Pediatric Cancer Pediatric Lymphoma

Approximately 1,700 children are diagnosed with lymphoma every year in the United States, making lymphoma the third most common childhood cancer.

Lymphoma includes cancers that develop in the body’s lymphatic system, such as Hodgkin’s disease and Non-Hodgkin’s lymphoma. The lymphatic system includes:

  • adenoids
  • bone marrow
  • lymphatic channels
  • lymph nodes
  • spleen
  • thymus
  • tonsils.

The lymphatic system is also a common location for secondary cancers, or cancers that have spread from their original location in other parts of the body. Lymphoma differs from secondary lymphatic cancers, and actually starts in the lymphatic system.

Lymphoma Varieties: Hodgkin’s Disease and Non-Hodgkin’s Lymphoma

Generally, lymphoma is divided into two categories:

  • Hodgkin’s disease
  • non-Hodgkin’s lymphoma.

The type of lymphatic cells affected by the cancer defines each category of lymphoma. Hodgkin’s disease is defined by the presence of abnormal Reed-Sternberg cells, while non-Hodgkin’s lymphoma results in an accumulation of abnormal lymphocytes. Lymphocytes are white blood cells that circulate in the blood and lymphatic system.

Hodgkin’s disease affects three out of every 100,000 Americans. Although lymphoma symptoms may develop at any age, Hodgkin’s disease is most prevalent between the ages of 15 and 40.

Non-Hodgkin’s lymphoma can also occur at any age, although a diagnosis of non-Hodgkin’s lymphoma earlier than the age of three is rare. Approximately 500 pediatric cases of non-Hodgkin’s lymphoma are diagnosed annually in the United States. Non-Hodgkin’s lymphoma is just slightly more common than Hodgkin’s disease in children younger than 15.

Non-Hodgkin’s Lymphoma, Leukemia and Lymphocytes

Both non-Hodgkin’s lymphoma and acute lymphocytic leukemia cause abnormalities in specific white blood cells called lymphocytes. As both cancers affect lymphocytes, distinguishing between non-Hodgkin’s lymphoma and leukemia can be difficult. Generally, leukemia causes higher numbers of abnormal cells to accumulate in the blood and bone marrow compared to lymphomas, which may cause large lymph node swellings.

Lymphoma Symptoms

Swollen glands, or enlarged lymph nodes, are among the most common lymphoma symptoms. Lymph nodes in the neck, under the arms, in the groin and above the collarbone can cause a painless swelling due to lymphoma.

Lymphoma symptoms can also include coughing and breathing difficulties if the thymus enlarges. The thymus is an immune system gland located in the chest. The thymus is larger in children than adults, so children are more likely to report breathing difficulties among their lymphoma symptoms. Blood flow to and from the heart may also be compromised.

One third of lymphoma patients experience general symptoms. These symptoms may not be immediately identified as lymphoma symptoms. Generalized symptoms include:

  • appetite loss
  • fatigue
  • fever
  • itching
  • night sweats
  • weight loss.

Lymphoma Diagnosis

A physical examination is the first step of a lymphoma diagnosis. The doctor checks for swollen glands, infection and pain. A history of possible lymphoma symptoms is recorded.

Lymph nodes often swell due to infections, as the lymphatic system and lymphocytes play an important role in the immune system. If symptoms suggest an infection, antibiotics may be prescribed, and lymph nodes may be monitored for signs of reduced swelling.

If symptoms and physical exam results suggest the need, a lymphatic system biopsy is required. A biopsy removes lymphatic cells for microscopic examination. Several biopsy methods may be employed:

  • An excision biopsy is required to remove entire lymph nodes or multiple lymph nodes. This form of biopsy requires a larger incision and general anesthetic.
  • A fine needle aspiration biopsy uses a thin needle to gather lymphatic cells.
  • A small surgical incision under local anesthetic removes biopsy samples.

Biopsy samples are examined for abnormal lymphocytes or Reed-Sternberg cells, verifying or ruling out a diagnosis of Hodgkin’s disease, non-Hodgkin’s lymphoma or secondary cancer.

Once a diagnosis of lymphoma is established, further diagnostic tests may be required to determine the spread of the cancer, including:

  • bone marrow biopsy
  • bone scan
  • complete blood count
  • CT scan
  • kidney function test
  • liver function test
  • magnetic resonance imagery (MRI)
  • spinal tap
  • ultrasound.

Lymphoma Treatment and Remission

Hodgkin’s disease and non-Hodgkin’s lymphoma are treated with radiation therapy, chemotherapy or a combination of the two treatments. Dosages and treatment options vary depending on the age of the patient and the severity or spread of lymphoma. For instance, a child with localized lymphoma may receive only radiation treatment, while an older child with widespread lymphoma may be treated with both radiation and chemotherapy.

Remission is defined as the absence of lymphoma symptoms and abnormal lymphatic system cells for more than five years. Ninety percent of Hodgkin’s disease and non-Hodgkin’s lymphoma cases go into remission.

New Lymphoma Treatments

High-risk lymphoma patients who experience a relapse (the return of abnormal lymphoma cells) may not respond well to chemotherapy and radiation therapy that worked in previous treatments. In such cases, bone marrow transplants may be employed. Healthy bone marrow is transplanted into the child’s system. If a bone marrow transplant works, the healthy bone marrow begins to produce normal lymphocytes and other white blood cells, helping the child fight disease.

New delivery methods for chemotherapy and radiation therapy are also under investigation. Antibodies are being developed that can carry lymphoma chemotherapy medication or radiation particles directly to lymphoma cells in the lymphatic system. Such delivery methods minimize the side effects as only cancerous cells are under attack.

Stem Cells and Lymphoma

Stem cell research may provide additional lymphoma treatment options. Stem cells are “primitive” cells that can be harvested from bone marrow or umbilical cord blood. The underlying theory is that an infusion of stem cells could help speed the repair of damage caused by chemotherapy and radiation treatment.

Resources

Lymphoma Information Network (2004). Childhood lymphoma. Retrieved September 4, 2007, from the Lymphoma Information Network Web site: http://www.lymphomainfo.net/childhood/lymphoma.html.

National Cancer Institute (2007). Childhood non-Hodgkin’s lymphoma treatment. Retrieved September 4, 2007, from the National Cancer Institute Web site: http://www.cancer.gov/cancertopics/pdq/treatment/childhodgkins/patient/.

Nemours Foundation (2007). Childhood cancer: Lymphoma. Retrieved September 4, 2007, from the Nemours Foundation Web site: http://www.kidshealth.org/parent/medical/cancer/cancer_lymphoma.html.