An Audit of Serial Stereotactic Biopsies at the WCFT Between 2018-2021

Abstract

Abstract AIMS (1) To assess how often serial stereotactic brain biopsies of gliomas perform at Walton Centre between 20018 and 2021 allow clinically requisite molecular results, within the expected turnaround times. (2)Assess reasons for delay or not obtaining molecular results. METHOD All data obtained from LIMS (TDHC) and electronic patient records (eP2) at the Walton Centre Foundation Trust, and analysed in MS Excel. High grade glioma cases explored in detail. RESULTS Of 61 cases included, 45 were gliomas. 37 (61%) were HGGs i.e. GBMs or AAs. All requested molecular data could be obtained on 74% GBMs and 40% of AAs. One Oligodendroglioma remained ungraded. All the 4 DMGs could be issued final histological diagnosis based on immunohistochemistry and required no extra molecular tests. All requested molecular data could be obtained in 71% of LGG cases. MGMT results were obtained in 89% of GBM cases. NGS results were obtained in 57% of GBM cases. The average turnaround time from date of biopsy to authorised report 13 – 97 days, with a mean of 26 days. CONCLUSION (1) The majority of GBM cases yielded all requested molecular results. (2) Sample size was a limiting factor in obtaining molecular results. (3) Turnaround times have been compounded by failed molecular tests, ultimately affecting patient waiting times in HGGs. (4) Histological grading by mitotic index is not possible on small biopsy fragments. (5) If viable tumour cells are present, immunohistochemical molecular markers have proved valuable.