Do Multiple Sclerosis patients have a lower cancer risk?

"Because the immune system plays important roles in both cancer and MS, we wanted to know whether the risk of cancer is different for people with MS. To date no other study has been able to link a clinical cohort together with population data to answer this question. The availability of these data puts Canada at the forefront of MS research."

Elaine Kingwell, Postdoctoral fellow, Faculty of Medicine and the Brain Research Centre, University of British Columbia

Multiple sclerosis (MS) is a relatively common disease affecting the brain and spinal cord. It typically attacks people in the prime of their lives and it’s causeis unknown.

Canada has one of the highest rates of MS in the world, with an estimated 75,000 people currently suffering from the disease.

The Malignancy and Multiple Sclerosis (MAMS) study brought together, for the first time, the BC Cancer Agency and University of British Columbia’s MS Clinics to link MS, health and cancer data. The project examined population data and data collected by specialist physicians for over two decades to determine the risk of cancer in the MS population.

The study was funded by the Canadian Institutes of Health Research, Multiple Sclerosis Society of Canada, and the Michael Smith Foundation for Health Research and involved an interdisciplinary team of researchers from the Department of Medicine and the BC Cancer Agency (PI: Dr Helen Tremlett).


Data sources linked

  • Cancer incidence files (BC Cancer Agency)
  • Medical Services Plan (BC Ministry of Health)
  • Hospital Separations (BC Ministry of Health)
  • Deaths (BC Vital Statistics Agency) 
  • BC MS Clinics data

What did we learn?

  • Compared to the general population MS patients have a lower overall cancer risk, in particular for colorectal cancer.
  • In patients with relapsing-onset MS, the risk for non-melanoma skin cancer was significantly greater.
  • For those MS patients who did develop cancer, tumour size tended to be larger at time of diagnosis.

Implications for population health

Further studies are needed to investigate possible causes of the reduction in cancer risk in people with MS. By considering alternative hypotheses, some biological factor, intrinsic to people with MS may be implicated. A more potent immune system detecting and destroying nascent cancer cells is one possible hypothesis requiring further research. It is also possible that common MS drug therapies, such as beta interferons, may have an effect on cancer risk.

Because the symptoms of MS can be broad and include feelings of fatigue, it’s possible that cancer symptoms are being masked or overlooked and not diagnosed until the cancer is late stage. MS patients and their physicians are encouraged to follow cancer screening guidelines to mitigate possible diagnostic neglect.

Linked data research — informing policy-making for healthier communities

Population Data BC provides researchers with access to the data and training they need to address research questions on human health, well-being and development. Population Data BC does not have its own researchers or research program.

Page last revised: August 13, 2014