Lymphomas are cancers that form in white blood cells, which circulate in the blood and are found in lymph nodes and other organs throughout the body. Lymphoma is called a cancer of the immune system because white blood cells, or lymphocytes, help the body defend against infection. It is the most common blood cancer and the third most common pediatric cancer.
Unlike some other cancers, lymphomas are not linked to such lifestyle factors as smoking or unhealthy eating. “Most lymphomas just occur sporadically, with no prior warning signs,” says Kenneth Roberts, MD, a radiation oncologist in the Department of Therapeutic Radiology at Yale Medicine.
Yale Medicine has a multidisciplinary team of experts--including radiation oncologist, pathologists, and oncologists--who work together to determine the best treatment plan for each patient.
What are the types of lymphoma?
Lymphomas are divided into two main categories: Hodgkin lymphoma and non-Hodgkin lymphoma.
Hodgkin lymphoma can occur at any age, though it’s often diagnosed in teenagers, people in their early 20s, or in people over 55. About 8,000 new cases of Hodgkin lymphoma are reported each year in the United States. It is one of the most curable forms of cancer, with a five-year survival rate of nearly 90%.
Non-Hodgkin lymphoma (NHL) is a blanket term used to describe dozens of other cancers of the immune system. These cancers make up about 74,000 new cases a year. NHLs are further divided into T-cell and B-cell lymphomas, depending on their cell of origin, in the thymus gland or in the bone marrow, respectively. Five-year survival rate for NHL, as a broad category, is about 72%, but each subtype has important nuances. Some forms of NHL can be cured, while others can be managed for many years.
What are risk factors for lymphoma?
Having a brother or sister who’s had Hodgkin disease can also increase a person’s risk, though most people who get it do not have a family history. Men are more likely than women to get Hodgkin disease and most types of NHL. Age also plays a role: Hodgkin disease is often diagnosed in people between 15 and 40 and over 55, while most types of NHL usually strike adults 60 and older. Children can get both types of lymphoma, although NHL is slightly more common in children under 15.
Exposure to radiation or toxic chemicals, such as some insecticides and pesticides, may modestly raise a person’s risk of lymphoma. Taking immunosuppressant drugs, or having a condition that weakens the body’s immune system (such as HIV), may also be associated with higher risk for lymphomas.
How is lymphoma diagnosed?
After a patient visits a doctor to have a strange lump examined, or receives abnormal blood-test results, the first step is usually to have a computed tomography (CT) or a magnetic resonance imaging (MRI) scan to determine whether a tumor is present and, if so, its size and location.
To determine whether a mass is cancerous, a surgeon performs a biopsy, removing a small piece of a tumor either with an incision in the skin or through a tiny, hollow needle. A pathologist examines the sample under a microscope to determine the type of cancer and how advanced it is and whether it has spread. Additional imaging tests, blood tests, and/or a bone marrow biopsy may also be performed to help determine the cancer’s stage.
Lymphoma ranges from Stage I (meaning the cancer is only in one lymph-node region, or in one area of a single organ) to Stage IV (meaning it has spread outside of the lymphatic system and into other organs, such as the liver, brain or lungs).
How is lymphoma treated?
Unlike many other cancers, lymphomas are almost never removed surgically.
Low-grade lymphomas are often treatable with radiation alone, typically through daily treatment sessions, Monday through Friday, for three to four weeks. Each session lasts just a few minutes, with the radiation beam aimed at the part of the body where the cancer is situated. If a lymphoma tumor has spread to the brain or is pressing on nerves, radiation may also be used to relieve pain or other symptoms.
For more advanced lymphomas, chemotherapy drugs are usually the first line of treatment. These drugs are administered via an I.V. or taken orally. Because they can harm healthy cells along with cancer cells, they often cause such side effects as hair loss, nausea, and low blood counts. As part of this systemic approach to treatment, some lymphomas are treated with monoclonal antibody drugs (man-made versions of natural antibody proteins that the immune system makes to fight infections).
Radiation is often used after chemotherapy to destroy residual cancer cells and reduce the risk of their return. “We can target those situations in which cancer might come back with localized radiotherapy treatment, and come up with a winning combination that allows us to use less chemotherapy and minimize side effects,” says Dr. Roberts.
If a lymphoma doesn’t vanish, or returns after treatment, some patients may need a stem cell transplant (also called a bone-marrow transplant) along with more intensive chemotherapy. Cells from the patient’s blood, or bone marrow, are removed and frozen, the patient receives a very high dose of chemotherapy, and then the cells are infused back into the bloodstream to help speed recovery and the growth of new, healthy blood cells. This is referred to as an autologous transplant.
Stem cells can also come from a donor (a relative or someone with a matched immune-tissue type). In this type of transplant, called an allogeneic transplant, the patient receives a whole new immune system. For this type of allo-transplant, some patients also receive total body irradiation.
How is Yale Medicine’s approach to treating lymphoma unique?
Scientists at Yale Medicine have played a role in discoveries that have led to new medications and changed the way cancer is treated. Yale Medicine also participates in clinical trials for new lymphoma treatments, giving patients access to new therapies before they are broadly available.
Lymphoma patients at Yale Medicine have a multidisciplinary team of experts, including radiation oncologist, pathologists, and oncologists, who work together to determine the best treatment plan for each patient. Yale Medicine is also the only center in Connecticut that offers stem-cell transplants using compatible donor cells. Those transplants have been performed at Yale since 1988, making it one of the early cancer centers to use the procedure to successfully treat cancer patients.