Surgical approach in thymectomy: Our experience and review of the literature

Impact of adjuvant radiotherapy and chemotherapy on thymoma

PURPOSE

Thymoma is a rare tumour. The most common treatment for thymoma is surgical resection, while the use of radiotherapy and chemotherapy remains controversial.

PATIENTS AND METHODS

We conducted a monocentric observational study of 31 patients diagnosed with thymoma from June 2004 to July 2020 at cancer centre in Strasbourg, France. We analysed the outcomes of the patients.

RESULTS

The 2- and 5- year locoregional relapse-free survival rates were 96.3% (95% confidence interval [CI]: 76.5-99.5%) and 68.0% (95% CI: 43.8-83.5%), respectively. Radiotherapy and chemotherapy significantly improved local tumour control (P=0.0008 and 0.04, respectively), while a larger initial tumour size significantly worsened local control rates (P=0.04). The 5- and 10-year overall survival rates were 87.1% (95% CI: 69.2-95%) and 81.7% (95% CI: 60.3-92.2%), respectively. The median overall survival was not reached, and no favourable factor was retrieved. For relapsed patients, the median overall survival after relapse was 115 months.

CONCLUSION

Despite the inherent limitations of retrospective studies with a limited patient sample size, we demonstrated that chemotherapy and radiotherapy in addition to surgery were effective in achieving local control and contributed to improving patient outcomes in thymoma. Notably, an aggressive treatment strategy at the time of relapse resulted in favourable outcomes for retreated patients.

Lobulated tumor contour as a predictor of preoperative tumor invasion of the lung or pericardium in thymoma patients

PURPOSE

Preoperative investigations to detect invasion to neighboring organs are important for deciding on the most appropriate surgical approach for thymoma. We evaluated preoperative computed tomography (CT) findings in thymoma patients to identify the CT features associated with tumor invasion.

METHODS

Clinicopathologic information on 193 patients who underwent surgical resection for thymoma at Chiba University Hospital between 2002 and 2016 was collected retrospectively. The surgical pathology identified invasion of thymoma in 35 patients: in the lung (n = 18), pericardium (n = 11), or both (n = 6). Contact lengths between the tumor contour and lung (CLTL) or pericardium (CLTP) were measured at the maximum section of the tumor on axial CT. Univariate and multivariate analyses were performed to analyze the relationship between pathological invasion of the lung or pericardium and the clinicopathologic features.

RESULTS

The mean CLTL and CLTP were significantly longer in patients with invasion of the neighboring organs than in those without invasion. A lobulated tumor contour was identified in 95.6% of the patients with invasion of the neighboring organs. A multivariate analysis revealed that a lobulated tumor contour was significantly associated with both lung and pericardial invasion.

CONCLUSIONS

A lobulated tumor contour was significantly associated with lung and/or pericardial invasion in thymoma patients.

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.

Incidental giant thymoma-a reminder of the importance of a global look of the imaging scans

A 49-year-old female patient, without previous medical history, underwent a thoracic CT due to SARS-CoV2 infection. This exam revealed a heterogeneous mass in the anterior mediastinum with 11 × 8.8 cm in close contact with main thoracic vessels and pericardium. Surgical biopsy documented a B2 thymoma. This clinical case reminds the importance of a systematic and global look of the imaging scans. Years before the thymoma diagnosis, the patient underwent a shoulder X-ray due to musculoskeletal pain, where an irregular shape of the aortic arch was visible, probably related to the growing mediastinal mass. An earlier diagnosis would allow a complete mass resection without such extensive surgery and less morbidity.

The Value of Postoperative Radiotherapy in Thymoma Patients with Myasthenia Gravis

INTRODUCTION

Surgery is the first-line treatment for patients with thymoma associated with myasthenia gravis (MG); however, the value of radiotherapy among these patients remains debatable. Herein, we examined the impact of postoperative radiotherapy (PORT) on the efficacy and prognosis of patients with thymoma and MG.

METHODS

This retrospective cohort study included 126 patients with thymoma and MG who were enrolled in the Xiangya Hospital clinical database between 2011 and 2021. Demographic and clinical data were collected including sex, age, histologic subtype, Masaoka-Koga staging, primary tumor, lymph node, metastasis (TNM) staging, and therapeutic modalities. To evaluate short-term MG symptom improvement following PORT, we examined changes in the quantitative myasthenia gravis (QMG) scores within 3 months post-treatment. Minimal manifestation status (MMS) was the main endpoint for assessing long-term improvement in MG symptoms. Overall survival (OS) and disease-free survival (DFS) were primary endpoints to determine the impact of PORT on prognosis.

RESULTS

Effects of PORT on MG symptoms: QMG scores significantly differed between the non-PORT and PORT groups (χ2= 6.300, p = 0.012). The median time to achieve MMS was significantly shorter in the PORT group than that in the non-PORT group (2.0 years vs. 4.4 years; p = 0.031). Multivariate analysis revealed that radiotherapy was associated with a reduced time to achieve MMS (hazard ratio [HR] 1.971, 95% confidence interval [CI]:1.102-3.525, p = 0.022). Effects of PORT on DFS and OS: The 10-year OS rate of the entire cohort was 90.5%, whereas OS rates for the PORT and non-PORT groups were 94.4 and 85.1%, respectively. The 5-year DFS rates for the whole cohort, PORT group, and non-PORT group were 89.7, 95.8, and 81.5%, respectively. PORT was associated with improved DFS (HR 0.139, 95% CI: 0.037-0.533, p = 0.004). In the high-risk histologic subgroup (type B2, B3), patients who received PORT had better OS (p = 0.015) and DFS (p = 0.0053) than those who did not receive PORT. PORT was associated with improved DFS (HR 0.232, 95% CI: 0.069-0.782, p = 0.018) in Masaoka-Koga stages II, III, and IV disease.

CONCLUSIONS

Overall, our findings indicate that PORT positively impacts thymoma patients with MG, particularly those with a higher histologic subtype and Masaoka-Koga staging.

Mediastinal Parathyroid Cancer

Parathyroid cancer (PC) is rare, but its pre-operative recognition is important to choose appropriate access strategies and achieve oncological clearance. This study characterizes features of mediastinal parathyroid cancer (MPC) and explores criteria aiding in the pre-operative recognition of malignancy. We assembled data from 502 patients with mediastinal parathyroid neoplasms (MPNs) from a systematic review of the literature 1968−2020 (n = 467) and our own patient cohort (n = 35). Thirty-two of the 502 MPNs (6.4%) exhibited malignancy. Only 23% of MPC patients underwent oncological surgery. Local persistence and early recurrence at a median delay of 24 months were frequent (45.8%), and associated with a 21.7-fold (95%CI 1.3−351.4; p = 0.03) higher risk of death due to disease. MPCs (n = 30) were significantly larger than cervical PC (n = 330), at 54 ± 36 mm vs. 35 ± 18 mm (χ2 = 20; p < 0.0001), and larger than mediastinal parathyroid adenomas (MPA; n = 226) at 22 ± 15 mm (χ2 = 33; p < 0.01). MPC occurred more commonly in males (60%; p < 0.01), with higher calcium (p < 0.01) and parathyroid hormone (PTH) levels (p < 0.01) than MPA. Mediastinal lesions larger than 3.0 cm and associated with a corrected calcium ≥ 3.0 mM are associated with a more than 100-fold higher odds ratio of being malignant (OR 109.2; 95%CI 1.1−346; p < 0.05). The composite 3 + 3 criterion recognized 74% of all MPC with an accuracy of 83%. Inversely, no MPN presenting with a calcium < 3.0 mM and size < 3.0 cm was malignant. When faced with pHPT in mediastinal location, consideration of the 3 + 3 rule may trigger an oncological team approach based on simple, available criteria.

Minimally invasive combined approach robotic thymectomy and transcervical total thyroidectomy

Myasthenia gravis (MG) is the most common autoimmune disorder affecting the neuromuscular junction in the USA. It is not uncommon for these patients to have concomitant autoimmune diseases including autoimmune thyroid disease. We describe here our method of performing a reproducible robotically assisted one-stage thymectomy and thyroidectomy. An African-American woman presented to our institution with a medical history of hypertension, morbid obesity, type 2 diabetes mellitus, symptomatic MG and symptomatic non-toxic substernal multinodular goitre. A one-stage minimally invasive right-sided robotic radical thymectomy and a transcervical total thyroidectomy with excision of the substernal goitre was successfully performed. The treatment of thyroid and thymus pathologies varies drastically from medical observation to surgery. This combined approach surgery clearly benefits the patient by offering similar operative time, fewer operative and postoperative recovery experiences, decreased anaesthesia risks associated with MG patients through fewer intubations, and a faster return to baseline function.

Maximal Thymectomy via Mini Sternotomy with Pleural Preservation

Gaurav PatelBackground  There are different surgical techniques used for maximal thymectomy. Each technique has its own advantages and disadvantages. We propose a mini sternotomy with pleural preservation approach for complete maximal thymectomy. Methods  Over time range of 5 years, 32 patients with diagnosis of thymoma with or without myasthenia gravis (MG) underwent maximal thymectomy by mini sternotomy in our institute. Patient records were examined for the following parameters: age, sex, preoperative medication, symptoms of MG as per Myasthenia Gravis Foundation of America grading system, operating time, duration of postoperative ventilation, length of stay in the intensive care unit, overall length of hospitalization, and postoperative complications. Results  The mean age of patients in our study was 43.66. Sex ratio in this study was almost equal. Sixty-nine percent of patients were stage I thymoma according to Masaoka staging. Size of the tumor ranged from 3 to 8 cm with mean size being 4.54 cm. Complete resection with negative tumor margins was possible in all the cases. Four patients had intraoperative pleural injury out of which two patients required intercostal tube insertion. We did not have any serious postoperative complications with no perioperative mortality. Conclusions  Mini sternotomy allows maximal removal of thymus through a less invasive approach and is associated with a significantly smoother postoperative course, less overall complications, and good clinical outcome. It is a simple technique that can be performed by any thoracic and surgical oncologists especially in Indian subcontinent where facilities of video-assisted thoracoscopic surgery and robotic video-assisted thoracoscopic surgery are not available in all areas and are expensive.

Complications of robot-assisted thymectomy: A single-arm meta-analysis and systematic review

BACKGROUND

Recently, thymectomy using minimally invasive approaches has been increasing with the development of robotic video-assisted thoracoscopic surgery (R-VATS). Although multimodal approach is effective for robot assisted thymectomy, it is necessary to determine the approach (left, right or subxiphoid) associated with the least complications.

METHODS

An electronic retrieval from PubMed, Embase, Web of Science, GreyNet International and The Cochrane Library. The single-arm meta-analysis was performed to compare the rate of complications of right- and left-side approaches by R-VATS.

RESULTS

A total of 21 studies including 930 patients were identified. The pooled incidence of total complications was 12.2% (confidence interval: 10.0%-14.8%) for all studies. The overall complication rate was 17.3% for the right-side compared with 7.4% for the left side (P < 0.001, odds ratio = 2.484, 1.601-3.852). The pooled incidence of air leak was significantly higher for the right versus left side (5.1% vs. 1.2%, respectively; p = 0.004). The incidence of atrial fibrillation was higher for the right-side compared with the left-side approach (4% vs. 1.2%, respectively; p = 0.004). The open conversion rate was significantly higher for the right versus the left-side (6.5% vs. 2.9%, respectively; p = 0.004). However, there was no significant difference in the pooled incidence of pleural effusion and thoracic duct fistula when comparing the right- and left-side approaches. In subgroup analysis, in the left approach, the incidence of overall complications (28.6% vs. 5.5%, respectively; p = 0.002) and pleural effusion (14.3% vs. 1%, respectively; p = 0.002) was higher for the 'Old Age' group compared with the 'Youth' group; However, In the subgroup analysis of gender, there was no significant difference in the incidence of complications after thymectomy.

CONCLUSION

Robotic video-assisted thoracoscopic surgery can be performed on the left- and right-sides; however, complications are minimal with the left-side approach. These data demonstrate that the incidence of overall complications, atrial fibrillation, open conversion ratios, and air leak rate of left-side R-VATS thymectomy are lower than those of right-side. Further subgroup analysis showed that the incidence of postoperative complications was higher in the older group.

Risk factors of prolonged ventilation after thymectomy in thymoma myasthenia gravis patients

BACKGROUND

To explore the risk factors for prolonged ventilation after thymectomy in patients with thymoma associated with myasthenia gravis (TAMG).

METHODS

We reviewed the records of 112 patients with TAMG after thymectomy between January 2010 and December 2019 in Peking University People's Hospital. Demographic, pathological, preoperative data and the Anesthesia, surgery details were assessed with multivariable logistic regression analysis to predict the risk of prolonged ventilation after thymectomy. A nomogram to predict the probability of post-thymectomy ventilation was constructed with R software. Discrimination and calibration were employed to evaluate the performance of the nomogram.

RESULTS

By multivariate analysis, male, low vital capacity (VC), Osserman classification (IIb, III, IV), total intravenous anesthesia, and long operation time were identified as the risk factors and entered into the nomogram. The nomogram showed a robust discrimination, with an area under the receiver operating characteristic curve (AUC) of 0. 835 (95% confidence interval [CI], 0.757-0.913). The calibration plot indicated that the nomogram-predicted probabilities compared very well with the actual probabilities (Hosmer-Lemeshow test: P = 0.921).

CONCLUSION

The nomogram is a valuable predictive tool for prolonged ventilation after thymectomy in patients with TAMG.

The role of thymectomy in myasthenia gravis: A programmatic approach to thymectomy and perioperative management of myasthenia gravis

BACKGROUND

Myasthenia gravis is a rare autoimmune disease caused by antibodies that probably originate from the thymus glands. This study examined the epidemiology of patients with MG, who underwent thymectomy over the last three decades.

METHODS

The objectives of this observational study were to investigate the clinicopathological features, treatment modalities, and prognostic factors for patients with thymic masses, over three decades at the Royal Hospital, Muscat, Oman.

RESULTS

There were 100 patients who underwent thymectomy with a mean (SD) age of 32.0 (8.6) years, of which 20% were men and 80% were women. Their follow up period, cardiac and neurology clinics, ranged from 1.5 to 12.0 years with a mean (SD) of 6.0 (3.0) years. Small percentage of MG patients had diabetes and hypertension and 10% of patients have positive family history of MG. Symptoms at the onset of the disease were ophthalmoplegia in 75%, limb weakness in 39%, bulbar symptoms in 57% and respiratory symptoms in 39% of patients. The Osserman grading was Grade I - 5%, Grade IIA - 39%, Grade IIB - 34%, and Grade III - 22%. Post thymectomy, 21% of patients had complete clinical remission, 76% of patients had significant clinical improvement and 3% had no apparent improvement in their clinical status. Histologically, hyperplasia was found in 57% and involuted thymus in 18% of patients.

CONCLUSION

Thymectomy can reduce patient's need for medication and reduce the severity of MG regardless of age, sex, severity, or length of sickness, or thymic masses. The early-onset, sever M.G, female, thymic hyperplasia benefit the most. Patients classified as Osserman Class IIA and IIB benefit most from this procedure.

Primary thymus tumors: retrospective case analysis at a reference center in Latin America, 2011-2019

BACKGROUND

Thymic tumors are unusual neoplasms, representing 0.2 to 1.5% of tumors in humans, but correspond to 20% of mediastinal tumors and 50% of those that occur in the anterior mediastinum. They tend to appear around the fourth and fifth decades of life without gender predilection. Up to 30% of patients are asymptomatic, therefore many are incidentally diagnosed. Radical thymectomy is the treatment of choice with high survival rates when detected in the early stages.

METHODS

This was a retrospective descriptive study, including 18 adult patients' diagnosis of thymic neoplasm, who were managed with surgical resection from 2011 to 2019. Information about demographics, clinical characteristics, imaging findings, surgical and medical management, plus histological findings was obtained and reported.

RESULTS

18 patients with thymic tumors were included, of which specific histologic studies reveled thymomas, carcinomas, neuroendocrine tumors, thymolipoma and thymic cyst. Mean age was 52.7 years, with a predominance of male population. The main symptom was dyspnea, followed by cough and chest pain. Paraneoplastic syndromes such as myasthenia gravis, aplastic anemia and Cushing syndrome were reported. 89% of cases were treated by radical thymectomy alone, while only 2 cases required chemotherapy and radiotherapy. There were no surgical complications. Mean hospital stay length was 11. 9 days, with only 1 mortality during hospital admission. 5-year survival rate was 81%.

CONCLUSIONS

The treatment of choice is radical thymectomy, which has been shown to positively impact patient mortality. Early detection is key to improve patient outcomes.

National Use and Short-term Outcomes of Video and Robot-Assisted Thoracoscopic Thymectomies

BACKGROUND

Transsternal open thymectomy has long been the most widely used approach for thymectomy, but recent decades have seen the introduction of minimally invasive surgery (MIS), such as video-assisted thoracoscopic surgery (VATS) and robot-assisted thoracoscopic surgery (RATS) thymectomy. This retrospective cohort study provides a national comparison of trends, outcomes, and resource utilization of open, VATS, and RATS thymectomy.

METHODS

Admissions for thymectomies from 2008 to 2014 were identified in the National Inpatient Sample. Patients were identified as undergoing open, VATS, or RATS thymectomy. Propensity score-matched analyses were used to compare overall complication rates, length of stay (LOS), and cost of VATS and RATS thymectomies.

RESULTS

An estimated 23,087 patients underwent thymectomy during the study period: open in 16,025 (69%) and MIS in 7217 (31%). Of the MIS cohort, 4119 (18%) underwent VATS and 3097 (13%) underwent RATS. Performance of RATS and VATS thymectomy increased while that of open thymectomy declined. Baseline characteristics between VATS and RATS were similar, except more women underwent VATS thymectomy. No differences in LOS or overall complication rates were appreciable in this study. VATS was associated with the lowest cost of the 3 approaches.

CONCLUSIONS

Our findings demonstrate the increasing adoption of MIS and declining use of the open surgical approach for thymectomy. There are no differences in overall complication rates between RATS and VATS thymectomy, but RATS is associated with greater cost and lower cardiac complication rates.

A mutational profile in multiple thymic squamous cell carcinoma

Background

Multiple thymic squamous cell carcinoma (TSCC) is a rare thymic epithelial tumor with a dismal prognosis. Mutational profiles of multiple TSCC may expand our understanding of tumorigenesis and treatment options for these tumors.

Methods

We sequenced the whole exomes of 3 TSCC nodules from a multiple TSCC patient and a paired peripheral blood sample and identified single-nucleotide variants and small insertions and deletions, and also performed gene ontological and pathway analyses.

Results

The 3 TSCC nodules were subjected to hematoxylin-eosin staining, and the results showed that these 3 nodules were highly similar with respect to histology. We identified 116, 94 and 98 non-synonymous somatic mutations in the 3 TSCC nodules, and 34 mutations, including mutations in TP53 and ARID1A, among others, were present in all 3 TSCC nodules. We then performed immunohistochemistry to assess two selected genes, TP53 and ARID1A, and found that the 3 TSCC nodules expressed similar levels of TP53 and ARID1A. Further gene ontological analysis and pathway analysis revealed that the 3 TSCC nodules also had similar significantly enriched pathways based on the identified genetic alterations. These results demonstrated that the 3 multiple TSCC nodules were spatially independent of each other but were highly similar with respect to histological sources and genetic characteristics, suggesting that 2 TSCC nodules were likely metastases of the third nodule.

Conclusions

These findings suggest that TSCC cells can be transferred to other sites inside the thymus and that total thymectomy is a good treatment option for thymic epithelial tumors.

A case of thymoma in myasthenia gravis: Successful outcome after thymectomy

INTRODUCTION

Thymic abnormalities occur as hyperplasia and thymoma. Myasthenia gravis is commonly present in thymoma. Thymectomy possesses risk due to anatomical proximity with vital thoracic structures and myasthenia crisis.

PRESENTATION OF CASE

Forty five years female with complaints of difficulty swallowing and weakness of upper limb muscles upon investigation showed mass in mediastinum and antibody test for myasthenia gravis positive. Medical management was done for a month followed by thymectomy. There were no intra and postoperative complications. Medical management was stopped one month after surgery and she is symptom free.

DISCUSSION

Thymectomy is the standard of care where median sternotomy is the mainstay approach to surgery. Various other surgical approaches and complications revolving around surgery has been discussed.

CONCLUSION

Surgical removal of thymoma cured myasthenia gravis in our case. We focused on proper preoperative optimization of myasthenia gravis symptoms before thymectomy.

Value of Adjuvant Radiotherapy for Thymoma with Myasthenia Gravis after Extended Thymectomy

Background:

The co-existence of myasthenia gravis (MG) and thymoma makes the surgical treatment more complicated and adjuvant radiation more controversial. The aim of this study was to investigate adjuvant radiotherapy for thymoma with MG after extended thymectomy.

Methods:

A total of 181 patients with both MG and thymoma were recruited between 2003 and 2014 at Tongren Hospital, China. Among all the patients, 157 patients received radiation therapy after surgery (Group A); whereas the other 24 patients did not receive radiation therapy (Group B). According to the time that patients started mediastinal radiation therapy, we subdivided the 157 patients in Group A into subgroups (1-month subgroup, n = 98; 2-month subgroup, n = 7; and 3-month subgroup, n = 52). We then compared the effect of the mediastinal radiation therapy across these different groups using the survival rate, the rate of postoperative myasthenic crisis, and the complete stable remission (CSR) rate as the primary endpoints.

Results:

There was a significant difference in the occurrence of postoperative myasthenic crisis between 1-month subgroup and Group B (χ² = 4.631, P = 0.031). The rates of reaching CSR were 32.6% in 1-month subgroup, 25% in 3-month subgroup, and 22.7% in Group B, respectively. The overall survival rates of 1-month subgroup, 3-month subgroup, and Group B were 88.8%, 83.3%, and 77.3%, respectively. Analysis on the Kaplan-Meier survival curves demonstrated that within 8 years after surgery, there was no significant difference in aspects of overall survival and disease-free survival between 1-month subgroup and Group B, and between 3-month subgroup and Group B; over 8 years after surgery, the disease-free survival rates in 1-month subgroup, 3-month subgroup and Group B were 79.4%, 70.6%, and 55.3%, respectively.

Conclusions:

Adjuvant radiation within 1 month after extended thymectomy may be helpful in controlling postoperative MG, such as decreasing the possibility of postoperative myasthenic crisis, and raising cumulative probabilities of reaching CSR.

Myasthenia Gravis and Thymoma Surgery: A Clinical Update for the Cardiothoracic Anesthesiologist

Myasthenia gravis (MG) is a rare neuromuscular disorder characterized by skeletal muscle weakness. Patients with MG who have thymoma and thymic hyperplasia have indications for thymectomy. The perioperative care of patients with MG scheduled for thymus resection should be focused on optimizing their neuromuscular function, identifying factors related to postoperative mechanical ventilation, and avoiding of triggers associated with myasthenic or cholinergic crisis. Minimally invasive surgical techniques, use of regional analgesia, and avoidance or judicious administration of neuromuscular blocking drugs (NMBs) is recommended during the perioperative period. If NMBs are used, sugammadex appears to be the drug of choice to restore adequately the neuromuscular transmission. In patients with postoperative myasthenic crisis, plasma exchange or intravenous immune globulin and mechanical support is recommended.

Diagnosis of thymic epithelial tumor subtypes by a quantitative proteomic approach

This study shows the first depth proteomic profiling of all TET subtypes and six candidate biomarkers were identified and validated.