Short-term outcome following surgery for rare brain tumor entities in adults: a Swedish nation-wide registry-based study and comparison with SEER database.

To investigate outcomes after surgery for rare brain tumors using the Swedish Brain Tumor Registry (SBTR). This is a nationwide study of patient in the SBTR, validated in the Surveillance, Epidemiology, and End Results (SEER) registries. We included all adults diagnosed 2009-2015 with a rare brain tumor entity (n = 216), defined as ependymoma (EP, n = 64), subependymoma (SUBEP, n = 21), ganglioglioma (GGL, n = 54), pilocytic astrocytoma (PA, n = 56) and primitive neuroectodermal tumor (PNET, n = 21). We analyzed symptomatology, tumor characteristics and outcomes. Mean age was 38.3 ± 17.2 years in GGL, 36.2 ± 16.9 in PA, 37.0 ± 19.1 in PNET, 51.7 ± 16.3 in EP and 49.8 ± 14.3 in SUBEP. The most common symptom was focal deficit (39.6-71.4%), and this symptom was most common in GGL patients with 64.2% of GGL presenting with seizures. Most patients had no or little restriction in activity before surgery (Performance Status 0-1), although up to 15.0% of PNET patients had a performance status of 4. Gross total resection was achieved in most (> 50%) tumor categories. Incidence of new deficits was 11.1-34.4%. In terms of postoperative complications, 0-4.8% had a hematoma of any kind, 1.9-15.6% an infection, 0-7.8% a venous thromboembolism and 3.7-10.9% experienced a complication requiring reoperation. There were 3 deaths within 30-days of surgery, and a 1-year mortality of 0-14.3%. We have provided benchmarks for the current symptomatology, tumor characteristics and outcomes after surgery for rare brain tumors as collected by the SBTR and validated our results in an independent registry. These results may aid in clinical decision making and advising patients.