Rheumatoid Arthritis Patients at Increased Risk for Malignancy

Lymphoma and lung cancer present significant risk to RA patients.

Those who suffer from rheumatoid arthritis may also be at risk for much more serious conditions such as lymphoma and lung cancer, according to a study that confirmed the findings of several prior studies.

Nine publications were analyzed in the literature evaluation that weighed findings from past studies against each other.

The meta-analysis evaluated studies that took place between 2008 and 2014 and looked for indications of rheumatoid arthritis patients suffering from malignancies including lymphoma and lung cancer. Additionally, the researchers screened for instances of breast, cervical, and prostate cancers in relation to rheumatoid arthritis.

In general, standardized incidence ratios for overall malignancy across the studies were similar. Six out of seven studies reported an increase in the risk of malignancy in patients with rheumatoid arthritis.

Lymphoma and lung cancer posed the greatest risk to patients, while other cancers such as breast and cervical cancer, actually decreased in rheumatoid arthritis patients compared with the general population.

Scientists have many theories as to why there is an increased risk of malignancy in rheumatoid arthritis patients. One theory proposes that ongoing immunologic stimulation over time may increase the risk of malignant transformation of immune system cells and decrease the number of T-suppressor lymphocytes, thus increasing rates of lymphoma malignancy in patients with rheumatoid arthritis.

Additionally, chronic lung inflammation in patients with rheumatoid arthritis may explain the increased risk of lung cancer in these patients. For the observed decreased risks for colorectal and breast cancers, this may be attributed to the increased use of non-steroidal anti-inflammatory drugs, which are known to decrease this risk.

Overall rate of malignancy may be attributed to the autoimmune pathogenesis of rheumatoid arthritis and common etiology between rheumatoid arthritis and malignancy, including genetic factors, smoking-related tissue necrosis, and viral infection.

The study confirms what has been previously reported in regards to malignancy with rheumatoid arthritis. In analyzing these data, scientists can now say beyond the shadow of a doubt that rheumatoid arthritis increases the likelihood of malignancies in patients with this condition.