Abstract
BackgroundPatients with advanced or recurrent thymic epithelial tumors (TETs) often need several consecutive lines of chemotherapy. The aim of this retrospective monocentric study was to test whether 18F-Fluorodeoxyglucose positron emission tomography-computed tomography (18F-FDG PET-CT) is able to monitor standard chemotherapy efficacy in those patients and whether metabolic response correlates with morphovolumetric response as assessed by Response Evaluation Criteria in Solid Tumor (RECIST).MethodsWe evaluated 27 consecutive patients with advanced (16 patients) or recurrent (11 patients) TETs. All patients underwent 18F-FDG PET-CT before and after at least 3 cycles of chemotherapy. Maximum standardized uptake value (SUVmax) of all detected lesions was recorded and the most 18F-FDG avid lesion in each patient was selected for determination of percentage change of SUVmax (ΔSUVmax) in pre- and post-treatment scans. Tumor response was assessed by contrast-enhanced computed tomography (CE-CT) using RECIST criteria. Receiver operating characteristic (ROC) curve analysis was performed to define the optimal threshold of ΔSUVmax discriminating responders from non-responders.ResultsMetabolic response expressed as ΔSUVmax was significantly correlated with morphovolumetric response (Spearman’s rank correlation, r = 0.64, p = 0.001). ROC curve analysis showed that a ΔSUVmax value of -25% could discriminate responders from non-responders with a sensitivity of 88% and a specificity of 80%. Conversely, basal SUVmax values were not predictive of morphovolumetric tumor response.ConclusionsOur findings indicate that metabolic response assessed by 18F-FDG PET-CT, through evaluation of ΔSUVmax, may allow identification of responders and non-responders thus guiding adaptation of therapy in patients with advanced or recurrent TETs.
Highlights
Patients with advanced or recurrent thymic epithelial tumors (TETs) often need several consecutive lines of chemotherapy
Patients and treatment In this retrospective monocentric study we evaluated the medical records of twenty-seven consecutive patients, 18 male and 9 female, with advanced (16 patients) or recurrent (11 patients) thymic epithelial tumors who had undergone whole-body 18F-FDG 18F-Fluorodeoxyglucose Positron Emission TomographyComputed Tomography (PET-CT) before and after standard chemotherapy regimens
Pretreatment 18F-FDG PET-CT scan showed abnormal 18F-FDG uptake in all patients detecting a total of 77 lesions, including 18 mediastinal masses, 15 lymph nodes, 23 pleura/pericardial implants, 16 visceral lesions and 5 bone lesions, with an average of 2.85 ± 2.03 lesions per patient
Summary
Patients with advanced or recurrent thymic epithelial tumors (TETs) often need several consecutive lines of chemotherapy. The aim of this retrospective monocentric study was to test whether 18F-Fluorodeoxyglucose positron emission tomography-computed tomography (18F-FDG PET-CT) is able to monitor standard chemotherapy efficacy in those patients and whether metabolic response correlates with morphovolumetric response as assessed by Response Evaluation Criteria in Solid Tumor (RECIST). The treatment strategy for thymic epithelial tumour is primarily based on whether the tumor can be radically resected or not at diagnosis [8,9,10]. Surgery remains the treatment of choice, most of these tumors are unresectable or in advanced stages at diagnosis and require chemotherapy, eventually followed by surgery if tumors become resectable after the planned regimen. Several consecutive lines of chemotherapy are available for patients presenting tumor progression
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