Medical oncologist Steven Horwitz discusses advances in the diagnosis and treatment of non-Hodgkin lymphoma.
“Getting the correct diagnosis, determining what kind of lymphoma you have, and confirming where it is in the body, or staging, are important steps in developing the most effective treatment plan,” says medical oncologist Steven Horwitz, who is one of more than 30 experts who care for people with lymphoma at Memorial Sloan-Kettering. “Consultation with an experienced physician who specializes in lymphoma is critical, especially when a rare type of lymphoma is diagnosed.”
Memorial Sloan-Kettering and the online cancer community CancerConnect recently partnered to air a live webinar in which Dr. Horwitz offered this and other essential information regarding the diagnosis and treatment of lymphoma — a disease that encompasses nearly 60 related types of cancer that develop in cells of the immune system called lymphocytes.
He described how treatment could be tailored based on the unique molecular, clinical, and prognostic features that characterize each type of lymphoma.
A variety of laboratory tests are used to determine which specific subtype of Hodgkin lymphoma or non-Hodgkin lymphoma a patient has and whether the disease is indolent (low grade), intermediate, or high grade. Non-Hodgkin lymphoma subtypes are generally indolent, slow growing, and treatable, but are difficult to cure. Intermediate and high-grade lymphomas tend to grow more quickly, and though aggressive, are curable and unlikely to recur.
A biopsy is performed in order for a pathologist to analyze a patient’s cancer cells under a microscope and distinguish lymphomas based on the appearance of the cells, their surface features (called immunochemistry), and their genetic features. Different genes are expressed, or turned on, in different cells, and certain gene patterns are known to be correlated with certain kinds of lymphoma. Experts are increasingly understanding how these features can affect prognoses and treatment choices.
“Teasing out these gene expression signatures, combined with other molecular and clinical details we obtain during the diagnostic workup, helps us determine which treatment will be most effective for a particular patient,” says Dr. Horwitz.
Imaging tests such as CT and PET scans are used to ascertain staging, providing information about where in the body the lymphoma is, how extensively it has spread, and whether or not the lymphoma is in the bone marrow. They can also be used to show how well a treatment is working, monitor someone who is in remission, and observe for signs of disease progression in a person who has chosen to delay therapy.
Choosing Active Therapy or Watchful Waiting
The majority of lymphomas can be effectively managed with active treatment. Chemotherapy and chemo-immunotherapy are the most common treatments for lymphoma, but optimal treatment may consist of other therapies such as radiation, stem cell transplant, targeted therapies, radio-immunotherapy, or investigational agents. These can be used alone or in combination, and all have the potential to cause side effects.
“Consultation with an experienced physician who specializes in lymphoma is critical, especially when a rare type of lymphoma is diagnosed.” “
Steven Horwitz, Medical oncologist
Indolent lymphomas may grow very slowly, remain stable, or even sometimes shrink on their own without treatment. Some people can live with an indolent lymphoma as a chronic problem for a decade or more before requiring therapy. Delaying active treatment, also known as watchful waiting or active surveillance, is a dynamic disease management option in which a patient is regularly monitored for signs or symptoms of disease progression.
“There is no evidence that treating these types of lymphoma sooner improves prognosis,” says Dr. Horwitz. “Active surveillance may be a reasonable approach among patients whose disease is unlikely to be cured with treatment, are medically able to delay therapy, and who would like to avoid the risks and unpleasant side effects associated with many cancer therapies.”
Considering New Therapies and Clinical Trials
“Understanding standard treatment options and how and when to access novel and innovative therapies is essential in order to achieve the best outcome,” explains Dr. Horwitz. “If standard treatments are not likely to work, thinking about a new treatment being studied in a clinical trial may be recommended.”
Immunomodulatory agents — targeted therapies that help the patient’s own body fight lymphoma by enhancing antitumor activity — are more frequently being used to treat people with non-Hodgkin lymphoma.
Monoclonal antibodies bind to certain proteins on the surface of the cancer cell and recruit healthy cells in the immune system to kill the cancer cell or induce cell death. Other immunomodulatory agents can be used to take the breaks off of normal lymphocytes and unleash a response from the immune system to specifically attack the lymphoma cells.
Some monoclonal antibodies can deliver toxic molecules to cancer cells specifically. Miniscule amounts of chemotherapy or radiation can be attached to these antibodies, which bind to certain proteins on the cancer cell. Like a Trojan horse, they destroy the cell from within when it takes up the antibody along with the treatment.
Another targeted approach involves the use of small molecule inhibitors, which can interfere with abnormal signaling pathways — an internal cascade of events that causes cells to divide and grow uncontrollably and disrupts the cancer cell’s efforts to stay alive.
“Many of these targeted therapies are in the form of a pill and may have fewer side effects than chemotherapy, so people may continue to take them for longer periods of time,” Dr. Horwitz points out. “We may ultimately see targeted therapies added to chemotherapy or potentially even replace it in some cases.”