Do people with MS have an increased risk of cancer?

A study has found some cancers to be slightly more frequent in people with multiple sclerosis (MS) than in people without MS. The study is published in the October 9, 2024, online issue of Neurology . Types of cancers found to have a small increased risk include bladder, brain and cervical cancers.

The study does not prove that MS increases a person's risk of cancer. It only shows an association. With MS, the body's immune system attacks myelin, the fatty, white substance that insulates and protects the nerves.

MS is chronic and can be unpredictable and disabling. "People with MS undergo an increased number of tests to monitor MS, making it more likely to detect other diseases," said study author Emmanuelle Leray, Ph.D.

, of Rennes University in France. "We found an association between some types of cancer and MS which may have different explanations depending on a person's age and the types of cancer. Overall, our study found the increased risk of cancer was quite small.

" For the study, researchers reviewed 10 years of data in the French national health care database. Researchers identified 140,649 people with MS and matched them for factors such as age, sex and residence to 562,596 people without MS. All participants were cancer free three years before the study.

They were followed for an average of eight years. During the study, 8,368 people with MS and 31,796 people without MS developed cancer. Researchers determined there were 799 cancers per 100,000 person-years for peop.