Last week I tried to explain the very complex non-Hodgkin lymphomas (NHL). This week I want to cover Hodgkin lymphoma, more commonly known as Hodgkin’s Disease (HD). It gets its eponymous name from Dr. Thomas Hodgkin who first described it in 1832.
Hodgkin’s is a potentially curable malignant lymphoma that carries a much better prognosis than non-Hodgkin lymphomas. It is a very specific type of lymphoma, defined by its microscopic appearance and by specific proteins that are found in the cell membranes of the tumor cells.
We expect about 8,500 new cases of Non-Hodgkin lymphomas to be diagnosed this year. The death rate from this cancer is declining due to improved treatment. The disease has what is called a bimodal age distribution, with occurrences between the ages of 15 and 34 and another in those over age 55. Most patients, if not cured, usually die from HD much later in life. Hodgkin’s is more common in Caucasians and slightly more common in men, except in childhood where 85 percent of the cases are found in boys.
The cause of HD is unknown. It’s hypothesized that a viral infection, perhaps Epstein-Barr virus (EBV) may cause HD. Epstein-Barr virus causes mononucleosis (mono). EBV is found in half of HD tumors in people with normal immune systems and all of the tumors in people infected with HIV. One percent of people with HD have a family history of the disease. Siblings of a person with HD are about three to seven times more likely to develop HD themselves.
Symptoms of HD are very similar to those of non-Hodgkin lymphomas. About 40 percent of patients develop B Symptoms (weight loss, fever and drenching night sweats). Hodgkin tumors are frequently found in the chest. Patients may therefore present with chest pain, cough and shortness of breath. Most patients present with enlarged lymph nodes in the neck (60-80%), armpits (6-20%) and less commonly, the groin. Patients may also present with an enlarged liver or spleen.
The diagnosis of HD is made by doing blood work and radiologic studies. A definitive diagnosis of HD can only be made by removing involved lymph nodes for microscopic examination. A simple chest X-ray may show a tumor. If the diagnosis is suspected, a CT scan of the chest, abdomen and pelvis are usually ordered to look at the internal lymph nodes.
More recently, the standard test for the diagnosis and staging of HD is the PET/CT scan. PET stands for positron emission tomography. These scans are performed by tagging sugar molecules with a radioactive tracer. Since cancer cells require a lot of energy, they take up a larger proportion of the tagged sugar molecules. This results in increased radioactivity in the tumor that is detected using a special camera. This information, combined with standard X-rays from the CT scan, is very specific for determining how extensive the HD is.
I mentioned staging. This is something that is done in cancers to describe how extensive the disease is. This is very important for determining treatment and prognosis. The staging of HD can vary from stage I (found in one lymph node area) to stage IV (found in many areas or involving other organs or the bone marrow). The presence or absence of B symptoms is also part of the staging of HD.
The five-year survival rate with stage I and II disease is about 90percent, while stage III carries an 84percent survival and stage IV roughly 65percent. Patients who have very large “bulky” disease, greater than three sites of involvement, B symptoms, or disease outside the lymph nodes have a worse prognosis.
Hodgkin lymphoma is considered curable. The goal of treatment is to induce a complete remission where there is no evidence of disease as evidenced by PET/CT, physical exam and lab studies. Treatment usually involves a combination of chemotherapy and radiation. These treatments can potentially cause long-term toxic effects. Newer combinations of chemotherapy are much less toxic than those used just a few years ago. Still, patients can develop heart disease, lung disease, thyroid problems, and other cancers (lung, breast & leukemias) as a result of treatment. The treatments can also reduce fertility.
– Dr. John Roberts is a member of the Franciscan Physician Network specializing in Family Medicine as well as the Deputy County Health Officer in Montgomery County.