Lymphoma is a cancer that starts in white blood cells called lymphocytes, which are a core part of your immune system. Unlike cancers that form solid tumors in a single organ, lymphoma develops within the lymphatic system, a network of vessels, nodes, and organs (like the spleen and thymus) that filters harmful substances and fights infection. An estimated 80,350 new cases of the most common form will be diagnosed in the United States in 2025 alone.
Because lymphocytes travel throughout the body, lymphoma can develop almost anywhere, though it most often shows up in the lymph nodes. The cancer begins when a lymphocyte acquires a genetic change that causes it to multiply uncontrollably, crowding out healthy cells and eventually interfering with your body’s ability to fight infection.
Hodgkin vs. Non-Hodgkin Lymphoma
All lymphomas fall into one of two broad categories: Hodgkin lymphoma and non-Hodgkin lymphoma. The distinction comes down to a specific type of abnormal cell. In Hodgkin lymphoma, a biopsy reveals what are called Reed-Sternberg cells, unusually large cells with multiple nuclei that collect in the lymph nodes. If those cells are absent, the diagnosis is non-Hodgkin lymphoma.
Non-Hodgkin lymphoma is far more common. It can arise in lymph nodes anywhere in the body, and the majority of patients are over 55 at diagnosis. Hodgkin lymphoma has a median diagnosis age of 39 and tends to start in the upper body: the neck, chest, or armpits. Hodgkin lymphoma also typically spreads in a more orderly, predictable pattern from one lymph node group to the next, which generally makes it easier to stage and treat.
Common Subtypes
Non-Hodgkin lymphoma is not a single disease. It includes more than 60 subtypes, broadly split by the type of white blood cell involved. About 85% of cases start in B cells, the lymphocytes responsible for producing antibodies. The remaining 15% begin in T cells, which directly attack foreign invaders.
The most common B-cell subtype is diffuse large B-cell lymphoma, an aggressive cancer that grows quickly but often responds well to treatment. Follicular lymphoma is the next most common and tends to be slow-growing, sometimes requiring no immediate treatment at all. Other notable subtypes include mantle cell lymphoma, Burkitt lymphoma (a very fast-growing form), and marginal zone lymphoma. T-cell lymphomas are less common overall, with subtypes that include peripheral T-cell lymphoma and cutaneous (skin) T-cell lymphoma.
Whether a lymphoma is “indolent” (slow-growing) or “aggressive” (fast-growing) shapes the entire treatment approach. Indolent lymphomas may be monitored for months or years before treatment is needed, while aggressive forms typically require prompt therapy but can also be more curable.
Symptoms to Recognize
The most noticeable early sign is a painless, swollen lymph node, usually in the neck, armpit, or groin. Many things cause swollen lymph nodes, including common infections, so a single swollen node is not cause for alarm. What raises concern is a node that persists for weeks, keeps growing, or appears without any obvious infection.
Doctors pay close attention to a specific cluster of systemic symptoms known as “B symptoms,” which carry prognostic significance in lymphoma. These are: a fever above 38°C (100.4°F) with no clear infection, drenching night sweats that soak through clothing or bedding, and unexplained weight loss of more than 10% of body weight over six months. The presence of B symptoms generally signals more advanced or aggressive disease. Other possible signs include persistent fatigue, itchy skin, and a feeling of fullness or pressure from an enlarged spleen or liver.
What Causes Lymphoma
No single cause explains all lymphomas, but two broad risk factors stand out: immune dysfunction and certain viral infections. People on long-term immune-suppressing medications, such as organ transplant recipients, have a higher risk because their weakened immune system is less able to detect and destroy abnormal cells early.
Several viruses are directly linked to lymphoma development. Epstein-Barr virus (the virus behind mononucleosis) is associated with multiple lymphoma types, including Hodgkin lymphoma. HIV significantly raises lymphoma risk. Hepatitis C virus is tied to certain B-cell lymphomas: roughly 10% of patients with a hepatitis C-related immune condition called mixed cryoglobulinemia develop non-Hodgkin lymphoma within five to seven years. Hepatitis B and a virus called KSHV (which also causes Kaposi sarcoma) are additional established risk factors.
Age, family history, and certain chemical exposures also play a role, though for most individual patients, no clear trigger is ever identified.
How Lymphoma Is Diagnosed
Diagnosis starts with a physical exam checking for swollen lymph nodes and an enlarged spleen or liver, followed by blood tests. If lymphoma is suspected, the key step is a biopsy, removing all or part of a lymph node (or tissue from another affected area) so it can be examined under a microscope. The biopsy determines whether lymphoma is present, what type it is, and whether Reed-Sternberg cells are involved.
Once lymphoma is confirmed, imaging scans map how far it has spread. PET scans, CT scans, and MRI are all used to pinpoint the location and extent of disease throughout the body. This information feeds directly into staging.
Staging
Lymphoma is staged from I to IV based on where the disease is found. Stage I means a single lymph node region is involved. Stage II means two or more regions are affected, but all on the same side of the diaphragm (the muscle that separates your chest from your abdomen). Stage III means lymph nodes on both sides of the diaphragm are involved. Stage IV means the cancer has spread beyond lymph nodes into organs like the liver, bone marrow, lungs, or cerebrospinal fluid.
About a third of non-Hodgkin lymphoma patients are already at Stage IV when first diagnosed, partly because indolent forms can grow silently for years before causing symptoms. Stage at diagnosis has a clear impact on outcomes: the five-year survival rate for Stage I non-Hodgkin lymphoma is roughly 88%, compared to about 64% for Stage IV.
Treatment Options
Treatment depends on the lymphoma type, stage, and how quickly it is growing. For many aggressive lymphomas, the standard first approach is combination chemotherapy, often paired with a targeted antibody that binds to a protein on the surface of lymphoma cells and helps the immune system destroy them. Radiation therapy may be added for localized disease. Indolent lymphomas that are not causing symptoms may be managed with a “watch and wait” strategy, with treatment starting only when the disease progresses.
For patients whose lymphoma returns after initial treatment or does not respond to standard chemotherapy, a newer option called CAR T-cell therapy has become increasingly available since receiving FDA approval in 2017. In this approach, a patient’s own immune cells are removed, genetically reprogrammed to recognize lymphoma cells, and infused back into the body. CAR T-cell therapy is currently approved for certain B-cell lymphomas after at least one or two rounds of standard chemotherapy have failed, and it can produce sustained remissions in patients who previously had limited options.
Survival and Prognosis
The overall five-year survival rate for non-Hodgkin lymphoma is 74.2%, though this number varies widely depending on subtype and stage. Hodgkin lymphoma generally has a higher cure rate, with five-year survival above 85% in most stages.
Doctors use tools like the International Prognostic Index to estimate outlook for individual patients. Five factors go into the score: age over 60, advanced stage (III or IV), disease in more than one site outside the lymph nodes, overall physical fitness, and whether a blood marker called LDH (which reflects how quickly cells are turning over) is elevated. Patients with none or one of these risk factors tend to do very well, while those with several face a more challenging course. Still, even patients with high-risk profiles today benefit from treatments that did not exist a decade ago, and outcomes continue to improve across nearly every subtype.