Rheumatoid Arthritis and Breast Cancer Risk

People with rheumatoid arthritis (RA) may have an increased risk of certain types of cancers. Researchers have tried to answer questions about RA and breast cancer risk looking at two factors: Does the disease itself raise breast cancer risk, and do the drugs and treatments for RA (like Enbrel and Humira) raise breast cancer risk? Several studies shed some light.

Rheumatoid Arthritis and Breast Cancer Risk

While rheumatoid arthritis does increase the risk of certain cancers, breast cancer is not among them. However, for those RA patients who do develop breast cancer, their RA may affect the outcome. Several studies have concluded the following about RA and breast cancer:

• Overall breast cancer rates in RA patients appear to be lower than breast cancer rates in the general population.
• Women with RA who are younger than age 40, as well as non-Caucasian women, may have an elevated risk of breast cancer. The reasons are not clear.
• For RA patients who develop breast cancer, the prognosis is worse than that of the general population. A study in Rheumatology of more than 6,300 RA patients who developed cancer, breast cancer (along with skin cancer and non-Hodgkin's lymphoma) had the worst survival rates.

RA is more commonly associated with an elevated risk of lymphoma (non-Hodgkin's being the most common). In fact, RA patients have twice the lymphoma risk as the general population.

Rheumatoid Arthritis Medications and Breast Cancer Risk

Research shows no evidence to date that rheumatoid arthritis therapy increases the risk of breast cancer.

More recent research has looked at the potential cancer risk associated with "biologics," biologic response modifiers now commonly used to treat RA. They include:

• Remicade (infliximab)
• Enbrel (etanercept)
• Humira (adalimumab)

Biologics have been compared to common, older drug therapies such as synthetic disease-modifying antirheumatic drugs (sDMARDs) to see if there may be an associated cancer risk.

Certain specific studies found the following:

• In one JAMA study of more than 29,000 RA patients taking biologics found no increased risk of malignancy after six months compared to patients on other antirheumatic drugs.
• A British study of more than 15,000 RA patients compared cancer rates of those taking the biologic tumor necrosis factor (TNF) inhibitors versus those taking sDMARDs. The results showed no difference in cancer rates between the two.
• For female RA patients who developed breast cancer, one study found no increased risk of cancer recurrence after surgery while undergoing anti-TNF therapy or methotraxate (another common RA drug).
• An Australian study of more than 3,000 RA patients split into anti-TNF and non-biologic therapy groups found no increased risk of breast cancer. However, there was an elevated risk of lymphoma and lung cancer.

A Word From Verywell

While no elevated risk of breast cancer has been found in RA patients from both the disease and the therapies used to treat it, there is a general elevated cancer risk with RA, particularly lymphoma.

If you have RA, discuss cancer risk with your healthcare provider, including risk associated with the severity of your disease, what therapies you're on, and what other factors (such as lifestyle) may play a part.