MS Tied to Increased Risk After Colorectal Cancer Diagnosis
People who develop colon cancer are more likely to die in the first year, from that cancer or other causes, if they also have multiple sclerosis (MS), a new study indicates. MS disability seems to contribute to this association.
“These results warrant further investigation to determine what factors may lead to shorter survival times,” Ruth Ann Marrie, MD, PhD, a professor at the University of Manitoba in Winnipeg, Canada, and co-author of the study, said in a press release.
“Are people with MS less likely to receive cancer treatment? Or are they less able to tolerate the effects of chemotherapy? Are factors specific to MS involved? How accommodating is the cancer care system for people with disabilities? These are among the many questions that need to be investigated,” Marrie said.
The study, “Colorectal Cancer Survival in Multiple Sclerosis: A Matched Cohort Study,” was published in Neurology.
Cancer is one of the leading causes of death among people with MS, but the interplay between the two diseases is poorly understood.
A separate study by Marrie and other scientists, published earlier this year, suggested that MS did not increase the risk of cancer-related deaths among breast cancer patients. However, breast cancer patients with MS were at significantly higher risk of death from any cause a decade after their cancer diagnosis.
Now, the researchers set out to assess how MS affects survival outcomes among people with colorectal cancer, which includes any cancer that affects the colon and rectum.
By analyzing Canadian databases, the researchers identified 338 people with MS who were diagnosed with colorectal cancer in the provinces of Manitoba and Ontario from 1994 to 2016. Their mean age was 64.6 years, and about two-thirds of the patients were female.
For comparison, the researchers also identified 1,352 people with colon cancer who did not have MS. The two groups were matched for age, sex, year at cancer diagnosis, and region of residence. The stage of colon cancer at diagnosis did not differ significantly between the MS and non-MS groups.
Results showed that MS was associated with an increased risk of death from any cause. This association was strongest, in a statistical sense, at six months after the diagnosis of cancer, when patients with MS were at 45% higher risk of all-cause death. The association was less remarkable, but still significant, at one year, and lost its statistical significance at later time points.
Notably, MS also was associated with an increased risk of death from cancer. Specifically, at six months after the cancer diagnosis, MS patients were about 29% more likely to die from cancer.
“We found that early survival was lower in persons with MS than without MS following the diagnosis of colorectal cancer,” the researchers concluded. “This has potential implications for clinical decision-making and further study is warranted to determine what factors underlie these worse outcomes.”
Of note, the association between MS and early mortality decreased when the analysis took disability into account. Disability in MS patients often is associated with frailty, and the findings suggest it may prevent patients from receiving adequate cancer treatments.
“Understanding more about the factors involved in treating cancer in people with MS and their outcomes will be helpful for people with MS and their doctors as they balance the benefits of cancer treatment with the potential adverse effects and consider life expectancy and quality of life,” Marrie said.
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