An estimated 761,659 people in the United States are living with, or are in remission from, lymphoma, according to the Leukemia and Lymphoma Society.
Lymphoma is not just one disease, but rather two distinctive forms of cancer with many subtypes. As such, the answer to the question of “What is lymphoma?” can differ from person to person, depending on the type of lymphoma that person has.
What Is Lymphoma? Two Main Types to Consider
In general, lymphoma is cancer that affects disease-fighting white blood cells known as lymphocytes. Experts have identified two broad categories of lymphoma: non-Hodgkin lymphoma (NHL) and Hodgkin lymphoma (Hodgkin disease).
NHL, the most common form of lymphoma, originates in B-lymphocytes and T-lymphocytes (B-cells and T-cells) as well as natural killer (NK) cells. These cells play direct and indirect roles in helping the immune system attack and destroy bacteria, viruses, and other germs.
Overall, about 60 non-Hodgkin lymphoma subtypes have been identified. And around 85 percent of NHLs in the United States are B-cell lymphomas. NHLs are also categorized based on how quickly they progress:
- High-grade, or aggressive, NHL makes up about 60 percent of NHL cases in the United States, according to the Leukemia & Lymphoma Society. The most common form is diffuse large B-cell lymphoma, which accounts for about 30 percent of all NHL cases.
- Low-grade, or indolent, NHL comprises about 40 percent of NHL cases in the United States. The most common form, follicular lymphoma, accounts for about 20 percent of all NHLs.
- Intermediate-grade NHL progresses at a rate between high-grade and low-grade forms and may transform into high-grade NHL.
Each year, NHL is newly diagnosed in more than 71,000 Americans, and nearly 20,000 die from it, according to the American Cancer Society (ACS). NHL can develop at any age, but 95 percent of cases occur in adults; about half of people with the disease are over age 66.
The prognosis for NHL can vary depending on the subtype, how rapidly the cancer has progressed, and how quickly the disease is diagnosed and treated. Overall, 69 percent of NHL patients survive at least five years after their diagnosis, while 59 percent survive at least 10 years, the ACS notes.
Hodgkin disease is less common than NHL, resulting in about 9,050 new diagnoses and 1,150 deaths each year in the United States, the ACS estimates. The disease is most prevalent among people in their 20s and adults over age 55.
Nearly all cases of Hodgkin disease originate in B-cells. Most commonly, Hodgkin disease begins in lymph nodes in the chest, neck, or under the arms, and usually spreads systematically from lymph node to lymph node. In later stages, it can enter the bloodstream and travel to the liver, lungs, and elsewhere in the body.
Classic Hodgkin disease comprises about 95 percent of Hodgkin cases, according to the ACS. This type of Hodgkin lymphoma, which encompasses four subtypes, features large B-cells (Reed-Sternberg cells) that are significantly larger than normal lymphocytes and differ from NHL cells. Nodular lymphocyte predominant Hodgkin disease accounts for the remaining 5 percent of Hodgkin disease cases. This form is characterized by large, popcorn-like cells, and is more common in men than in women.
With advances in diagnosis and treatment, survival rates for people with Hodgkin disease have improved significantly, to the point that the Leukemia & Lymphoma Society now considers Hodgkin disease one of the most curable forms of cancer.
But, as with NHL, the stage of the cancer when it’s diagnosed and other factors help determine a Hodgkin patient’s outlook. For instance, about 90 percent of people diagnosed with early-stage (Stage 1 or 2) Hodgkin disease survive at least five years, but that rate drops to about 80 percent for people diagnosed with Stage 3 and 65 percent for those with Stage 4, the ACS notes.
Symptoms of Lymphoma
No screening tests are recommended for any type of lymphoma, so paying attention to signs and symptoms of the disease is crucial for early detection.
The most common symptom of early lymphoma is persistent swelling of lymph nodes in the armpit, neck, or groin (although this symptom more commonly signals a noncancerous condition, such as an infection.) These swollen lymph nodes usually are painless but sometimes may become painful after you consume alcohol.
Aside from lymph node abnormalities, lymphoma may cause what are known as B symptoms, which include fever, severe night sweats, and unintentional weight loss (especially a loss of 10 percent or more of body weight over six months). Other potential lymphoma symptoms include fatigue, loss of appetite, persistent cough, shortness of breath, chest pain, abdominal discomfort, and itchy skin or skin rashes.
See your doctor if you’re troubled by any of these symptoms.
Originally published in May 2016 and updated.