Surg-16. sampling and processing of tumor tissue during resection of diffuse intracranial glioma: international survey and recommendations for standardization on behalf of four rano groups

Abstract BACKGROUND Surgical resection represents the standard of care for newly diagnosed diffuse gliomas and allows neuropathological evaluation for diagnosis. Moreover, tissue specimens form the basis for research allowing the identification of pathogenetic mechanisms and targets. However, there is no consensus which tumor portions should be systematically sampled to achieve a genuinely representative evaluation in a condition characterized by intratumoral heterogeneity. Guidelines for biospecimen handling and long-term storage are also lacking, limiting comparative analyses between different biobanks. METHODS Four international RANO groups from the fields of surgical and medical neuro-oncology, radiation oncology, neuroimaging, and neuropathology aimed to generate a framework for tissue sampling and processing during resection of diffuse glioma. RESULTS A core committee of 21 representatives from the four RANO groups identified areas of interest based upon expert consensus and drafted recommendations for best practice guidelines. Those were eventually sent to 38 leading experts in the field for further evaluation using a two-staged eDelphi process, leading to refinement of the recommendations. Only recommendations which were scored as of ‘critical importance’ by ≥ 70% of the expert panelists were accepted. Consensus recommendations were developed for (I) tissue volume and (neuroimaging-based) tumor-specific regions from where the tumor should be sampled; (II) definitions how regions for sampling of non-contrast-enhancing tumor on MRI should be identified; (III) blood and CSF sampling; (IV) handling and storage to enable both neuropathological diagnosis and in-depth research analyses; and (V) the preferred sample labelling to avoid communication errors. These recommendations resulted in a sophisticated intraoperative workflow proposal to accurately depicture the tumor composition during sampling. CONCLUSION These RANO recommendations offer a framework to standardize the surgical and post-surgical workflow for prospective biobanking studies which will be presented together with the results of the eDelphi survey at the SNO meeting.