WCLC 2025 - Posters & ePosters-EP.14.13 Utility of Visual Assessment of PET/CT for Differentiating Malignancy in Thymic Epithelial Tumors

Pdf Summary

This study by Asami et al. from Shizuoka Cancer Center evaluates the utility of the visual Deauville scoring system applied to 18F-FDG PET/CT scans in differentiating malignancy in thymic epithelial tumors, particularly distinguishing thymoma from thymic carcinoma. While maximum standardized uptake values (SUVmax) on PET correlate with tumor malignancy per WHO classification, SUVmax measurements vary widely depending on institution and scanner, limiting standardization. The Deauville score, a five-point visual scale originally developed for lymphoma and validated in lung cancer, compares tumor uptake to mediastinum and liver background uptake offering potential standardization.<br /><br />In this retrospective study of 123 patients undergoing surgical resection for thymic tumors (2002–2024), cases were grouped by Deauville scores ≤3 (uptake ≤ liver) versus 4 (uptake > liver). Higher Deauville scores correlated significantly with thymic carcinoma histology, advanced Masaoka staging (III-IV), larger tumor size, and higher SUVmax values. The optimal SUVmax cutoff to differentiate carcinoma from thymoma was 4.81, yielding 87% sensitivity and specificity. The study highlights strong concordance between visual Deauville assessment and quantitative SUVmax measurements.<br /><br />The authors note that prior SUVmax cutoffs lack consensus and have variable diagnostic performance due to heterogenous protocols and small sample sizes. The Deauville scoring system may provide a reproducible, standardized, and visually intuitive method improving interobserver agreement and multicenter applicability. High inter- and intra-observer agreement has been documented in lung cancer studies using this score.<br /><br />In conclusion, a Deauville score of 4 or higher is associated with thymic carcinoma and more invasive disease, suggesting this visual PET/CT assessment could aid in preoperative evaluation of thymic epithelial tumors to better predict malignancy and invasiveness, thus supporting clinical decision-making.

Asset Subtitle

Momoko Asami

Meta Tag

Speaker Momoko Asami

Topic Mesothelioma, Thymoma, and Other Thoracic Tumors

Keywords

Deauville scoring system

18F-FDG PET/CT

thymic epithelial tumors

thymoma

thymic carcinoma

SUVmax

Masaoka staging

tumor malignancy differentiation

visual assessment

preoperative evaluation