Cancer risk in multiple sclerosis: findings from British Columbia, Canada

Abstract

Findings regarding cancer risk in people with multiple sclerosis have been inconsistent and few studies have explored the possibility of diagnostic neglect. The influence of a relapsing-onset versus primary progressive course on cancer risk is unknown. We examined cancer risk and tumour size at diagnosis in a cohort of patients with multiple sclerosis compared to the general population and we explored the influence of disease course. Clinical data of patients with multiple sclerosis residing in British Columbia, Canada who visited a British Columbia multiple sclerosis clinic from 1980 to 2004 were linked to provincial cancer registry, vital statistics and health registration data. Patients were followed for incident cancers between onset of multiple sclerosis, and the earlier of emigration, death or study end (31 December 2007). Cancer incidence was compared with that in the age-, sex- and calendar year-matched population of British Columbia. Tumour size at diagnosis of breast, prostate, colorectal and lung cancers were compared with population controls, matched for cancer site, sex, age and calendar year at cancer diagnosis, using the stratified Wilcoxon test. There were 6820 patients included, with 110 666 person-years of follow-up. The standardized incidence ratio for all cancers was 0.86 (95% confidence interval: 0.78-0.94). Colorectal cancer risk was also significantly reduced (standardized incidence ratio: 0.56; 95% confidence interval: 0.37-0.81). Risk reductions were similar by sex and for relapsing-onset and primary progressive multiple sclerosis. Tumour size was larger than expected in the cohort (P = 0.04). Overall cancer risk was lower in patients with multiple sclerosis than in the age-, sex- and calendar year matched general population. The larger tumour sizes at cancer diagnosis suggested diagnostic neglect; this could have major implications for the health, well-being and longevity of people with multiple sclerosis.

Inverse and Direct Cancer Comorbidity in People with Central Nervous System Disorders: A Meta-Analysis of Cancer Incidence in 577,013 Participants of 50 Observational Studies

“…Exclusion of irrelevant references and/or duplicates left 204 potential full-text articles. Fifty-one articles [3,7,23,24,25,26,27,28,29,30,31,32,33,34,35,36,37,38,39,40,41,42,43,44,45,46,47,48,49,50,51,52,53,54,55,56,57,58,59,60,61,62,63,64,65,66,67,68,69,70,71] (with a total of 577,013 participants) fulfilled our inclusion criteria (fig. 1) and were included in the qualitative data synthesis.…”

“…Eight studies [32,36,37,38,39,40,41,42] on 54,929 patients with MS reflected a reduced incidence of cancer in general (ES = 0.91; 95% CI: 0.87-0.95; I 2 = 30.3%), with low between-study heterogeneity (Q statistic: p = 0.19; fig. 2).…”

Dramatically changing rates and reasons for hospitalization in multiple sclerosis

“…The lower frequency of admissions for cancer is consistent with the lower reported incidence of cancer in the MS population. 32 However, the lower frequency of admissions for circulatory diseases was not. We previously reported an increased incidence and prevalence of ischemic heart disease in the MS population but did not examine hospitalizations for ischemic heart disease specifically.…”

Neuro-oncology dilemma: Tumour or tumefactive demyelinating lesion

“…The prevalence of brain tumour in MS has been reported to be increased in some studies (Kingwell et al, 2012;Sumelahti et al, 2004;Fois et al, 2010), but not in others (Møller et al, 1991; Kingwell et al, 2012;Lebrun et al, 2008;Midgard et al, 1996;Nielsen et al, 2006). The elevated risk for brain cancer was most evident soon after disease onset of MS, suggesting a surveillance bias given that patients were being investigated for another condition and brain tumours were found unexpectedly.…”

“…MS patients exposed to long-term immunosupressive-immunomodulatory treatment may have an increased risk for cancer (Kingwell and Tremlett, 2009). Studies of cancer co-morbidity in MS have yielded inconsistent findings, with rates higher (Kingwell and Tremlett, 2009;Møller et al, 1991), lower (Bahmanyar et al, 2009;Kingwell et al, 2012;Lebrun et al, 2008) or no difference from the general population (Midgard et al, 1996;Sumelahti et al, 2004). The general trend and meta-analysis showed even a diminished risk of cancer in MS population (Handel and Ramagopalan, 2010).…”