Lymphoma is a group of blood cell tumors that begin in cells of the body's immune system. In the United States, about 79,990* new cases of lymphoma are diagnosed every year. In lymphoma, cancer cells are found in the lymphatic system, which is comprised of the bone marrow, lymph nodes, spleen, stomach, intestines and skin. Because lymph tissues are present in many parts of the body, lymphoma can start almost anywhere.

Normal lymph nodes are tiny, beanlike structures that trap cells containing poisons and waste materials. They also serve as a reservoir of cells that supply microorganism-fighting antibodies. Tubelike vessels carrying milk-colored fluid called lymph connect lymph nodes to each other. Lymph allows white blood cells (lymphocytes) to circulate. When white blood cells multiply abnormally, they cause masses to form and lymph nodes become enlarged. Some lymphomas may affect the bone marrow and interfere with its making of blood cells. The result is anemia, or low red blood cell count.

*American Cancer Society, Cancer Facts & Figures 2014

Classification of Lymphomas

Lymphomas are graded as low, intermediate and high depending on the kind of lymphoma cells present and how they affect lymph nodes and chromosomes. Some lymphomas grow faster and require specific treatment. Classifying them is complex because many kinds of lymphocyte cells can be involved.

Low-Grade Lymphoma

These grow so slowly that patients can live for many years mostly without symptoms, although some may experience pain from an enlarged lymph gland. After five to 10 years, low-grade disorders begin to progress rapidly to become aggressive or high-grade and produce more severe symptoms.

Intermediate-Grade Lymphoma

This type progresses fairly rapidly without treatment. With treatment, remission can be induced in between 50 to 75 percent of cases. Initial treatment has been so successful that people who stay in remission for three years after diagnosis are often considered cured. Stage I disorders are treated with radiotherapy.

High-Grade Lymphoma

Without treatment, these can progress rapidly regardless of stage. They are treated aggressively. With treatment, between 50 to 75 percent of patients enter remission. Those who stay in remission one year can look forward to a life free from recurrence. Treatment consists of intensive combination chemotherapy, which is sometimes supplemented with radiation therapy. Drug regimens used are determined by a number of factors, the most important being tissue study.

Types of Lymphomas

Based on the course of disease and the kind of lymphocytes affected, lymphomas are divided into two types: Hodgkin disease and non-Hodgkin lymphoma.

Hodgkin Disease

About 75 percent of those diagnosed with Hodgkin disease recover fully. About 90 percent of all people diagnosed with early-stage illness and more than 50 percent of those with more advanced stage are now living longer than 10 years with no signs of the disease coming back. The stage of the disease at diagnosis is critical in planning treatments. Sometimes giving the patient aggressive chemotherapy and then introducing young cells from the bone marrow (bone marrow transplantation) may increase chances of the patient living longer. A bone marrow transplant should be considered for every patient whose disease comes back after undergoing chemotherapy.

Non-Hodgkin Lymphoma

In the past 10 years, this disease has become easier to treat as more procedures are found to be effective. Overall, 50 to 60 percent of patients with non-Hodgkin lymphoma now live five years or longer without a recurrence. While a number of factors determine the best treatment for these disorders, the most significant is tissue classification followed by determination of the disease's stage.