Diagnostic yield from minimally invasive pediatric brain tumor biopsies in the molecular era

This study aimed to evaluate the diagnostic yield from minimally invasive biopsies of pediatric brain tumors using endoscopic, robot-guided, and optical image-guided techniques.

A single-center retrospective review was conducted on the data of children (< 18 years of age) who underwent minimally invasive brain tumor biopsies using optical image-guided, endoscopic, or robot-assisted needle biopsies. Data collected consisted of demographic details, tumor location, simultaneous CSF diversion, and macroscopic details of collected specimens. Primary outcomes were histological and molecular diagnostic yield, histological accuracy, need for repeat biopsy, and reasons for biopsy failure. Adverse events were prospectively recorded. Statistical analysis was conducted in SPSS and Prism using Pearson's chi-square and Fisher's exact tests.

Between January 2004 and February 2023, 188 biopsies were performed using endoscopic (41.5%), optical image-guided (37.2%), and robot-guided (21.3%) techniques. Tumor location was classified as suprasellar (28.2%), pineal region (20.2%), brainstem (19.1%), basal ganglia/thalamic (16.5%), supratentorial lobar (10.1%), intraventricular (5.3%), and cerebellar (0.5%). Histological diagnosis was achieved in 88.3% (166/188) and consisted of low-grade glioma (33.5%), high-grade glioma (31.9%), germ cell tumor (10.6%), embryonal tumor (5.3%), craniopharyngioma (2.1%), lymphoma (1.6%), pineoblastoma (1.6%), choroid plexus papilloma (0.5%), meningioma (0.5%), and pineal cyst (0.5%). Overall, 11.7% (22/188) of biopsies were nondiagnostic: 19.2% for endoscopic, 8.6% for optical image-guided, and 2.5% for robot-guided techniques. Thirteen (6.9%) patients required further biopsy. A molecular diagnosis was achieved in 82.0% (109/133) of eligible cases. All tumors with a molecular diagnosis had a histological diagnosis; of 24 patients for whom molecular diagnosis was not possible, 79.2% (19/24) had a histological diagnosis. Larger-sized biopsies were more likely to result in a positive diagnosis for histology and molecular analysis. Hemorrhage in the specimen did not affect results. Endoscopic biopsies were most likely to be small and yield a lower volume of core specimens. Histological diagnostic accuracy for glioma was more likely for high-grade tumors, larger-sized biopsies, and tumors in which a molecular diagnosis was achieved.

Through the use of contemporary minimally invasive techniques, pediatric brain tumor biopsy has a histological diagnostic yield of 88.3% and molecular diagnostic yield of 82.0%. Robot-guided and optical image-guided techniques provided the highest diagnostic yield (97.5% and 91.4%, respectively, for histological analysis), while endoscopic biopsies had the highest rate of nondiagnostic results (19.2%), likely due to smaller specimen volumes.