June 21, 2012 – People with multiple sclerosis have a lower risk of developing cancer, according to a new study from the University of British Columbia and Vancouver Coastal Health. The study, published in the journal Brain, is the first in North America to investigate the odds of developing all cancers in people with multiple sclerosis. “The immune system plays an important role in the course of both cancer and multiple sclerosis, so we wanted to know if people with multiple sclerosis had the same risk of developing cancer as the general population,” said study leader Elaine Kingwell, a postdoctoral fellow in the Department of Pharmacy and the Centre for Brain Research at the University of British Columbia. “Not only do people with MS have a lower incidence of cancer overall, they have a particularly low incidence of colorectal cancer.” The researchers compared cancer rates in British Columbians with MS to those in the general population. They found that MS patients had lower overall cancer rates – especially for colorectal cancer. However, MS patients had a slightly higher risk of developing brain and bladder cancer (not a significant difference). In patients with multiple sclerosis relapses, the odds of developing non-melanotic skin cancer were significantly higher than in the general population. The reasons for the lower risk of cancer in patients with multiple sclerosis remain to be revealed by further studies. Another surprising finding was that once MS patients developed cancer, the tumors tended to be large at the time of initial diagnosis. Why the initial diagnosis of tumors is late for MS patients is worth investigating. “Because MS has a wide range of symptoms, including non-specific symptoms such as fatigue, these can lead to symptoms of cancer being masked or overlooked,” said senior investigator Helen Tremlett, associate professor in the Department of Pharmacy at the University of British Columbia. In any case, MS patients and physicians should follow cancer screening guidelines.” She also mentioned that they will further study whether MS patients have a different mortality rate due to cancer than the general population.