Women with multiple sclerosis (MS) are less likely to have breast cancers detected through cancer screenings than women without MS, according to new research published in the April 27, 2022, online issue of Neurology^®, the medical journal of the American Academy of Neurology. Conversely, researchers also found that people with MS are more likely to have colorectal cancers detected at an early stage than those without MS.

“MS can be a debilitating disease and mobility issues may make it difficult for people with MS to get to regular cancer screenings,” said study author Ruth Ann Marrie, MD, PhD, of the University of Manitoba, Winnipeg, in Canada, and a member of the American Academy of Neurology. “We conducted this study because little is known about whether having MS plays a role in getting regular cancer screenings. Early detection and timely diagnosis are important because they can affect a person’s cancer survival.”

For the study, researchers looked at heath care data for 14.8 million people living in Ontario to identify people with breast or colorectal cancer who either did or did not have MS. Researchers identified 351 women with breast cancer and MS and compared them to 1,404 women with breast cancer and no MS matched for age, sex, and date of cancer diagnosis. Similarly, they identified 54 people with colorectal cancer and MS who they compared to 216 people with colorectal cancer and no MS.

Researchers then looked at medical data for study participants. They found that breast cancer was detected by a routine screening in 103, or 29%, of the women with MS, and in 529, or 38%, of the women without MS. After adjusting for age, diagnosis year and income, researchers determined the odds of breast cancer being detected through a routine screening was 32% lower in women with MS.

“Disability from MS increases with age, as does cancer risk, so it is likely that those with MS may find it more difficult to get regular mammograms as they get older,” said Marrie.

Researchers also found that people with MS were twice as likely as people without MS to have colorectal cancer detected at stage one, the earliest stage of cancer.

“There is a high occurrence of bowel symptoms and gastrointestinal disorders in patients with MS, which could lead to shared symptoms with colorectal cancer,” said Marrie. “Increased gastrointestinal exams may help detect colorectal cancer sooner.”

Researchers also found that 21% of the people with MS and breast cancer and 33% of the people with MS and colorectal cancer had a level of disability high enough that required home care services or long-term care. Marrie said, “More research is needed regarding the role of MS-related disability on screenings.”

A limitation of the study was that it did not include the time frame from when a person first noticed cancer symptoms to when they told their doctor. Also, Marrie said people experiencing marginalization due to race or ethnicity have different access to cancer screening, and this may be exacerbated among people with MS. She said race and ethnicity data were not available for this study and should be examined in future research.