BackgroundTo evaluate the role of computed tomography (CT) and positron emission tomography (PET)/CT in patients with thymic cancer and thymoma at initial staging.MethodsWe retrospectively reviewed CT and PET/CT scans of 26 patients with a thymic cancer (n = 9) or thymoma (n = 17). Chest CT findings documented were qualitative and quantitative. Both qualitative and semiquantitative data were recovered by PET/CT. The comparisons among histological entities, outcome, and qualitative data from CT and PET/CT were made by non-parametric analysis.ResultsPET/CT resulted positive in 15/17 patients with thymoma. CT was available in 5/9 (56%) patients with thymic cancer and in 3/17 with thymoma. All quantitative CT parameters were significantly higher in patients with thymic cancer than thymoma (maximum axial diameter: 45 vs. 20 mm, maximum longitudinal diameter: 69 vs. 21 mm and volume: 77.91 vs. 4.52 mL; all P < 0.05). Conversely, only metabolic tumor volume (MTV) and total lesion glycolysis were significantly different in patients with thymic cancer than thymoma (126.53 vs. 6.03 cm3 and 246.05 vs. 20.32, respectively; both P < 0.05). After a median follow-up time of 17.45 months, four recurrences of disease occurred: three in patients with thymic cancer and one with a type B2 thymoma. CT volume in patients with recurrent disease was 102.19 mL versus a median value of 62.5 mL in six disease-free patients. MTV was higher in the recurrent than disease-free patient subset (143.3 vs. 81.13 cm3), although not statistically significant (P = 0.075).ConclusionOur preliminary results demonstrated that both morphological and metabolic volume could be useful from a diagnostic and prognostic point of view in thymic cancer and thymoma patients. A large multi-center clinical trial experience for confirming the findings of this study seems mandatory.

Objectiveto determine the clinical significance of ground glass pulmonary nodules, either pure (GGNs) or mixed with the presence of solid component (MPNs), in patients with known pulmonary or extra-thoracic malignancies and to evaluate the role of computed tomography (CT) and positron emission tomography (PET)/CT in their diagnosis and follow-up.MethodsA total of 130 nodules in 68 patients were revealed: 119 GGNs and 11 MPNs. GGN lesions were found in 58 patients, MPNs in eight, and in two cases, both. The median diameter of the nodules was 7 mm (3–30 mm). Moreover, 27 patients, who had a pars-solid >5 mm in the GGN or a pure GGN with a diameter > 5 mm, underwent FDG PET/CT. The median follow-up with CT was >3 years.ResultsThe comparison between the first and the last positive CT scan showed that GGNs and/or MPNs remained unchanged for a median period of 18 months (range 11–48 months) in 53 patients, they disappeared after a median of 3.5 months (range 2–11 months) in 12 and increased in diameter after a median period of 17 months (range 12–67 months) in 3. In particular of these latter patients, two had malignant lesions. Only three patients with a single nodule showed a significant uptake of FDG at PET/CT.Conclusionin the evaluation of GGNs and MNPs, CT examinations performed after 3 months often showed some changes, mainly with respect to nodules disappearing. PET/CT often plays no role but it can exclude malignancy at the end of staging. Finally, in patients with known pulmonary or extra-thoracic malignancies showing GGNs or MPNs, a 3-year CT follow up is justified, due to the slow growth rate of these lesions.

e20574 Background: Recent evidences have suggested potential applications of radiomics in early diagnosis, prognostic stratification and treatment outcome prediction of Non-Small Cell Lung Cancer (NSCLC) patients. The purpose of this study is to evaluate the ability of radiomic analysis to discriminate between different clinical-pathological conditions in patients with stage III NSCLC. Methods: Baseline CT studies from 59 patients with stage III NSCLC referred to our Institution from 2010 and 2020 were retrospectively reviewed, and the segmentation of the main lung lesion and the extraction of 517 radiomic features performed using a commercial software. The number of features was reduced to 46 by means of principal component analysis applied using the R package “RadAR” (Radiomics Analysis with R). The Kruskal-Wallis test was applied to all the radiomic features in order to evaluate which of them can discriminate between 7 clinical dichotomous characteristics: tumor stage, type, presence of mutation, treatment response, relapse free survival (RFS), smoking habit, patient outcome. P < 0.05 means that there is a statistically significant difference between the two subgroups. Results: The median age at diagnosis was 69 years (range 43-83). Most patients were males (40/59 = 67.8%) and heavy smokers (36/59 = 61.0%). Adenocarcinoma was the most common histology (41/59 = 70.7%), while cases were almost equally splitted between stage IIIA (45.8%) and stage IIIB or IIIC (54.2%). Most selected radiomic features (29/46 = 63.0%) showed a statistically significant difference between patients with and without mutations. Ten (10/46 = 21.7%) radiomic features were associated with patient sex. Seven features (7/45 = 15.2%) were “sensitive” to the tumor clinical stage (stage IIIA vs. stage IIIB+IIIC), 4 (4/46 = 8.7%) to the histological type, and 2 (2/46 = 4.3%) to the patient outcome. None of the selected radiomic features was able to discriminate between responder and non-responder patients, current/previous smokers and never smokers, and patients with RFS lower than 12 months versus RFS equal or higher than 12 months. Conclusions: This preliminary analysis showed that radiomics has the potential of identifying mathematical features associated with clinical and histopathological characteristics in stage III NSCLC patients, which might feed multiparametric predictive models. Larger datasets and further analysis are necessary in order to confirm initial results.

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