Long-term follow-up of non-myasthenic patients with early-stage thymoma who underwent extended thymectomy or limited resection.

BACKGROUD: The standard resection for early-stage thymoma is total thymectomy and complete tumour excision with or without myasthenia gravis but the optimal surgery mode for patients with early-stage non-myasthenic thymoma is debatable. This study analysed the oncological outcomes for non-myasthenic patients with early-stage thymoma treated by thymectomy or limited resection in the long term. METHODS: Patients who had resections of thymic neoplasms at Taipei Veteran General Hospital, Taiwan between December 1997 and March 2013 were recruited, exclusive of those combined clinical evidence of myasthenia gravis were reviewed. A total of 113 patients were retrospectively reviewed with pathologic early stage (Masaoka stage I and II) thymoma who underwent limited resection or extended thymectomy to compare their long-term oncologic and surgical outcomes. RESULTS: The median observation time was 134.1 months [interquartile range (IQR) 90.7-176.1 months]. In our cohort, 52 patients underwent extended thymectomy and 61 patients underwent limited resection. Shorter duration of surgery (p < 0.001) and length of stay (p = 0.006) were demonstrated in limited resection group. Six patients experienced thymoma recurrence, two of which had combined myasthenia gravis development after recurrence. There was no significant difference (p = 0.851) in freedom-from-recurrence, with similar 10-year freedom-from-recurrence rates between the limited resection group (96.2 %) and the thymectomy group (93.2 %). Tumour-related survival was also not significantly different between groups (p = 0.726).result CONCLUSION: Patients with early-stage non-myasthenic thymoma who underwent limited resection without complete excision of the thymus achieved similar oncologic outcomes during the long-term follow-up and better peri-operative results compared to those who underwent thymectomy.

Modified En Bloc Esophagectomy for Squamous Cell Carcinoma After Neoadjuvant Chemoradiotherapy.

BACKGROUND: The optimal type of esophagectomy and extent of lymphadenectomy for patients after neoadjuvant chemoradiotherapy (nCRT) for esophageal squamous cell carcinoma remain controversial. We hypothesized that a more radical resection is associated with better survival. METHODS: Data of patients who received nCRT followed by resection for esophageal squamous cell carcinoma between 2012 and 2021 were analyzed. Modified en bloc esophagectomy (mEBE) involves total mediastinal lymphadenectomy and resection of all periesophageal node-bearing tissues. Perioperative outcomes and survival rates of mEBE were compared with those of conventional esophagectomy (CE). RESULTS: A total of 238 patients were included. Compared with CE, mEBE was associated with a longer operative time, higher total number of resected lymph nodes, fewer complications, and less anastomotic leakage; length of stay was similar between the 2 groups. There was no difference in overall survival rates between patients with ypT0 N0 stage in the mEBE and CE groups; however, in patients with non-ypT0 N0 stage in the mEBE and CE groups, the 3-year overall survival rates were 58.5% and 28.5%, respectively (P < .001). On disease-free survival analysis, no difference was observed in patients with ypT0 N0 stage, whereas patients with non-ypT0 N0 stage after nCRT had significantly better disease-free survival after mEBE compared with CE (49.7% vs 27.2%; P = .017). CONCLUSIONS: Survival after mEBE was significantly better than that after CE. The mEBE did not increase postoperative hospital stay and complication rates.

Old age and EGFR mutation status in inoperable early-stage non-small cell lung cancer patients receiving stereotactic ablative radiotherapy: A single institute experience of 71 patients in Taiwan.

BACKGROUND: Stereotactic ablative radiotherapy (SABR) is now the standard of care for patients with inoperable early-stage lung cancer. Many of these patients are elderly. EGFR (epidermal growth factor receptor) mutation is also common in the Asian population. METHODS: To evaluate the effects of old age and EGFR mutation on treatment outcomes and toxicity, we reviewed the medical records of 71 consecutive patients with inoperable early-stage non-small cell lung cancer (NSCLC) who received SABR at Taipei Veterans General Hospital between 2015 and 2021. RESULTS: The study revealed that median age, follow-up, Charlson comorbidity index, and ECOG score were 80 years, 2.48 years, 3, and 1, respectively. Of these patients, 37 (52.1%) were 80 years or older, and 50 (70.4%) and 21 (29.6%) had T1 and T2 diseases, respectively. EGFR mutation status was available for 33 (46.5%) patients, of whom 16 (51.5%) had a mutation. The overall survival rates at 1, 3, and 5 years were 97.2, 74.9, and 58.3%, respectively. The local control rate at 1, 3, and 5 years was 97.1, 92.5, and 92.5%, respectively. Using Cox proportional hazards regression we found that male sex was a risk factor for overall survival (p = 0.036, 95% CI: 1.118-26.188). Two patients had grade 2 pneumonitis, but no other grade 2 or higher toxicity was observed. We did not find any significant differences in treatment outcomes or toxicity between patients aged 80 or older and those with EGFR mutations in this cohort. CONCLUSION: These findings indicate that age and EGFR mutation status do not significantly affect the effectiveness or toxicity of SABR for patients with inoperable early-stage NSCLC.

Overall Survival for Esophageal Squamous Cell Carcinoma with Multiple Primary Cancers after Curative Esophagectomy-A Retrospective Single-Institution Study.

Background: Advances in surgical techniques and treatment modalities have improved the outcomes of esophageal cancer, yet difficult decision making for physicians while encountering multiple primary cancers (MPCs) continues to exist. The aim of this study was to evaluate long-term survival for esophageal squamous cell carcinoma (SCC) associated with MPCs. Methods: Data from 544 patients with esophageal SCC who underwent surgery between 2005 and 2017 were reviewed to identify the presence of simultaneous or metachronous primary cancers. The prognostic factors for overall survival (OS) were analyzed. Results: Three hundred and ninety-seven patients after curative esophagectomy were included, with a median observation time of 44.2 months (range 2.6−178.6 months). Out of 52 patients (13.1%) with antecedent/synchronous cancers and 296 patients without MPCs (control group), 49 patients (12.3%) developed subsequent cancers after surgery. The most common site of other primary cancers was the head and neck (69/101; 68.3%), which showed no inferiority in OS. Sex and advanced clinical stage (III/IV) were independent risk factors (p = 0.031 and p < 0.001, respectively). Conclusion: Once curative esophagectomy can be achieved, surgery should be selected as a potential therapeutic approach if indicated, even with antecedent/synchronous MPCs. Subsequent primary cancers were often observed in esophageal SCC, and optimal surveillance planning was recommended.

Post-recurrence survival analysis in patients with oligo-recurrence after curative esophagectomy.

BACKGROUND: Recurrent esophageal cancer is associated with dismal prognosis. There is no consensus about the role of surgical treatments in patients with limited recurrences. This study aimed to evaluate the role of surgical resection in patients with resectable recurrences after curative esophagectomy and to identify their prognostic factors. METHODS: We retrospectively reviewed patients with recurrent esophageal cancer after curative esophagectomy between 2004 and 2017 and included those with oligo-recurrence that was amenable for surgical intent. The prognostic factors of overall survival (OS) and post-recurrence survival (PRS), as well as the survival impact of surgical resection, were analyzed. RESULTS: Among 654 patients after curative esophagectomies reviewed, 284 (43.4%) had disease recurrences. The recurrences were found resectable in 63 (9.6%) patients, and 30 (4.6%) patients received surgery. The significant prognostic factors of PRS with poor outcome included mediastinum lymph node (LN) recurrence and pathologic T3 stage. In patients with and without surgical resection for recurrence cancer, the 3-year OS rates were 65.6 and 47.6% (p = 0.108), while the 3-year PRS rates were 42.9 and 23.5% (p = 0.100). In the subgroup analysis, surgery for resectable recurrence, compared with non-surgery, could achieve better PRS for patients without any comorbidities (hazard ratio 0.36, 95% CI: 0.14 to 0.94, p = 0.038). CONCLUSIONS: Mediastinum LN recurrence or pathologic T3 was associated with worse OS and PRS in patients with oligo-recurrences after curative esophagectomies. No definite survival benefit was noted in patients undergoing surgery for resectable recurrence, except in those without comorbidities.

Preoperative consolidation-to-tumor ratio is effective in the prediction of lymph node metastasis in patients with pulmonary ground-glass component nodules.

BACKGROUND: Preoperative positron emission tomography/computed tomography (PET/CT) is recommended as a guideline for staging of lung cancer. However, for patients with pulmonary ground-glass opacity (GGO) nodules who are supposed to have a relatively low risk of incidence of lymphatic metastasis, it remains uncertain whether PET/CT is more effective than consolidation-to-tumor ratio (CTR) in the prediction of regional lymphatic metastasis. METHODS: The data on patients who underwent surgery for lung cancer from 2011 to 2016 were collected retrospectively, which included CTR, results of PET/CT, and pathological characteristics. The patients who had undergone preoperative PET/CT were identified to find the risk factors for lymphatic metastasis. A receiver operating characteristic (ROC) curve and multiple logistic regression was utilized to clarify the predictive value of CTR and main tumor maximal standardized uptake value (SUVmax). RESULTS: Among 217 patients who had PET/CT before lobectomy, chest computed tomography revealed that 75 patients had CTR greater than 62%. The patients with lymphatic metastasis were shown to have higher CTR and higher main tumor SUVmax. Multiple logistic regression showed that younger age (<60 years), higher main tumor SUVmax on PET/CT, and greater CTR were independent predictive factors for lymphatic metastasis. The area under the ROC curve was comparable, 0.817 for CTR, and 0.816 for main tumor SUVmax. CONCLUSIONS: The present study revealed that CTR was not inferior to main tumor SUVmax considering the predictive power for lymphatic metastasis preoperatively in lung cancer patients with a GGO component. PET/CT might not be necessary preoperatively in selected patients.

Multidisciplinary team discussion results in survival benefit for patients with stage III non-small-cell lung cancer.

BACKGROUND: The treatment for stage III non-small cell lung cancer (NSCLC) often involves multi-modality treatment. This retrospective study aimed to evaluate whether multidisciplinary team (MDT) discussion results in better patient survival. MATERIALS AND METHODS: MDT discussion was optional before February 2016 and was actively encouraged by the MDT committee beginning February 2016. We reviewed the medical charts and computer records of patients with stage III NSCLC between January 2013 and December 2018. RESULTS: A total of 515 patients were included. The median survival of all the patients was 33.9 months (M). The median survival of patients who were treated after MDT discussion was 41.2 M and that of patients treated without MDT discussion was 25.7 M (p = 0.018). The median survival of patients treated before February 2016 was 25.7 M and that of patients treated after February 2016 was 33.9 M (p = 0.003). The median survival of patients with stage IIIA tumors and those with stage IIIB tumors was 39.4 M and 25.7 M, respectively (p = 0.141). Multivariate analysis showed that MDT or not (p<0.001), T staging (p = 0.009), performance status (p<0.001), and surgery (p = 0.016) to be significant prognostic factors. CONCLUSION: The results of the study show that MDT discussion results in survival benefit in patients with stage III NSCLC. The MDT discussion, performance status, and if surgery was performed were independent prognostic factors for patients with stage III NSCLC.

Lymphadenectomy is Unnecessary for Pure Ground-Glass Opacity Pulmonary Nodules.

BACKGROUND: Lobectomy plus lymph node dissection is the standard treatment of early-stage lung cancer, but the low lymph node metastasis rate with ground-glass opacity (GGO) makes surgeons not perform lymphadenectomy. This study aimed to re-evaluate the lymph node metastasis rate of GGO to help make a clinical judgment. METHODS: We performed this retrospective study to enroll patients who received lung cancer surgery from 2011 to 2016. Patient characteristics collected included tumor size, solid part size and lymph node metastasis rate. These patients were categorized into pure GGO and part solid GGO groups to undergo analysis. RESULTS: Lymph node metastasis rates were 0%, 3.8% and 6.9% in order of the pure GGO group, the GGO predominant group and the solid predominant group. In the lobectomy patients, the solid predominant group still showed to have the highest lymph node metastasis rate and recurrence rate (8.3% and 10.1%). CONCLUSION: It is unnecessary to perform lymphadenectomy for patients with pure GGO in view of the 0% lymph node metastasis rate. The higher lymph node metastasis rate in the patients with the solid predominant group, 6.9%, suggested that surgeons should choose a rational lymphadenectomy method according to their GGO property and clinical judgment.

Author Correction: Overexpression of Aiolos promotes epithelial-mesenchymal transition and cancer stem cell-like properties in lung cancer cells.

An amendment to this paper has been published and can be accessed via a link at the top of the paper.

Preoperative biopsy and tumor recurrence of stage I adenocarcinoma of the lung.

PURPOSE: To evaluate whether preoperative biopsy affects the outcomes of patients undergoing at least lobectomy for stage I lung adenocarcinoma. METHODS: We reviewed the medical records of patients who underwent surgery for stage I lung adenocarcinoma between 2006 and 2013. Tumor recurrence and survival were compared between patients who underwent preoperative biopsy, including computed tomographic-guided needle biopsy and transbronchial biopsy, and those who underwent intraoperative frozen section. RESULTS: Among 509 patients, 229 patients (44.9%) underwent preoperative biopsy and 280 patients had lung adenocarcinoma diagnosed by intraoperative frozen section (reference group). Recurrence developed in 65 (12.8%) patients within a median follow-up period of 54.4 months. Multivariate analysis demonstrated that preoperative biopsy (OR 1.97, p = 0.045), radiological solid appearance (OR 5.43, p < 0.001), and angiolymphatic invasion (OR 2.48, p = 0.010) were independent predictors of recurrence. In the overall cohort, preoperative biopsy appeared to worsen 5-year disease-free and overall survival significantly (76.6% vs. 93.0%, p < 0.001; and 83.8% vs. 94.5%, p = 0.002, respectively) compared with the reference group. After propensity matching, multivariable logistic regression still identified preoperative biopsy as an independent predictor of overall recurrence (OR 2.21, p = 0.048) after adjusting for tumor characteristics. CONCLUSION: Preoperative biopsy might be considered a prognosticator of recurrence of stage I adenocarcinoma of the lungs in patients who undergo at least anatomic lobectomy without postoperative adjuvant chemotherapy.

Overexpression of Aiolos promotes epithelial-mesenchymal transition and cancer stem cell-like properties in lung cancer cells.

Aiolos/Ikaros family zinc finger 3 (IKZF3), a member of the Ikaros family of lymphocyte maturation-driving transcription factors, is highly expressed in hematopoietic malignancies. However, its role in epithelial-mesenchymal transition (EMT) and cancer stem cell (CSC)-like properties in lung cancer remains unknown. Human lung cancer cell lines H1299 with overexpressing Aiolos (H1299-Aiolos) and A549 with overexpressing Aiolos (A549-Aiolos) were generated by stable transfection. Cell migration and invasion assays were done to demonstrate their invasion and migration ability. Sphere formation assay was used to determine their tumor-initiating capability. Aiolos overexpression induced EMT and increased migration/invasiveness in H1299 and A549 cells. Aiolos overexpression also increased metastatic ability in vivo. Aiolos overexpression upregulated the expression of Twist and matrix metalloproteinase 16 (MMP16). By using knockdown of Twist or an inhibitor of phosphatidylinositol (PI) 3-kinase, EMT, migration/invasiveness ability, and MMP16 expression were reversed in H1299-Aiolos and A549-Aiolos cells. Overexpression of Aiolos upregulated the CSC-like properties in lung cancer cells, and were also reversed by an inhibitor of PI 3-kinase. For lung cancer cells, Aiolos overexpression promotes EMT and CSC-like properties through upregulating the PI 3-kinase/Akt pathway. The information is helpful for developing therapeutic strategies targeting Aiolos expression for lung cancer treatment.

Prognostic significance of basal versus superior segment in patients with completely resected lung adenocarcinoma in the lower lobe.

BACKGROUND: Although the lower lobes of the lungs occupy half of the chest on both sides, the prognostic value of tumor location in lung cancer in the lower lobe has not been well demonstrated. This study investigated the prognostic value of tumor location (basal vs. superior) in patients with resected lung adenocarcinoma in the lower lobe. METHODS: A total of 207 patients undergoing lobectomy for lung adenocarcinoma in the lower lobe were included in the study. The association between tumor location and mediastinal lymph node metastasis was analyzed. Prognostic factors of overall survival and probability of freedom from recurrence (FFR) were also investigated. RESULTS: During follow-up, 71 (34.3%) patients developed recurrence. Patients with basal segment tumors had a significantly higher possibility of developing N2 lymph node metastasis than those with superior segment tumors (P = 0.025). Univariate analysis showed that location in the basal (vs. superior) segment was a significant prognostic factor for a lower probability of FFR (P = 0.013). Basal (vs. superior) segment remained a significant prognostic factor for a lower probability of FFR (P = 0.010) in multivariate analysis. CONCLUSIONS: Basal segment tumors have a significantly higher possibility of developing N2 lymph node metastasis than superior segment tumors in resected lung adenocarcinoma in the lower lobe. Tumor location at the basal segment was a significant prognostic factor for a lower probability of FFR. This information is useful for patient stratification of risk of postoperative recurrence.

Prognostic significance of AKR1B10 in patients with resected lung adenocarcinoma.

BACKGROUND: Aldo-keto reductases (AKRs) modify carbonyl groups on aldehyde or ketones to form primary or secondary alcohols, which are then conjugated with sulfates or glucuronide for excretion. The AKR1B10 gene encodes a member of the AKR superfamily. Overexpression of AKR1B10 plays an important role in the tumorigenesis of lung cancer cells; however, the prognostic value of AKR1B10 expression in patients with lung adenocarcinoma has not been well demonstrated. METHODS: A total of 96 patients with resected lung adenocarcinoma were included in the study. AKR1B10 expression was determined by immunohistochemistry in tumor specimens. The prognostic value of AKR1B10 overexpression and its relationship with clinicopathological variables were investigated. RESULTS: AKR1B10 overexpression was identified in 22 (22.9%) of the 96 patients and tended to be significantly associated with N1 or N2 status (P = 0.055). AKR1B10 overexpression was not a significant prognostic factor for overall survival (P = 0.301) but was a significant prognostic factor for poor recurrence-free survival (P = 0.015). T status (T3 or T4 vs. T1 or T2; P = 0.020), N1 or N2 (vs. N0; P = 0.019), predominant pattern group (lepidic/acinar/papillary vs. micropapillary/solid; P = 0.023), and AKR1B10 overexpression (P = 0.013) were significant prognostic factors for poor recurrence-free survival in multivariate analysis. CONCLUSIONS: AKR1B10 overexpression was a significant prognostic factor for poor recurrence-free survival in patients with resected lung adenocarcinoma. This information is useful to stratify patients at high-risk of recurrence after lung adenocarcinoma resection.

Pleuroparenchymal fibroelastosis presenting with pneumothorax.

A 47-year-old woman presented with spontaneous right side pneumothorax. Image studies showed consolidations and reticular opacities involving the pleural and subpleural regions of bilateral lungs. Wedge biopsy specimens of right upper, middle and lower lobes showed fibrosis of the visceral pleura and subpleural area in all three lobes, more significant in the upper lobe. Elastic Van Gieson stain showed a pattern of alveolar septal elastosis with intra-alveolar fibrosis. The clinical presentation and pathological findings are compatible with pleuroparenchymal fibroelastosis, a rare and distinct type of interstitial lung disease. This entity is different from usual interstitial pneumonia by its relationship to pleura, upper lobe predominance and temporal homogeneity. It is different from non-specific interstitial pneumonia by its pleural involvement and scanty inflammatory cell infiltration. Pleuroparenchymal fibroelastosis is a slowly progressive disease; about half of the patients die in 10 years. No curative treatment is available at present time.

Effect of postoperative systemic therapy on pulmonary adenocarcinoma with unexpected pleural spread detected during thoracotomy or thoracoscopy.

BACKGROUND: Occasionally, malignant pleural disease is only detected unexpectedly during surgery in patients with pulmonary adenocarcinoma. Previous studies mostly focused on the role of main tumor resection on patient's outcome, barely addressing the position of postoperative systemic therapy. METHODS: The medical records of 5321 non-small cell lung cancer patients who underwent thoracic surgery between January 1990 and December 2012 were reviewed. Pulmonary adenocarcinoma patients with unexpected pleural spread noted during surgery were included. The clinical and postoperative treatment variables were assessed for correlation with overall survival. RESULTS: In 134 patients identified, main tumor resection was performed in 87 (64.9%) patients, while 89 (66.4%) and 57 (42.5%) patients received postoperative chemotherapy and epidermal growth factor receptor- tyrosine kinase inhibitor (EGFR -TKI) therapy, respectively. Overall, the 5-year survival rate was 30.2% and median survival time was 29.3 months. Multivariate analysis showed main tumor resection and EGFR-TKI therapy were associated with better survival. Mutational status of EGFR was available in 57 patients and 43 (75.4%) had activating mutations. Resection of the main tumor conferred a better outcome in patients without EGFR mutation or with unknown EGFR mutation status and had not been treated with EGFR-TKI therapy (P = 0.003), but not in those with activating EGFR mutation and had been treated with EGFR-TKI (P = 0.857). CONCLUSIONS: In pulmonary adenocarcinoma patients with unexpected pleural spread detected during surgery, main tumor resection and EGFR-TKI therapy correlated with better survival. Identifying EGFR mutation status before surgery can provide useful information for clinical decision during surgery.

Generating a robust prediction model for stage I lung adenocarcinoma recurrence after surgical resection.

Lung cancer mortality remains high even after successful resection. Adjuvant treatment benefits stage II and III patients, but not stage I patients, and most studies fail to predict recurrence in stage I patients. Our study included 211 lung adenocarcinoma patients (stages I-IIIA; 81% stage I) who received curative resections at Taipei Veterans General Hospital between January 2001 and December 2012. We generated a prediction model using 153 samples, with validation using an additional 58 clinical outcome-blinded samples. Gene expression profiles were generated using formalin-fixed, paraffin-embedded tissue samples and microarrays. Data analysis was performed using a supervised clustering method. The prediction model generated from mixed stage samples successfully separated patients at high vs. low risk for recurrence. The validation tests hazard ratio (HR = 4.38) was similar to that of the training tests (HR = 4.53), indicating a robust training process. Our prediction model successfully distinguished high- from low-risk stage IA and IB patients, with a difference in 5-year disease-free survival between high- and low-risk patients of 42% for stage IA and 45% for stage IB (p < 0.05). We present a novel and effective model for identifying lung adenocarcinoma patients at high risk for recurrence who may benefit from adjuvant therapy. Our prediction performance of the difference in disease free survival between high risk and low risk groups demonstrates more than two fold improvement over earlier published results.

Correction: Long term oncological outcome of thymoma and thymic carcinoma - an analysis of 235 cases from a single institution.

[This corrects the article DOI: 10.1371/journal.pone.0179527.].

Prognostic Factors in Completely Resected Node-Negative Lung Adenocarcinoma of 3 cm or Smaller.

INTRODUCTION: The role of adjuvant chemotherapy for patients with stage I NSCLC remains unknown. The prognostic value of histological subtypes in resected node-negative small lung adenocarcinoma has not been widely investigated. This study investigated the prognostic factors in patients with node-negative lung adenocarcinoma 3 cm or smaller to find potential candidates for adjuvant chemotherapy. METHODS: A total of 726 patients with completely resected node-negative lung adenocarcinoma 3 cm or smaller were included in the study. Prognostic factors for overall survival or probability of freedom from recurrence (FFR) were investigated. RESULTS: During follow-up, recurrence developed in 59 patients (8.1%). Univariate analysis showed that the micropapillary/solid predominant pattern group was associated with a significantly lower probability of FFR (p = 0.001) in node-negative lung adenocarcinoma 3 cm or smaller. Those with greater tumor size (p = 0.001) and the micropapillary/solid predominant pattern group (p = 0.035) had a significantly lower probability of FFR in multivariate analysis. For tumors 2 cm or smaller, the micropapillary/solid predominant pattern group had a trend toward a lower probability of FFR (p = 0.053) in multivariate analysis. Presence of the solid pattern was a prognostic factor for lower probability of FFR (p = 0.001) in multivariate analysis. CONCLUSIONS: The new adenocarcinoma classification has significant impact on recurrence in node-negative lung adenocarcinoma 3 cm or smaller. Patients with the micropapillary/solid predominant pattern have a significantly higher risk for recurrence. For tumors 2 cm or smaller, presence of the solid pattern was a prognostic factor for higher probability of recurrence. This information is useful for patient stratification for adjuvant therapy.

Long term oncological outcome of thymoma and thymic carcinoma - an analysis of 235 cases from a single institution.

BACKGROUND AND OBJECTIVES: Thymoma has a variable long-term oncological outcome after surgical resection. Survival and tumor recurrence were analyzed to determine the predisposing factors for tumor recurrence. METHODS: A total of 235 patients who underwent surgery for thymoma or thymic carcinoma from December 1997 to March 2013 were analyzed using Masaoka staging system and World Health Organization (WHO) histological classification. Surgical intervention included extended thymothymectomy via median sternotomy and thymomectomy via thoracotomy/ video-assisted thoracoscopic surgery (VATS). RESULTS: The median duration of follow-up was 105 months (12-198 months). Among these 235 patients, recurrence was observed in 25 patients (10.7%). according to Masaoka stage I, IIA, IIB, III, IVA, IVB, recurrence rates were 1/65(1.5%), 8/106(7.5%), 1/32(3.1%), 6/20(30.0%), 8/10(80.0%), 1/1(100.0%), respectively. Disease or treatment-related mortality was observed in 13 patients. Overall survival rate was 94.4%. After univariate analysis, predisposing factors for tumor recurrence included Masaoka stage, WHO histologic type, tumor size, adjuvant therapy and margin status. CONCLUSIONS: Due to the indolent behavior of thymoma, tumor recurrence appears to be a better assessment of oncological outcome rather than survival. Factors associated with tumor recurrence include Masaoka stage, WHO histologic type, tumor size, adjuvant therapy and margin status.

WITHDRAWN: Prognostic Significance of Programmed Cell Death-Ligand 1 Expression in Patients With Resected Lung Adenocarcinoma.

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