Cancers fall into two general categories: solid cancers and hematologic (blood) cancers. When most people think of cancer, they think of solid cancer, which involves a tumor that grows and sometimes spreads to other places in the body. In contrast, blood cancers affect blood, bone marrow and lymph nodes and may not create an actual tumor.
Lymphoma is a type of blood cancer that arises in the lymphatic system, which is part of the immune system. It is the most common blood cancer in the United States, accounting for approximately five percent of all cancer diagnoses. It is estimated that nearly 81,000 people will be diagnosed with lymphoma in 2015.
Lymphoma develops when normal lymphocytes (a type of white blood cell) transform into abnormal cancer cells that reproduce uncontrollably. As these cancer cells multiply, they collect in the lymph nodes, bone marrow, spleen, tonsils, adenoids or thymus, where they can form tumors. These cells eventually begin to outnumber normal cells, causing an enlargement of the lymph nodes, spleen or other organs.
About the lymphatic system
To fully understand lymphoma, it’s important to first gain a general understanding of the lymphatic system. The lymphatic system is a network of tissues and vessels that carry fluid, called lymph, throughout the body. Lymph contains lymphocytes that attack infectious agents.
The two main types of lymphocytes that can develop into lymphomas are B lymphocytes (B cells) and T lymphocytes (T cells).
B cells produce protein antibodies that attach to infectious organisms, such as bacteria and viruses, marking them for destruction.
T cells attack infectious organisms directly and play a part in controlling the immune system.
Both B cells and T cells can transform into lymphoma cells. However, in the United States, B cell lymphomas are much more common.
Types of lymphoma
Lymphoma represents more than 60 different cancer subtypes that involve lymphocytes, and it can occur in adults and children of any age. The two main types of lymphoma are Hodgkin lymphoma and non-Hodgkin lymphoma.
With an estimated 9,000 new cases of Hodgkin lymphoma in the United States in 2015, it is not as common as non-Hodgkin lymphoma.
Hodgkin lymphoma is characterized by the presence of abnormal B cells (called Reed-Sternberg [R-S] cells), although other abnormal cell types may be present. Hodgkin lymphoma usually starts in the lymph nodes and often spreads from one lymph node to another. It can also spread to other organs.
Non-Hodgkin lymphoma (NHL) is the most common cancer of the lymphatic system. Approximately 71,850 new cases of NHL are diagnosed annually in the United States.
NHL is not a single disease but rather a group of several closely related cancers. The World Health Organization estimates that there are more than 60 types of NHL, some of which are more common than others. Although the various types of NHL share some common features, they differ in their microscopic appearance, molecular features, growth patterns, impact on the body and treatment options.
NHLs are broadly divided into two major groups: B cell lymphomas and T cell lymphomas. B cell lymphomas develop from abnormal B lymphocytes and account for 85 percent of all NHLs, and T cell lymphomas develop from abnormal T lymphocytes and account for the remaining 15 percent of all NHLs. NHLs may also be classified as indolent (slow-growing) or aggressive (fast-growing).
Follicular lymphoma is the second most common form of low-grade NHL and the second most common type of lymphoma overall diagnosed in the United States. Approximately 25 to 30 percent of people with NHL in the United States have this type. Most follicular lymphoma diagnoses occur in adults over the age of 60, with equal rates of occurrence in male and female individuals; this specific lymphoma is rare in young people.
Follicular lymphoma affects B cell lymphocytes and is indolent, which means it grows very slowly. Like most lymphomas, follicular lymphoma usually begins in the lymph nodes. The cells can spread into the blood and bone marrow. Other internal organs, including the liver and spleen, may also be affected.
Because follicular lymphoma grows so slowly, doctors may decide not to treat it right away and instead adopt a “watchful waiting” approach. Several treatment options are available, though. (Learn more about treatment options here.) Over time, some follicular lymphomas transform into an aggressive (fast-growing) diffuse B cell type of lymphoma, so it’s important for people with follicular lymphoma to be monitored closely.
Risk factors for follicular lymphoma
Although the exact cause of follicular lymphoma is unknown, mutations in DNA (the hereditary genetic material found in cells) lead to the development of the disease. What triggers these mutations is also largely unknown, but research suggests that certain risk factors may play a role in the development of all NHLs:
Age – The risk of NHL increases with age, with most cases occurring in people 60 years or older.
Autoimmune disorders – Certain autoimmune disorders and some drugs used to treat them increase the risk of NHL.
Body weight – Some studies show that the risk of NHL is greater for people who are overweight or who consume a high-fat diet.
Chemical exposure – Long-term exposure to chemicals such as pesticides and fertilizers may increase the risk of NHL.
Chronic infections – People who experience chronic infections have an increased risk of NHL, likely because their immune systems are constantly producing new lymphocytes to fight the infection.
Family history – The children and siblings of people with NHL are at an increased risk for developing the disease.
Immune deficiency disorders – People with certain immune deficiency disorders have a greater chance of developing NHL.
Organ transplantation – Recipients of organ transplants often have a higher risk of developing NHL because they must take drugs to lower their immune system function.
Previous cancer treatment – People who have previously been treated for cancer may be at an increased risk for the development of NHL.
Race – In the United States, NHL is more likely to occur in white individuals than in African and Asian Americans.
Radiation exposure – People who have been exposed to radiation have an increased risk of NHL.
Symptoms of follicular lymphoma
Some people with NHL do not experience any symptoms. When symptoms do occur, they generally include swelling or enlargement of the lymph nodes (which is often but not always painless), fatigue, fever, night sweats, unexplained weight loss, easy bruising or bleeding and frequent infections.
Other symptoms, such as abdominal pain, chest pain and difficulty breathing, may also be present, depending on the area of the body in which the lymphocytes collect.
If you have follicular lymphoma, you can help yourself feel more in control by learning as much as you can about the specific characteristics of your disease, your treatment options and ways you can help make yourself healthier, both physically and emotionally. Numerous survivors have credited a balance of regular exercise and plenty of rest to feeling better during and after follicular lymphoma treatment. Healthy eating habits also help, as they can help people achieve — and maintain — a healthy weight. Spending time with family and friends, getting involved in support groups and/or participating in religion or spirituality are also credited by survivors as helping them thrive during treatment for follicular lymphoma.
This medical journal will help you keep track of all of the medications that you're taking. Note the name and contact information for the doctor who prescribed each drug, and give this list to your cancer care team so they can help you manage your medications and avoid drug interactions.