Lymphoma is the name for a group of blood cancers that develop in certain immune cells. The two main types are Hodgkin lymphoma and non-Hodgkin lymphoma (NHL). About 90% of lymphomas are the non-Hodgkin type, while about 10% are Hodgkin.
In 2016, in the U.S., it is estimated that there will be 72,580 new cases of non-Hodgkin lymphoma and 8,500 new cases of Hodgkin lymphoma, for a total of 81,080 cases. An estimated 21,270 deaths from lymphoma will occur in the U.S. in 2016, most of which are NHL (20,150).
Hodgkin lymphoma has characteristics that distinguish it from NHL, including the presence of Reed-Sternberg cells. These are large, cancerous cells with a distinct appearance, named for the scientists who first identified them. Hodgkin lymphoma is one of the most curable forms of cancer.
NHL represents a diverse group of diseases distinguished by the characteristics of the cancer cells associated with each disease type. Most people with NHL have a B cell type (about 85%). The others have a T cell type or a natural killer (NK) cell type of lymphoma. Some patients with fast-growing NHL can be cured. For patients with slow-growing NHL, treatment may keep the disease in check for many years.
Non-Hodgkin lymphoma patients are usually treated with rituximab (Rituxan®, a monoclonal antibody) in combination with chemotherapy. Radiotherapy is used less often and typically when the disease is localized to a single site in the body. Other monoclonal antibodies directed at lymphoma cells are used for some types of NHL, as are antibodies linked to a radioactive molecule and a cytokine therapy. In addition, new small molecule drugs are being used that target important survival pathways in NHL tumor cells. If NHL persists or recurs after initial treatments, high dose chemotherapy followed by stem cell transplantation may be an option. As of May 2018, two CAR T cell immunotherapies—axicabtagene ciloleucel (Yescarta™) and tisagenlecleucel (KymriahTM)—have been approved for adult patients with several forms of non-Hodgkin lymphoma.
Hodgkin lymphoma is usually treated with chemotherapy, radiation therapy, or a combination of the two, depending on the stage and cell type. Stem cell transplantation may be an option if these are not effective. The targeted drug brentuximab vedotin (Adcetris®)—a monoclonal antibody linked to a chemotherapy drug—is approved to treat Hodgkin lymphoma in patients whose disease has failed to respond to other treatment and, as of August 2015, to prevent relapse following a stem cell transplant. In 2016, nivolumab (Opdivo®) was approved to treat Hodgkin lymphoma that has relapsed or progressed after treatment. In 2017, pembrolizumab (Keytruda®) was approved for both children and adults with relapsed or refractory Hodgkin lymphoma, while the combination of rituximab and hyaluronidase (Rituxan HycelaTM) has been approved for follicular lymphoma (FL) and diffuse large B cell lymphoma (DLBCL).