The short answer
Lymphoma is staged using the Ann Arbor system, updated as the Lugano classification. Stages I to IV describe how many lymph node areas are involved and whether the disease is on one or both sides of the diaphragm, or has spread beyond the lymph system.
Lymphoma staging uses the Ann Arbor system, modernized as the Lugano classification, which is different from how most solid tumors are staged.
Stage I means one lymph node area is involved. Stage IV means the lymphoma has spread widely into an organ outside the lymph system, such as the liver, bone marrow, or lungs.
The letters A and B are added to note whether B symptoms — unexplained fever, drenching night sweats, or major weight loss — are present.
"Bulky disease" describes a large tumor mass and can affect treatment choices even within an early stage.
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The full explanation.
The simple version
Lymphoma is staged with a system called Ann Arbor. It was first developed for Hodgkin lymphoma, then adapted for non-Hodgkin lymphoma too. A modern, imaging-focused update of the same system is called the Lugano classification. Both describe lymphoma using stages I through IV. The stage rests mainly on how many lymph node areas are involved, and where.
Lymphoma staging asks a simple question: how many lymph node areas are involved, and on which side, or sides, of the diaphragm?
The four stages
- Stage I: Lymphoma is in only one lymph node area, or in only one part of one organ outside the lymph system.
- Stage II: Lymphoma is in two or more lymph node areas on the same side of the diaphragm. The diaphragm is the muscle separating the chest from the abdomen. Stage II also covers lymphoma that extends from a node into a nearby organ on that same side.
- Stage III: Lymphoma is in lymph node areas on both sides of the diaphragm, for example in the chest and in the abdomen. It may also involve the spleen.
- Stage IV: Lymphoma has spread widely into at least one organ outside the lymph system, such as the liver, bone marrow, or lungs.
The letters that come with the number
A or B. The letter B is added when a person has one or more B symptoms. Those are unexplained fever, drenching night sweats, or losing more than 10% of body weight over six months without trying. A means none of these symptoms are present. These letters describe symptoms, not the extent of disease. They still factor into treatment decisions.
E. This is used with an earlier stage, I or II. It means the lymphoma affects an organ outside the lymph system in a limited, local way, rather than through widespread involvement.
X, or "bulky." This describes a large tumor mass. That generally means a chest mass at least about a third as wide as the chest, or a mass larger than 10 centimeters elsewhere. Bulky disease can call for a more intensive treatment approach, even within an earlier stage.
Limited versus advanced disease
For many treatment decisions, doctors group lymphoma more simply:
- Limited stage: stage I, or stage II without bulky disease.
- Advanced stage: stage III or IV, or a bulky stage II.
This grouping is often more useful for choosing a treatment approach than the exact stage number.
Why stage doesn't tell the whole story
Unlike some solid tumors, a higher lymphoma stage does not automatically mean a worse outlook. Some stage III and IV Hodgkin lymphomas remain highly treatable. Other things matter just as much as stage. One is the specific subtype, and whether it is fast-growing or slow-growing. Another is the set of prognostic factors tied to that subtype. A third is how the lymphoma responds to initial treatment. Ask your care team to explain your stage alongside these factors, not on its own.
Questions to ask
- What stage is my lymphoma, and how was it determined?
- Do I have B symptoms according to my results?
- Is my disease bulky, and does that change my options?
- Is my lymphoma limited or advanced, and what does that mean for my plan?
Sources
Words to know
Tap any term to see what it means.
Common questions
What is the Ann Arbor staging system?
It's the staging system originally developed for Hodgkin lymphoma and later adapted for non-Hodgkin lymphoma. It stages lymphoma from I to IV based on how many lymph node areas are involved, whether they are on one or both sides of the diaphragm (the muscle that separates the chest from the abdomen), and whether the lymphoma has spread to an organ outside the lymph system.
What is the Lugano classification, and how is it different from Ann Arbor?
The Lugano classification is a modern update of the Ann Arbor system, refined for use with PET-CT imaging and adjusted for both Hodgkin and non-Hodgkin lymphoma. The stage numbers (I through IV) mean essentially the same thing; Lugano refines how imaging and certain organ involvement are interpreted.
What do the letters A and B mean after my stage number?
B means you have at least one B symptom: unexplained fever, drenching night sweats, or losing more than 10% of your body weight over six months without trying. A means none of these are present. The letters describe symptoms, not how much disease is present.
What does "bulky disease" mean?
It refers to a large tumor mass — generally a chest mass at least about a third as wide as the chest, or a mass larger than 10 centimeters elsewhere. Bulky disease can affect treatment choices even at an earlier stage, so it is tracked separately from the stage number.
Does a higher stage mean a worse outlook?
Not automatically, and less so than with many solid tumors. Some higher-stage lymphomas, including some stage III and IV Hodgkin lymphomas, are still very treatable. Lymphoma outlook depends heavily on the specific subtype, other prognostic factors, and treatment response, not on stage number alone.
Questions to ask your doctor
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Last updated: 2026-08-10Next planned review: 2027-08-03
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How this page was created
Cancer Explained does not originate medical claims. Every page restates guidance already published by the National Cancer Institute, the CDC, the USPSTF and the FDA, in plain language, with the source cited so you can check the original yourself. AI does the translating and organizing; automated checks test claims, citations, clarity and safety before anything publishes. We do not employ clinicians and do not intend to — our work is translation and navigation, not clinical judgment. Nothing here is personal medical advice, and no page can account for your particular situation.
Editorial status: Source checked — This page was written with AI assistance and checked line by line against the sources listed on it. That confirms the sources support what the page says. It is not a medical review, and it does not confirm the page is complete or right for your situation.
Human medical review: not completed. Pages here are not signed off by a clinician before they publish. That is not an oversight we are quietly working around: we restate published guidance and cite it, so the authority belongs to the source rather than to us, and every page names where its claims come from — you can verify us instead of trusting us. Where a volunteer clinician has reviewed a page, their name and credentials appear on it; where no name appears, no clinician has checked it. We are glad to have reviewers and are recruiting them, and we do not hold pages back waiting for one. Use this site to understand your situation and to ask better questions of the people treating you.
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