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Cancer risk in multiple sclerosis: findings from British Columbia, Canada
Elaine Kingwell1, Chris Bajdik2, Norm Phillips2, Feng Zhu1, Joel Oger1, Stanley Hashimoto1 and Helen Tremlett1
+ Author Affiliations
1 Division of Neurology, Faculty of Medicine, Multiple Sclerosis Program, University of British Columbia, Vancouver, BC, Canada V6T 2B5
2 Population Oncology, BC Cancer Agency, Vancouver, BC, Canada V5Z 4E6
Correspondence to: Elaine Kingwell, Faculty of Medicine (Neurology), UBC Hospital, 2211 Wesbrook Mall, University of British Columbia, Vancouver BC, Canada V6T 2B5
Received December 7, 2011.
Revision received April 28, 2012.
Accepted April 28, 2012.
Summary
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.
http://brain.oxfordjournals.org/cont...f-b166f9d29a40
Elaine Kingwell1, Chris Bajdik2, Norm Phillips2, Feng Zhu1, Joel Oger1, Stanley Hashimoto1 and Helen Tremlett1
+ Author Affiliations
1 Division of Neurology, Faculty of Medicine, Multiple Sclerosis Program, University of British Columbia, Vancouver, BC, Canada V6T 2B5
2 Population Oncology, BC Cancer Agency, Vancouver, BC, Canada V5Z 4E6
Correspondence to: Elaine Kingwell, Faculty of Medicine (Neurology), UBC Hospital, 2211 Wesbrook Mall, University of British Columbia, Vancouver BC, Canada V6T 2B5
Received December 7, 2011.
Revision received April 28, 2012.
Accepted April 28, 2012.
Summary
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.
http://brain.oxfordjournals.org/cont...f-b166f9d29a40
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