Low-Grade Metaplastic Carcinomas of the Thymus: Biphasic Thymic Epithelial Tumors with Mesenchymal Metaplasia — An Update

Abstract Background Recent advance in tissue characterization with parametric mapping imaging has the potential to be a novel biomarker for histopathologic correlation with thymic epithelial tumors (TETs). The purpose of our study is to evaluate MRI T1 mapping with the calculation of extracellular volume (ECV) fraction for histologic correlation with thymic epithelial tumor based on lymphocyte abundance. Methods A retrospective study including 31 consecutive patients (14 men and 17 women, median age, 56 years; interquartile range, 12 years) with TETs was performed. The T1 values and ECV were assessed by using quantitative MRI mapping techniques. Mann-Whitney U test, Kruskal-Wallis H test, and receiver operating characteristic curve analyses were used to assess discrimination between different types of TETs based on lymphocyte abundance. Results Extracellular volume was significantly higher in TETs with sparse lymphocyte, including type A, type B3, and thymic carcinoma, compared with those with abundant lymphocyte, including type B1, B2, and AB thymomas (42.5% vs 26.9%, respectively; p < 0.001). Extracellular volume was significantly higher in thymic carcinoma compared with low grade and high grade thymomas (48.6% vs 31.1% vs 27.6%, respectively; p = 0.002). Conclusions T1 mapping with the calculation of extracellular volume (ECV) fraction correlate with the WHO histologic classification of thymic epithelial tumor based on lymphocyte abundance.

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The tumor doubling time is a useful parameter for predicting the histological type of thymic epithelial tumors

Surgery Today ◽

10.1007/s00595-019-01822-9 ◽

2019 ◽

Vol 49 (8) ◽

pp. 656-660 ◽

Cited By ~ 1

Author(s):

Koichi Fukumoto ◽

Takayuki Fukui ◽

Koji Kawaguchi ◽

Shota Nakamura ◽

Shuhei Hakiri ◽

...

Keyword(s):

Doubling Time ◽

Histological Type ◽

Tumor Doubling Time ◽

Thymic Epithelial Tumors ◽

Epithelial Tumors

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Prognostic Significance of Metabolic Parameters by 18F-FDG PET/CT in Thymic Epithelial Tumors

Cancers ◽

10.3390/cancers13040712 ◽

2021 ◽

Vol 13 (4) ◽

pp. 712

Author(s):

Joohee Lee ◽

Young Seok Cho ◽

Jhingook Kim ◽

Young Mog Shim ◽

Kyung-Han Lee ◽

...

Keyword(s):

Multivariate Analysis ◽

Prognostic Factors ◽

Fdg Pet ◽

Univariate Analysis ◽

Thymic Epithelial Tumors ◽

Epithelial Tumors ◽

Masaoka Stage ◽

Pet Ct ◽

18F Fdg ◽

Fdg Pet Ct

Background: Imaging tumor FDG avidity could complement prognostic implication in thymic epithelial tumors. We thus investigated the prognostic value of volume-based 18F-fluorodeoxyglucose (18F-FDG) positron emission tomography (PET)/CT parameters in thymic epithelial tumors with other clinical prognostic factors. Methods: This is a retrospective study that included 83 patients who were diagnosed with thymic epithelial tumors and underwent pretreatment 18F-FDG PET/CT. PET parameters, including maximum and average standardized uptake values (SUVmax, SUVavg), metabolic tumor volume (MTV), and total lesion glycolysis (TLG), were measured with a threshold of SUV 2.5. Univariate and multivariate analysis of PET parameters and clinicopathologic variables for time-to-progression was performed by using a Cox proportional hazard regression model. Results: There were 21 low-risk thymomas (25.3%), 27 high-risk thymomas (32.5%), and 35 thymic carcinomas (42.2%). Recurrence or disease progression occurred in 24 patients (28.9%). On univariate analysis, Masaoka stage (p < 0.001); histologic types (p = 0.009); treatment modality (p = 0.001); and SUVmax, SUVavg, MTV, and TLG (all p < 0.001) were significant prognostic factors. SUVavg (p < 0.001) and Masaoka stage (p = 0.001) were independent prognostic factors on multivariate analysis. Conclusion: SUVavg and Masaoka stage are independent prognostic factors in thymic epithelial tumors.

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296 Immune correlates of clinical response to Avelumab in patients with advanced thymic epithelial tumors

Journal for ImmunoTherapy of Cancer ◽

10.1136/jitc-2020-sitc2020.0296 ◽

2020 ◽

Vol 8 (Suppl 3) ◽

pp. A323-A323

Author(s):

Yo-Ting Tsai ◽

Arun Rajan ◽

James Gulley ◽

Jeffrey Schlom ◽

Renee Donahue

Keyword(s):

Clinical Response ◽

Mononuclear Cells ◽

Predictive Biomarkers ◽

Lymphocytic Infiltration ◽

Peripheral Blood Mononuclear ◽

Thymic Epithelial Tumors ◽

Link Type ◽

Epithelial Tumors ◽

Immune Correlates ◽

Tcr Diversity

BackgroundThymic epithelial tumors (TET), consisting of thymomas and thymic carcinomas, are PD-L1-expressing tumors characterized by varying degrees of lymphocytic infiltration and a predisposition towards the development of paraneoplastic autoimmunity. As part of a phase I study (NCT01772004), the anti-tumor activity of patients with relapsed, advanced TET to avelumab (anti-PD-L1), was demonstrated and was accompanied by a high frequency of immune related adverse events (irAE). The current study aimed to identify immune related signatures that associate with clinical response and/or the development of irAE.MethodsEight patients with recurrent TET were treated with avelumab at doses of 10 mg/kg to 20 mg/kg every 2 weeks until disease progression or development of intolerable side effects. Peripheral blood mononuclear cells (PBMC) were obtained before and during therapy, and interrogated by multicolor flow cytometry to evaluate 123 immune subsets, as well as by T-cell receptor (TCR) sequencing to evaluate TCR diversity.ResultsFour of 8 TET patients had partial responses and 3 had stable disease. All responders developed irAEs that resolved with immunosuppressive therapy, compared to only 1 of 4 non responders. Analyses of PBMC subsets prior to therapy showed that responders had higher absolute lymphocyte counts, and lower frequencies of B cells, Tregs, conventional dendritic cells (cDCs), and NK cells, compared to non-responders. There was also a trend towards a higher level of TCR diversity in those patients who subsequently had a radiological response and developed irAE.ConclusionsImmune profiling identified specific immune measures prior to therapy that differed between responders and non-responders, that may serve as predictive biomarkers to identify patients with relapsed TET most likely to benefit from avelumab and/or to develop irAE.Trial RegistrationNCT01772004Ethics ApprovalAll patients provided written informed consent for participation in a clinical trial that was approved by the Institutional Review Board at the National Cancer Institute (NCT01772004).

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