What is Hodgkin's disease?

Hodgkin's disease is a disease of lymph nodes and lymphatic tissues, called a lymphoma. There are other types of lymphomas besides Hodgkin's disease, but they will not be discussed in this review. Hodgkin's disease occurs when cells in the lymph nodes begin to grow out of control and compress nearby tissues or spread throughout the body via the lymphatic circulation. Hodgkin's disease is distinguished from the other types of lymphomas by the way it looks under a microscope and by the way it grows and spreads.

Am I at risk for Hodgkin's disease?

Hodgkin's disease is a fairly uncommon cancer, with 7,350 cases expected to be diagnosed in the United States during 2005. Of those patients, it is expected that Hodgkin's disease will cause 1,410 deaths. Hodgkin's disease occurs slightly more commonly in men, and much more frequently in Caucasians. Most of the patients who are diagnosed with Hodgkin's disease are either in their 20s or older than the age of 55.

No one knows what causes Hodgkin's disease. It has been theorized that the development of Hodgkin's disease is related to infection with a virus, although no one can say for sure. No clear-cut associations have been found with exposures to toxins, chemicals, or environmental agents. First degree relatives of patients with Hodgkin's disease have a higher chance of developing it, but exactly how genetics control this disease is poorly understood.

Contracting the HIV virus may be a risk factor for developing Hodgkin's disease. It has been recognized that Hodgkin's disease in HIV-infected patients is generally more aggressive and advanced than in non-HIV-infected patients. However, researchers disagree as to the importance of this finding.

How can I prevent Hodgkin's disease?

Because no one knows exactly what causes Hodgkin's disease, there are no specific steps anyone can take to prevent developing it.

What screening tests are available?

Hodgkin's disease is rare enough that it is not screened for with any specific tests. The best way to pick up a diagnosis of Hodgkin's disease early is to see your doctor regularly for a thorough physical examination.

What are the signs of Hodgkin's disease?

Unfortunately, the early stages of Hodgkin's disease may not have any symptoms. As the tumor grows in size, however, it can produce a variety of symptoms, including:

• swelling of nodes in the neck, groin or underarm
• pain in nodes when consuming alcohol
• fever
• night sweats
• weight loss
• itching
• cough

Many of these symptoms are non-specific, and could represent a variety of different conditions; however, your doctor needs to see you if you have any of these problems. The most common presenting symptom of Hodgkin's disease is swelling of nodes in the neck or underarm.

How is Hodgkin's disease diagnosed and staged?

When a patient presents with symptoms suggestive of Hodgkin's disease, his/her physician will perform a thorough history and physical examination. If there is a node that is enlarged, it will likely be surgically removed in what is called an "excisional biopsy". The entire node is removed so that another doctor known as a pathologist can look at it under a microscope. A biopsy specimen is required to make the diagnosis of Hodgkin's disease.

Once the diagnosis is made, a physician will order a number of tests to get a sense of the extent of the disease. A few different blood tests will probably be ordered. The physician will also get a CT scan (3D X-ray) to stage the patient. Often, a PET scan will be ordered as well. Staging is performed in order to guide the choice of treatment and offer information about prognosis. A simplified version of the staging system for Hodgkin's disease (called the Modified Ann Arbor Staging System) is offered below:

Stage 1. Single lymph node region involved with disease

Stage 2. Two or more lymph node regions involved on the same side of the diaphragm (the muscle that controls breathing and that separates the chest from the abdomen)

Stage 3. Lymph node regions involved on both sides of the diaphragm

Stage 4. Diffuse involvement of an organ that is not considered part of the lymphatic system (like the lung or liver).

If a patient has certain symptoms, this can affect the stage classification. High fevers, night sweats, or weight loss (greater than 10% of original body weight) are all called "B" symptoms. If a patient has B symptoms, then his/her stage will include the letter "B" after the stage number. If a patient doesn't have any of these B symptoms, then his/her stage will include the letter "A" after the stage number.

What are the treatments for Hodgkin's disease?

Chemotherapy

Chemotherapy is the use of anti-cancer drugs that go throughout the entire body. These drugs may be given through a vein as liquid or by mouth as pills. Chemotherapy has become the mainstay of treatment for patients with Hodgkin's disease, and combinations of different chemotherapy drugs are used to kill the tumor cells. One of the most common chemotherapy regimens is called "ABVD". ABVD stands for four different drugs: Adriamycin, Bleomycin, Vinblastine, and Dacarbazine. There are many other chemotherapy drugs besides ABVD that are used for Hodgkin's disease, and your oncologist can explain why he or she recommends one particular regimen over another.

Radiation Therapy

Early stage Hodgkin's disease patients (stage IA or IIA) are generally treated with radiation therapy. Radiation therapy uses high-energy rays (similar to x-rays) from an external source to kill cancer cells. Radiation therapy requires patients to come in 5 days a week for about 4-5 weeks to a radiation therapy treatment center. The treatment takes just a few minutes, and it is painless. Stage IA or IIA patients are usually given some chemotherapy first, and then they receive radiation to the sites of their body that are (or were, before the chemotherapy) involved by disease. Radiation is also used for big, bulky areas of disease. Your radiation oncologist can answer questions about the indications, process, and side effects of radiation therapy in your particular case.

Stem Cell Transplantation

Sometimes patients receive chemotherapy +/- radiation therapy and their Hodgkin's disease isn't cured. When this happens, they may be recommended to undergo a stem cell transplantation. Stem cells are precursor cells that can develop into other cells of the body when placed in the right environment. Stem cell transplantation is used along with high doses of chemotherapy. The high doses of chemotherapy are so intense that they wipe out a patient's bone marrow. Without bone marrow, a person can't make the components of blood and the immune system that are necessary to survive. In order to replace the patient's bone marrow, stem cells are given. In the case of autologous stem cell transplants, a patient's own stem cells are harvested before the high dose chemotherapy is given, stored, and finally returned to the patient after the chemotherapy is done. This way, the bone marrow can re-grow from the stem cells. This enables a patient to tolerate the super high doses of chemotherapy that work against Hodgkin's disease but have the unwanted side effect of wiping out healthy bone marrow. Stem cell transplantation can sometimes cure patients when other treatment strategies have failed. However, stem cell transplantation is a complex and intense treatment, so it is typically reserved for patients who aren't cured with the initial regimens of chemotherapy +/- radiation therapy.

Follow-up testing

Once a patient has been treated for Hodgkin's disease, they need to be closely followed for a recurrence. At first, follow-up visits will be fairly often. The longer a patient is free of disease, the less often the checkups. The oncologist will tell you when he or she wants follow-up CT scans or PET scans. It will also be very important to screen all Hodgkin's patients for the development of any new cancers that may arise.

Clinical trials

Clinical trials are extremely important in furthering our knowledge of this disease. It is through clinical trials that we know what we do today, and many exciting new therapies are currently being tested. Talk to your doctor about participating in clinical trials in your area.

This article is meant to give you a better understanding of Hodgkin's disease. Use this knowledge when meeting with your physician, making treatment decisions, and continuing your search for information. You can learn more about Hodgkin's disease on OncoLink through the related links to the left.

References

Connors, Joseph M. "Hodgkin's Lymphoma" from Clinical Oncology 3 rd Edition., Abeloff et al. Elsevier Churchill Livingstone. Philadelphia, PA, 2004. pg. 2985-3014
Yung, Lynny and Lynch, David. Hodgkin's Lymphoma. The Lancet. Vol 361, March 15 th, 2003. pg943-951