Importance of resection for locoregional disease control in Masaoka stage IVA thymic neoplasms

Risk factors and prognostic factors of pleural metastases in thymic epithelial tumors: A narrative review

INTRODUCTION

Pleural metastases are common in thymic epithelial tumors (TET), which include pleural recurrence and stage IVa at initial diagnosis. However, the specific risk factors predicting its recurrence (i.e., pleural recurrence group) and prognostic factors for pleural metastasis (i.e., stage IVa) remain unclear. This review aims to identify and discuss the predictors associated with pleural metastases in patients with TET.

METHODS

A systematic literature search was conducted on PubMed, MEDLINE, Embase, and Cochrane for articles published between 1/1/1990 and 3/11/2023. The selection process was independently carried out by three researchers, and the quality of the selected papers was assessed using the Newcastle-Ottawa Scale (NOS).

RESULTS

Out of the 4932 papers reviewed, 22 were included in the final analysis: 15 papers on risk factors of pleural recurrence after primary treatment(i.e., recurrence group) and 7 papers on the prognostic factors of patients with stage IVa at diagnosis(i.e., stage IVa group). Of the 15 former articles, 5 identified pleural invasion and invasion of other tissues as significant risk factors for pleural recurrence. Four of 15 papers identified the Masaoka-Koga stage as a significant risk factor, while two of 15 papers identified the contact length between the tumor contour and the lung as a contributing factor for pleural recurrence. Additionally, two papers suggested that tumor size may be a risk factor for pleural recurrence. Six other papers discussed various factors, including a lobulated tumor contour, WHO histologic classifications B2 and B3, radiotherapy doses of≤50Gy, incomplete resection, and Entire hemithorax radio therapy, as potential risk factors. Furthermore, one paper specifically addressed the decreased risk for pleural dissemination associated with Video-Assisted Thoracoscopic Surgery (VATS) thymectomy. In patients with stage IVa at diagnosis group, three of 7 papers mentioned that resection influenced the prognosis. Two papers discussed the number of nodules in the pleura but arrived at different conclusions. One paper suggested that patients older than 50 years might have worse outcomes, while another analyzed the invasion of structures but did not find any significant results.

CONCLUSION

For pleural recurrence patients, the most commonly discussed risk factor is pleural invasion. Other identified risk factors include the Masaoka-Koga stage, contact length between the tumor contour and the lung, tumor size, lobulated tumor contour, WHO histologic classifications B2 and B3, radiotherapy doses of≤50Gy, and incomplete resection. For patients with stage IVa at diagnosis, non--extrapleural pneumonectomy, incomplete or no resection, and histological subtype may contribute to a poorer prognosis in patients diagnosed with pleural dissemination. The number of disseminated pleural nodules remains controversial and may be correlated with resectability.

Spatial Distribution Patterns of Pleural Dissemination in Patients With Thymoma and Survival Analysis

Background: Thymoma is a common malignancy with low incidence, and pleural metastases are common pattern of recurrence. It is necessary that the spatial location of pleural metastatic lesions be analyzed. This study aimed to analyze the spatial distribution patterns of pleural dissemination in patients with thymoma and evaluate the variables that influence the survival of pleural metastasis in this population. Methods: This retrospective study investigated hospital admissions of patients diagnosed with pleural metastasis from thymoma. The spatial distribution pattern and visualization of the pleural metastases were analyzed after establishing a coordinate system. We further analyzed the survival and influencing factors in patients with pleural metastases from thymoma. Results: The analysis included 56 patients with a cumulative count of 365 pleural metastases, with 351 metastases from Zones 1-5 finally included in the analysis. The spatial distribution of the 285 initially diagnosed pleural metastases was significantly concentrated in Zones 3 and 4 near the lateral half of the spine (56.5%), followed by Zone 5 (17.5%). Collectively, these two components accounted for 74.0% (211/285) of all initial metastatic lesions. The survival rates at 5 years for those who underwent surgery versus nonsurgical treatment were 68.3% and 37.1%, respectively (p=0.015). Univariate Cox regression analysis showed that surgical intervention reduced the risk of death by 61%. Conclusions: The distribution of pleural metastatic lesions exhibited a nonuniform pattern, primarily concentrated on the spinal aspect below the aortic arch of the costal pleura and the spinal aspect of the diaphragmatic pleura.

Nomogram predicts the prognosis of patients with thymic carcinoma: A population-based study using SEER data

BACKGROUND

Thymic carcinoma (TC) is a rare malignant tumor that can have a poor prognosis, and accurate prognostication prediction remains difficult. We aimed to develop a nomogram to predict overall survival (OS) and cancer-specific survival (CSS) based on a large cohort of patients.

METHODS

The Surveillance Epidemiology and End Results (SEER) database was searched to identify TC patients (1975-2016). Univariate and multivariable Cox regression analyses were used to identify predictors of OS and CSS, which were used to construct nomograms. The nomograms were evaluated using the concordance index (C-index), calibration curve, receiver operating characteristic curve, and decision curve analysis (DCA). Subgroup analysis was performed to identify high-risk patients.

RESULTS

The analysis identified six predictors of OS (Masaoka stage, surgical method, lymph node metastasis, liver metastasis, bone metastasis, and radiotherapy) and five predictors of CSS (Masaoka stage, surgical method, lymph node metastasis, tumor size, and brain metastasis), which were used to create nomograms for predicting three-year and five-year OS and CSS. The nomograms had reasonable C-index values (OS: 0.687 [training] and 0.674 [validation], CSS: 0.712 [training] and 0.739 [validation]). The DCA curve revealed that the nomograms were better for predicting OS and CSS, relative to the Masaoka staging system.

CONCLUSION

We developed nomograms using eight clinicopathological factors that predicted OS and CSS among TC patients. The nomograms performed better than the traditional Masaoka staging system and could identify high-risk patients. Based on the nomograms' performance, we believe they will be useful prognostication tools for TC patients.

Thymic tumours and their special features

Thymic tumours are rare thoracic malignancies, that may be aggressive and difficult to treat. The pillars of the management include pathological review, consideration of differential diagnoses, staging and multidisciplinary discussion. Assessment of resectability is key to drive the treatment sequencing. Association with autoimmune diseases, especially myasthenia gravis, is observed, which impacts the oncological management. Networks are being built at the national and international levels. This article provides an overview of the most recent findings in the diagnosis, staging, histology, and management strategies of thymic tumours.

Thymic tumours are rare and heterogeneous tumours. Management is based on multidisciplinary discussion and networking.https://bit.ly/3kYAZ7u