Kingwell E, Evans C, Zhu F, Oger J, Hashimoto S, Tremlett H. Assessment of cancer risk with β-interferon treatment for multiple sclerosis. J Neurol Neurosurg Psychiatry. 2014 Mar. doi: 10.1136/jnnp-2013-307238. [Epub ahead of print]
OBJECTIVE: The risk of cancer after exposure to the β-interferons (IFNβs) for multiple sclerosis (MS) has not been established. We assessed whether IFNβ treatment for MS is associated with cancer risk or the risk of specific cancers in a population-based observational study.
METHODS:The British Columbia MS database was linked to the provincial Cancer Registry, Vital Statistics death files and Health Registration files. Using a nested case-control design, MS cancer cases were matched with up to 20 randomly selected MS controls at the date of cancer diagnosis by sex, age (±5 years) and study entry year using incidence density sampling. Associations between treatment exposure and overall or specific (breast, colorectal, lung and prostate) cancers were estimated, adjusted for MS disease duration and age. Tumour size at cancer diagnosis was compared between treated and untreated patients.
RESULTS: The cohort included 5146 relapsing-onset MS patients and 48 705 person-years of follow-up, during which 227 cancers were diagnosed. Exposure to IFNβ was not significantly different for cases and controls (OR 1.28; 95% CI 0.87 to 1.88). There was a non-significant trend towards an increased risk of IFNβ exposure in the breast cancer cases (OR 1.77; 95% CI 0.92 to 3.42), but no evidence of a dose-response effect. Tumour size was similar between IFNβ treated and untreated cases.
CONCLUSIONS: There was no evidence of an increased cancer risk with exposure to IFNβ over a 12-year observation period. However, the trend towards an association between IFNβ and breast cancer should be investigated further.
We have made a few posts on this recently a study in Taiwan suggested some relationship to breast cancer but read the other posts to put this in context.