Non-Hodgkin lymphoma (NHL) is a blood cancer. Specifically, it’s a group of blood cancers that develop in your lymphatic system, starting in white blood cells called lymphocytes. Because lymphocytes are blood cells produced in bone marrow, NHL falls squarely under the blood cancer umbrella, even though it primarily shows up as swollen lymph nodes or masses in organs rather than abnormal counts on a routine blood draw.
Why Lymphoma Counts as a Blood Cancer
Blood cancers develop from genetic mutations in the DNA of blood cells. There are three main categories: leukemia, lymphoma, and multiple myeloma. All three start in cells made by the bone marrow, but they behave differently and show up in different places.
Leukemia affects white blood cells and typically floods the bloodstream with abnormal cells. Multiple myeloma targets plasma cells, a type of white blood cell that builds up in the bone marrow. Lymphoma starts in lymphocytes, the immune cells that normally travel through your lymph nodes, spleen, tonsils, and bone marrow to fight infections. Because the lymphatic system touches nearly every part of your body, NHL can spread to multiple sites.
The confusion is understandable. When most people picture “blood cancer,” they think of something detected through a blood test. But NHL is usually discovered through a tissue biopsy, not bloodwork. A doctor who suspects lymphoma will remove a sample from a swollen lymph node or affected area so a pathologist can examine the cells under a microscope. Blood tests alone can’t diagnose it. They may be ordered to rule out infections, which are by far the most common reason lymph nodes swell in the first place.
How NHL Differs From Hodgkin Lymphoma
Both Hodgkin and non-Hodgkin lymphoma start in lymphocytes, but the distinction comes down to one specific cell type visible under a microscope. If the tissue sample contains Reed-Sternberg cells, large abnormal cells with a distinctive appearance, it’s classified as Hodgkin lymphoma. If those cells aren’t present, it’s non-Hodgkin lymphoma. This isn’t just a naming detail: the two diseases behave differently, respond to different treatments, and have different prognoses.
NHL is far more common. An estimated 79,320 new cases will be diagnosed in the United States in 2026, compared to roughly 8,000 to 9,000 cases of Hodgkin lymphoma annually.
What Goes Wrong at the Cellular Level
Your immune system normally produces B cells, T cells, and natural killer (NK) cells, all types of lymphocytes. NHL develops when your body produces too many of these cells and they begin growing out of control. The vast majority of cases involve B cells.
B cells go through several stages of development, starting in the bone marrow and continuing in lymph nodes, the spleen, and tonsils. At multiple points during this process, the cell’s DNA is intentionally cut and rearranged to create diverse antibodies. These controlled DNA breaks are necessary for a functioning immune system, but they also create opportunities for errors. Chromosomes can get shuffled incorrectly, placing genes that promote cell growth next to switches that are always turned on. The result is a cell that won’t stop dividing.
Different errors at different stages of development produce different subtypes of NHL. An error during early bone marrow development, for example, can lead to follicular lymphoma. Errors that happen later, when B cells are actively responding to an infection in a lymph node, can lead to diffuse large B-cell lymphoma or Burkitt lymphoma.
Subtypes and How Aggressively They Grow
NHL isn’t a single disease. It includes dozens of subtypes, grouped by how fast they grow.
- Low-grade (indolent): These grow slowly and may not need immediate treatment. Follicular lymphoma is the most common in this group. Others include marginal zone lymphoma and MALT lymphoma.
- Intermediate-grade: These grow at a moderate pace and typically require treatment. Diffuse large B-cell lymphoma (DLBCL), the most common NHL subtype overall, falls here, along with primary mediastinal large cell lymphoma.
- High-grade (aggressive): These grow quickly and need prompt treatment. Burkitt lymphoma and lymphoblastic lymphoma are in this category.
Mantle cell lymphoma is sometimes classified as low-grade but often behaves more aggressively than other indolent lymphomas, which is why treatment decisions depend heavily on the specific subtype, not just the grade.
Survival Rates and Outlook
The overall five-year relative survival rate for NHL is 74.3%, based on data from 2016 to 2022. That number is an average across all subtypes and stages, so individual outcomes vary widely. Indolent subtypes like follicular lymphoma often have survival rates well above that average, while aggressive subtypes depend heavily on how well they respond to initial treatment.
About 19,970 deaths from NHL are projected in the United States in 2026. Survival rates have improved steadily over the past two decades, largely because of advances in targeted therapies and immunotherapy.
How NHL Is Treated Today
Treatment varies by subtype and stage, but the landscape has shifted significantly with newer approaches. Chemotherapy remains a common first-line treatment for many subtypes. For aggressive B-cell lymphomas that don’t respond to initial chemotherapy or come back afterward, a form of immunotherapy called CAR T-cell therapy has become an increasingly important option.
CAR T-cell therapy works by collecting your own immune cells, engineering them in a lab to recognize and attack lymphoma cells, and then infusing them back into your body. Clinical trials have shown that patients who received CAR T-cell therapy after just one round of chemotherapy lived longer without their disease progressing compared to the traditional approach of additional chemotherapy followed by a stem cell transplant. For people with aggressive B-cell NHL whose cancer has relapsed after multiple treatments, CAR T-cell therapy is estimated to cure 35% to 40% of patients.
The treatment isn’t without risks. A common side effect called cytokine release syndrome, essentially an overreaction of the immune system, occurs in roughly half to 90% of patients depending on the specific therapy used. In most cases it’s mild, with severe reactions occurring in only 1% to 6% of patients across major trials. The side effect is well-recognized and managed in treatment centers that offer the therapy.