18F-FDG PET/CT characteristics of IASLC grade 3 invasive adenocarcinoma and the value of 18F-FDG PET/CT for preoperative prediction

Purpose This study is performed to investigate the imaging characteristics of the International Association for the study of lung cancer (IASLC) grade 3 invasive adenocarcinoma (IAC) on PET/CT and the value of PET/CT for preoperative predicting this tumor. Materials and Methods We retrospectively enrolled patients with IAC from August 2015 to September 2022. The clinical characteristics, serum tumor markers, and PET/CT features were analyzed. T test, Mann-Whitney U test, χ2 test, Logistic regression analysis, and receiver operating characteristic (ROC) analysis were used to predict grade 3 tumor and evaluate the prediction effectiveness. Results Grade 3 tumors had a significantly higher maximum standardized uptake value (SUVmax) ( P < 0.001), while Grade 1 - 2 tumors were prone to present with air bronchogram sign or vacuole sign ( P < 0.001). Multivariate logistic regression analysis revealed that only SUVmax (OR = 1.137; 95% CI: 1.037, 1.247; P < 0.05) and air bronchogram sign or vacuole sign (OR = 0.225; 95% CI: 0.088, 0.572; P < 0.05) were independent predictors for Grade 3 tumors. The established prediction formula for Grade 3 tumors was P = one / [one + EXP (1.112 - 0.187 × SUVmax + 1.395 × air bronchogram sign or vacuole sign)], which generated a high AUC (0.825) and negative predictive value (0.924), respectively. Conclusion Our study demonstrates that grade 3 IAC has a unique PET/CT imaging feature. The prediction model established with SUVmax and air bronchogram sign or vacuole sign can effectively predict grade 3 tumors before the operation. ### Competing Interest Statement The authors have declared no competing interest. ### Funding Statement This work was supported by the National Natural Science Foundation of China [grant numbers 82171984]. ### Author Declarations I confirm all relevant ethical guidelines have been followed, and any necessary IRB and/or ethics committee approvals have been obtained. Yes The details of the IRB/oversight body that provided approval or exemption for the research described are given below: Ethics committee of Nanfang Hospital,Southern Medical University waived ethical approval for this work. I confirm that all necessary patient/participant consent has been obtained and the appropriate institutional forms have been archived, and that any patient/participant/sample identifiers included were not known to anyone (e.g., hospital staff, patients or participants themselves) outside the research group so cannot be used to identify individuals. Yes I understand that all clinical trials and any other prospective interventional studies must be registered with an ICMJE-approved registry, such as ClinicalTrials.gov. I confirm that any such study reported in the manuscript has been registered and the trial registration ID is provided (note: if posting a prospective study registered retrospectively, please provide a statement in the trial ID field explaining why the study was not registered in advance). Yes I have followed all appropriate research reporting guidelines, such as any relevant EQUATOR Network research reporting checklist(s) and other pertinent material, if applicable. Yes All data produced in the present study are available upon reasonable request to the authors. * IAC : invasive adenocarcinoma ROC : receiver operating characteristic SUVmax : maximum standardized uptake value IASLC : the International Association for the study of lung cancer 18F-FDG : 18F-fluorodeoxyglucose PET/CT : positron emission tomography/computed tomography ROI : region of interest MTV : metabolic tumor volume TLG : and total lesion glycolysis pGGN : pure ground glass nodule PACS : picture archiving and communications system CYFRA21 - 1 : cytokeratin fragment 21 - 1 CEA : carcinoembryonic antigen SCC : squamous cell carcinoma antigen NSE : neuron-specific enolase CTR : consolidation-tumor-ratio RFP : recurrence - free probability OSEM : ordered subsets expectation maximization SUV : standardized uptake value CT : computed tomography PET : positron emission tomography [M (Q25, Q75)] : median (25% quantile, 75% quantile)