Finding the right arthritis treatment
Dear Doctors: Is there a treatment for psoriatic arthritis that doesn’t carry the risk of lymphoma or other cancers? I have this kind of arthritis, and it is very painful. However, I don’t want to jump from the frying pan into the fire with a treatment that is going to give me a more dangerous disease.
Dear Reader: Psoriatic arthritis is a chronic inflammatory condition in which the body’s immune system attacks and damages the tissues of joints. As the name indicates, it is associated with psoriasis, also a chronic inflammatory condition. The most common type of psoriasis is plaque psoriasis, which causes raised, scaly and reddened patches of skin, most often on the elbows, knees, torso and scalp.
The data show that, over time, up to one-third of people living with psoriasis develop psoriatic arthritis. It typically appears between the ages of 30 and 50 and is seen equally in women and men. The disease typically affects the larger joints in the lower extremities, the small joints of the fingers and toes, and it may also involve the spine and the pelvis. It can range from quite mild to severe enough to interfere with daily life. Symptoms include fatigue, swelling, tenderness or pain in the joints, morning stiffness and reduced range of motion. There is no connection between the severity of someone’s psoriasis and their likelihood of developing psoriatic arthritis in the future.
Some research suggests that psoriasis or psoriatic arthritis may lead to a higher risk of developing some types of cancer. This includes a type of lymphoma, a blood cancer that affects certain cells in the body that help to fight infection.
As you point out, there is discussion of a link between medications to manage psoriatic arthritis and an increased risk of lymphoma. The medications in question are known as biologic therapies. This is a class of drugs that act as immunosuppressants. That is, they selectively target and repress the biological chain of events that allows psoriatic arthritis to develop. There have been several cases of patients who, while being treated with biologic therapies, were later diagnosed with lymphoma. However, it’s not yet clear whether or not the drugs were the cause. Some researchers argue the cancers in these cases were already present and that the immunosuppressant therapies allowed symptoms to emerge more quickly. Others suggest that heightened awareness of this possible outcome led to an increase in reported cases.
In 2020, a study in an American Medical Association peer-reviewed journal questioned the psoriatic arthritis-cancer connection. The researchers analyzed 112 studies with more than 2 million patients. They found that individuals with psoriasis had a slightly higher incidence of lymphoma than did the general populace, but that psoriatic arthritis did not further increase that risk. They also failed to find a link between biologic therapies and increased cancer risk.
We know you were hoping for a clear-cut answer, but this is a complex and evolving issue. We urge you to talk to your rheumatologist about what biologic therapies might achieve in your own case and to also share your concerns.
Eve Glazier, M.D., MBA, is an internist and associate professor of medicine at UCLA Health. Elizabeth Ko, M.D., is an internist and assistant professor of medicine at UCLA Health. Send your questions to askthedoctors@mednet.ucla.edu, or write: Ask the Doctors, c/o UCLA Health Sciences Media Relations, 10960 Wilshire Blvd., Suite 1955, Los Angeles, CA, 90024. Owing to the volume of mail, personal replies cannot be provided.