Conflicting or complementary role of computed tomography (CT) and positron emission tomography (PET)/CT in the assessment of thymic cancer and thymoma: Our experience and literature review

Background: To evaluate the role of computed tomography (CT) and positron emission tomography (PET)/CT in patients with thymic cancer and thymoma at initial staging. Methods: We 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. Results: PET/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). Conclusion: Our 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

Ground glass pulmonary nodules: their significance in oncology patients and the role of computer tomography and 18F–fluorodeoxyglucose positron emission tomography

Abstract Objective to 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. Methods A 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. Results The 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. Conclusion in 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

Indeterminate Lung Nodules in Cancer Patients: Pretest Probability of Malignancy and the Role of18F-FDG PET/CT

OBJECTIVE. The purpose of this study was to determine likelihood of malignancy for indeterminate lung nodules identified on CT comparing two standardized models with 18F-FDG PET/CT. MATERIALS AND METHODS. Fifty-nine cancer patients with indeterminate lung nodules (solid tumors; diameter, 65 5 mm) on CT had FDG PET/CT for lesion characterization. Mayo Clinic and Veterans Affairs Cooperative Study models of likelihood of malignancy were applied to solitary pulmonary nodules. High probability of malignancy was assigned a priori for multiple nodules. Low ( 60%) pretest malignancy probabilities were analyzed separately. Patients were reclassified with PET/CT. Histopathology or 2-year imaging follow-up established diagnosis. Outcome-based reclassification differences were defined as net reclassification improvement. A null hypothesis of asymptotic test was applied. RESULTS. Thirty-one patients had histology-proven malignancy. PET/CT was true-positive in 24 and true-negative in 25 cases. Negative predictive value was 78% and positive predictive value was 89%. On the basis of the Mayo Clinic model (n = 31), 18 patients had low, 12 had intermediate, and one had high pretest likelihood; on the basis of the Veterans Affairs model (n = 26), 5 patients had low, 20 had intermediate, and one had high pretest likelihood. Because of multiple lung nodules, 28 patients were classified as having high malignancy risk. PET/CT showed 32 negative and 27 positive scans. Net reclassification improvements respectively were 0.95 and 1.6 for Mayo Clinic and Veterans Affairs models (both p < 0.0001). Fourteen of 31 (45.2%) and 12 of 26 (46.2%) patients with low and intermediate pretest likelihood, respectively, had positive findings on PET/CT for the Mayo Clinic and Veterans Affairs models, respectively. Of 15 patients with high pretest likelihood and negative findings on PET/CT, 13 (86.7%) did not have lung malignancy. CONCLUSION. PET/CT improves stratification of cancer patients with indeterminate pulmonary nodules. A substantial number of patients considered at low and intermediate pretest likelihood of malignancy with histology-proven lung malignancy showed abnormal PET/ CT findings

Conflicting or complementary role of computed tomography (CT) and positron emission tomography (PET)/CT in the assessment of thymic cancer and thymoma

Purpose: To evaluate the role of CT and PET/CT in thymic cancer and thymoma patients at initial staging. Methods and Materials: We retrospectively reviewed CT and PET/CT of 26 patients with a proven-diagnosis of thymic cancer (n=9)and thymoma (n=17).Chest CT findings documented were qualitative (calcification, peritumoral fat infiltration,pleural-pericardial effusion, degree of abutment of vessel circumference, et al)and quantitative (maximum axial and longitudinal diameter and volume).Both qualitative and semiquantitative data (standardised uptake value, total lesion glicolysis-TLG, metabolic tumor volume-MTV)were recovered by PET/CT.The outcome of all patients was retrieved by clinical chart or observational follow-up.The comparisons among histological entities, outcome and CT and PET/CT findings were evaluated using a non-parametric analysis. Results: PET/CT resulted positive in 15 patients with thymoma.100%of patients with thymic cancer had a positive scan.CT was available in 5/9 patients with thymic cancer and in 3/17 subjects with thymoma.All quantitative CT parameters were significantly higher in patients with thymic cancer than thymoma (MAD:45vs.20 mm,MLD:69vs.21 mm and volume:77.91vs.4.52 ml;all p < 0.05).Conversely, only MTV and TLG were significantly different in patients with thymic cancer than the counterpart (126.53vs.6.03 cm3 and 246.05vs.20.32,respectively;both p < 0.05).After a median follow-up of 17.45 months, four recurrences of disease occurred (three in patients with thymic cancer and one with a type B2 thymoma).Follow-up data were lost in three subjects.CT volume in a patient with recurrent disease was 170.12 ml vs. a median value of 10.5 ml in seven disease-free patients.MTV was higher in recurrent than disease-free subset (143.3vs.81.13 cm3),although not statistically significant (p=0.075). Conclusion: Both morphological and metabolic volume can be useful for diagnostic and prognostic meaning in thymic cancer and thymoma patients

Prognosi tomografia ad emissione di positroni (PET)-guidata: ruolo promettente dell\u2019imaging metabolico nel cancro dell\u2019 esofago (CE)

Scopo: Valutare valore prognostico di PET/TC dopo terapia neoadiuvante nel CE localmente avanzato. Materiali e metodi: 56 pazienti. Risultati PET/TC correlati con gestione paqziente e prognosi. Curve di sopravvivenza con Kaplan-Meier. Risultati: dopo neoadiuvante, 15 pz con PET/TC negativa e 41 positiva. In 6/15 e 31/41 intervento chir. radicale (p=0,02). Dopo 10 mesi mediani 28 pz. liberi da malattia, 15 recidiva, 11 morti. Sopravvivenza libera pi\uf9 alta in pz con PET/TC negativa (73% vs 41%; p=0,01). Conclusioni: la PET/TC pu\uf2 stratificare il rischio di recidiva nei pz con CE