Management and Long-Term Outcomes of Advanced Stage Thymoma in the United States

Automated segmentation by SCA-UNet can be directly used for radiomics diagnosis of thymic epithelial tumors

BACKGROUND

Automatic segmentation of thymic lesions in preoperative computed tomography (CT) images is crucial for accurate diagnosis but remains time-consuming. Although UNet is widely used in medical imaging, its performance is limited by the inherent drawbacks of convolutional neural networks (CNNs), such as restricted receptive fields and limited global context modeling, which affect segmentation efficiency.

METHOD

712 patients with mediastinal lesions admitted to Shanghai General Hospital between October 2014 and January 2023 were included in the study. Each lesion was manually delineated on CT images using the 3D slicer workstation. To enhance global context awareness for lesion segmentation, previously collected training data was used to develop a deep learning network called Space Channel Attention UNet (SCA-UNet). The model was further utilized for radiomics-based identification and risk assessment of thymic epithelial tumors (TETs). The code of SCA-UNet is available at: https://github.com/GovernTony/SCA-UNet.

RESULT

The SCA-UNet model was developed using 107 selected radiomic features. Based on our CT dataset, SCA-UNet outperformed several state-of-the-art models in segmentation accuracy and generalization, achieving the highest Dice Similarity Coefficient (DSC) of 87.48%. Furthermore, in subsequent radiomics classification, the segmentation results produced by SCA-UNet were comparable to those obtained through manual segmentation, with an Area Under the Curve (AUC) of 0.8457 for SCA-UNet versus 0.8514 for manual segmentation in TET identification, and 0.7735 for SCA-UNet versus 0.7780 for manual segmentation in risk assessment.

CONCLUSION

Overall, SCA-UNet demonstrated high accuracy in automatic segmentation and can be effectively applied to radiomics analysis, showing significant potential for the clinical application of TET treatment.

Development and Validation of a CT-Radiomics Nomogram for the Diagnosis of Small Prevascular Mediastinal Nodules: Reducing Nontherapeutic Surgeries

RATIONALE AND OBJECTIVES

The preoperative diagnosis of small prevascular mediastinal nodules (SPMNs) presents a challenge, often leading to unnecessary surgical interventions. Our objective was to develop a nomogram based on preoperative CT-radiomics features, serving as a non-invasive diagnostic tool for SPMNs.

MATERIALS AND METHODS

Patients with surgically resected SPMNs from two medical centers between January 2018 and December 2022 were retrospectively reviewed. Radiomics features were extracted and screened from preoperative CT images. Logistic regression was employed to establish clinical, radiomics, and hybrid models for differentiating thymic epithelial tumors (TETs) from cysts. The performance of these models was validated in both internal and external test sets by area under the receiver operating characteristic curve (AUC), while also comparing their diagnostic capability with human experts.

RESULTS

The study enrolled a total of 363 patients (median age, 53 years [IQR:45-59 years]; 175 [48.2%] males) for model development and validation, including 136 TETs and 227 cysts. Lesions' enhancement status, shape, calcification, and rad-score were identified as independent factors for distinction. The hybrid model demonstrated superior diagnostic performance compared to other models and human experts, with an AUC of 0.95 (95% CI:0.92-0.98), 0.94 (95% CI:0.89-0.99), and 0.93 (95% CI:0.83-1.00) in the training set, internal test set, and external test set respectively. The calibration curve of the model demonstrated excellent fit, while decision curve analysis underscored its clinical value.

CONCLUSION

The radiomics-based nomogram effectively discriminates between the most prevalent types of SPMNs, namely TETs and cysts, thus presenting a promising tool for treatment guidance.

Surgical management of thymic tumors: a narrative review with focus on robotic-assisted surgery

Background and Objective

Thymic epithelial tumors, including thymomas and thymic carcinomas, represent the most common mediastinal tumors and account for up to 50% of all anterior mediastinal tumors. For early stages of these thymic tumors, complete resection of the entire thymus is the recommended treatment. The transition from open surgery to video-assisted thoracoscopic surgery (VATS) and recently to robotic-assisted thoracic surgery (RATS) has fundamentally altered the treatment of thymic tumors. While RATS has been widely implemented due to its many advantages including good visualization with magnification and three-dimensional vision, improved maneuverability and precise instrument control, different techniques have been described. This narrative review focuses on the main approaches and outcomes of RATS thymectomy. It compares the technical, perioperative and clinical outcomes of RATS thymectomy, in particular, with VATS and open thymectomy.

Methods

A non-systematic review for full text studies written in the English language was conducted using the PubMed search engine and literature was summarized.

Key Content and Findings

We present an overview of robotic-assisted resection for thymomas and review the main approaches and outcomes of RATS thymectomy. Critical points of the RATS approach, including surgical specifics and pitfalls, are presented. Technical advantages and disadvantages of each technique are discussed. The perioperative and clinical outcomes of RATS thymectomy are compared, where possible, to those for VATS and open thymectomy. Currently, retrospective analyses demonstrate comparable or even more favorable outcomes following a RATS approach in comparison to VATS and open approaches in terms of operating time, conversion rates, intraoperative complications, completeness of resection and mortality. Certain analyses also report better outcomes for patients undergoing RATS thymectomy in terms of blood loss, postoperative complications, duration of pleural drainage and length of hospital stay compared to VATS and open thymectomy.

Conclusions

Overall, RATS has shown promising results and could become the preferred technique for resection of thymic tumors. It shows good outcomes compared to VATS and open thymectomy in the current literature. However, especially for extended tumors with the need for extended resection and reconstruction, open thymectomy remains a valuable approach.

Socioeconomic Factors Associated With Thymoma Survival in the United States

INTRODUCTION

The effects of socioeconomic factors on patients diagnosed with thymomas have not been previously studied. We propose these factors have an important association with survival. Thymoma is the most common tumor of the anterior mediastinum. Compared to other neoplasms which can integrate different therapeutic approaches for treatment, the most effective therapy for local and locally advanced thymoma is complete surgical resection. This study aimed to elaborate on socioeconomic variables and their potential effects on the survival outcomes in patients diagnosed with thymoma.

METHODS

Clinical data from the Surveillance, Epidemiology, and End Results 22 registry from 1975-2019 was used to define overall and cancer-specific survival of thymoma. The unadjusted analysis was followed by fitting a Cox proportional hazards model that included all variables assessed with Kaplan-Meier curves. An unadjusted Kaplan-Meier analysis was performed first comparing time to death by decade, age, race, ethnicity, sex, income, and region separately. The primary outcome was survival measured in months.

RESULTS

We identified 1821 patients aged 18 y or over from the Surveillance, Epidemiology, and End Results database with a thymoma diagnosis between the years 1975 and 2019. The demographic variables considered were age, race, ethnicity (Hispanic/non-Hispanic), sex (male/female), inflation-adjusted income in 2019 dollars, and community size. We observed a decrease in mortality from thymic neoplasm across the decades. For each subsequent year, mortality risk decreased by 3.5% (P <0.001). The mortality risk of older patients was significantly higher. Compared to the youngest group, the mortality risk was 52.8% higher in the 50-year-old to 65-year-old category (P = 0.021). The mortality risk was 339% times higher in the 65 + age group (P <0.001). Income may be associated with risk reduction. Patients making greater than $75,000 had a 40.1% lower mortality risk than those making less than $50,000 (P = 0.029). The survival rate categorized by race was similar between Blacks and Whites but tended to be higher for the Asian and Pacific Islander groups without reaching statistical significance (P = 0.12).

CONCLUSIONS

Medical advancements have improved the overall thymoma survival in the past four decades. Yet, demographic, and socioeconomic factors such as age, income, and race may also play a role.

Surgical, Radiation, and Systemic Treatments of Patients With Thymic Epithelial Tumors: A Systematic Review

INTRODUCTION

Thymic epithelial tumors are rare and are classified as thymoma, thymic carcinoma, and thymic neuroendocrine tumors. The objective of this systematic review was to evaluate the treatment options for patients with thymic epithelial tumors.

METHODS

This systematic review was developed by Ontario Health (Cancer Care Ontario)'s Program in Evidence-Based Care and by the Lung Cancer Disease Site Group. MEDLINE, EMBASE, and the Cochrane Library were searched for studies comparing surgical, radiotherapy, or systemic treatments against any combination of these treatments in patients with thymic epithelial tumors. Meta-analyses were conducted with clinically homogenous studies.

RESULTS

A total of 106 studies were included, mainly from observational studies. There was an overall survival benefit with postoperative radiotherapy for patients with thymic carcinoma (hazard ratio = 0.65, 95% confidence interval: 0.47-0.89) and for patients with thymoma (hazard ratio = 0.70, 95% confidence interval: 0.59-0.82), especially for those with a high risk for mortality. Patients with thymic carcinoma or thymoma had a response to chemotherapy. Selection bias affected the results for studies that evaluated neoadjuvant chemotherapy or minimally invasive surgical techniques. Furthermore, the overall survival benefit found for adjuvant chemotherapy may have been confounded by the administration of postoperative radiotherapy.

CONCLUSIONS

For patients with thymoma or thymic carcinoma, the literature is of low quality and subject to bias. There were overall survival benefits with postoperative radiotherapy. The results of this systematic review were used to inform treatment recommendations in a clinical practice guideline. Future large-scale prospective studies that control for confounders are needed.

Open redo thymectomy for a large recurrent thymoma in a patient with myasthenia gravis: a case report

Thoracoscopic and robotic approaches are becoming increasingly popular for thymoma surgery. Yet open thymectomy must still be mastered today, as it may be the only viable option in challenging cases. In this study, we report a case of an extended local recurrence of myasthenia gravis associated thymoma and a history of previous sternotomy. The mediastinal mass infiltrated the left upper lobe of the lung, the pericardium, and presumably the aortic arch. Although the standard for thymoma resection at our institution is the robotic approach, we performed primary open redo thymectomy in standby of cardiopulmonary bypass in this case. Intraoperatively, bleeding from the aortic arch occurred, which was promptly controlled due to the open approach and due to immediate availability of cardiopulmonary bypass. The patient was transferred to the normal ward on the first postoperative day, was treated according to fast-track principles and recovered well. The pathology revealed a WHO B2:B1 thymoma with negative resection margins. Thymectomy is recommended as the principal treatment for thymoma and is also advised in the case of recurrence. However, there is no evidence regarding the optimal surgical approach. Our case indicates that in the era of minimally invasive thymectomy, the decision to conduct open surgery is wise when the risk of serious bleeding is anticipated or adherence to oncologic principles is challenged by tumor size or growth pattern.

A novel risk classifier for predicting the overall survival of patients with thymic epithelial tumors based on the eighth edition of the TNM staging system: A population-based study

OBJECTIVE

Thymic epithelial tumors (TETs) are rare tumors that originated from thymic epithelial cells, with limited studies investigating their prognostic factors. This study aimed to investigate the prognostic factors of TETs and develop a new risk classifier to predict their overall survival (OS).

METHODS

This retrospective study consisted of 1224 TETs patients registered in the Surveillance, Epidemiology, and End Results (SEER) database, and 75 patients from the First Affiliated Hospital of Xi'an Jiaotong University. The univariate and multivariate Cox regression analyses were adopted to select the best prognostic variables. A nomogram was developed to predict the OS of these patients. The discriminative and calibrated abilities of the nomogram were assessed using the receiver operating characteristics curve (ROC) and calibration curve. Decision curve analysis (DCA), net reclassification index (NRI), and integrated discrimination improvement (IDI) were adopted to assess its net clinical benefit and reclassification ability.

RESULTS

The multivariate analysis revealed that age, sex, histologic type, TNM staging, tumor grade, surgery, radiation, and tumor size were independent prognostic factors of TETs, and a nomogram was developed to predict the OS of these patients based on these variables. The time-dependent ROC curves displayed that the nomogram yielded excellent performance in predicting the 12-, 36- and 60-month OS of these patients. Calibration curves presented satisfying consistencies between the actual and predicted OS. DCA illustrated that the nomogram will bring significant net clinical benefits to these patients compared to the classic TNM staging system. The estimated NRI and IDI showed that the nomogram could significantly increase the predictive ability of 12-, 36- and 60-month OS compared to the classic TNM staging system. Consistent findings were discovered in the internal and external validation cohorts.

CONCLUSION

The constructed nomogram is a reliable risk classifier to achieve personalized survival probability prediction of TETs, and could bring significant net clinical benefits to these patients.

CT-Based Radiomics Nomogram for Differentiation of Anterior Mediastinal Thymic Cyst From Thymic Epithelial Tumor

Objectives

This study aimed to distinguish preoperatively anterior mediastinal thymic cysts from thymic epithelial tumors via a computed tomography (CT)-based radiomics nomogram.

Methods

This study analyzed 74 samples of thymic cysts and 116 samples of thymic epithelial tumors as confirmed by pathology examination that were collected from January 2014 to December 2020. Among the patients, 151 cases (scanned at CT 1) were selected as the training cohort, and 39 cases (scanned at CT 2 and 3) served as the validation cohort. Radiomics features were extracted from pre-contrast CT images. Key features were selected by SelectKBest and least absolute shrinkage and selection operator and then used to build a radiomics signature (Rad-score). The radiomics nomogram developed herein via multivariate logistic regression analysis incorporated clinical factors, conventional CT findings, and Rad-score. Its performance in distinguishing the samples of thymic cysts from those of thymic epithelial tumors was assessed via discrimination, calibration curve, and decision curve analysis (DCA).

Results

The radiomics nomogram, which incorporated 16 radiomics features and 3 conventional CT findings, including lesion edge, lobulation, and CT value, performed better than Rad-score, conventional CT model, and the clinical judgment by radiologists in distinguishing thymic cysts from thymic epithelial tumors. The area under the receiver operating characteristic (ROC) curve of the nomogram was 0.980 [95% confidence interval (CI), 0.963–0.993] in the training cohort and 0.992 (95% CI, 0.969–1.000) in the validation cohort. The calibration curve and the results of DCA indicated that the nomogram has good consistency and valuable clinical utility.

Conclusion

The CT-based radiomics nomogram presented herein may serve as an effective and convenient tool for differentiating thymic cysts from thymic epithelial tumors. Thus, it may aid in clinical decision-making.

Induction Strategy for Locally Advanced Thymoma

Surgery remains cornerstone for the management of thymoma. Complete surgical resection (R0), is recognized as the constant and significant factor for prognosis. However, in locally advanced (Masaoka-Koga stages III-IVa) thymomas, achieving R0 resection remains challenging due to local-regional invasion of the disease. Induction treatment, with the aim of reducing bulky tumor mass, offers new strategy to facilitate totally surgical resection. Herein, we reviewed recent progress and provided a comprehensive overview of induction strategy in locally advance thymoma.

Vascular Involvement in Thymic Epithelial Tumors: Surgical and Oncological Outcomes

BACKGROUND

The involvement of mediastinal great vessels is common in advanced stage thymic tumors, which makes their surgical resection challenging. Moreover, the impact of vascular involvement on the oncological prognosis is still unclear. The aim of this study is to investigate the surgical and oncological outcomes and the impact of vascular involvement in a population of patients operated for advanced stage thymic tumors.

METHODS

A retrospective analysis on four hundred and sixty-five patients undergoing resection for advanced stage (Masaoka III-IV) thymic tumors in a single high-volume center was performed. One hundred forty-four patients met the inclusion criteria and were eligible for the study. Patients were divided in two groups according to the presence or absence of vascular involvement.

RESULTS

the two groups did not differ for the baseline characteristics and showed comparable surgical outcomes. Vascular involvement was not associated with worse overall survival but with an increased recurrence rate (p = 0.03). Multivariable analysis demonstrated a higher risk of recurrence in patients without R0 resection (HR 0.11, 0.02-0.54, p = 0.006) and with thymic carcinoma (HR 2.27, 1.22-4.24, p = 0.01).

CONCLUSIONS

resection of thymic tumors with vascular involvement can be performed with optimal surgical results in a high volume center. From the oncological point of view, the involvement of the great vessels seems to be associated with a higher recurrence rate without affecting long-term survival.

Surgical feasibility and long-term outcome of superior vena cava replacement for advanced thymoma in patients undergoing preoperative chemotherapy or chemoradiotherapy

Background

The aim of this study was to investigate the long‐term outcome of superior vena cava (SVC) replacement after chemotherapy or chemoradiotherapy for advanced thymoma.

Methods

The medical information of patients with advanced thymoma who underwent thymoma resection and SVC replacement in Beijing Tongren Hospital from 2002 to 2017 were reviewed. We compared surgical outcomes, postoperative complications and long‐term prognosis in the chemoradiotherapy + surgery group (CRT + surgery group, 19 cases) and the surgery group (26 cases).

Results

The operation time (486.05 ± 148.01 vs. 370.77 ± 124.32 min; p = 0.007) and intraoperative blood loss (1400 ml [IQR 1125–2105 ml] vs. 855 ml [IQR 555–1682.5 ml], p = 0.036), poor wound healing (three cases [15.79%] vs. zero cases [0.0%], p = 0.036) in the CRT + surgery group were significantly higher than those of the surgery group. There was no significant difference between the CRT + surgery group and the surgery group in postoperative chest tube drainage time, hospitalization time, postoperative arrhythmia and incidence of pneumonia. Kaplan Meier analysis showed that the recurrence‐free survival (RFS) curves of the CRT + surgery group patients were better than those of the surgery group (p = 0.031). However, overall survival (OS) between the two groups was not significantly different (p = 0.069).

Conclusions

Thymoma resection and SVC replacement is feasible for patients undergoing preoperative induction chemotherapy or chemoradiotherapy for advanced thymoma. Although patients in the CRT + surgery group had a longer operation time and increased intraoperative bleeding, the RFS rate seemed to be better than that in the surgery group.