At least one study has shown an increased rate of breast cancer in women with multiple sclerosis.
Same as rheumatoid arthritis – researchers at University of North Carolina at Charlotte found a link between metastatic breast cancer and autoimmune arthritis.
In another study, ulcerative colitis has shown a tentative association with breast cancer.
Other connections between breast cancer and autoimmune disease are more tentative. For example, some studies have shown an increased risk of breast cancer in women with lupus, though other studies have not confirmed this.
Maybe, but maybe not. The topic remains hotly debated and very controversial.
While some studies have shown that thyroid disease is more common in women with breast cancer, others have not. Almost every type of thyroid disease has at one time been reported as more common in women with breast cancer, including both autoimmune and non-autoimmune thyroid disease.
Some research has also showed increased levels of antithyroid peroxidase autoantibodies in breast cancer patients. Breast cancer patients who have these autoantibodies may actually have a better prognosis than those who don’t.
It’s not clear how exactly Hashimoto’s disease might increase the risk of breast cancer. We do know that thyroid hormone has multiple cellular effects on estrogen dependent tissue, such as that found in the breast.
Both Hashimoto’s and breast cancer are relatively common conditions, so it makes sense that some women might experience both, even if there really isn’t a connection between the two. Even if Hashimoto’s does increase the risk of breast cancer, it might not increase the risk by very much.
Hashimoto’s disease does appear to increase the risk of certain kinds of thyroid cancer.
The answer, again, is maybe but maybe not. There is less information available about the possible relationship between Graves’ disease and breast cancer, but at least one study has found that women with breast cancer were slightly more likely to have Graves’ disease than the general population.
Graves’ disease and Hashimoto’s disease are both autoimmune diseases that affect the thyroid, but they might have different associations with breast cancer development.
Some. Researchers are just beginning to understand the potential links between autoimmune diseases and cancer. And we are still learning about the potential relationships between specific autoimmune diseases and specific types of cancer.
Autoimmune disease may cause ongoing activation of the immune system, with the generation of immune signaling molecules, free radicals, and the rapid production of immune cells. All of these might potentially increase the risk of a cancer forming.
Autoimmune disease might also in some way alter parts of the immune system that have an anti-tumor response.
A specific autoimmune disease might make specific kinds of cancer more likely, or it might increase the risk of multiple different kinds of cancer. Or another factor (like smoking or vitamin D levels) might make both cancer and autoimmune disease more likely.
A few relationships are well documented, according to a 2012 article in the Anticancer Research journal, which reviewed studies done on autoimmune and cancer between 2001 and 2011.
For example, celiac disease and inflammatory bowel disease are known to increase the risk of various types of cancers of the gut.
On the other hand, in some cases, autoimmune disease may affect the immune system in a way that actually reduces the risk of cancer (though this appears to be less common).
For example, having multiple sclerosis may actually decrease the risk of certain kinds of cancers.
With further research, clinicians will learn more about the potential relationships between these conditions.
About the Author
Ruth J. Hickman, MD, is a freelance health, science, and medical writer. She specializes in writing about medical topics for the lay public and for health science students. She can be reached at [email protected] or through her website: ruthjhickmanmd.com.
This blog post was originally published by AutoimmuneMom.com, written by Ruth J. Hickman, and first published on Oct 14, 2015.