Cancer related mortality in multiple sclerosis. A population based cohort study

•Multiple Sclerosis patients have a two fold increased risk of dying following a cancer diagnosis compared to controls•Mortality was highest following diagnosis of urinary, hematological, breast and ovarian cancers•The hypothesis of diagnostic neglect for specific cancers in the MS population was raised•The cohort study of MS patients (n= 6950) and controls (n= 37 922) were followed up during 65 years, and sampled from the Norwegian MS Registry, the Norwegian Cancer Registry, the Cause of Death Registry and the National Education Database.