Systemic lupus erythematosus (“lupus” or “SLE”) and other autoimmune diseases are linked to an increased risk of certain types of cancer. Specifically, lupus patients may experience an elevated risk of lymphoma and other cancers, such as cancer of the cervix. Researchers have elucidated certain connections between lupus and cancer.
For example, it is widely accepted that immunosuppressive medications, such as azathioprine (Imuran) and mycophenolate mofetil (Cellcept) contribute to elevated cancer risk. However, one of the largest studies to investigate this connection suggests that the risk of cancer is actually greatest during the earlier stages of lupus, indicating that exposure to immunosuppressive therapy is not the only link between lupus and cancer. Physicians do not yet understand the precise relationship between lupus and cancer.
Lupus and lymphoma
Studies show an increased risk of both Hodgkin’s and non-Hodgkin lymphoma in lupus patients. It is believed that the elevated risk of lymphoma results from the disease process of lupus—specifically the overstimulation of B-cells coupled with defects in the immune system’s surveillance system—and not just from medications or other associated risk factors. Some suggest that immunosuppressive medications also increase the risk of lymphoma and other blood cancers, especially 5 or more years after taking the drug. In addition, people with Sjogren’s syndrome, which is relatively common in lupus, experience an even greater elevation of lymphoma risk, suggesting that lymphoma in lupus patients may also be linked to this condition.
Lupus and breast cancer
Some data indicate that women with lupus experience an increased risk of breast cancer. Increased estrogen levels might contribute to a higher risk of breast cancer in women with lupus.
Lupus and lung cancer
Lung cancer is about 1.4 times more common in people with lupus than in the general population. Interestingly, people with lupus and lung cancer are more likely to experience rare types of lung cancer. However, like the general population, many of the people with lupus who develop lung cancer are smokers. In fact, 85% of lung cancer is caused by tobacco. It is very important that people with lupus do not smoke. Smoking not only increases the chance of developing lung cancer, it also ups the risk for cardiovascular disease (which is also markedly increased in people with lupus), and prevents lupus drugs like Plaquenil from working properly. If you need help quitting, talk to your doctor. S/he can help you find the most effective strategy to curb your smoking habit.
Lupus and cervical cancer
Certain studies have shown an elevated risk of cervical cancer and abnormal PAP tests in women with lupus. One study linked the increased incidence of abnormal PAP tests with histories of sexually transmitted disease, contraceptive use, and immunosuppressive medications.
Some physicians suggest that either the use of immunosuppressives or flawed inherent immunity lead to a decrease in the ability of lupus patients to fight off human papilloma virus (HPV), a virus associated with cervical cancer. [Gardasil (the HPV vaccine) is recommended for young women with lupus to reduce the risk of later cervical cancer.] However, like much of our knowledge of cancer in lupus, these connections are not fully known or understood.
Lupus and endometrial cancer
New evidence suggests that lupus patients also experience an elevated incidence of endometrial cancer, although the cause for this risk is unknown.
NSAIDs and cancer
It has been found that people with Rheumatoid Arthritis, another autoimmune disease, experience a lower incidence of colorectal cancer than the general population. Although the precise cause of this phenomenon is unknown, it has been attributed to the long-term (10 years or more) use of non-steroidal anti-inflammatory drugs (NSAIDS) and aspirin. Evidence has also been found that long-term aspirin and NSAID use may also reduce the risk of colorectal, breast, and prostate cancer in the general population. It is likely that this benefit also holds for people with lupus, but that does not mean that one should begin taking aspirin and NSAIDs for this reason. In fact, long term NSAID use can increase cardiovascular disease. Therefore, you should only take medications as directed by your physician.
The importance of regular cancer screenings
Despite the increased risk of cancer in people with lupus, studies show that lupus patients are actually equally or even less likely than the general population to undergo cancer screenings. Thus, it is very important that you speak with your doctor about lupus and cancer to ensure that you see the appropriate physicians for cancer screenings as often as recommended.
Certain risk factors, such as smoking, obesity, hormone replacement therapy, and exposure to immunosuppressive medications, increase the chance that an individual will develop cancer. Therefore, it is also important that you practice healthy lifestyle habits. Obesity also increases the risk of certain cancers, so try to eat foods that help you maintain a healthy weight.
Sunlight causes lupus flares and also increases the risk of skin cancer. People with lupus should avoid the sun whenever possible. If you need to be outdoors, wear sunscreen with an SPF of 85 or greater and be sure that your sunscreen contains Helioplex to protect you from both UV-A and UV-B rays.
Gayed M, Bernatsky S, Ramsey-Goldman R, Clarke A, Gordon C. Lupus and cancer. Lupus. 209; 18(6); 479-85.
Research Update: Cancer in Lupus. (Based on presentation by Dr. Sasha Bernatsky at BC Lupus Society Symposium.) 22 Oct. 2005. Available at <http://www.bclupus.org/resources.html>.