Rheumatoid arthritis and cancer: a tangled web

Cancer and arthritis. These two conditions may not seem related to you, but in fact, research and treatment studies have shown that they are intimately connected in a way that’s difficult to pick apart.

Treating these two diseases in one body presents conflicting needs.

While activating and strengthening the immune system is one path to fighting cancer, an overactive immune system is exactly what causes an autoimmune disease like rheumatoid arthritis (RA).

And, to make matters worse, some medications that treat RA appear to bring on specific types of cancer, and some cancer drugs have been shown to induce RA.

If you or a loved one are being treated for either of these diseases, you’ll want to be aware of their relationship, and of what the research is saying about your risks.

Immune checkpoint inhibitors cause RA

Immune checkpoints are a normal part of the immune system. Their job is to prevent an immune response from becoming so strong that it destroys healthy cells along with diseased ones.

Among other things, they prevent an autoimmune response from taking place.

When a drug known as an immune checkpoint inhibitor (ICI) is administered as part of cancer treatment, it keeps the body’s immune response in high gear, which allows T cells to kill cancer cells.

There’s a problem, though.

Because the immune checkpoints are blocked and the immune response heightened, many people develop the conditions that ICIs prevent, inflammatory conditions like hepatitis (inflammation of the liver) or diabetes, caused by inflammation of the pancreas.

Rheumatoid arthritis, an autoimmune disease, frequently develops when a patient takes ICIs.

RA increases certain cancer risks

Research over the last dozen years or so has highlighted the connection between having rheumatoid arthritis and the risk of cancer.

In 2008 and again in 2015, literature reviews that searched five databases concluded that patients with RA are at higher risk of lymphomas (cancers of the immune system) and of lung cancer.

A recent small study undertaken by nine researchers at the Hospital for Special Surgery in New York City looked at patients who had both RA and cancer.

The Clinical Disease Activity Index (CDAI) is a tool used by rheumatologists to judge the severity of rheumatoid arthritis at any given time. It involves counting the number of swollen and painful joints, as well as factoring in the patient’s subjective experience and the doctor’s clinical judgment.

The study found that each one-point increase in a patient’s CDAI score was associated with a 9 percent increase in the likelihood that their cancer would get worse.

Do RA drugs cause cancer? The jury is still out

The jury is still out on whether certain RA drugs make cancer more likely and more dangerous. But the question is out there and is being researched as we speak.

Disease-modifying anti-rheumatic drugs (DMARDs) reduce the number of overactive immune cells that cause unwanted inflammation.

Biologics are a type of DMARD that targets specific parts of the immune system. It’s been said that, if DMARDs were a soldier, they’d be a sniper, aiming for a specific target, while other rheumatic drugs take a more scattershot approach.

Recent studies show that taking biologics known as TNF blockers may raise your chances of developing non-melanoma skin cancers.

And methotrexate, another drug commonly used to treat the inflammation of RA, is known to increase the likelihood of lymphatic cancer.

The bottom line

If you or a loved one are being treated for rheumatoid arthritis, talk with your doctor about the medications he’s prescribing.

There are many options, depending upon the severity of your condition and other factors. Your doctor should be able to help you find treatments that you feel comfortable with.

There are also ways to help manage the disease that might lower dependence on medication. Here are some resources:

How yoga relieves RA symptoms and boosts remission

The right food for real RA relief

30 foods that crush crippling RA symptoms

8 supplements for calming RA

Unlocking vitamin D’s autoimmune superpowers

Sources:

ICI Arthritis Tied to Cancer Progression — MedPage Today

Higher Checkpoint Inhibitor Arthritis Disease Activity may be Associated with Cancer Progression: Results from an Observational Registry — American College of Rheumatology

People with Rheumatoid Arthritis May Be at Higher Risk for Certain Cancers — Healthline

Immune checkpoint inhibitors — National Cancer Institute

Incidence of malignancy in adult patients with rheumatoid arthritis: a meta-analysis Arthritis Research & Therapy