MD2B - Pediatric Oncology: Hodgkin's Lymphoma

Overview

Hodgkin's lymphoma, also sometimes referred to as Hodgkin's disease, is a cancer that arises in the lymphatic system of the body. The lymphatic system is a group of organs that make, store, and transport white blood cells throughout the body to sites of infection. Lymphatic tissue is found throughout the body, so Hodgkin's can develop and spread at almost any body site. Hodgkin's lymphoma has a bimodal age distribution, with one peak seen in young adults and a second peak seen in the elderly. Hodgkin's lymphoma accounts for 6% of childhood cancers and is the most common type of cancer observed in children ages 15-19. In this pediatric age group, Hodgkin's is more common in males than females. Under the microscope, Hodgkin's can be identified by the presence of the classic "owl-eyed" Reed-Sternberg multinucleated giant cells amidst a multitude of inflammatory cells. The Epstein Barr Virus is observed in 20% of pediatric Hodgkin cases.

Symptoms

Hodgkin's lymphoma can present in a variety of ways. Most typically, patients present with painless swollen lymph nodes in the neck, under the arms, or in the groin. The liver and spleen are considered lymphatic organs, and may also be enlarged. Children may have nonspecific systemic symptoms, including fatigue and loss of appetite. The "classic symptoms" of fever, night sweats, unexplainable weight loss, and pruritis (itchy skin) are only seen in 20% of children. However, when these symptoms are present, they have important prognostic and staging value. Other diseases that can present with similar symptoms include other types of cancer, various infections, lymphatic disorders, and lupus.

Diagnosis

A careful history and physical exam is the first step in evaluating a child for Hodgkin's lymphoma. Parents should be asked specific questions regarding the child's previous health history, the family's history of cancer and lymphatic disease, and any changes in the child's health over the past several months. During the physical exam, all lymph nodes should be examined and measured. The tonsils, liver, and spleen must also be evaluated. In Hodgkin's disease, enlarged lymph nodes are painless and typically feel rubbery and firm. Any pulmonary or neurological changes must also be noted as they can be clues to disease spread.

Lab studies

• CBC (complete blood count) with differential: a blood sample is taken to look at the number and shape of the various blood cells including red blood cells, white blood cells, and platelets.
• Chemistry panel: a blood sample is taken to evaluate the functioning of the liver and spleen and to look at the levels of various salts and chemicals in the blood
• ESR (erythrocyte sedimentation rate) and CRP (C-reactive protein): a blood sample to measure whether inflammatory markers are elevated

Imaging studies

• Chest x-ray and chest CT scan: the chest radiograph provides important information to the physician about structures in the chest, including the lungs and airway. Two thirds of children with Hodgkin's disease have a mass in the mediastinum (chest).
• Abdominal and pelvic CT scans: diagnostic imaging tests to help evaluate the extent of abdominal and pelvic disease spread
• PET( positron emission tomography): diagnostic imaging test that evaluates glucose uptake in the body and can help to identify areas where cancer is present

Lymph node biopsy

A tissue sample taken from an enlarged lymph node is the preferred method of establishing the diagnosis of Hodgkin lymphoma. A definite diagnosis is made when the classic multinucleated giant Reed-Sternberg cell is observed under the microscope. Subclassification is also possible by observing specific cells in the sample.

Staging and Prognostic Factors

A staging system has been developed for Hodgkin Lymphoma

Stage I: Involvement of a single lymph node region or direct extension from that node to an adjacent extralymphatic region.

Stage II: Involvement of two or more lymph node regions on the same side of the diaphragm, or extension from any one of these lymph nodes to an extralymphatic adjacent organ

Stage III: Involvement of lymph node regions on both sides of the diaphragm, or extension to an adjacent extralymphatic organ or to the spleen

Stage IV: Noncontinuous involvement of one or more organs

Many factors contribute to survival prognosis. Extensive disease, presence of "B symptoms" (fever, night sweats, weight loss, and itchy skin), elevated erythrocyte sedimentation rate, male sex, and poor initial response to treatment are all factors that worsen prognosis.

Treatment

Multidrug c hemotherapy and low-dose radiation therapy are combined to maximize treatment efficacy while limiting the serious side effects of each individual therapy. Side effects of radiation are a function of the total dose delivered and the volume irradiated. Potential immediate toxicities include reddening of the skin, hair thinning, change in taste, or GI discomfort. Important long-term effects of radiation include bone growth retardation and short stature, pulmonary dysfunction, cardiac complications, endocrine abnormalities, and the development of secondary malignancies in the field of irradiation. Side effects of chemotherapy include nausea, vomiting, infection, and possible lung and heart complications specific to individual drugs.