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The risk of amyotrophic lateral sclerosis after cancer in U.S. elderly adults: A population‐based prospective study
Author(s) -
Freedman D. Michal,
Wu Jincao,
Daugherty Sarah E.,
Kuncl Ralph W.,
Enewold Lindsey R.,
Pfeiffer Ruth M.
Publication year - 2014
Publication title -
international journal of cancer
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.475
H-Index - 234
eISSN - 1097-0215
pISSN - 0020-7136
DOI - 10.1002/ijc.28795
Subject(s) - amyotrophic lateral sclerosis , medicine , prospective cohort study , population , cancer , oncology , gerontology , physical medicine and rehabilitation , disease , environmental health
Although epidemiologic studies have examined the risk of amyotrophic lateral sclerosis (ALS) in relation to cancer, none have been large population‐based studies using incident ALS and adjusting for medical surveillance. Addressing those limitations, all first primary cancer cases from the Surveillance, Epidemiology and End Results (SEER) Program (1992–2005), linked to Medicare claims data were used. Cases were followed from cancer diagnosis until the earliest date of ALS diagnosis, a break in Medicare claims data, death, age 85 or December 31, 2005. A comparison group from a 5% random Medicare sample in the SEER areas who were cancer‐free and censored as above, or until a cancer diagnosis were selected. ALS outcomes were derived from medical claims. The proportional hazards models to estimate ALS hazard ratios (HRs), using age as the time scale, adjusting for sex, race and physician visits, and stratifying the baseline hazard on birth year and SEER registry were used. A total of 303 ALS cases were ascertained in cancer patients (2,154,062 person‐years) compared with 246 ALS cases (2,467,634 person‐years) in the reference population. There was no overall relationship between cancer and ALS (HR = 0.99; 95% CI = 0.81–1.22), nor by gender or race. Except for an elevated ALS risk in the first year after a leukemia diagnosis, the relationship between site‐specific cancers and ALS was null after correcting for multiple comparisons. Having a cancer diagnosis was not associated with an overall risk of incident ALS. The short‐term ALS risk after leukemia may reflect screening or reporting errors.