MS linked to greater risk for certain cancers

Key takeaways:

• Overall, people with MS had a 6% greater risk for any cancer type.
• The risk was higher in people with MS aged younger than 55 years.
• In contrast, the risk was lower in people with MS aged 65 years and older.

People with MS had an increased risk for bladder, brain and cervical cancers compared with people without MS, according to a new study in Neurology, the medical journal of the American Academy of Neurology.

However, they also had a lower risk for prostate, colorectal and breast cancer.

“People with MS undergo an increased number of tests to monitor MS, making it more likely to detect other diseases,” Emmanuelle Leray, PhD, of Rennes University in France, said in a press release related to the study. “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.”

People with MS may have a higher risk for cancer due to “the inflammatory nature of MS, alongside potential toxicity associated with new disease-modifying therapies, and the high prevalence in this population for suspected cancer risk factors, such as hypertension and chronic lung diseases,” Leray and colleagues wrote.

Previous studies examining the link between MS and cancer yielded mixed results. To learn more, the researchers conducted a 10-year retrospective matched cohort study using data from a French health care database that covers 99% of the country’s population.

The analysis included 140,649 people with MS who were matched to 562,596 controls without MS based on factors such as age, sex, residence and insurance. None of the participants had a history of cancer 3 years before study inclusion.

Over a mean follow-up period of 8 years, Leray and colleagues reported that the incidence of cancer was 799 per 100,000 person-years in people with MS and 736 per 100,000 person-years in matched controls.

Overall, people with MS had a 6% greater risk for developing any cancer type compared with people without MS, according to the release. The association was mostly observed in women (HR = 1.08, 95% CI 1.05-1.11).

When looking at specific cancer types, Leray and colleagues identified a 71% increased risk for bladder cancer (HR = 1.71; 95% CI, 1.54-1.89), a 68% increased risk for brain cancer (HR = 1.68; 95% CI, 1.42-1.98) and a 24% increased risk for cervical cancer (HR = 1.24; 95% CI, 1.12-1.38) compared with people without MS.

In contrast, people with MS had a 20% lower risk for prostate cancer (HR = 0.8; 95% CI, 0.73-0.88), a 10% lower risk for colorectal cancer (HR = 0.9; 95% CI, 0.84-0.97) and a 9% lower risk for breast cancer (HR = 0.91; 95% CI, 0.86-0.95) vs. those without MS.

The results further showed that the risk for cancer was higher in people with MS aged younger than 55 years (HR = 1.2; 95% CI, 1.15-1.24) but lower in those aged 65 years and older (HR = 0.89; 95% CI, 0.85-0.94) compared with people without MS. This association was observed in all cancer locations, the researchers noted.

There were several limitations to the study, including the lack of information on education, income, smoking status and alcohol use, Leray and colleagues noted.

“While our study found a higher risk for brain cancer, it may be due in part to earlier detection in those with MS since they regularly have brain scans, which may detect cancers earlier before a person has symptoms,” Leray said in the release. “Frequent urinary tract infections in people with MS and the use of immunosuppressant drugs may contribute to their higher risk of bladder and cervical cancers.”

Meanwhile, the lower risk for breast and colorectal cancers may be partly attributed to fewer screenings in older people with MS “when they may be experiencing more MS symptoms,” she added.

“More research is needed, including studies that look at more closely at how cancer screenings may play a role,” Leray said.

Reference:

• Do people with MS have an increased risk of cancer? https://www.aan.com/PressRoom/Home/PressRelease/5204. Published Oct. 9, 2024. Accessed Oct. 9, 2024.