Lymphoma is a cancer that starts in white blood cells called lymphocytes, which are part of your immune system. When these cells develop genetic mutations, they can multiply uncontrollably and accumulate, most often in the lymph nodes but also in the spleen, bone marrow, and other organs. Globally, more than 669,000 new cases of lymphoma were diagnosed in 2021, making it one of the more common cancers worldwide.
How Lymphoma Develops
Your body constantly produces lymphocytes in the bone marrow and lymph tissue. During their normal development, these cells undergo several rounds of genetic reshuffling to build the antibodies and receptors they need to fight infections. Each of those reshuffling steps is a vulnerability point. If something goes wrong during the process, a cell can acquire mutations that switch on growth-promoting genes or switch off the genes meant to keep cell division in check.
The result is a single rogue lymphocyte that begins copying itself without stopping. These clones pile up, typically in one or more lymph nodes, forming painless lumps. In roughly 40% of cases, the cancer starts outside the lymph nodes entirely, appearing in the stomach, skin, brain, or other organs.
Hodgkin vs. Non-Hodgkin Lymphoma
The two broad categories of lymphoma are Hodgkin lymphoma and non-Hodgkin lymphoma, and the distinction comes down to what a pathologist sees under a microscope. If the tissue sample contains a specific large, abnormal cell called a Reed-Sternberg cell, it’s classified as Hodgkin lymphoma. If that cell isn’t present, it’s non-Hodgkin lymphoma.
Hodgkin lymphoma almost always arises from B lymphocytes and tends to start in the lymph nodes of the neck, chest, groin, or armpits before spreading in a predictable, orderly pattern. Non-Hodgkin lymphoma can arise from B cells, T cells, or natural killer cells, and it often shows up in less predictable locations. Non-Hodgkin lymphoma is considerably more common, accounting for about 90% of all lymphoma diagnoses. Hodgkin lymphoma, while less common, generally carries a better prognosis and higher cure rates.
Common Non-Hodgkin Subtypes
Non-Hodgkin lymphoma isn’t a single disease. It includes more than 60 subtypes, but a handful make up the majority of cases:
- Diffuse large B-cell lymphoma (DLBCL): The most common type in adults, representing 25% to 45% of all non-Hodgkin cases. It grows quickly and usually requires prompt treatment.
- Follicular lymphoma: The second most common, at 12% to 20% of cases. It grows slowly and can sometimes be monitored for years before treatment is needed.
- Marginal zone lymphoma: Another slow-growing type, making up 7% to 11% of cases, often linked to chronic infections or autoimmune conditions.
- Mantle cell lymphoma: A rarer, aggressive form at 3% to 6% of cases, more common in older adults.
- Peripheral T-cell lymphoma: The most common T-cell variety, accounting for 4% to 7% of cases in Western countries.
The distinction between fast-growing (aggressive) and slow-growing (indolent) subtypes is one of the most important factors in deciding how and when to treat.
Symptoms and Warning Signs
The most common early sign is a painless, swollen lymph node that you can feel as a lump under the skin, usually in the neck, armpits, or groin. Unlike the swollen glands you get with a cold or infection, lymphoma-related swelling typically doesn’t hurt and doesn’t go away after a few weeks.
Beyond the lumps, doctors look for a specific cluster of symptoms sometimes called “B symptoms”: drenching night sweats (the kind that soak your sheets), unexplained weight loss of more than 10% of your body weight over six months, and persistent fevers without an obvious infection. Not everyone with lymphoma develops all of these, but their presence can signal a more advanced or aggressive form and often influences treatment decisions. Fatigue that doesn’t improve with rest is also common.
Risk Factors
Family history plays a measurable role. If a first-degree relative (parent, sibling, or child) has had non-Hodgkin lymphoma, your risk of developing it is roughly 1.7 to 1.8 times higher than average. For Hodgkin lymphoma, the genetic component appears even stronger: identical twins of someone with Hodgkin lymphoma face a 100-fold higher risk compared to the general population, while fraternal twins show no excess risk at all. This suggests a significant inherited genetic susceptibility rather than just shared environment.
Certain infections are also linked. Epstein-Barr virus, the virus behind mononucleosis, is connected to several lymphoma subtypes. Conditions that weaken or chronically stimulate the immune system, including autoimmune diseases and immunosuppressive medications taken after organ transplants, raise risk as well.
How Lymphoma Is Diagnosed and Staged
A definitive diagnosis requires a biopsy, where a doctor removes part or all of a suspicious lymph node and examines the cells under a microscope. Blood tests and imaging alone can’t confirm lymphoma. The biopsy tells the pathologist which type and subtype you’re dealing with, which is critical because treatment varies dramatically between them.
Once lymphoma is confirmed, staging determines how far it has spread. The system used is called Ann Arbor staging, and it has four stages. Stage I means cancer is in a single group of lymph nodes. Stage II involves two or more groups on the same side of the diaphragm (the muscle separating your chest from your abdomen). Stage III means lymph node groups on both sides of the diaphragm are involved. Stage IV indicates the cancer has spread beyond the lymph nodes into organs like the bone marrow, liver, or lungs. CT scans and PET scans are the primary tools for staging, sometimes supplemented by a bone marrow biopsy.
Treatment Approaches
Treatment depends heavily on the type, subtype, and stage. For slow-growing lymphomas that aren’t causing symptoms, the first step may actually be no treatment at all. Doctors call this “watchful waiting” or active surveillance, and it can continue for months or even years, with regular checkups and scans to track whether the disease is progressing.
When treatment is needed, the main options include chemotherapy, immunotherapy, radiation, or some combination. Chemotherapy targets rapidly dividing cells. Immunotherapy uses lab-made antibodies that latch onto specific proteins on the surface of lymphoma cells, flagging them for destruction by your immune system. These two approaches are frequently combined. Radiation therapy, which uses focused energy beams to kill cancer cells in a specific area, may be used alone for very early-stage disease or alongside chemotherapy for more advanced cases.
For lymphomas that come back after initial treatment or don’t respond to it, more intensive options exist, including stem cell transplants and a newer approach called CAR T-cell therapy, where your own immune cells are collected, genetically reprogrammed in a lab to recognize the lymphoma, and infused back into your body.
Survival Rates
Survival varies widely depending on the type and stage. For non-Hodgkin lymphoma overall, the five-year relative survival rate is 74.2%, based on data from 2015 to 2021. Broken down by stage, the numbers tell a clearer story: 87.7% for stage I, 79.1% for stage II, 73.9% for stage III, and 63.8% for stage IV. About a third of non-Hodgkin lymphoma cases are diagnosed at stage IV, partly because slow-growing forms can spread quietly before causing noticeable symptoms.
Hodgkin lymphoma generally has higher survival rates, with five-year survival above 85% across all stages combined. These numbers reflect outcomes for people diagnosed years ago and don’t capture the full benefit of newer therapies now in use, so actual outcomes for people diagnosed today may be better than these figures suggest.