A meta-analysis has shown that patients with MS have an approximate 10% reduced risk of developing cancer of any type as compared with controls.1
This is unlikely to be the result of decreased survival in MS patients, since age-adjusted analyses still showed a decreased risk. Similarly, under-diagnosis is unlikely because patients with MS are more frequently in contact with health professionals than are those without this disease.
Because smoking is a risk factor for both MS and lung cancer, it is perhaps surprising that the risk of lung cancer is reduced in MS patients. The reduced risk of skin cancer is perhaps to be expected given an association of decreased sunshine exposure with MS risk.
As more potent disease-modifiying therapies become available for MS, cancer risks in MS patients need to be carefully monitored in the future.
The overall decreased cancer prevalence in patients with MS warrants further study and may represent an effect of increased immune surveillance in this autoimmune disease.
1. Handel AE, Sreeram V, Ramagopalan SV. Multiple sclerosis and risk of cancer: a meta-analysis
J Neurol Neurosurg Psychiatry. 2010;81:1413-1414.