Development of a New Score Based on Image Defined Risk Factors to Standardize Surgical Risk in Neuroblastoma Resection - a SIOPEN Collaborative Study

assess surgical risk in neuroblastoma (NB) and guide neoadjuvant therapy decisions. Despite chemotherapy, IDRFs persist in 70% of cases. Several studies have suggested that not all IDRFs hold equal significance and that the presence of an IDRF does not inherently signify unresectability. This current study seeks to stratify and assign a score to each IDRF based on its impact on surgical risk. Methods: This collaborative study entailed the retrospective gathering of patient data from NB surgeries conducted between 2016 and 2020, along with the computation of the Surgical Complexity Index (SCI) for each patient. The SCI values obtained were correlated with preoperatively identified IDRFs. Mann- Whitney statistical testing was employed to assign a relevance score to the association between individual IDRFs and SCI. Results: Fourteen Centers contributed to a retrospective collection of 427 index cases meeting study inclusion criteria. Three hundred and three patients had 1 or more IDRFs. The presence and number of IDRFs in a given patient significantly correlated with the SCI value (p<0.0001). The most frequently encountered IDRF was renal pedicle involvement. There was a significant association between clusters of abdominal IDRFs and the occurrence of postoperative complications (p<0.05), while a weak association was found with intra-operative complications. A relevance score for individual IDRFs allowed their stratification based on surgical risk. The most relevant IDRFs were extension within two body compartments, infiltration of the hepato-pancreatic block, encasement of the superior mesenteric artery and coeliac axis, and tumor compressing the trachea. Conclusions: This study facilitated the assignment of a relevance score to each IDRF, correlating it with surgical risk. Considering this stratification of surgical risk alongside the oncologic risk defined by the patient’s risk group should enable a more precise definition of surgical objectives and optimal conditions for its execution.