Cohort study of risk of cancer in patients with first-time seizure

Seizures are a known complication of cancer, but whether they may be the first signi of undiagnosed neurological and nonneurological cancer is unclear. A population-based cohort study in Denmark examined cancer risk in patients with first-time seizures compared with the general population. The study included 49,894 adults with a first-time seizure from 1996 through 2022 without a history of cancer. Within the first year of follow-up, 1172 neurological and 850 nonneurological cancers were observed; from year 1 to 5 there were 87 neurological and 1226 nonneurological cancers; from year 5 to 20 there were 112 neurological and 2120 nonneurological cancers. In these time periods, the standardized incidence ratios relative to the general population for any cancer were 5.30 (95% CI 5.07-5.54), 1.18 (1.12-1.25), and 1.34 (1.28-1.40) and for neurological cancer 76.1 (71.1-80.6), 1.85 (1.48-2.28), and 1.46 (1.20-1.75). The authors conclude that first-time seizures were associated with clearly elevated short-term relative risk of cancer, and slightly elevated long-term risk, indicating they may be an early clinical sign of both neurological and nonneurological cancer.