Types of Cancer Linked to Rheumatoid Arthritis

If you have rheumatoid arthritis (RA), you may be at increased risk for certain cancers and at decreased risk for others. RA is a chronic autoimmune inflammatory disease that causes joint pain and swelling.

Sometimes, the medications used to treat RA can drive up the risk of cancer. Other times, it's the inflammation caused by the disease itself.

While still relatively rare, lymphoma, lung cancer, and skin cancer appear to be more common in RA. At the same time, other types of cancer seem to be less common. Here's what to know about different types of cancers and how they relate to RA.

Lymphomas

Lymphomas are cancers of the blood. They're relatively rare, to begin with, but people with RA have twice the average risk of developing them.

The two main types of lymphomas are non-Hodgkin's lymphoma and Hodgkin's lymphoma.

Non-Hodgkin's Lymphoma and Hodgkin's Lymphoma

RA increases the risk of non-Hodgkin's lymphoma and Hodgkin's lymphoma, cancers of immune cells called lymphocytes. Non-Hodgkin is more common than Hodgkin's in RA patients.

The reasons for the increased risk of these lymphomas are continued disease activity and immune stimulation. Inflammation is present when RA is active, and the immune system responds to inflammation. Good management of RA can help reduce disease activity.

Lymphoma Linked to TNF Inhibitors

There have been cases of RA patients developing a rare and fatal subtype of non-Hodgkin's lymphoma called hepatosplenic T-cell lymphoma while taking a tumor necrosis factor (TNF) inhibitor. The risk of this rare lymphoma is relatively small, however, and TNF inhibitors remain to be an important part of RA therapy.

TNF inhibitors are also used to treat other inflammatory conditions including Crohn's disease and ulcerative colitis. The FDA has approved TNF inhibitors infliximab (Remicade), adalimumab (Humira), etanercept (Enbrel), golimumab (Simponi), and certolizumab (Cimzia).

Lung Cancer

Lung cancer occurs when cells in the lungs start to grow out of control.

RA has been linked to lung cancer risk—and smoking is a major factor. Compared to the general population, people with RA have a higher chance of developing this form of cancer. Your risk goes up even more if you have RA and smoke.

If you smoke, the best thing you can do for your health is to quit. For instance, smoking can increase your risk of developing RA and can even make the disease worse.

However, even people who don't smoke and have RA have a 40% higher risk of getting lung cancer than people who smoke and don't have RA. Chronic inflammation may be one reason for the increased risk, but it's not the only one.

Skin Cancer

Skin cancer is the most common type of cancer among the general population. It causes skin cells to grow uncontrollably.

RA doesn't necessarily put you at higher risk of skin cancer, but the treatment may. Certain RA medications come with a higher risk of certain skin cancers.

Methotrexate and biologic drugs may slightly increase the risk of two types of nonmelanoma skin cancer: basal cell carcinoma (BCC) and squamous cell carcinoma (SCC). Overall, it's a relatively small concern, however, and both of these forms of cancer are highly treatable.

TNF inhibitors used in RA treatment also increase the risk of nonmelanoma skin cancer, especially SCC. The risk of developing BCC is not increased, however.

There has also been some concern that treatment with TNF inhibitors may increase the risk of melanoma, the most dangerous type of skin cancer. While RA itself doesn't seem to increase or decrease the risk of melanoma, there is some evidence that TNF inhibitors may drive it up.

The link between melanoma and RA is not all too clear, however. Evidence from another study of more than 130,000 patients with RA did not show an increased risk among patients who were taking TNF inhibitors.

If you have a history of melanoma, you'll likely be receiving disease-modifying antirheumatic drugs (DMARDs) instead of biologics like TNF inhibitors. DMARDs include methotrexate, leflunomide, hydroxychloroquine, and sulfasalazine.

Myeloma

Multiple myeloma is a relatively uncommon form of cancer that affects white blood cells called plasma cells. The American Cancer Society predicts about 35,730 new cases will be diagnosed in 2023.

Chronic inflammatory diseases like RA may increase the risk of a condition called monoclonal gammopathy of undetermined significance, or more simply, MGUS. MGUS is when there is an abnormal protein in your blood. In some patients, this condition can progress into multiple myeloma.

Leukemia

A rare form of blood cancer, large granular lymphocyte (LGL) leukemia, seems to show up more often in people with RA. In one study, as many as 36% of people with LGL leukemia also had RA.

LGL leukemia is rare. It's also associated with other autoimmune disorders, including celiac disease.

Prostate Cancer

Prostate cancer is relatively common. It's the second most common cancer in American males, after skin cancer. The prostate is a gland in the male reproductive system, and cancer results when cells in this gland grow uncontrollably.

Research has looked into the relationship between prostate cancer and RA. Overall, the consensus seems to be that there is no consistent trend in risk among patients with RA. Patients with RA appear to have about the same risk of developing prostate cancer as the general population.

Colorectal Cancer

Colorectal cancer affects the cells of the colon or rectum, causing uncontrolled growth.

It's one of the cancers that seems to appear less often in people with RA. Research has found a decreased risk of colorectal cancer in patients with RA.

Still, colorectal cancer patients with RA tend to have more metastasis and poorer prognosis than those without RA.

Breast Cancer

After skin cancer, breast cancer is the next most common cancer in females in the United States. It occurs when cells in the breasts grow out of control.

Research shows people with RA tend to have a slightly decreased risk of breast cancer. Conversely, people with a history of breast cancer also tend to have a lower risk of RA. It's not yet clear what's driving this relationship between breast cancer and RA, however.

A Quick Review

Rheumatoid arthritis can increase the risk of certain cancers like lymphoma, lung cancer, and skin cancer. The increased risk of these cancers may be due to inflammation, medications, or both. Yet, RA may also lower the risk of breast cancer.

Talk to your healthcare provider if you're concerned about how RA or its treatment affects your risk of cancer. Several of these cancers are rare, so the risk is already relatively low. Keep up with recommended cancer screenings, and do your best to manage symptoms and reduce inflammation.