Malignant diseases among patients with multiple sclerosis.

The frequency of malignant diseases among 1866 living and 340 deceased multiple sclerosis (MS) patients was investigated in Finland. The study revealed a low prevalence (0.64%) and mortality (0.07%) rate of cancer among MS patients. The difference between MS patients and general population was significant. The highest rate was found in the group from 40 to 49 years while in the general population the rate of cancer among MS patients tended to fall after the age of 50. The possible role of selenium, one of the antioxidants in the pathogenesis of MS and cancer, is discussed because recent data have shown a very high negative correlation between selenium and cancer death rates.