based on different types of lymphocytes:

• Non-Hodgkin lymphoma. This is the more common type of lymphoma and can originate from various types of lymphocytes, including B and T lymphocytes. It includes a range of lymphatic cancers that require different treatment approaches.
• Hodgkin lymphoma. This type typically starts in B lymphocytes and is characterized by cancer cells known as Reed-Sternberg cells. Hodgkin lymphoma is less common, but is generally easier to treat.

Related reading: Understanding a Diffuse Large B-cell Lymphoma (DLBCL) Diagnosis: What You Need to Know

Lymphoma can rapidly spread from the lymph nodes to other parts of the body through the lymphatic system. Abnormal lymphocytes start out growing in the lymph nodes, but as the disease progresses, these abnormal cells may affect other areas of the body. Cancers that originate in the lymphatic system but spread to another area in the body are still considered lymphoma, not a new type of cancer.

Common signs and symptoms of lymphoma may include:

• Fever
• Fatigue
• Unintentional weight loss
• Frequent infections
• Unusual bleeding or bruising
• Persistent painless swelling of lymph nodes in the belly, neck, armpits, or groin

Keep in mind that these symptoms do not necessarily indicate that you have lymphoma. However, it's important to discuss any symptoms that last more than a couple of weeks with your doctor so they can determine the cause and provide treatment if necessary.

What Does It Mean When Cancer Spreads to the Lymph Nodes?

Sometimes, cancer cells collect in the lymph nodes because they have broken away from a tumor elsewhere in the body and traveled through the bloodstream or lymphatic system. Once in the lymph nodes, these cells can migrate elsewhere in the body to form new tumors away from the original site. When cancer spreads to different parts of the body, it is called metastasis.

Cancer that spreads to lymph nodes typically first affects those nearest to the original tumor. The main role of these nearby (regional) nodes is to filter out or kill cancer cells, but if left untreated, cancers can also spread to distant lymph nodes located further away from the initial site. 

Any nodes with cancer, whether near the original site or elsewhere, mean that the disease is advancing. Treatment plans are based on whether cancer is present in the lymph nodes and, if so, how many nodes are affected.

Other cancers that often spread to lymph nodes include breast cancer, lung cancer, melanoma, and gastrointestinal cancers.

Key Differences Between Lymphoma and Cancer in the Lymph Nodes

There are some important differences between lymphoma and cancer found in the lymph nodes:

Primary Cancer vs Cancer Spread

Lymphoma is classified as a primary cancer because it originates in the lymphatic system. In contrast, cancer that spreads to the lymph nodes is considered the same type as the original type of cancer, such as breast cancer or prostate cancer. It will be treated with therapies known to work well for the original cancer type. 

Diagnosis Differences

Doctors use different methods to diagnose lymphoma versus cancers that have spread to the lymph nodes. When diagnosing lymphoma, they are looking for signs of cancer and may perform imaging scans, complete blood count (CBC) tests, lymph node biopsies, and bone marrow aspirations.

When looking for cancer that has spread to the lymph nodes, the oncologist is already aware of a specific diagnosis. During surgery to remove the cancer, the surgeon will also identify the first lymph node the tumor would drain to, called the sentinel lymph node. It is removed and tested for cancer cells. If found in the lymph nodes, the oncologist will adjust the stage of cancer to account for lymph node involvement.

Treating Lymphoma vs Cancer that Spreads to Lymph Nodes

The recommended treatment plan depends on whether the patient has lymphoma or another type of cancer affecting the lymph nodes. Lymphoma is often treated with systemic therapies, such as chemotherapy, targeted therapy, and immunotherapy. If lymphoma has developed into a new tumor, radiation therapy may also be used. Patients diagnosed with recurrent lymphoma may require a bone marrow transplant. 

Treatment for other cancers that spread to the lymph nodes depends on where the original cancer began. For instance, breast cancer that spreads to the lymph nodes is typically treated with chemotherapy and/or targeted therapy according to the breast cancer treatment pathways.

What is the Outlook for Patients Who Have Lymphoma or Cancer in the Lymph Nodes? 

A patient's outcome depends on many factors, including the type and stage of cancer, age, overall health, and response to treatment.

Fortunately, advancements continue to be made in the treatment of lymphoma and metastatic cancer. Newer approaches, such as immunotherapy for non-Hodgkin lymphoma subtypes like follicular lymphoma, allow individuals to live longer and healthier lives. Clinical trials are also underway, and available through Rocky Mountain Cancer Centers, bringing the most recent treatments for both lymphoma and other types of metastatic cancer to patients in Colorado.

Related reading: New Immunotherapy for Non-Hodgkin Lymphoma Subtype Showing Promise

Expert Cancer Care Specialists in Colorado

Whether you or a loved one was diagnosed with lymphoma or another type of cancer, our team of oncologists will guide you through your cancer care journey. Request an appointment at one of our locations to discuss your treatment options and next steps. We are also available for second opinions.