Brain Abscess and Risk of Cancer

Abstract

Background and ObjectivesUnderlying occult cancer could potentially explain some of the observed increased long-term mortality among patients with brain abscess.MethodsNationwide, population-based health care registries were used to examine long-term risks of cancer in patients with brain abscess from 1982 to 2016 compared with a population comparison cohort individually matched (10:1) on age, sex, and residence. Cumulative incidences and adjusted cause-specific hazard rate ratios (HRRs) with 95% CIs for cancer were computed. Potential confounding by family-related factors was explored by comparing cumulative incidences of cancer among siblings of both groups.ResultsAmong 1,384 patients with brain abscess (37% female, median age 50 years, interquartile ranges [IQR] 33–63), cancer was observed in 218 (16%) compared with 1,657 of 13,838 (12%) in the comparison cohort yielding an adj. HRR of 2.09 (95% CI 1.79–2.45). The median time to diagnosis of cancer was 1.8 years (IQR 0.02–9.1) in patients with brain abscess and 8.6 years (IQR 3.9–15.9) in comparison cohort. Among patients with brain abscess, CNS and eye cancer was diagnosed in 59 (4.3%), of which 47 of 59 (80%) occurred within 90 days of the admission date, metastasizing cancer in 54 (3.9%), respiratory tract cancer in 48 (3.5%), and gastrointestinal cancer in 36 (2.6%). Results remained consistent in almost all subgroups and in sensitivity analyses. Accounting for competing risk of death, the 1-, 5-, 10-, and 35-year cumulative incidence of cancer was 7% (95% CI 6–8), 11% (95% CI 9–12), 13% (95% CI 11–15), and 24% (95% CI 20–27) in patients with brain abscess compared with 0.7% (95% CI 0.6–0.9), 4% (95% CI 4–5), 8% (95% CI 8–9), and 25% (95% CI 23–27) in the comparison cohort, respectively. The cumulative incidences of cancer among siblings of patients with brain abscess were 10% and 12% among siblings of the comparison cohort.DiscussionBrain abscess was associated with substantially increased risk of cancer during the first 10 years after diagnosis.