Colorectal Cancer Survival in Multiple Sclerosis

Abstract

Background and Objectives:We tested the hypothesis that overall and cancer-specific survival following colorectal cancer diagnosis is lower in persons with multiple sclerosis (MS) than without MS, using a retrospective matched cohort design.Methods:Using population-based administrative data in Manitoba and Ontario we identified persons with MS using a validated case definition, and linked these cohorts to cancer registries to identify those with colorectal cancer. We selected persons with colorectal cancer and without MS matching 4:1 on birth year, sex, cancer diagnosis year and region. We used Cox proportional hazards regression to compare all-cause survival between cohorts adjusting for age at cancer diagnosis, cancer diagnosis year, income, region, and Elixhauser comorbidity score. We compared cancer-specific survival between cohorts using a cause-specific hazards model. We pooled findings across provinces using random-effects meta-analysis. Complementary analyses using a subcohort from Ontario adjusted for cancer stage and disability status, as measured based on the use of home care or long-term care services.Results:We included 338 MS cases and 1352 controls with colorectal cancer. The mean (SD) age at cancer diagnosis was 64.7 (11.1) years. After adjustment, MS was associated with an increased hazard for all-cause death which was highest six months post-diagnosis (hazard ratio [HR] 1.45; 95%CI: 1.19-1.76), then declined over time (HR [95%CI] 1 year: 1.34 [1.09-1.63], 2 years: 1.24 [0.99-1.56]; 5 years: 1.10 [0.80-1.50]). MS was associated with increased cancer-specific death at 6 months post-diagnosis only (HR 1.29; 95%CI: 1.04-1.61). After adjusting for cancer stage, MS was associated with an increased hazard of death due to any cause (1.60; 95%CI: 1.16, 2.21) and with cancer-specific death (HR 1.47; 95%CI: 1.02, 2.12). The association of MS and all cause death was partially attenuated after adjustment for disability status (HR 1.37; 95%CI: 0.97, 1.92), as was the association with cancer-specific death (HR 1.34; 95%CI: 0.91, 1.97).Discussion:Overall and cancer-specific survival was lower in persons with than without MS in the early period following colorectal cancer diagnosis. Further study is warranted to determine what factors underlie these worse outcomes.

Multiple Sclerosis and the Cancer Diagnosis

“…By studying these 3 aspects of the diagnostic process together, we isolated cancer screening of patients with MS as a topic for further investigation. This finding in conjunction with previously documented survival disparities 1,2 suggests that disparities in the care of patients with MS need to be addressed. Other design strengths of this population-based study include robust calculation of the diagnostic interval, control for important potential confounders, and the use of sensitivity analyses to assess for any effect of missing stage on our results.…”

“…Less cancer detection through screening in patients with MS compromises control of the cancer, which can adversely affect survival. 1,2,4-6…”

“…The study populations were drawn from cohorts developed for earlier work on this project. 1,2 Exclusions included non-Ontario residents, those <18 or >105 years of age at the cancer diagnosis, those who were diagnosed with cancer on the date of death, those whose breast or colorectal cancer was not their first cancer, those with a concurrent cancer diagnosis (diagnosed within 6 months), cancer stage = 0, men (breast cancer only), and those who were not OHIP eligible for ≥12 months before the cancer diagnosis. Also, for the patients without MS, we excluded those with any ICD-9/ICD-10-CA code for demyelinating disease (323, 377.3, 340, 341.9, G35, G36, G37) before their cancer diagnosis date.…”

“…Survival after diagnosis of breast cancer or colorectal cancer is compromised for people with multiple sclerosis (MS). 1,2 Cancer screening, through early detection, and timely diagnosis are important drivers of cancer survival in breast and colorectal cancer. [3][4][5][6][7] Screen detection may be lower in persons with MS and a cancer diagnosis.…”

Cancer Screening in Patients With Multiple Sclerosis

“…Similarly, in a group of 338 patients with MS and colorectal cancer and 1,352 patients with colorectal cancer without MS, survival for patients with MS was lower in the early period following cancer diagnosis. 5 The cause for this increased mortality remains to be elucidated but possible explanations include a lower rate of cancer screening in the MS population, either because of limitations to access due to MS disability or competing health interests from MS-related symptoms. Alternatively, complications from MS disease may worsen cancer outcomes directly.…”