Many autoimmune diseases have been associated with higher rates of certain cancers, although it’s not well understood if it’s directly related to the disease process or a consequence of the drug therapy. Furthermore, the risk of developing any type of cancer is so high for the general population, estimated to be about 35 percent, that the connection with autoimmune disease may be over-reported. Regardless of the degree of increased risk, current research supports the idea that a link exists but the cause of link remains uncertain.
Are there any studies that show a higher risk of certain types of cancer if you have certain types of autoimmune conditions?
Yes, studies dating back to the early 1990s show distinct correlations between autoimmune conditions and certain types of cancer. However, the results of the research are complicated by the fact that some drug treatments for common autoimmune conditions – by suppressing the immune system – may also increase the risk. Specific examples for certain diseases include:
- Systemic sclerosis: People who have systemic sclerosis have a five time greater risk of lung cancer, four time greater risk for non-melanoma skin cancer and three time greater risk of liver cancer.
- Lupus erythematosus: Lupus patients, who are mostly women, have a two time greater risk of esophageal and pancreatic cancer.
- Celiac disease: People who have celiac disease have a higher risk of non-Hodgkin’s lymphoma.
- Psoriasis: Men who have PUVA treatment for psoriasis have a higher risk of penile cancer.
- Rheumatoid arthritis: Untreated or naturally (non-pharmaceutical) treated rheumatism is actually associated with a 30 percent reduced bowel cancer risk. However, when anti-inflammatory and analgesic drugs are taken the risk of digestive tract cancers dramatically increase.
- Hashimoto’s thyroiditis: Researchers discovered that Hashimoto’s thyroiditis is associated with an increased risk of developing papillary thyroid cancer. The risk is greatest for women. Female patients with Hashimoto’s who undergo a thyroidectomy are 30 percent more likely to develop thyroid cancer.
- Colitis and Crohn’s: People with ulcerative colitis and Crohn’s disease are five times more likely to develop colon cancer than the general public.
What role might the medications play?
A possible cause of the increase cancer risk of patients with autoimmune diseases is medication because many of these diseases are treated with powerful immunosuppressive drugs. Once suppressed, the immune system may not be able to efficiently fight cancer cells and prevent tumor formation. This results in a higher cancer risk, especially in areas that metabolize the medications, such as the gastrointestinal system and liver.
After cancer treatment, are autoimmune conditions more likely to onset due to a weakened immune system and after-effects of chemotherapy?
That depends on the cause / definition of some autoimmune conditions. As mentioned, immunosuppressive therapies can certainly increase the risk of cancer, but toxic chemotherapy agents can also damage the immune system, leaving the body highly susceptible to a variety of infections by microorganisms. Some autoimmune diseases, such as rheumatoid arthritis and colitis, are thought to be sometimes caused by pathogenic microorganisms, which would greatly proliferate with a severely weakened immune system.
What else could cause the increased rates of cancer among those with autoimmune disease?
Researchers are currently focusing on the role of genetics in these disease states. Multiple studies across a variety of disciplines (immunology, oncology, microbiology) show a recurrent theme of faulty gene coding which leads to the body’s inability to fight abnormal cell growth (cancer) and abnormal immune responses (autoimmunity). Interestingly, though the diseases vary widely, the number of faulty genes that have been discovered thus far, is relatively small.
Questions for your doctor:
- If I develop cancer, am I at greater risk for autoimmune diseases?
- Do autoimmune diseases get worse when the immune system is strengthened by vitamin and herbal supplements?
- What are some natural treatment options instead of chemotherapy?
- What if my family has several cases of cancer or autoimmunity or both?