Value of metabolic parameters in distinguishing primary mediastinal lymphomas from thymic epithelial tumors

Objective:A high rate of unnecessary thymectomies has been reported.This study aimed to distinguish primary mediastinal lymphomas(PMLs)from thymic epithelial tumors(TETs)by evaluating volumetric and metabolic parameters with l8F-FDG PET/CT.Methods:A total of 136 patients who were pathologically diagnosed with TETs or PMLs were enrolled,and 18F-FDG PET/CT was performed before therapy.Volumetric parameters,including the mean SUV(SUVmean),metabolic tumor volume(MTV),total lesion glycolysis(TLG),and SUVmax,were determined and compared between the 2 subtypes.The diagnostic performance of these parameters was evaluated with receiver operating characteristic(ROC)curve analysis.Results:All parameters significantly differed between patients with PMLs and TETs.Patients with lymphomas were younger and had higher SUVmean,SUVmax,TLG,and MTV values than patients with TETs.The MTV and TLG values had similar diagnostic performance.ROC analysis indicated that the areas under the curves of the SUVmean and SUVmax values performed similarly(approximately 0.76)in differentiating patients with PMLs from TETs,and both values were better than the MTV and TLG values.When age was included with the SUVmax in differentiating TETs from PMLs,the AUC was 0.91,and the sensitivity and specificity increased to 80%and 93%,respectively.Conclusions:The SUVmax and volumetric parameters of 18F-FDG PET/CT can be used to distinguish patients with PMLs versus TETs,and thus may aid in preventing unnecessary thymectomies or other invasive operations.

GOECP/SEOR radiotherapy guidelines for thymic epithelial tumours

Thymic epithelial tumours(TET)are rare,heterogeneous neoplasms that range from resectable indolent tumours to aggressive thymic carcinomas with a strong tendency to metastasize.The pathological diagnosis is complex,in part due to the management of TETs is scant and mainly based on non-randomised studies and retrospective series.Consequently,the clinical management of TETs tends to be highly heterogenous,which makes it difficult to improve the evidence level.The role of technological advances in the field of radiotherapy and new systemic therapies in the treatment of TETs has received little attention to date.In the present clinical guidelines,developed by the GOECP/SEOR,we review recent developments in the diagnosis and classification of TETs.We also present a consensus-based therapeutic strategy for each disease stage that takes into consideration the best available evidence.These guidelines focus primarily on the role of radiotherapy,including recent advances,in the management of TETs.The main aim of this document is to promote the standardisation of clinical practice and lay the foundations for future studies to clarify the main unresolved questions related to the optimal management of TET.