Lymphoma is a cancer of the lymphatic system — the network of vessels, nodes, and organs that forms a core part of the body's immune defence. It is one of the more common blood cancers, and while a diagnosis understandably causes concern, lymphoma is also one of the more treatable cancers overall, with many patients — including most people with Hodgkin lymphoma — achieving long-term remission with modern treatment.
Lymphoma develops when lymphocytes — the white blood cells responsible for identifying and fighting infection — grow and divide abnormally instead of functioning as part of the immune system. These abnormal cells can accumulate in lymph nodes, causing the characteristic painless swelling many patients first notice, but lymphoma can also arise in the spleen, bone marrow, or almost any other organ, since lymphatic tissue is distributed throughout the body.
What Is Lymphoma, and How Does It Develop?
The lymphatic system is a network of vessels and nodes that runs throughout the body, closely linked to the bloodstream. Lymph nodes — small, bean-shaped structures found in clusters in the neck, underarms, groin, chest, and abdomen — filter lymph fluid and house immune cells that respond to infection. The spleen, thymus, tonsils, and bone marrow are also part of this system, all working together to protect the body from disease.
Lymphoma begins when a lymphocyte — usually a B cell, less often a T cell — undergoes a genetic change that causes it to grow and divide without the usual controls. Because lymphocytes normally travel throughout the body via the blood and lymphatic system, these abnormal cells can accumulate in a single lymph node, in multiple sites simultaneously, or in organs such as the spleen or bone marrow, which is why lymphoma can present very differently from one patient to the next.
Hodgkin vs Non-Hodgkin Lymphoma
Lymphoma is divided into two broad categories, distinguished under the microscope by the presence or absence of a specific abnormal cell. This distinction shapes both cell behaviour and treatment approach.
Hodgkin Lymphoma is defined by the presence of an abnormal cell called a Reed-Sternberg cell. It is less common overall, accounting for a smaller share of lymphomas. Hodgkin lymphoma often spreads in a predictable, step-wise fashion between adjacent lymph node groups. It is among the most curable cancers, particularly at early stages.
Non-Hodgkin Lymphoma is characterised by the absence of Reed-Sternberg cells and includes a large, diverse group of subtypes. It is the more common category, encompassing dozens of distinct subtypes. Behaviour varies considerably by subtype, with some being indolent and slow-growing while others are more aggressive. The outlook is highly variable depending on the subtype; many types are very treatable, and some indolent forms are managed for years.
Common Types of Non-Hodgkin Lymphoma
Non-Hodgkin lymphoma is not a single disease but a large group of subtypes, generally grouped by how quickly they grow.
- Diffuse Large B-Cell Lymphoma: : The most common aggressive subtype. It grows quickly but is also one of the more curable forms of non-Hodgkin lymphoma with prompt treatment.
- Follicular Lymphoma: The most common indolent (slow-growing) subtype. It often does not require immediate treatment and can, in some cases, be monitored closely before treatment is needed.
- Mantle Cell, Marginal Zone, and Other B-Cell Lymphomas: Less common subtypes, each with its own typical behaviour and treatment approach.
- T-Cell Lymphomas: A smaller group of subtypes arising from T lymphocytes rather than B lymphocytes, generally less common and sometimes more challenging to treat.
Stages of Lymphoma
Lymphoma is staged using the Lugano classification (an update of the older Ann Arbor system), which describes how many lymph node regions are involved and whether the disease has spread beyond the lymphatic system.
- Stage I–II: The lymphoma is confined to one lymph node region, or two or more regions on the same side of the diaphragm. Treatment often involves a shorter course of chemotherapy, sometimes combined with radiotherapy, with the aim of achieving a cure.
- Stage III: The lymphoma involves lymph nodes on both sides of the diaphragm. Treatment is usually systemic and typically involves a full course of chemotherapy or immunotherapy-based regimens.
- Stage IV: The lymphoma has widespread involvement, including organs beyond the lymphatic system such as the bone marrow, liver or lungs. Treatment is tailored to the specific lymphoma subtype, and many patients can still achieve good, durable responses.
Unlike many solid cancers, a later stage at diagnosis does not always mean a substantially worse outlook in lymphoma. The specific subtype is often just as important, if not more important, than the stage in determining prognosis and guiding treatment.
Symptoms of Lymphoma
Lymphoma symptoms vary depending on subtype and which parts of the body are involved, but a recognisable pattern often emerges, particularly with more advanced or aggressive disease.
Common symptoms
- Painless swelling of lymph nodes in the neck, underarms, or groin
- Persistent fatigue
- Itchy skin, sometimes without a visible rash
- Mild, unexplained fevers
- Fever above 38°C without an identified infection
- Drenching night sweats that soak clothing or bedding
- Unintentional weight loss of more than 10% of body weight over six months
Symptoms of more advanced or bulky disease
- Shortness of breath or chest discomfort, if lymph nodes in the chest are enlarged
- Abdominal swelling or discomfort, if the spleen or abdominal nodes are involved
- Increased susceptibility to infection
- Easy bruising or bleeding, if the bone marrow is affected
Causes and Risk Factors for Lymphoma
In most cases, no single clear cause is identified, but several factors are known to increase risk.
Non-modifiable risk factors
- Age, some lymphomas are more common in young adults, while others are more common after age 55
- Family history of lymphoma
- Certain infections, including Epstein-Barr virus, Helicobacter pylori, and HIV, which are each linked to specific lymphoma subtypes
- A weakened immune system, whether from a medical condition, organ transplant medication, or other immunosuppressive treatment
- Certain autoimmune conditions
Modifiable factors
- Where relevant, treating and monitoring chronic infections linked to specific lymphoma subtypes, such as Helicobacter pylori
- Discussing immune status with your doctor if you are on long-term immunosuppressive medication
How Is Lymphoma Diagnosed?
Diagnosis requires a tissue sample from an affected lymph node — blood tests and imaging support the diagnosis but cannot confirm it on their own. Getting the right type of biopsy the first time matters, since the specific lymphoma subtype directly determines treatment.
- Excision Lymph Node Biopsy: Surgical removal of an entire affected lymph node is generally the preferred method of biopsy in suspected lymphoma, as it preserves the tissue architecture needed to accurately identify the specific subtype.
- Blood Tests: A complete blood count and other blood tests assess general health, look for markers suggestive of lymphoma, and help evaluate how far the disease may have progressed.
- CT or PET-CT Scan: Imaging maps the full extent of lymph node involvement throughout the body and checks for spread to organs beyond the lymphatic system, forming the basis for staging.
- Bone Marrow Biopsy: A sample of bone marrow, usually ta ken from the hip bone, checks whether lymphoma has spread there — relevant to staging and, in some subtypes, to treatment planning.
- Immunophenotyping & Molecular Testing: Specialised laboratory testing of biopsy tissue identifies specific markers and genetic features that distinguish lymphoma subtypes and can guide the choice of targeted treatment.
- Interventional Radiology-Guided Biopsy: For lymph nodes in harder-to-reach locations, image-guided needle biopsy can obtain tissue with minimal invasiveness, supporting diagnosis when excision biopsy is not practical.
Living with Lymphoma
Whether undergoing active treatment, in a period of surveillance, or in long-term remission, a number of everyday factors support recovery and overall wellbeing.
- Attend all scheduled appointments and scans, including during periods of active surveillance for indolent subtypes
- Take precautions against infection during chemotherapy, when the immune system is temporarily weakened — your care team will advise on specific measures
- Maintain adequate nutrition and stay hydrated, particularly during active treatment
- Pace activity around treatment cycles — fatigue is common but most people can maintain some level of normal activity between sessions
- Report new fevers, unusual bruising, or signs of infection promptly during treatment, rather than waiting for the next scheduled visit
- Seek support for the emotional impact of diagnosis and treatment — many patients find counselling or peer support genuinely helpful alongside medical care
- Continue routine follow-up after treatment ends, even once in remission, since some lymphoma subtypes require longer-term monitoring
