Changes in clinical management of diffuse IDH-mutated lower-grade gliomas: patterns of care in a 15-year period

Background Isocitrate dehydrogenase ( IDH ) mutated diffuse lower-grade gliomas (dLGG) are infiltrating brain tumors and increasing evidence is in favor of early multimodal treatment. In a Scandinavian population-based setting, we wanted to study treatment patterns over the last 15 years, focusing on the short-term postoperative course to better understand the potential negative consequences of treatment. Methods Patients ≥ 18 years with primary IDH -mutated dLGG grade 2 and 3, operated between January 2007–June 2021 were identified. Patients were divided into subgroups (2007–2011, 2012–2016, and 2017–2021) and comparisons regarding tumor- and disease characteristics, treatment, and postoperative outcome were performed. Results We identified 202 patients (n = 61, 2007–2011; n = 72, 2012–2016; n = 69, 2017–2021), where of 193 underwent resection without change in proportion of resections over time. More patients underwent complete resections in recent times (6.1%; 15.7%; 26.1%, respectively; p = 0.016). Forty-two patients had any neurological deficit postoperatively (14.8%; 23.6%; 23.2%; p = 0.379), mostly minor and transient. Differences in oncological therapy were seen between the investigated subgroups. Early radiotherapy alone (32.8%; 7%; 2.9%; p