Study reassures breast of MS patients, colorectal cancer risk

The incidence of breast and colorectal cancers was similar between people with and without multiple sclerosis (MS), but MS patients had a higher incidence of other cancers, including bladder cancer, according to a population study .

Among 54,000 people with MS and 267,000 people without the disease, the risk of breast cancer (HR 0.92, 95% CI 0.78-1.09) or colorectal cancer (HR 0.83, 95% CI 0.64-1.07) did not differ, reported Ruth Ann Marrie, MD, PhD, of the University of Manitoba in Winnipeg, Canada, and colleagues in Neurology.

“This is good news for people with MS because previous studies have shown a link between MS and breast and colorectal cancers,” Marrie said in a statement. “While we didn’t find this link, our study showed that people with MS had a 72% higher risk of developing bladder cancer.”

“The increased risk of bladder cancer in people with MS may have to do with the fact that people with the disease are more likely to have urinary tract infections and use catheters,” he added. “However, more research is needed to confirm our findings.”

In 2015, a systematic review found that cancers of the cervix, breast, and digestive tract had the highest incidence in MS, but the results on the relative risks of cancer among MS patients were inconsistent. “Studies published since 2014 continue to report disparate results on cancer risk in MS,” wrote Marrie and colleagues.

Incidence rates are needed to support pharmacovigilance in clinical trials of disease-modifying therapies (DMTs), they added: Sometimes, the only way to determine if an excessive number of cancer cases is to compare it to incidence rates. specific to MS. Breast cancer incidence is of particular concern as several cases of breast cancer have been reported in phase III clinical trials of ocrelizumab (Ocrevus). The drug, which was approved for MS in 2017 in the United States, carries a breast cancer warning.

In their analysis, the researchers identified MS cases in Manitoba and Ontario and matched each case to five controls without MS by year of birth, gender and region, linking the cohorts to cancer registries. The records in Manitoba were from 1984-85 to 2017-18; in Ontario, they were from 1994-95 to 2017-18.

In total, the researchers evaluated 53,984 cases of MS and 266,920 controls; 70% of both groups were female.

Neither cancer incidence nor mortality differed between MS patients and controls for breast and colorectal cancer. This was consistent over two time periods, 1998 to 2007, when DMTs including interferon beta and glatiramer acetate (Copaxone) were first introduced for MS and 2008-2017 when second-rate DMTs generation included natalizumab (Tysabri), dimethyl fumarate (Tecfidera), fingolimod (Gilenya), teriflunomide (Aubagio), and alemtuzumab (Lemtrada).

From 2008 to 2017, the incidence of bladder cancer was 25.7 cases per 100,000 person-years among MS patients and 14.60 cases among controls (IRR 1.72, 95% CI 1.28 -2.30).

The incidence of ovarian cancer was high in the MS cohort from 2008-2017 (IRR 1.50, 95% 1.01-2.24). The incidence of cervical and uterine cancer was lower among MS cases than in controls. The incidence of CNS cancer was consistently high in MS patients during 1998-2007 and 2008-2017, even after excluding meningiomas from the analysis (IRR 2008-2017 2.14, 95% CI 1 , 49-3.07).

The findings “add to our knowledge, helping to provide baseline rates that can inform how we monitor patients and choose treatments,” said Robert Bermel, MD, of the Cleveland Clinic in Ohio, who was not part of the study. .

“The data on bladder and ovarian cancers underscore the importance of monitoring MS patients for symptoms suggestive of these diseases,” he said. MedPage Today. “When doubts arise as to whether specific MS treatments can increase the risk of a certain type of cancer, we rely on studies like this one to determine the specific risk of the disease from which to plan further studies and to guide patients.”

Although Marrie and colleagues adjusted the data for comorbidities, they were unable to incorporate health behaviors such as smoking, diet, and physical activity into their analyzes. They were also unable to determine how the clinical features of MS, such as relapsing onset versus primary progression course, were linked to cancer incidence. Prescribing data was not available in Ontario, and researchers were unable to assess how DMT use might be related to cancer.