Background Brain tumors (BTs) in adolescence and young adulthood (AYA) differ from those in childhood or late adulthood. However, research concerning late effects in this particular survivor group is limited. This study evaluates late morbidity of survivors diagnosed in AYAs.

Methods We identified from the Finnish Cancer Registry all survivors diagnosed with BT at the ages 16–24 years between 1970 and 2004 (N = 315) and used data from the Hospital Discharge Registry to evaluate their late (≥5 y after diagnosis) morbidity requiring treatment in a specialized health care setting. A sibling cohort of BT patients diagnosed before the age of 25 years was used as a comparison cohort (N = 3615).

Results The AYA BT survivors had an increased risk for late-appearing endocrine diseases (HR, 2.9; 95% CI, 1.1–8.0), psychiatric disorders (HR, 2.0; 95% CI, 1.2–3.2), diseases of the nervous system (HR, 9; 95% CI, 6.6–14.0), disorders of vision/hearing loss (HR, 3.6; 95% CI, 1.5–8.5), diseases of the circulatory system (HR, 4.9; 95% CI, 2.9–8.1), and diseases of the kidney (HR, 5.9; 95% CI, 2.5–14.1). Survivors with irradiation had an increased risk for diseases of the nervous system compared with non-irradiated survivors (HR, 3.3; 95% CI, 1.8–6.2). The cumulative prevalence for most of the diagnoses remained significantly increased for survivors even 20 years after cancer diagnosis.

Conclusions The AYA BT survivors have an increased risk of morbidity for multiple new outcomes for ≥5 years after their primary diagnosis. This emphasizes the need for structured late-effect follow-up for this patient group.