Non-Hodgkin’s lymphoma (NHL) is a cancer that starts in white blood cells called lymphocytes, which are part of your immune system. It’s one of the most common cancers, with roughly 80,000 new cases diagnosed in the United States each year. Unlike many cancers that form solid tumors in a single organ, NHL develops within the lymphatic system, a network of vessels, nodes, and organs spread throughout your body that helps fight infection.
How NHL Develops
Your lymphocytes normally go through a tightly controlled life cycle: they grow, divide, fight infections, and eventually die off to make room for new cells. In NHL, genetic errors accumulate in these cells and give them a growth advantage over normal ones. The damaged cells keep dividing when they shouldn’t, eventually forming masses in lymph nodes or other lymphatic tissue.
About 85% to 90% of NHL cases start in B cells, a type of lymphocyte responsible for making antibodies. The remaining cases arise in T cells, which directly attack infected or abnormal cells. The genetic errors that trigger NHL often happen during normal immune processes. When B cells mature, they undergo DNA changes to improve their ability to recognize threats. These natural modifications occasionally go wrong, creating chromosome rearrangements that switch on genes promoting uncontrolled growth. A single rearrangement usually isn’t enough on its own. Additional genetic hits are typically needed before a cell becomes fully cancerous, which is why NHL tends to appear later in life after mutations have had decades to accumulate.
How It Differs From Hodgkin Lymphoma
The distinction between Hodgkin and non-Hodgkin lymphoma comes down to what pathologists see under a microscope. Hodgkin lymphoma contains a distinctive abnormal cell called the Reed-Sternberg cell. If that cell is present, it’s Hodgkin. If it’s absent, it’s classified as non-Hodgkin. This isn’t just a naming convention. The two diseases behave differently, affect different age groups, and respond to different treatments. Hodgkin lymphoma is less common and generally has a higher cure rate, while NHL encompasses more than 60 distinct subtypes that range from very slow-growing to highly aggressive.
Types and How They Behave
NHL subtypes fall into two broad categories based on how quickly they grow. Indolent (slow-growing) lymphomas, like follicular lymphoma, can take years to cause problems. Some people with indolent NHL don’t need treatment right away and instead undergo a monitoring approach called “watch and wait.” Aggressive lymphomas, like diffuse large B-cell lymphoma (the most common subtype), grow quickly and need prompt treatment but are often more responsive to chemotherapy.
The subtype matters enormously for prognosis and treatment planning. Two people with “non-Hodgkin’s lymphoma” can have very different diseases, different treatment paths, and different outlooks.
Risk Factors
Several factors raise the likelihood of developing NHL, though many people diagnosed have no identifiable risk factor at all.
- Weakened immune system. People with HIV have a significantly elevated risk. Organ transplant recipients taking immune-suppressing medications are also at higher risk.
- Autoimmune diseases. Conditions like rheumatoid arthritis, lupus, Sjögren’s disease, and celiac disease are linked to increased NHL risk. When the immune system is chronically overactive, lymphocytes divide more frequently than normal, raising the chance of genetic errors.
- Certain infections. The Epstein-Barr virus (the virus behind mono) is an important risk factor for Burkitt lymphoma, particularly in parts of Africa. Human herpes virus 8 can infect lymphocytes and lead to a rare subtype called primary effusion lymphoma.
- Chemical exposures. Some research links benzene and certain herbicides and insecticides to increased risk, though this area is still being studied.
- Age. Risk rises with age. Most people are diagnosed in their 60s or older.
Common Symptoms
The most typical first sign is a painless, swollen lymph node, often in the neck, armpit, or groin. Because swollen lymph nodes are far more commonly caused by infections, many people don’t think much of it at first. What sets lymphoma apart is that the swelling persists or grows over weeks without an obvious cause like a cold or sore throat.
Other symptoms can include unexplained fevers, drenching night sweats that soak through clothing or sheets, unintentional weight loss (more than 10% of body weight over six months), persistent fatigue, and abdominal pain or fullness if lymph nodes in the belly are enlarged. These are sometimes called “B symptoms,” and their presence can influence how the disease is staged and treated.
How NHL Is Diagnosed
A definitive diagnosis requires a biopsy of an affected lymph node. The preferred approach is an excisional biopsy, where a surgeon removes an entire lymph node through a small incision. This gives pathologists enough tissue to identify the exact subtype. Fine-needle aspiration, which uses a thin needle to extract a small sample, is less reliable for lymphoma because it often doesn’t capture enough of the node’s structure for accurate classification.
After the biopsy confirms NHL, imaging scans (usually PET-CT) and sometimes a bone marrow biopsy help determine how far the disease has spread. NHL is staged from I through IV based on how many lymph node regions are involved and whether the cancer has moved beyond the lymphatic system.
Survival Rates by Stage
Five-year relative survival rates for NHL vary considerably depending on how advanced the disease is at diagnosis. Based on cases from 2016 to 2022:
- Stage I (confined to a single region): 87.6% five-year survival, representing about 21% of cases
- Stage II (involving multiple regions on the same side of the body): 79.7%, about 15% of cases
- Stage III (spread to both sides of the diaphragm): 74.0%, about 17% of cases
- Stage IV (widespread involvement): 63.6%, about 37% of cases
The fact that 37% of people are diagnosed at Stage IV reflects how NHL can spread silently through the lymphatic system before causing noticeable symptoms. Even so, a 63.6% five-year survival at the most advanced stage is substantially better than many other cancers at that point, partly because some Stage IV NHL subtypes are indolent and manageable for years.
Treatment Options
Treatment depends heavily on the NHL subtype, stage, and how aggressive the disease is. For indolent lymphomas that aren’t causing symptoms, active monitoring with regular check-ups and scans may be the initial approach.
For aggressive B-cell lymphomas like DLBCL, the standard first-line treatment is a combination of chemotherapy drugs paired with a targeted therapy that homes in on a protein found on the surface of B cells. This regimen is typically given in cycles over several months. Each cycle involves a few days of treatment followed by a recovery period. Side effects commonly include fatigue, nausea, hair loss, and increased vulnerability to infections during treatment.
Radiation therapy is sometimes used alone for very early-stage NHL confined to one area, or in combination with chemotherapy for more advanced cases.
CAR T-Cell Therapy for Relapsed Cases
For people whose aggressive B-cell NHL comes back after initial treatment or doesn’t respond to it, CAR T-cell therapy represents a significant advance. This treatment involves collecting a patient’s own immune cells, genetically engineering them in a lab to recognize and attack lymphoma cells, then infusing them back into the body. The process from cell collection to infusion takes several weeks.
CAR T-cell therapy is currently used after other treatments have failed, not as a first option. In that difficult-to-treat population, the results are notable: roughly 35% to 40% of people with relapsed or treatment-resistant aggressive B-cell NHL appear to be cured by CAR T-cell therapy after standard salvage chemotherapy has stopped working. For a group of patients who previously had very few options, that cure rate has changed the landscape of NHL treatment significantly.