A recent study indicates that certain cancers occur slightly more often in individuals with multiple sclerosis (MS) compared to those without the condition. The types of cancers that show a minor increased risk include bladder, brain, and cervical cancers. However, it’s important to note that the study does not establish a direct link indicating that MS raises cancer risk; it only identifies a correlation.
A recent study indicates that certain cancers occur slightly more often in individuals with multiple sclerosis (MS) compared to those without the condition. The research was published in the October 9, 2024, online edition of Neurology®, the journal of the American Academy of Neurology. The study highlights a slight increase in the risk of bladder, brain, and cervical cancers among those with MS. However, it is crucial to understand that this study only shows a correlation and does not establish that MS directly increases cancer risk.
Multiple sclerosis is an illness where the immune system attacks myelin, the protective fatty covering of nerves. This chronic condition is often unpredictable and can lead to disability.
“Individuals with MS frequently undergo numerous tests to monitor their condition, making it more likely for other diseases, including cancers, to be detected,” explained study author Emmanuelle Leray, PhD, of Rennes University in France. “We discovered a link between certain cancer types and MS, although the explanations may vary based on factors like a person’s age and the specific cancers involved. Overall, the study revealed the increased cancer risk to be relatively minor.”
To conduct the research, scientists analyzed a decade’s worth of data from the French national health care database. They identified 140,649 individuals with MS and matched them with 562,596 individuals without MS, considering factors like age, sex, and location. All participants were cancer-free at least three years prior to the study, and they were monitored for an average duration of eight years.
Throughout the study, 8,368 individuals with MS and 31,796 without developed cancer.
Researchers found a cancer incidence rate of 799 cases per 100,000 person-years among those with MS, compared to 736 cases per 100,000 person-years in those without MS. The term “person-years” accounts for both the number of participants and the length of time they were observed.
From this analysis, it was determined that individuals with MS had a 6% increased risk of developing any form of cancer, regardless of their age, sex, or location. Additionally, the cancer risk was notably higher in those under 55 years old and comparatively lower in individuals aged 65 and older than in those without MS.
Further investigation into specific cancer types revealed that individuals with MS had a 71% higher risk of bladder cancer, a 68% higher risk of brain cancer, and a 24% higher risk of cervical cancer. Conversely, they exhibited a 20% lower risk of prostate cancer, a 10% lower risk of colorectal cancer, and a 9% lower risk of breast cancer.
“Although our findings indicate a heightened risk for brain cancer, this could partly be attributed to more frequent detections in MS patients, as they regularly undergo brain scans that might uncover cancers before symptoms arise,” Leray noted. “Additionally, the prevalence of urinary tract infections among those with MS and their use of immunosuppressant medications could play a role in increasing their risks of bladder and cervical cancers.”
Leray remarked, “The reduction in colorectal and breast cancer risks could also relate to fewer screening opportunities for cancer in older MS patients, who might face more severe MS symptoms. We require more research to explore how cancer screenings may influence these results.”
One limitation of the study is that the researchers could not adjust for factors like education, income, smoking status, and alcohol consumption due to the lack of this data in the national database.
The study received support from the Rennes Institute of Clinical Neurosciences and the EDMUS-ARSEP Foundation.
