To Örebro University

Background: There is a trend in brain tumor treatments over time to treat patients at a higher age and to perform more advanced and radical surgery. Despite this little is known about the perioperative morbidity and mortality after intracranial tumor surgery, especially regarding the elderly. The Swedish brain tumor registry has collected data since 1999 with good coverage and is considered population based. Among the parameters registered are perioperative complications such as postoperative hematoma and thromboembolism as well as newly diagnosed epilepsy, new focal neurologic deficit and date of death.

Methods: Data from the registry has been collected and analyzed in this retrospective population based study. This study includes patients in the registry at age 65 or older, with high grade glioma (GBM, astrocytoma grIII), low grade glioma (astrocytoma grI-II, oligodendroglioma grII-III and gangliogliomas) registered from 1999 to 2015. Formation of diagnose groups are in conjunction with suggestions from the Swedish National Brain Tumor Trialist Group. From this data we have excluded patients that have not undergone surgery, where surgery (or not) cannot be determined and where data on complications is unavailable. Only the national regions with a high enough coverage are included.

Results: The material contains 1467 evaluable patients. High grade gliomas were 1277 (male 59%, female 41%), median age at surgery 71 (range 65 to 86), women not older (72 VS 71; NS). 17,5% (male 16,4%, female 20,0%; NS) had WHO/ECOG-PS >2. Perioperative mortality was 7,8% (male 9,2%, female 5,9%; p=0,03), associated with WHO/ECOG-PS >2 (p<0,0001). 15,7% (male 17,3%, female 13,5%; NS) had perioperative complications. The most common complication was worsening of neurologic function (7,6%, male 8,4%, female 6,5%; NS) and most patients (10,8%, male 12,8%, female 8,0%; NS) had one recorded complication. The mortality and morbidity remains consistent regardless of year of surgery. Low grade gliomas were 190 (male 55% VS female 45%), median age 70 (65 to 83), men not significantly older (71 VS 69; NS). 16,8% (male 15,7%, female 19,5%; NS) had WHO/ECOG-PS >2. Perioperative mortality was 5,3% (male 6,7%, female 3,5%; NS). 20,0% (male 21%, female 18,8%; NS) had perioperative complications. As with high grade gliomas the most common complication was worsening of neurologic function (13,7%, male 15,2%, female 11,8%; NS) and the mortality and morbidity remains without significant changes regardless of year of surgery.

Conclusion: In this material we can conclude that the perioperative mortality as well as morbidity is higher than in published younger patient materials for gliomas. We cannot see an increase in perioperative mortality or morbidity with higher age within the material but this could be from lack of power and we hope to be able to get a clearer view in a later comparison with the younger patients in the registry.