Hodgkin's disease

Epidemiology

Unlike other lymphomas, whose incidence increases with age, Hodgkin's lymphoma has a bimodal incidence curve: that is, it occurs more frequently in two separate age groups, the first being young adulthood (age 15-35), the second being in those over 50 years old. It is more common in males.

Symptoms

Swollen, but non-painful, lymph nodes are the most common sign of Hodgkin's disease, often occurring in the neck. The lymph nodes of the chest are often affected and these may be noticed on chest X-ray.

About one-third of people with Hodgkin's disease may also notice some systemic symptoms, such as low-grade fever, night sweats, weight loss, or fatigue.

Diagnosis

Hodgkin's disease must be distinguished from non-cancerous causes of lymph node swelling (such as various infections) and from other types of cancer. Definitive diagnosis is by lymph node biopsy (removal of a lymph node for pathological examination).

Hodgkin's disease can be sub-classified by histological type. The cell histology in Hodgkin's lymphoma is not as important as it is in non-Hodgkin's lymphoma: the treatment and prognosis in Hodgkin's lymphoma depend on the stage of disease rather than the cell type.

Staging

After Hodgkin's disease is diagnosed, a patient will be staged: that is, they will undergo a series of tests and procedures which will determine what areas of the body are affected. These procedures will always include documentation of their histology, a physical examination, blood tests, chest X-Ray, CT scans or MRI (magnetic resonance imaging) scans of the chest, abdomen and pelvis, and a bone marrow biopsy. Some patients will also require liver biopsy, lymphangiograms, gallium scans, bone scans, and surgical laparotomy, which involves opening the abdominal cavity and visually inspecting for tumors.

On the basis of this staging, the patient will be classified according to a staging classification (the Ann Arbor staging classification scheme is a common one):

• Stage I is involvement of a single lymph node region or single extralymphatic site;
• stage II is involvement of two or more lymph node regions on the same side of the diaphragm or of one lymph node region and a contiguous extralymphatic site;
• stage III is involvement of lymph node regions on both sides of the diaphragm;
• stage IV is disseminated involvement of one or more extralymphatic organs.

The absence of systemic symptoms is signified by adding 'A' to the stage; the presence of systemic symptoms is signified by adding 'B' to the stage.

In 1996, an international effort identified seven prognostic factors that accurately predict the success rate of conventional treatment in patients with locally extensive or advanced stage Hodgkin's disease. Freedom from progression (FFP) at 5 years was directly related to the number of factors present in a patient. The 5-year FFP for patients with zero factors is 84%. Each additional factor lowers the 5-year FFP rate by 7%, such that the 5-year FFP for a patient with 5 or more factors is 42%.

The prognostic factors identified in the international study are:

• Age >= 45 years
• Stage IV disease
• Hemoglobin < 10.5 mg/dl
• Lymphocyte count < 600/ul or < 8%
• Male sex
• Albumin < 4.0 mg/dl
• White blood count >= 15,000/ul

Treatment

Patients with early stage disease (IA or IIA) are effectively treated with radiation therapy. Patients with later disease (III, IVA, or IVB) are treated with combination chemotherapy alone. Patients of any stage with a large mass in the chest are usually treated with combined chemotherapy and radiation therapy.

Currently, the ABVD chemotherapy regimen is the gold standard for treatment of Hodgkin's disease. Developed in Italy in the 1970s, the ABVD treatment typically takes between six and eight months, although longer treatments may be required.

With appropriate treatment, over 85% of Hodgkin's disease cases are curable.

The American National Cancer Institute's "Hodgkin's Lymphoma Home Page" is http://www.cancer.gov/cancer_information/cancer_type/hodgkins_disease/

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