Lymphoma

Overview

By Sarah Maurer

Lymphoma is cancer of the lymphatic system, which includes the following disease-fighting organs:

Lymph tissue is also found in many other parts of the body, including the tonsils and digestive system.

thymus gland, spleen and lymph nodesLymphoma starts when a white blood cell called a lymphocyte is damaged and begins to reproduce rapidly. These new "lymphoma" cells are flawed like the parent cell and don't help the body fight infection. Eventually lymphoma cells crowd out healthy lymphocytes and form tumors in the organs of the lymphatic system. In the advanced stages of the disease, these tumors can metastasize (spread) beyond the lymphatic system.

Lymphoma usually (but not always) begins in the lymph nodes. There are about 600 lymph nodes scattered throughout the human body. Their function is to store white blood cells and to trap and destroy bacteria and other harmful substances. In addition, lymphoma can start in the lungs, stomach, intestines, brain, bones and skin.

There are two main types of lymphoma. Each has many subtypes.

  • Hodgkin lymphoma (also called Hodgkin's lymphoma) is characterized by the presence of large, abnormal cells. It affects a type of lymphocyte called a B cell.
  • Non-Hodgkin lymphoma (NHL) is a collection of about 50 subtypes of lymphoma that grow at different rates and affect different kinds of lymphocytes.

Hodgkin lymphoma usually affects young adults and people over 55. About 10 to 15 percent of cases are in children and teens. In 2014, about 9,000 people will be diagnosed with Hodgkin lymphoma, and 1,000 will die from the disease.

Non-Hodgkin lymphoma is one of the most common cancers in the United States, accounting for about four percent of all cancers. About 70,000 people are diagnosed with NHL every year, and about 20,000 die annually from the disease. The lifetime risk of developing NHL is about 1 in 50. Ninety-five percent of people with NHL are adults, and half of all patients are over 65.

 

Causes and Risk Factors

All cancers, including lymphoma, begin when a cell's genetic information is damaged.

Every cell in the body has a genetic "blueprint" located in its nucleus. This information is encoded in a series of proteins called DNA. Every time the cell divides, its DNA replicates (copies itself). If something goes wrong during this process, it can cause permanent changes to the DNA. Substances in the environment can also damage DNA. In some (but not all) cases, cells with damaged DNA become cancer cells.

No one knows exactly what causes the genetic damage that leads to lymphoma. Some possible risk factors for the disease include:

  • Family history. Some types of Hodgkin lymphoma are more common in people whose relatives also have the disease.
  • Radiation exposure. This usually occurs during a previous cancer treatment.
  • Exposure to environmental toxins. Incidence of lymphoma appears to be higher in agricultural communities where certain pesticides are used.
  • Immune-suppressing medications. These are most commonly prescribed to treat cancer or prevent rejection of a transplanted organ.
  • Certain infections. People who have been infected with Epstein-Barr virus (mono), HIV, HTLV and H. pylori are more likely to develop lymphoma.
  • Autoimmune diseases. Lupus and rheumatoid arthritis are examples.
  • Lifestyle factors. A few studies have linked lymphoma to obesity and a high fat diet, though more research is needed to explore this.

Many people with lymphoma have no known risk factors.

Symptoms

The most common symptom of lymphoma is an enlarged lymph node, which usually appears in the neck, groin, armpit or above the collarbone. Infections like colds or flu can also cause lymph nodes to puff up temporarily, but see a doctor if the swelling persists for two weeks or more.

Other possible lymphoma symptoms include:

  • Swollen belly
  • Feeling of fullness, even when you haven't eaten much
  • Chest pain or pressure
  • Coughing or shortness of breath
  • Fever
  • Weight loss
  • Sweating at night
  • Bruising
  • Frequent infections
  • Feeling very tired for no apparent reason
  • Unusual sensitivity to alcohol, or pain in the lymph nodes after drinking alcohol.

Diagnosis

If you have symptoms of lymphoma, your doctor may refer you to an oncologist (cancer specialist) or hematologist (blood disorders specialist).

Diagnosis of lymphoma begins with a history and physical exam. The physician palpates (feels) the organs and lymph nodes for swellings and abnormalities.

If lymphoma is suspected, the doctor will order a biopsy (surgical removal) of lymph node tissue. This is sent to lab for microscopic examination and other diagnostic tests.

When a diagnosis of lymphoma is confirmed, the doctor will usually order additional tests to see how far the disease has spread:

  • Imaging tests (MRI, PET, CT scan)
  • Bone marrow biopsy
  • Lumbar or pleural puncture (a needle is used to draw fluid from around the spine or chest cavity).

Based on the results, the doctor will "stage" the lymphoma to describe how far it has spread. Stage I lymphoma is confined to a single organ or group of lymph nodes, while stage IV lymphoma has spread throughout the body to multiple organs.

Treatment

Lymphoma treatment varies by disease type, stage and the patient's preferences and overall health. The first goal of treatment is to destroy all lymphoma cells and achieve full remission. If this isn't possible, the disease can sometimes be maintained in "partial" remission, meaning cancer cells are present, but the disease isn't progressing.

Many lymphoma treatments have side effects such as nausea and decreased immune function. During treatment, it's important to work closely with your medical team to monitor your overall health. Your doctor may prescribe additional medication and treatment (called palliative treatment) to help lessen side effects.

Treatment for lymphoma may involve one or several of the following:

  • Watchful waiting. For some slow-growing lymphomas, treatment may not be necessary until the disease progresses.
  • Chemotherapy. These cancer-fighting drugs are taken by mouth or intravenously. They're usually given in cycles that alternate a few weeks of treatment with a few weeks of rest.
  • Biological therapy. Biological treatments are man-made versions of antibodies, hormones and other infection-fighting and immune-boosting substances. These treatments can stimulate the immune system to target and destroy lymphoma cells. The course of this treatment is often similar to chemotherapy, with a few weeks of treatment followed by a few weeks of rest.
  • Radiation. High-energy rays are used to target and kill cancer cells. In some cases, the radiation is delivered by a machine that aims radioactive beams into the tumor or target organ. In other cases, radioactive material is injected so that it can travel throughout the body.
  • High-dose chemotherapy/radiation and stem cell transplant. The patient receives aggressive treatment that kills the cancer but also kills the blood-forming cells in the bone marrow. These blood-forming cells are then "transplanted" back into the patient in the form of stem cells (primitive cells that develop into new blood-forming cells). The transplant can come from the person's own blood or bone marrow (which is harvested ahead of time) or from a compatible donor.

Prognosis for lymphoma depends on many factors. It is generally best for early-stage lymphoma that is contained to a single organ or group of lymph nodes. However, unlike other types of cancer, stage III and IV lymphoma may be quite curable depending on the subtype present.

About 60 percent of NHL cases involve aggressive forms of the disease that spread quickly if left untreated. (However, aggressive lymphomas are often easier to cure completely than slower-growing types, which tend to recur over time.)

In 2014:

  • The five-year survival rate for Hodgkin lymphoma was 85 percent and the 10-year survival rate was 80 percent.
  • The five-year survival rate for NHL was 69 percent, and the 10-year survival rate was 58 percent.

Prevention

Because no one is sure what causes it, there is really no practical way to prevent lymphoma. Maintaining good overall health, adhering to a nutritious diet, practicing safe sex (to prevent sexually transmitted infections) and seeking prompt treatment for health problems may decrease your risk.

Sources

  • "Hodgkin's Lymphoma." Mayo Foundation for Medical Education and Research, 2011. http://www.mayoclinic.org/diseases-conditions/hodgkins-lymphoma/basics/definition/con-20030667. Accessed Aug. 4, 2014.
  • "Non-Hodgkin Lymphoma." American Cancer Society, 2014. http://www.cancer.org/acs/groups/cid/documents/webcontent/003126-pdf.pdf. Accessed July 31, 2014.
  • "Non-Hodgkin Lymphoma." The Leukemia & Lymphoma Society, 2013. http://www.lls.org/content/nationalcontent/resourcecenter/freeeducationmaterials/lymphoma/pdf/nhl.pdf. Accessed July 30, 2014.
  • "Treatment for Non-Hodgkin Lymphoma." Sloan Kettering Medical Center, 2014. http://www.mskcc.org/cancer-care/adult/treatment-non-hodgkin-lymphoma. Accessed July 30, 2014.
  • "What Are the Key Statistics About Hodgkin Disease?" American Cancer Society, 2014. http://www.cancer.org/cancer/hodgkindisease/detailedguide/hodgkin-disease-key-statistics. Accessed Aug. 4, 2014.
  • "What You Need to Know About Non-Hodgkin Lymphoma." National Cancer Institute, 2008. http://www.cancer.gov/cancertopics/wyntk/non-hodgkin-lymphoma/page1. Accessed July 30, 2013.