Comparison of surgical approach and extent of resection for Masaoka-Koga Stage I and II thymic tumours in Europe, North America and Asia: an International Thymic Malignancy Interest Group retrospective database analysis

Thymic Carcinomas-A Concise Multidisciplinary Update on Recent Developments From the Thymic Carcinoma Working Group of the International Thymic Malignancy Interest Group

Thymic carcinomas are rare malignancies that in general arise in the prevascular (anterior) mediastinum. These tumors are usually invasive, often present at advanced stages, and typically behave aggressively. Studies are hampered by the paucity of these tumors, the large variety of carcinoma subtypes, and the lack of unique morphologic and immunophenotypic features. Despite these challenges, advances in diagnostic imaging, surgical approaches, systemic therapies, and radiation therapy techniques have been made. The WHO classification of thymic epithelial tumors has been updated in 2021, and the eighth tumor nodal metastasis staging by the American Joint Committee on Cancer/Union for International Cancer Control included thymic carcinomas in 2017. Molecular alterations that provide more insight into the pathogenesis of these tumors and that potentially permit use of novel targeted therapies are increasingly being identified. New approaches to radiation therapy, chemotherapy, and immunotherapy are under evaluation. International societies, including the International Thymic Malignancy Interest Group, European Society of Thoracic Surgeons, and Japanese, Chinese, and Korean thymic associations, have been critical in organizing and conducting multi-institutional clinical studies. Herein, we review contemporary multidisciplinary perspectives in diagnosis and management of thymic carcinoma.

[Long-term outcomes of thoracoscopic thymectomy for thymoma stage i-ii]

OBJECTIVE

To compare long-term outcomes of video-assisted thoracoscopic (VATS) and conventional open surgery in patients with early-stage (Masaoka stage I-II) thymic malignancies.

MATERIAL AND METHODS. A

Retrospective study included patients after VATS and open thymectomy for the period 2000-2019. Long-term outcomes were analyzed.

RESULTS

VATS thymectomy was performed in 53 (54.1%) patients, open thymectomy - in 45 (45.9%) cases. Median follow-up period was 66.9 months. Overall 5-year survival was 89.8% and 97% in the Open and VATS groups, respectively (p=0.076). Disease-free survival rates were 79.6% and 86.6% (p=0.279), respectively. There was no significant difference in cumulative incidence of recurrence (13.3% vs 7.5%, p=0.505). Age <50 years and tumor size >5 cm were the independent risk factors of recurrence.

CONCLUSION

VATS thymectomy is an effective approach ensuring similar long-term outcomes in patients with early stages of thymic malignancies.

[Comparative analysis of thoracoscopic and open thymectomy for thymoma stage I-II]

OBJECTIVE

To improve the short-term postoperative outcomes in patients with thymoma stage I-II by using of thoracoscopic thymectomy (VATS TE) and to compare this technique with open (OTE) thymectomy.

MATERIAL AND METHODS

A retrospective analysis included 98 patients who had undergone surgery for thymoma stage I and II for the period from January 2001 to December 2019. VATS TE (main group) was performed in 53 (54.1%) cases, OTE (control group) - in 45 (45.9%) patients.

RESULTS

Duration of VATS TE and OTE was similar. VATS procedure was characterized by less intraoperative blood loss (50 vs 225 ml, p=0.000), lower pain scores and morphine consumption (p=0.000), shorter postoperative pleural drainage (1.5 vs 3.8 days, p=0.000), and postoperative hospital-stay (7.6 vs 12.7 days, p=0.000). Incidence of major complications was significantly less in the main group (9.4% vs. 1.9%, p=0.001).

CONCLUSION

VATS TE is effective and safe procedure for thymoma stage I-II. Postoperative period after VATS TE is characterized by less intraoperative blood loss, incidence of complications, duration of pleural drainage and hospital-stay.

Clinicopathological features and current treatment outcomes of neuroendocrine thymic tumours

OBJECTIVES

Neuroendocrine thymic tumours (NETTs) are a distinct subgroup of rare malignancies. An international, multicentre retrospective analysis was used to study the clinicopathological features, current pattern of diagnosis, treatment and outcomes of patients with NETT.

METHODS

One hundred and forty-six NETT treated from 1989 to 2016 at 21 centres in China, Europe and North America were retrospectively collected and reclassified according to the World Health Organization histological type and International Thymic Malignancy Interest Group (ITMIG)/International Association for Studies in Lung Cancer (IASLC)/Union for International Cancer Control (UICC) staging. Clinicopathological features, diagnostic and therapeutic approaches and outcomes were investigated. Results in the earlier and latter halves of the study period were also compared.

RESULTS

The pretreatment work-up relied exclusively on computed tomography in 85.6% (125/146) of cases. Most patients had advanced disease, with 32.2% (47/146) having lymph node involvement. Higher-grade histological type was associated with more advanced disease (P < 0.05). Induction therapies and surgical procedures were used more often in the latter half of the study. However, the complete resection rate remained unchanged, being 71.5% (98/137) in the whole group. Complete resection was associated with significantly longer 5-year overall survival (77.2% vs 51.2%; P < 0.001) than incomplete or no resection. Significant survival differences were seen with the T, N and M categories of ITMIG/IASLC/UICC staging. Poorly differentiated carcinoma, ITMIG/IASLC/UICC stage IIIa or above and incomplete or no resection were independent risk factors for worse survival. No survival difference was noted between the earlier and the latter halves of the study (58.2% vs 71.9%; P = 0.299).

CONCLUSIONS

Current management similar to that for thymomas is unsatisfactory in providing disease control or long-term survival for patients with NETT. Specific diagnostic tools and novel therapeutic agents are needed to improve management outcomes of this disease.

Dual-scopic robotic thymectomy for a large thymic malignant tumor

Minimally invasive surgery for large thymic malignant tumors remains challenging. Here, we demonstrate dual-scopic robotic thymectomy for a challenging malignant thymic tumor. An asymptomatic 70-year-old woman clinically diagnosed with a large thymic malignant tumor invading the left phrenic nerve and pericardium underwent surgery. After dissecting the left phrenic nerve and pericardium under left unilateral video-assisted thoracic surgery, a robotic subxiphoid approach was conducted to achieve complete thymectomy. During robotic surgery, the large tumor sometimes limited the surgical view. To overcome this limitation, we added a conventional thoracoscope and utilized both images of the conventional thoracoscopic view and robotic camera via TilePro display to achieve complete resection of the thymic epithelial tumor. The patient was discharged with no complications except left phrenic palsy. The pathological diagnosis was a thymic neuroendocrine tumor invading the left phrenic nerve. This approach is potentially useful in surgery for challenging thymic malignant tumors.

Thymoma and thymic carcinoma in children and adolescents: The EXPeRT/PARTNER diagnostic and therapeutic recommendations

Thymic tumors are epithelial tumors arising from the anterior mediastinum and constitute 0.2-1.5% of all adult malignancies but are exceptional in pediatric population. Thymic epithelial tumors (TETs) encompass a variety of histologic subtypes associated with different clinical outcomes. Due to its rarity in children, TETs' management requires a multidisciplinary approach. However, prognosis remains still poor, especially among patients with thymic carcinoma. This study presents the internationally recognized recommendations for the diagnosis and treatment of thymic tumors in children and adolescents, established by the European Cooperative Study Group for Pediatric Rare Tumors (EXPeRT) group within the EU-funded project Paediatric Rare Tumours Network - European Registry (PARTNER).

Video-assisted thoracoscopic thymectomy is feasible for large thymomas: a propensity-matched comparison

OBJECTIVES

Video-assisted thoracoscopic thymectomy is becoming the preferable approach for early-stage thymoma. However, large thymomas are still recognized as a relative contraindication due to the possible risk of incomplete resection or capsular disruption. Thus, the aim of this study is to evaluate the feasibility of video-assisted thoracoscopic thymectomy for large thymomas.

METHODS

Patients diagnosed with Masaoka stage I-IV thymoma between April 2001 and December 2018 were retrospectively reviewed. All patients were divided into 2 groups: thymoma <5.0 cm (group A) and thymoma ≥5.0 cm (group B). Propensity score matching analysis was performed to compare postoperative results. Recurrence-free survival and overall survival were compared for oncological evaluation.

RESULTS

A total of 346 patients were included in this study. In the propensity score matching analysis, 126 patients were included both in group A and group B. There was no significant difference between these 2 groups in terms of the R0 resection rate (95.2% vs 94.4%, P = 1.000), conversion rate (1.6% vs 3.2%, P = 0.684), operation time (119.4 ± 48.4 vs 139.1 ± 46.6 min, P = 0.955), blood loss (93.2 ± 231.7 vs 100.5 ± 149.3 ml, P = 0.649), duration of chest drainage (2.7 ± 1.6 vs 2.8 ± 2.0 days, P = 0.184), length of hospitalization (5.0 ± 3.9 vs 5.2 ± 2.9 days, P = 0.628) or postoperative complications (5.9% vs 8.5%, P = 0.068). There was no significant difference between these 2 groups in terms of the overall survival (P = 0.271) and recurrence-free survival (P = 0.288).

CONCLUSIONS

Video-assisted thoracoscopic thymectomy is a safe and effective approach for large thymomas (≥5 cm) with comparable surgical and oncological results.

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.

Comparison of Subxiphoid and Intercostal Uniportal Thoracoscopic Thymectomy for Nonmyasthenic Early-Stage Thymoma: A Retrospective Single-Center Propensity-Score Matching Analysis

OBJECTIVE

The aim of this study was to compare early outcome between intercostal uniportal video-assisted thoracoscopic surgery (IU-VATS) versus subxiphoid uniportal video-assisted thoracoscopic surgery (SU-VATS) in thymectomy for non-myasthenic early-stage thymoma.

METHOD

Retrospective analysis of 76 cases completed in our hospital from May 2018 to September 2019 with subxiphoid uniportal thoracoscopic thymectomy; a single incision of ∼3 cm was made ∼1 cm under the xiphoid process. The control group included 213 patients who received intercostal uniportal thoracoscopic thymectomy from August 2015, and propensity score matching was conducted. All patients who were clinically diagnosed with thymic tumor before surgery were treated with thymectomy. Perioperative outcomes between SU-VATS (n = 76) and IU-VATS, n = 76 were compared.

RESULT

After propensity score matching, there were no statistically significant differences between the two groups in terms of age, gender, disease stage, maximal tumor size, or other baseline demographic and clinical variables. All operation was successfully completed; there were no significant differences in the operative time (88 vs. 81 minutes, p = 0.63), intraoperative blood loss (55 vs. 46 mL, p = 0.47), postoperative drainage time (2.2 vs. 2.5 days, p = 0.72), and postoperative hospital stay (3.2 vs. 3.4 days, p = 0.78) between the two groups. The visual analog scale (VAS) on postoperative days 1, 3, 7, and 30 was less in the SU-VATS group than that in the IU-VATS group. The VAS on days 60 and 180 did not differ significantly between the two groups.

CONCLUSION

Thymectomy using SU-VATS is a feasible procedure; it might reduce early postoperative pain and lead to faster recovery.

Optimal management of thymic malignancies: current perspectives

Thymic epithelial tumors (TETs) belong to orphan oncology. The incidence of TETs is about 1.3–3.2 cases per million worldwide. Following pathology, evolution and prognosis are variable. The World Health Organization classification distinguishes thymomas and thymic carcinomas. TETs are composed of thymic epithelial tumoral cells and normal lymphocytes. The mean age at diagnosis is 50–60 years-old. There are no identified risk factors. TETs are frequently associated with paraneoplastic syndromes as myasthenia gravis. The complete R₀ surgical resection is the most significant prognosis factor on survival. In 2010, the French National Institute of Cancer labeled the RYTHMIC network as a specific tumor board including thoracic surgeons, oncologist, and radiation therapist to define standard of care for the management of TETs. The aim of the review was to update knowledge to optimize the standard of care.

Technique for Myasthenia Gravis: Subxiphoid Approach

Kido and colleagues in 1999 used for the first time the subxiphoid approach. Recently, video-assisted thoracoscopic surgery (VATS) thymectomy has been improved for the advancement of surgical materials and new instruments. The most important aspect regarding the subxiphoid approach is the possibility to avoid the intercostal nerve damage with the consequence of a decreased use of postoperative analgesics, quite short surgical duration, fast discharge from hospital and a guarantee of successful cosmetics results.

A systematic review of robotic versus open and video assisted thoracoscopic surgery (VATS) approaches for thymectomy

Background

Median sternotomy has been the most commonly used approach for thymectomy to date. Recent advances in video-assisted thoracoscopic surgery (VATS) and robotic access with CO₂ insufflation techniques have allowed more minimally invasive approaches. However, prior reviews have not compared robotic to both open and VATS thymectomy.

Methods

A systematic review was conducted in accordance with the PRISMA guidelines using PubMed, Embase and Scopus databases. Original research articles comparing robotic to VATS or to open thymectomy for myasthenia gravis, anterior mediastinal masses, or thymomas were included. Meta-analyses were performed for mortality, operative time, blood loss, transfusions, length of stay, conversion to open, intraoperative and postoperative complication rates, and positive/negative margin rates.

Results

Robotic thymectomy is a valid alternative to the open approach; advantages include: reduced blood loss [weighted mean difference (WMD): -173.03, 95% confidence interval (95% CI): -305.90, -40.17, P=0.01], fewer postoperative complications (odds ratio: 0.37, 95% CI: 0.22, 0.60, P<0.00001), a shorter hospital stay (WMD: -2.78, 95% CI: -3.22, -2.33, P<0.00001), and a lower positive margin rate (relative difference: -0.04, 95% CI: -0.07, -0.01, P=0.01), with comparable operative times (WMD: 6.73, 95% CI: -21.20, 34.66, P=0.64). Robotic thymectomy was comparable with the VATS approach; both have the advantage of avoiding median sternotomy.

Conclusions

While randomized controlled studies are required to make definitive conclusions, current data suggests that robotic thymectomy is superior to open surgery and comparable to a VATS approach. Long-term follow-up is required to further delineate oncological outcomes.

Thoracoscopic thymectomy with partial superior vena cava resection for locally advanced thymomas

Background

Video-assisted thoracoscopic surgery (VATS) is now increasingly used for the treatment of early stage thymic malignancies. However, VATS has not been advocated for patients with locally advanced diseases. We reviewed our initial experience in VATS thymectomy with partial superior vena cava (SVC) resection for IASLC/ITMIG stage III thymic tumors.

Methods

From August 2017 to October 2018, patients who underwent VATS thymectomy with partial SVC resection were retrospectively reviewed, and peri-operative outcomes and short-term follow-up results were analyzing.

Results

Four patients with partial SVC resection via VATS were identified. All of them had pathologically confirmed IASLC/ITMIG stage III thymic tumors invading the SVC. The average of operative time was 228 minutes and mean blood loss was 88 mL. The mean duration of chest tube drainage and post-operative hospital stay were 4.5 and 7.3 days respectively. No major complication was encountered after surgery. No mortality was observed. And no recurrence was detected with the longest follow-up time of 14 months.

Conclusions

With careful patient selection and plenty surgical expertise, VATS thymectomy for locally invasive thymic tumors with limited the SVC invasion is challenging yet technically feasible.

Minimally invasive surgery in thymic malignances: the new standard of care

Surgery is the most important therapy for thymic malignancies. The last decade has seen increasing adoption of minimally invasive thymectomy (MIT) for thymic tumors. MIT for early stage diseases has been shown to yield similar oncological results while being helpful in minimizing surgical trauma, improving postoperative recovery, and reducing incisional pain. Similar surgical and oncological principles should be observed in both minimally invasive and open procedures so as to ensure radical resection and accurate staging of the tumor.

[Minimally Invasive Surgery in Thymic Malignances]

手术是胸腺肿瘤最重要的治疗方式。近年来，胸腺肿瘤的微创手术在国内外获得迅速推广。微创手术目前主要用于早期胸腺肿瘤的外科治疗，已有证据表明，微创手术可有效减少手术创伤、有效加快患者的术后恢复以及降低术后疼痛，并且目前已有一定临床证据初步证实其肿瘤学效果与开放手术相当。同时随着外科技术的不断进步，在保证外科学和肿瘤学原则的前提下，微创手术有可能使包括局部进展期、诱导治疗后以及复发转移的患者从中获益。

VATS thymectomy for early stage thymoma and myasthenia gravis: combined right-sided uniportal and left-sided three-portal approach

The traditional approach to thymectomy requires median sternotomy based on the assumption that it is the best means to achieve adequate resection margins, complete removal of the thymus and clearance of the anterior mediastinal fat. However, in recent years, VATS thymectomy has been gaining acceptance as a means to achieve adequate oncologic results and symptomatic improvement of myasthenic symptoms with less impact on the patient. We have adopted a flexible approach based on the location of the tumor and on whether the patient has myasthenia gravis (MG) or not when planning minimally invasive VATS thymectomy. A preferential approach from the left side is chosen for clinical stage I-II thymomas located on the left side or on the midline in patients without MG, and a bilateral approach (uniportal VATS on the right side and three-portal VATS on the left side) for MG patients with or without thymoma in order to achieve complete clearance of the anterior mediastinal fat on both sides. Such techniques are herewith clearly illustrated in hope that surgeons wishing to endeavor in such an effort will be facilitated.