Hodgkin's lymphoma (HL) and non-Hodgkin's lymphoma (NHL) are both blood cancers that develop in the lymphatic system. These cancers occur when lymphocytes—types of white blood cells in the immune system that help protect the body from infection and disease—start to grow abnormally and develop into lymphomas.
Differences
Although these diseases share similar names, and are both blood cancers, it is important to understand that they are two distinct diseases. The main difference between Hodgkin's and non-Hodgkin's lymphoma is the composition of the cells that indicate the disease. When viewed under a microscope, if a specific type of abnormal cell, called a Reed-Sternberg cell, is detected, that indicates Hodgkin's lymphoma. If a Reed-Sternberg cell is not present, that signals non-Hodgkin's lymphoma.
"Hodgkin's lymphoma doesn't spread via the blood system, rather it spreads lymph node to lymph node in an orderly fashion," explains Dr. Owen O'Connor, Director, Center for Lymphoid Malignancies in New York. "It is treated with a classic chemotherapy regimen, which cures about 70 percent of all cases."
Non-Hodgkin's lymphoma, on the other hand, is not a single disease, but rather a group of related cancers. "It spreads via the blood and is a systemic disease from the onset,” explains Dr. O'Connor. "The treatment is tailored to the specific type and aggressiveness that you have."
While these different subtypes of NHLs share common characteristics, they look different when viewed with a microscope, have different molecular features, exhibit different growth patterns, affect the body in different ways and require different approaches to treatment.
Non-Hodgkin lymphomas are divided into two major groups: B-cell and T-cell lymphomas. B-cell lymphomas develop from abnormal B-lymphocytes and account for the majority of NHL cases—approximately 85 percent. The remaining 15 percent of cases are T-cell lymphomas, which develop from abnormal T-lymphocytes. Treatment usually includes some form of chemotherapy, radiation, biologic therapy or a combination.
Signs and symptoms
As these are diseases of cells that play a role in our immune systems, symptoms are not lymphoma-specific and are similar to those of other illnesses. Common symptoms include:
- Enlarged lymph nodes, which may be causing pain, but may also be painless
- Weight loss without an explanation
- Fever, chills, sweating and/or night sweats
- Fatigue
- Itching
As these symptoms are common for other illnesses, most people who have these complaints will not have lymphoma. However, if you have persistent symptoms, it is important that you visit your doctor for an examination.
Who is at risk?
Though the causes remain unknown, the risk may be higher in individuals who:
- Have a family history
- Are affected with an autoimmune disease
- Have a weakened immune system
- Have been exposed to chemicals such as pesticides, fertilizers or organic solvents for a long period
- Have been infected with viruses such as Epstein-Barr, human T-lymphotropic virus type 1 (HTLV-1), HIV/AIDS, hepatitis C or certain bacteria, such as H-pylori
