Utilization of Minimally Invasive Thymectomy and Margin-Negative Resection for Early-Stage Thymoma

Impact of the expanded indication of robot-assisted thoracic surgery for mediastinal tumors

OBJECTIVE

Following the introduction of robot-assisted thoracoscopic surgery (RATS) as a health insurance-covered treatment in Japan, we investigated the current status and impact of the expansion of the indications for RATS for mediastinal tumors.

METHODS

Between 2018 and 2022, 209 cases of total mediastinal tumor resection were performed in our hospital. The study period was divided into the first half (January 2018 to June 2020) and the second half (July 2020 to December 2022), and perioperative parameters were compared between the two groups.

RESULTS

Ninety-six surgical procedures were performed in the first half and 113 in the second half. The percentage of RATS approach was significantly higher in the second half compared with the first half (P < 0.001). Indications for RATS in the second half compared with the first half were significantly increased in patients with stage II (P < 0.001) and stage III (P = 0.026) thymomas, tumor diameter ≥ 50 mm (P < 0.011), and patients undergoing extended thymectomy for myasthenia gravis (P < 0.009). In respect of short-term postoperative parameters, the estimated intraoperative blood loss (P < 0.035), postoperative drain duration (P < 0.037), and postoperative hospital stay (P < 0.011) were significantly lower in the second half than in the first half.

CONCLUSIONS

RATS has recently been expanded for mediastinal tumors with improved short-term outcomes in our hospital after health insurance was applied in Japan. In the future, it will be necessary to discuss the further expansion of its indications by taking into account safety and long-term outcomes.

Epidemiological Trends and Survival Outcomes for Thymic Epithelial Tumours: An Australian Population-Based Retrospective Cohort Study

BACKGROUND

Thymic epithelial tumours (TETs) represent a heterogenous group of relatively uncommon lesions which have varied disease behaviour. There is limited literature on the epidemiology and survival outcomes of these tumours in an Australian context.

METHOD

We conducted a population-based retrospective cohort study of patients diagnosed with TETs in the Australian state of Queensland between 2000 and 2021, recruited via the Queensland Oncology Repository.

RESULTS

Four hundred and ninety-seven (497) patients were identified, with a significant increase in the incidence of TETs over the study period. The 5-year overall survival for the full study cohort was 80.7%, declining to 67.1% at 10 years. Disease-specific survival was higher at 87.1% by 5 years, and 79.3% at 10 years. The majority of patients underwent upfront surgical resection, with a trend towards better survival.

CONCLUSIONS

Survival outcomes to 5 years and beyond are generally favourable, particularly for patients with less histologically aggressive lesions. Patients treated surgically, either with or without neoadjuvant chemotherapy/radiotherapy, had favourable survival and disease control compared to patients receiving definitive intent chemotherapy and/or radiotherapy.

Initial Evaluation of the Safety and Performance of Single-Port Robotic-Assisted Thymectomy Through a Subxiphoid Incision

BACKGROUND

Sternotomy is the traditional approach for thymectomy. However, over the last 2 decades, minimally invasive surgical approaches (multiport thoracoscopic and robotic-assisted surgery) have proven feasible, offering similar survival, lower morbidity, and shorter length of stay. Single-port (SP) subxiphoid thymectomy potentially offers less pain and allows bilateral visualization of the mediastinum.

METHODS

A prospective, multicenter, single-arm clinical study was conducted to evaluate the performance and safety of the da Vinci SP surgical system (Intuitive) for thymectomy through a subxiphoid incision. Primary performance end points included ability to achieve R0 resection and completion of the procedure without conversion. The primary safety end point was all adverse events up to 30 days postoperatively.

RESULTS

The study enrolled 13 individuals (benign, n = 6; malignant, n = 7) at 6 centers in the United States. All SP thymectomy procedures were completed through a small (mean, 3.8 cm) subxiphoid incision without conversion to other minimally invasive or open approaches. For malignant cases, the rate of complete resection was 100%. No study participants experienced any intraoperative or serious adverse events. No unanticipated adverse device effects were reported.

CONCLUSIONS

Thymectomy using the da Vinci SP surgical system through a subxiphoid approach is feasible, and there are no early indications of safety or procedural concerns. Larger clinical studies are warranted to further evaluate the relative benefits and limitations of the SP system compared with multiport robotic thymectomy.

Does Surgical Removal of the Thymus Have Deleterious Consequences?

The role of immunosenescence, particularly the natural process of thymic involution during aging, is increasingly acknowledged as a factor contributing to the development of autoimmune diseases and cancer. Recently, a concern has been raised about deleterious consequences of the surgical removal of thymic tissue, including for patients who undergo thymectomy for myasthenia gravis (MG) or resection of a thymoma. This review adopts a multidisciplinary approach to scrutinize the evidence concerning the long-term risks of cancer and autoimmunity postthymectomy. We conclude that for patients with acetylcholine receptor antibody-positive MG and those diagnosed with thymoma, the removal of the thymus offers prominent benefits that well outweigh the potential risks. However, incidental removal of thymic tissue during other thoracic surgeries should be minimized whenever feasible.

Development and Validation of Contrast-Enhanced CT-Based Deep Transfer Learning and Combined Clinical-Radiomics Model to Discriminate Thymomas and Thymic Cysts: A Multicenter Study

RATIONALE AND OBJECTIVES

This study aims to evaluate the feasibility and effectiveness of deep transfer learning (DTL) and clinical-radiomics in differentiating thymoma from thymic cysts.

MATERIALS AND METHODS

Clinical and imaging data of 196 patients pathologically diagnosed with thymoma and thymic cysts were retrospectively collected from center 1. (training cohort: n = 137; internal validation cohort: n = 59). An independent external validation cohort comprised 68 thymoma and thymic cyst patients from center 2. Region of interest (ROI) delineation was performed on contrast-enhanced chest computed tomography (CT) images, and eight DTL models including Densenet 169, Mobilenet V2, Resnet 101, Resnet 18, Resnet 34, Resnet 50, Vgg 13, Vgg 16 were constructed. Radiomics features were extracted from the ROI on the CT images of thymoma and thymic cyst patients, and feature selection was performed using intra-observer correlation coefficient (ICC), Spearman correlation analysis, and least absolute shrinkage and selection operator (LASSO) algorithm. Univariate analysis and multivariable logistic regression (LR) were used to select clinical-radiological features. Six machine learning classifiers, including LR, support vector machine (SVM), k-nearest neighbors (KNN), Light Gradient Boosting Machine (LightGBM), Adaptive Boosting (AdaBoost), and Multilayer Perceptron (MLP), were used to construct Radiomics and Clinico-radiologic models. The selected features from the Radiomics and Clinico-radiologic models were fused to build a Combined model. Receiver operating characteristic curve (ROC), calibration curve, and decision curve analysis (DCA) were used to evaluate the discrimination, calibration, and clinical utility of the models, respectively. The Delong test was used to compare the AUC between different models. K-means clustering was used to subdivide the lesions of thymomas or thymic cysts into subregions, and traditional radiomics methods were used to extract features and compare the ability of Radiomics and DTL models to reflect intratumoral heterogeneity using correlation analysis.

RESULTS

The Densenet 169 based on DTL performed the best, with AUC of 0.933 (95% CI: 0.875-0.991) in the internal validation cohort and 0.962 (95% CI: 0.923-1.000) in the external validation cohort. The AdaBoost classifier achieved AUC of 0.965 (95% CI: 0.923-1.000) and 0.959 (95% CI: 0.919-1.000) in the internal and external validation cohorts, respectively, for the Radiomics model. The LightGBM classifier achieved AUC of 0.805 (95% CI: 0.690-0.920) and 0.839 (95% CI: 0.736-0.943) in the Clinico-radiologic model. The AUC of the Combined model in the internal and external validation cohorts was 0.933 (95% CI: 0.866-1.000) and 0.945 (95% CI: 0.897-0.994), respectively. The results of the Delong test showed that the Radiomics model, DTL model, and Combined model outperformed the Clinico-radiologic model in both internal and external validation cohorts (p-values were 0.002, 0.004, and 0.033 in the internal validation cohort, while in the external validation cohort, the p-values were 0.014, 0.006, and 0.015, respectively). But there was no statistical difference in performance among the three models (all p-values <0.05). Correlation analysis showed that radiomics performed better than DTL in quantifying intratumoral heterogeneity differences between thymoma and thymic cysts.

CONCLUSION

The developed DTL model and the Combined model based on radiomics and clinical-radiologic features achieved excellent diagnostic performance in differentiating thymic cysts from thymoma. They can serve as potential tools to assist clinical decision-making, particularly when endoscopic biopsy carries a high risk.

Contrast-enhanced CT-based radiomics differentiate anterior mediastinum lymphoma from thymoma without myasthenia gravis and calcification

AIM

To explore the value of a radiomics model based on enhanced computed tomography (CT) in differentiating anterior mediastinal lymphoma (AML) and thymoma without myasthenia gravis (MG) and calcification.

MATERIALS AND METHODS

The present study analysed patients who were diagnosed histologically with AML and thymoma in three independent institutions. All pre-treatment patients underwent enhanced CT. In the training group of patients from institutions 1 (the First Affiliated Hospital of Kunming Medical University) and 3 (the Yunnan Cancer Hospital), two radiologists independently analysed the enhanced CT images and performed manual segmentation of each tumour. Radiomics features were screened using interobserver interclass coefficient (ICC) analysis, feature correlation analysis, and L1 regularisation. The discriminative efficacy of the logistic regression model was evaluated using receiver operating characteristic (ROC) analysis. Validation group of patients from institution 2 (the Second Affiliated Hospital of Zhejiang University School of Medicine) was used to validate the proposed models.

RESULTS

A total of 114 patients were enrolled in this study and 1,743 radiomics features were extracted from the enhanced CT images. After feature screening, the remaining 37 robust radiomics features were used to construct the model. In the training group, the AUC of the model was 0.987 (95% confidence interval [CI]: 0.976-0.999), the sensitivity, specificity, and accuracy were 0.912, 0.946, and 0.924, respectively. In the validation group, the AUC of the model was 0.798 (95% CI: 0.683-0.913), the sensitivity, specificity, and accuracy were 0.760, 0.700, and 0.743, respectively.

CONCLUSION

The radiomics model created provided effective information to assist in the selection of clinical strategies, thus reducing unnecessary procedures in patients with AML and guiding direct surgery in patients with thymoma to avoid biopsy.

Perioperative outcomes of minimally invasive surgery for large malignant thymic epithelial tumors and for total thymectomy

PURPOSE

Minimally invasive surgery (MIS) for thymic tumors is now accepted widely, in line with improved surgical techniques; however, we occasionally encounter complicated cases of large tumors or of total thymectomy requiring prolonged operative duration or conversion to an open procedure (OP). We reviewed patients registered in a nationwide database to identify the technical feasibility of MIS for thymic epithelial tumors.

METHODS

Data on patients treated surgically between 2017 and 2019 were extracted from the National Clinical Database of Japan. Clinical factors and operative outcomes were calculated by tumor diameter using trend analyses. Perioperative outcomes of MIS for non-invasive thymoma were investigated using propensity score-matched analyses.

RESULTS

MIS was performed in 46.2% of the patients. The operative duration and conversion rate increased with the tumor diameter (p < .001). After propensity score-matching, operative duration and postoperative hospital stay were shorter (p < .001), and the transfusion rate was lower (p = .007) in patients who underwent MIS than in those who underwent OP for thymomas ≥ 5 cm. Among patients who underwent total thymectomy, blood loss was less (p < .001) and the postoperative hospital stay was shorter (p < .001) in those who underwent MIS than in those who underwent OP. There were no significant differences in postoperative complications and mortality.

CONCLUSIONS

MIS is technically feasible even for large non-invasive thymomas or for total thymectomy, although the operative duration and open conversion rate increase with the tumor diameter.

Thymoma and Thymic Carcinoma: Surgical Resection and Multidisciplinary Treatment

Thymoma and thymic carcinoma are the most common tumors of the anterior mediastinum and a relatively rare type of thoracic cancer. The prerequisite for surgery is clinical staging and operative evaluation, both of which are based on medical imaging. The best strategy for treating a thymic epithelial tumor is surgical resection of the organ and surrounding tissue. Thymectomy modalities vary, including open surgery and minimally invasive surgery, and surgeons have used various innovations to better meet the needs of the procedure; therefore, it is critical to select the appropriate procedure based on the patient's characteristics. Evaluation of resectability is the first step of surgical resection for thymic tumors without distant metastasis. The decision regarding unresectability should be made carefully. During subsequent chemotherapy or chemoradiotherapy, reevaluation of whether an area is resectable or not remains essential. Despite numerous technological advances in the surgical treatment of thymic tumors, several contentious issues remain, including the selection of surgical approaches for difficult cases, the selection of video-assisted thoracoscopic approaches, the evaluation of resectability, minimally invasive surgery for locally advanced thymic tumors, lymphadenectomy in thymic tumors, neoadjuvant therapy for thymic tumors, debulking surgery, and salvage surgery. In solving these problems, the surgeon's judgment, surgical experience, and surgical skills are especially important.

Enhanced metabolic activation of and platelet response to clopidogrel in T cell-deficient mice through induction of Cyp2c and Cyp3a and inhibition of Ces1

BACKGROUND

T cells and platelets reciprocally coordinate mutual functions through crosstalk or interaction. However, it is not known whether metabolic activation of and platelet response to clopidogrel could be changed if T cells were deficient or impaired in some cases and, if any, how it would work.

OBJECTIVES

The objective of this study was to dissect the potential changes in platelet responses to and metabolic activation of clopidogrel in the case of T cell deficiency and to elucidate their mechanisms involved.

METHODS

BALB/c athymic nude mice or euthymic mice (controls) pretreated with cyclosporine A (CsA), thymosin α1 (Tα1), or their combination were used to investigate the changes in ADP-induced platelet activation and aggregation, systemic exposure of clopidogrel and its metabolites, and mRNA/protein expression and activity levels of clopidogrel-metabolizing enzymes in the liver, respectively.

RESULTS

Nude mice exhibited significantly enhanced antiplatelet effects of clopidogrel due to increased formation of clopidogrel active metabolite in the liver, where the enzyme activity levels of Cyp2c and Cyp3a were significantly elevated compared with control mice. Furthermore, the effects of CsA pretreatment on the metabolism of clopidogrel in euthymic mice were identical to those seen in athymic mice. As expected, concomitant use of Tα1 reversed all the observed effects of CsA on clopidogrel metabolism and relevant metabolic enzymes.

CONCLUSIONS

T cell deficiency or suppression enhances the antiplatelet effects of clopidogrel due to the boosted metabolic activation of clopidogrel in the liver through a dramatic induction of Cyp2c and Cyp3a in mice, suggesting that the metabolism of substrate drugs of Cyp2c and Cyp3a may be enhanced by T cell impairment.

Neoadjuvant radiotherapy plus single-incision thoracoscopic surgery in the treatment of type B3 thymomas

Background

Although minimally invasive surgery is the standard treatment for thymomas, minimally invasive thymectomy is difficult for patients with type B3 thymomas, especially for giant or aggressive lesions. These tumors are frequently treated with radical radiation therapy or surgery plus adjuvant radiotherapy. Few studies, however, have tested the efficacy of neoadjuvant radiotherapy prior to thoracoscopic surgery.

Methods

Patients with type B3 thymomas >5 cm or with infiltrates into vital organs on CT-guided puncture biopsy who underwent neoadjuvant radiotherapy followed by single-incision minimally invasive thymectomy from March 2016 to July 2020 were retrospectively evaluated. Reduction ratios, TNM stage changes according to WHO stage criteria, resectability, long-term survival, and the response in terms of RECIST v1.1 criteria achieved by preoperative RT were analyzed.

Results

The 11 patients who underwent neoadjuvant radiotherapy plus minimally invasive thymectomy included five men and six women, of mean age 49.5 years. Four patients had myasthenia gravis. Neoadjuvant radiotherapy consisted of 50 Gy in 25 fractions, with all patients showing varying degrees of lesion reduction after radiotherapy. Surgery was performed about 1 month after neoadjuvant radiotherapy, with none of these patients having severe radiation pneumonitis. All patients underwent radical resection of the tumor and adjacent tissue, with none experiencing tumor seeding or rupture during surgery. The median postoperative hospital stay was 3 days (range: 2-6 days) and the frequency of additional regular analgesics (including those for wound pain and neuralgia) was 2.5 times per person. On follow-up, one patient experienced pleural metastasis and one experienced pulmonary metastasis, with the other nine patients showing no evidence of tumor recurrence.

Conclusion

Neoadjuvant radiotherapy followed by minimally invasive surgery was a safe and efficacious procedure for the treatment of type B3 thymomas, with less postoperative pain and faster recovery. This strategy, of tumor shrinkage prior to surgery, may make possible the easier removal of type B3 thymomas by single-incision thoracoscopy.

Difficult Decisions in Minimally Invasive Surgery of the Thymus

A minimally invasive resection of thymomas has been accepted as standard of care in the last decade for early stage thymomas. This is somewhat controversial in terms of higher-staged thymomas and myasthenia gravis patients due to the prognostic importance of complete resections and the indolent characteristics of the disease process. Despite concerted efforts to standardize minimally invasive approaches, there is still controversy as to the extent of excision, approach of surgery, and the platform utilized. In this article, we aim to provide our surgical perspective of thymic resection and a review of the existing literature.

Robotic vs. Transsternal Thymectomy: A Single Center Experience over 10 Years

Introduction: Thymomas are the most common tumors of the mediastinum. Traditionally, thymectomies have been performed through a transsternal (TS) approach. With the development of robot-assisted thoracic surgery (RATS), a promising, minimally invasive, alternative surgical technique for performing a thymectomy has been developed. In the current paper, the oncological and surgical outcomes of the TS vs. RATS thymectomies are discussed. Methods: For the RATS thymectomy, two 8 mm working ports and one 12 mm camera port were used. In the transsternal approach, we performed a median sternotomy and resected the thymic tissue completely, in some cases en bloc with part of the lung and/or, more frequently, a partial pericardiectomy with consequent reconstruction using a bovine pericardial patch. The decisions for using the TS vs. RATS methods were mainly based on the suspected tumor invasion of the surrounding structures on the preoperative CT scan and tumor size. Results: Between January 2010 and November 2020, 149 patients were submitted for an anterior mediastinal tumor resection at our institution. A total of 104 patients met the inclusion criteria. One procedure was performed through a hemi-clamshell incision. A total of 81 (78%) patients underwent RATS procedures, and 22 (21.1%) patients were treated using a transsternal (TS) tumor resection. Thymoma was diagnosed in 53 (51%) cases. In the RATS group, the median LOS was 3.2 ± 2.8 days and the median tumor size was 4.4 ± 2.37 cm compared to the TS group, which had a median LOS of 9 ± 7.3 days and a median tumor size of 10.4 ± 5.3 cm. Both differences were statistically significant (p < 0.001). Complete resection was achieved in all patients. Conclusion: While larger and infiltrating tumors (i.e., thymic carcinomas) were usually resected via a sternotomy, the RATS procedure is a good alternative for the resection of thymomas of up to 9.5 cm, and the thymectomy is a strong approach for myasthenia gravis. The oncological outcomes and survival rates were not influenced by the chosen approach.

Limited resection for early-stage thymoma: minimally invasive resection does not mean limited resection

Standard resection for patients with thymoma is resection of thymoma with total thymectomy (TTx) via median sternotomy. Hence, limited resection for thymoma means a lesser extent of resection of normal thymus compared with a standard procedure, i.e. resection of thymoma with partial thymectomy (PTx). In contrast, minimally invasive resection has been defined as resection of thymoma with TTx via a less-invasive approach. However, to date, few studies have precisely evaluated the differences in surgical and oncological outcomes among these three procedures. This report summarizes the differences among these three procedures with a review of studies (January 2000 to December 2020) focusing on the difference in surgical and oncological outcomes and presents current issues in the surgical management of thymoma. In this report, 16 studies were identified; 5 compared standard resection to limited resection, 9 compared standard resection to minimally invasive resection and 2 compared limited resection to minimally invasive resection. Most studies reported that the surgical and oncological outcomes of limited resection or minimally invasive resection were similar to those of standard resection in patients with early-stage thymoma. However, they did not include a sufficient follow-up period. Both limited resection and minimally invasive resection for early-stage thymoma might be reasonable treatment options. However, they are still promising modes of resection. Further studies with a long follow-up period are needed.

Clinical Outcomes and Technical Approach of Thymectomy in the Veterans Health Administration

BACKGROUND

Thymectomy is traditionally performed via transsternal incision, but less invasive modalities have emerged, including transcervical, thoracoscopic, and robotic approaches. Despite the advantages of video-assisted thoracoscopic surgery(VATS) over thoracotomy, most thymectomies are performed via sternotomy. This study compared the utilization and 30-day post-operative outcomes of transsternal, transcervical, and VATS thymectomy in the Veterans Health Administration.

METHODS

This was a retrospective review of veterans that underwent thymectomy via the Veterans Affairs Surgical Quality Improvement Program. 30-day outcomes were compared between techniques, adjusting for confounding covariates. Temporal trends were analyzed using Spearman's rank correlation coefficient, rho(ρ).

RESULTS

From 2008-2019, 594 thymectomies were performed: 376(63.3%) transsternal, 113(19.0%) VATS(including robotic approaches), and 105(17.7%) transcervical cases. VATS utilization increased from 0% in 2008 to 61% of case volume in 2019. Relative to transsternal technique, VATS thymectomy was associated with decreased odds of pulmonary complications (adjusted odds ratio=0.06;p=0.028) and shorter hospital stay (2.9±0.4 days shorter;p<0.001). No difference in outcomes was detected between VATS and transcervical thymectomy. Post-operative complication rate decreased from 17.7% in 2008 to 5.6% in 2019 (ρ=-0.101;p=0.014). Length of stay decreased from median 4 days in 2008 to 3 days in 2019 (ρ=-0.093;p=0.026). In thymic cancer, VATS 5-year overall survival was non-inferior to transsternal approach(71.3% vs. 74.6%; p=0.54).

CONCLUSIONS

Transsternal approach comprised most thymectomy cases amongst veterans, while VATS thymectomy utilization increased over time and was associated with favorable outcomes. 30-day outcomes after thymectomy improved over time, which may reflect a trend towards wider utilization of less invasive approaches. Future studies should examine long-term outcomes.

Can computed tomography-based radiomics potentially discriminate between anterior mediastinal cysts and type B1 and B2 thymomas?

Background

Anterior mediastinal cysts (AMC) are often misdiagnosed as thymomas and undergo surgical resection, which caused unnecessary treatment and medical resource waste. The purpose of this study is to explore potential possibility of computed tomography (CT)-based radiomics for the diagnosis of AMC and type B1 and B2 thymomas.

Methods

A group of 188 patients with pathologically confirmed AMC (106 cases misdiagnosed as thymomas in CT) and thymomas (82 cases) and underwent routine chest CT from January 2010 to December 2018 were retrospectively analyzed. The lesions were manually delineated using ITK-SNAP software, and radiomics features were performed using the artificial intelligence kit (AK) software. A total of 180 tumour texture features were extracted from enhanced CT and unenhanced CT, respectively. The general test, correlation analysis, and LASSO were used to features selection and then the radiomics signature (radscore) was obtained. The combined model including radscore and independent clinical factors was developed. The model performances were evaluated on discrimination, calibration curve.

Results

Two radscore models were constructed from the unenhanced and enhanced phases based on the selected four and three features, respectively. The AUC, sensitivity, and specificity of the enhanced radscore model were 0.928, 89.3%, and 83.8% in the training dataset and 0.899, 84.6%, and 87.5% in the test dataset (higher than the unenhanced radscore model). The combined model of enhanced CT including radiomics features and independent clinical factors yielded an AUC, sensitivity and specificity of 0.941, 82.1%, and 94.6% in the training dataset and 0.938, 92.3%, and 87.5% in the test dataset (higher than the unenhanced combined model and enhanced radscore model).

Conclusions

The study suggested the possibility that the combined model in enhanced CT provided a potential tool to facilitate the differential diagnosis of AMC and type B1 and B2 thymomas.

Intermediate oncologic outcomes after uniportal video-assisted thoracoscopic thymectomy for early-stage thymoma

Background

Recent years have seen a trend towards utilizing a video-assisted thoracic surgery (VATS) approach for treatment of thymoma. Although increasing in practice, intermediate- and long-term oncologic outcome data is lacking for the VATS approach. There is no oncologic data for the uniportal VATS approach. We sought to evaluate the feasibility and impact on patient survival of uniportal VATS thymectomy for early-stage thymoma.

Method

The clinical outcomes for 17 patients with Masaoka stage I to II thymomas treated between January of 2009 and July of 2014 at a single institution were collected retrospectively. Primary endpoint was overall survival (OS) and secondary endpoint was recurrence-free survival (RFS).

Results

Ten women and seven men underwent uniportal VATS thymectomy; eleven had stage I thymoma and six had stage II thymoma. There were no conversions to open surgery. Operative mortality was zero. Mean tumor size was 3.8±1.0 centimeters, with a range of 1.9 to 6.0 centimeters. All patients underwent a R0 resection. Five-year survival was 100%, and the estimated RFS was 100%.

Conclusions

Our findings suggest that uniportal VATS thymectomy for early-stage thymoma is feasible, and the intermediate-term oncologic outcomes are comparable to historic standards for open and multi-incision VATS thymectomy. However, additional follow-up is required to evaluate for long-term oncologic outcomes.

Thymic Malignancy-Updates in Staging and Management

Thymomas are relatively indolent tumors that present with locally advanced disease in 30% of the patients. Thymic carcinoma is a more aggressive histology with shorter disease-free and overall survival. Early-stage tumors are managed best with complete resection. Multimodal therapy is the standard of care for locally advanced tumors and neoadjuvant therapy may help improve respectability. Stage and complete resection are the strongest prognostic factors for long-term survival. Based on early experience, targeted and immunotherapies have shown limited promise in advanced disease.

A national analysis of open versus minimally invasive thymectomy for stage I to III thymoma

OBJECTIVE

The oncologic efficacy of minimally invasive thymectomy for thymoma is not well characterized. We compared short-term outcomes and overall survival between open and minimally invasive (video-assisted thoracoscopic and robotic) approaches using the National Cancer Data Base.

METHODS

Perioperative outcomes and survival of patients who underwent open versus minimally invasive thymectomy for clinical stage I to III thymoma from 2010 to 2014 in the National Cancer Data Base were evaluated using multivariable Cox proportional hazards modeling and propensity score-matched analysis. Predictors of minimally invasive use were evaluated using multivariable logistic regression. Outcomes of surgical approach were evaluated using an intent-to-treat analysis.

RESULTS

Of the 1223 thymectomies that were evaluated, 317 (26%) were performed minimally invasively (141 video-assisted thoracoscopic and 176 robotic). The minimally invasive group had a shorter median length of stay when compared with the open group (3 [2-4] days vs 4 [3-6] days, P < .001). In a propensity score-matched analysis of 185 open and 185 minimally invasive (video-assisted thoracoscopic + robotic) thymectomy, the minimally invasive group continued to have a shorter median length of stay (3 vs 4 days, P < .01) but did not have significant differences in margin positivity (P = .84), 30-day readmission (P = .28), 30-day mortality (P = .60), and 5-year survival (89.4% vs 81.6%, P = .20) when compared with the open group.

CONCLUSIONS

In this national analysis, minimally invasive thymectomy was associated with shorter length of stay and was not associated with increased margin positivity, perioperative mortality, 30-day readmission rate, or reduced overall survival when compared with open thymectomy.