Does the dural resection bed need to be irradiated? Patterns of recurrence and implications for postoperative radiotherapy for temporal lobe gliomas

Abstract

Background Patterns of recurrence and survival with different surgical and radiotherapy (RT) techniques were evaluated to guide RT target volumes for patients with temporal lobe glioma. Methods And Materials This retrospective cohort study included patients with WHO Grade II-IV temporal lobe glioma treated with either partial (PTL) or complete temporal lobectomy (CTL) followed by RT covering both parenchymal and dural resection bed (whole cavity radiotherapy [WCRT]) or the parenchymal resection bed only (partial cavity radiotherapy [PCRT]). Patterns of recurrence, progression-free survival (PFS) and overall survival (OS) were evaluated. Results 51 patients were included and 84.3% of patients had high grade glioma (HGG). CTL and PTL were performed for 11 (21.6%) and 40 (78.4%) patients, respectively. Median RT dose was 60 Gy (40-76). There were 82.4% and 17.6% of patients received WCRT and PCRT, respectively. Median follow-up time was 18.4 months (4-161). 46 patients (90.2%) experienced disease recurrence, most commonly at parenchymal resection bed (76.5%). No patients experienced an isolated dural recurrence. The median PFS and OS for the PCRT and WCRT cohorts were 8.6 vs 10.8 months (p=0.979) and 19.9 vs 18.6 months (p=0.859), respectively. PCRT was associated with a lower RT dose to brain stem, optic and ocular structures, hippocampus and pituitary. Conclusion We identified no isolated dural recurrence and similar PFS and OS regardless of post-operative RT volume, whereas PCRT was associated with dose reduction to critical structures. Omission of dural RT may be considered a reasonable alternative approach. Further validation with larger comparative studies is warranted.