[Clinical Features of Endocrine Disorders with Immune Checkpoint Inhibitor in Patients with Non-Small Cell Lung Cancer].

Immune checkpoint inhibitors(ICIs)could cause immune-related adverse events(irAEs), of which endocrine disorders are relatively common. Symptoms include fatigue, anorexia, and shock, making diagnosis and treatment difficult. This study aimed to analyze the characteristics of patients with non-small cell lung cancer concomitant with endocrine disorders as irAEs. In total, 83 patients who were administered ICIs for advanced or postoperative recurrent non-small cell lung cancer between February 2016 and February 2021 were identified. We retrospectively studied the clinical course and findings of 7 patients who developed endocrine disorders after treatment. Four patients had hypopituitarism, and 3 patients had thyroid dysfunctions. There were 6 male patients and 1 female patient. Regarding anticancer agents, 5 patients received ICI alone, and 2 patients received ICI plus cytotoxic chemotherapies. The patients received treatment from the irAE treatment team in our hospital, and 5 of 7 patients could were able to be readministered ICIs. Endocrine disorders as irAEs require collaboration with specialized departments for early diagnosis and treatment.

The clinical significance of tertiary lymphoid structure and its relationship with peripheral blood characteristics in patients with surgically resected non-small cell lung cancer: a single-center, retrospective study.

INTRODUCTION: The presence of tertiary lymphoid structure (TLS) in tumor tissues has been reported to be a factor associated with a good prognosis in several types of cancers. However, the relationship between TLS formation and peripheral blood findings remains unclear. The purposes of the study were to evaluate the effect of the presence of TLS on survival and determine the peripheral blood characteristics associated with TLS formation in non-small cell lung cancer (NSCLC) patients. METHODS: A total of 147 consecutive NSCLC patients who underwent lung resection at Fukushima Medical University Hospital between 2013 and 2017 were enrolled. TLS expression was evaluated, and the relationships between clinical parameters and outcomes were analyzed. Peripheral blood mononuclear cells (PBMCs) were further analyzed by mass cytometry to characterize the TLS-positive microenvironment. RESULTS: Forty-six patients had high TLS expression, and the remaining 101 patients had low TLS expression. In stage II to IV patients (n = 35), disease-free survival was longer in the high TLS expression group (p = 0.027). A low neutrophil to lymphocyte ratio (NLR) < 2.75 in the peripheral blood was associated with high TLS expression (p = 0.003). Citrus analysis after mass cytometry assay showed that the number of cells expressing HLA-DR and CD9 in PBMCs was lower in the high TLS expression group. CONCLUSION: High TLS expression is associated with a good prognosis after surgery in stage II and III NSCLC patients. In the peripheral blood, a low NLR and few antigen-presenting cells indicate the presence of TLS in the tumor microenvironment.

[Resistance Mechanisms to Immune Checkpoint Inhibitor and Its Overcome with Focus on ß-Catenin in Lung Cancer].

Although the indications for immune checkpoint inhibitors are expanding rapidly, the disease will eventually progress in many patients. Elucidating and overcoming the resistant mechanisms to immune checkpoint inhibitors is a major challenge. WNT/ß-catenin pathway has long been known as one of the mechanisms involved in cell proliferation and epithelial-mesenchymal transition in cancer development. Recently, it has become clear that WNT/ß-catenin pathway also plays a role in cancer immune escape, as reported in melanoma. We have also studied WNT/ß-catenin pathway as a mechanism of immune escape in lung cancer. In this article, we review how WNT/ß-catenin pathway is involved in immune escape and resistance to immune checkpoint inhibitors, mainly in non-small cell lung cancer. In addition, we discuss how to overcome the tumor immune mechanism caused by WNT/ß-catenin pathway in the context of current combination therapies and therapies in development.

[ß-Catenin Expression in Non-Small Cell Lung Cancer and Therapeutic Effect of Immune Checkpoint Inhibitors].

Recently, ß-catenin mediated immune escape mechanism has been reported in several cancers. We investigated whether ß-catenin is associated with resistance to immune checkpoint inhibitor therapy in non-small cell lung cancer. Non-small cell lung cancer patients expressing high levels of ß-catenin showed poor progression-free survival and overall survival after single agent anti-PD-1 therapy. They had less infiltration of CD8-positive cells and antigen-presenting cells. Microarray analysis also showed low gene expression of CD8A and IFNG. siRNA knockdown of CTNNB1 in the ß-catenin-positive lung cancer cell line LK-2 tended to decrease CTNNB1 and ATF3 expression and increase CCL4 expression. The results suggest that ß- catenin suppresses tumor infiltration by antigen-presenting cells and confers resistance to immune checkpoint inhibitors in non-small cell lung cancer via downregulation of CCL4 production.

Tumor mutation burden and immunological, genomic, and clinicopathological factors as biomarkers for checkpoint inhibitor treatment of patients with non-small-cell lung cancer.

Cancer treatment using immune checkpoint inhibitors is widely used, although biomarkers predictive of response are not well established. However, both the expressions of programmed cell death ligand 1 (PD-L1) and the tumor mutation burden (TMB) hold promise as such biomarkers for immune checkpoint inhibitors; however, its characteristics and clinical and immunological impacts have not been fully analyzed. We, therefore, evaluated the clinical and immunological parameters related to TMB to identify potential new biomarkers. We enrolled 92 patients with non-small-cell lung cancer who underwent surgery at Fukushima Medical University Hospital from 2013 to 2016. TMB of individual tumors was calculated by whole-exome sequencing analysis. Major cancer-related gene mutations were evaluated using panel sequencing. Expression of PD-L1 and abundance of tumor-infiltrating lymphocytes were evaluated by immunohistochemistry using surgical samples. The median TMB value was 60. TMB was significantly higher in men, current or former smokers, and in patients with squamous cell carcinoma, tumor size ≥ 2.8 cm, wild-type EGFR, TP53 gene mutation-positive status, and cyclin-dependent kinase-inhibitor gene 2A mutation-positive status. According to multivariate analysis, TMB was significantly associated with EGFR gene mutation-negative status (p = 0.0111) and TP53 gene mutation-positive status (p = 0.0425). If TMB is identified as a robust biomarker for immune checkpoint inhibitor administration, analysis of TP53 and EGFR mutations may provide a relatively rapid and easy proxy for predicting TMB.

[Monitoring Tumor Infiltrating Lymphocytes by Peripheral Blood in Lung Cancer Patients].

There have been many reports on the association between tumor infiltrating lymphocytes and cancer prognosis. It is known that tumor infiltrating lymphocytes contain not only cytotoxic T lymphocytes but also bystander lymphocytes and immunosuppressive cells. In most of previous reports, tumor infiltrating lymphocytes were defined as CD3 or CD8 T cells. It is generally thought that patients with cancer rich in tumor infiltrating lymphocytes have a good prognosis. Most tumor infiltrating lymphocytes are thought to be cytotoxic T lymphocytes. It is also reported that cancer rich in tumor infiltrating lymphocytes is responsive to immune checkpoint inhibitors. In recent years, several reports revealed clonal replacement in tumor infiltrating lymphocytes after administration of immune checkpoint inhibitors. This change was also detectable in peripheral blood. From the viewpoint of lung cancer treatment, combination of immune checkpoint inhibitors and chemotherapy became the standard therapy. We need to understand the tumor immune microenvironment in order to select the best treatment regimen for each patient. However, it is often difficult to obtain an adequate amount of tissue biopsy sample in standard of care. It is hoped that we can understand the tumor immune microenvironment using the peripheral blood. Thus, studying the association between treatment response, tumor infiltrating lymphocytes, and peripheral blood is considered to be important to research and develop peripheral blood biomarkers in lung cancer.

Thin-section computed tomography findings of lung adenocarcinoma with inherent metastatic potential.

PURPOSE: The solid component of lung ground-glass nodules on thin-section computed tomography (TSCT) reflects cancer cell progression and invasiveness. The purpose of this study was to clarify the cut-off value of preoperative TSCT findings in treating a lesion suspected of being adenocarcinoma and to recognize the timing of surgical resection for lung nodules. METHODS: We reevaluated the TSCT findings in 392 patients with clinical stage IA lung adenocarcinoma who underwent surgical resection between 2003 and 2007. We identified the clinical parameters that were most useful for predicting recurrence and identified a cut-off level for each parameter. RESULTS: Recurrence was observed in 75 (19 %) of 392 patients (median follow-up: 7 years). The size of internal consolidation of a lung nodule (SCL) and the ratio of the SCL to the maximum tumor diameter (C/T ratio) were extracted as independent factors that predicted recurrence. Only 1 (0.3 %) patient each with a lung nodule C/T ratio ≤0.5 and SCL ≤10 mm recurred. These conditions were associated with a significantly better overall survival and recurrence-free survival. CONCLUSION: In patients with clinical stage I lung adenocarcinoma with a C/T ratio ≤0.5 and/or SCL ≤10 mm on TSCT, surgery is extremely likely to achieve a cure.

[Exploring the Possibility of New Biomarkers of Immune Checkpoint Inhibitors for Non-Small Cell Lung Cancer (NSCLC)].

Mutation burden in a tumor, presumably involving neo-antigens in the tumor tissue, is also thought to be one of the better predictors for the efficacy of immune checkpoint inhibitors. However, it is difficult to analyze the mutation burden routinely in the clinic. Here, we describe more convenient factors that can be used as surrogate markers of mutation burden. Ninety-four patients with NSCLC who underwent resection in our institution were recruited for this study. Mutation burden and major gene alterations were analyzed by using next generation sequencing. Several immunological parameters were also assessed using immunohistochemistry. Statistical analysis was performed on mutation burden, major gene alternations, immunohistochemistry, and clinical parameters. The median mutation load was 54 mutations(range, 10-363 mutations). Squamous cell carcinoma, EGFRmutation -negativity, and TP53 alteration-positivity were closely connected with higher mutation burden. Multiple regression analysis showed that mutation burden in the tumor could be associated with EGFRmutation and TP53 alteration status.

The Outcomes of a Limited Resection for Non-Small Cell Lung Cancer Based on Differences in Pathology.

OBJECTIVE: A precise preoperative diagnosis of in situ or minimally invasive carcinoma may identify patients who can be treated by limited resection. Although some clinical trials of limited resection for lung cancer have started, it will take a long time before the results will be published. We have already reported a large-scale study of limited resection. We herein report the data for a subclass analysis according to differences in pathology. METHODS: Data from multiple institutions were collected on 1710 patients who had undergone limited resection (segmentectomy or wedge resection) for cT1N0M0 non-small cell carcinoma. The disease-free survival (DFS) and recurrence-free proportion (RFP) were analyzed. Small cell carcinomas and carcinoid tumors were excluded from this analysis. Adenocarcinomas were sub-classified into four groups using two factors, the ratio of consolidation to the tumor diameter (C/T) and the tumor diameter alone. RESULTS: The median patient age was 64 (20-75) years old. The mean maximal diameter of the tumors was 1.5 ± 0.5 cm. The DFS and RFP at 5 years based on the pathology were 92.2 and 94.7 % in adenocarcinoma (n = 1575), 76.3 and 82.4 % in squamous cell carcinoma (SqCC) (n = 100), and 73.6 and 75.9 % in patients with other tumors (n = 35). The prognosis of adenocarcinoma in both groups A (C/T ≤0.25 and tumor diameter ≤2.0 cm) and B (C/T ≤0.25 and tumor diameter >2.0 cm) was good. In SqCC, only segmentectomy was a favorable prognostic factor. In the groups with other pathologies, large cell carcinomas were worse in prognosis (the both DFS and RFP: 46.3 %). CONCLUSION: Knowing the pathological diagnosis is important to determine the indications for limited resection. Measurement of the tumor diameter and C/T was useful to determine the indications for limited resection for adenocarcinoma. Limited resection for adenocarcinomas is similar with a larger resection, while the technique should be performed with caution in squamous cell carcinoma and other pathologies.

Prognostic impact of microscopic vessel invasion and visceral pleural invasion in non-small cell lung cancer: a retrospective analysis of 2657 patients.

OBJECTIVE: We aimed to assess the prognostic significance of microscopic vessel invasion (MVI) and visceral pleural invasion (VPI) in non-small cell lung cancer (NSCLC). BACKGROUND: VPI is included in the current tumor-node-metastasis (TNM) classification in NSCLC; however, MVI is not incorporated in TNM classification. METHODS: From August 1992 to December 2009, 2657 consecutive patients with pathological T1-4N0-2M0 NSCLC underwent complete resection. In addition to conventional staging factors, we evaluated MVI histologically and analyzed its significance in NSCLC recurrence prognosis. The recurrence-free period in several NSCLC subgroups was analyzed using the Kaplan-Meier method and Cox regression analysis. RESULTS: The proportion of patients with a 5-year recurrence-free period was 52.6% and 87.5%, respectively, in those with and without MVI (P < 0.001). Multivariate analysis showed that MVI, similarly to VPI, was found to be an independently significant predictor of recurrence [hazard ratio (HR): 2.78]. In particular, MVI and VPI were the 2 strongest significant independent predictors of recurrence in 1601 patients with pathological stage I disease treated without adjuvant chemotherapy (HR: 2.74 and 1.84, respectively). In each T subgroup analysis, evident and significant separation of the recurrence-free proportion curves were observed among the 3 groups (VPI and MVI absent, VPI or MVI present, and VPI and MVI present). CONCLUSIONS: This study demonstrated that MVI was a significant independent risk factor for recurrence in patients with a resected T1-4N0-2M0 NSCLC. Further data on MVI prognostic impact should be collected for the next revision of the TNM staging system.

Catalytic enantioselective inverse electron demand hetero-Diels-Alder reaction with allylsilanes.

The first diastereo- and enantioselective inverse electron demand hetero-Diels-Alder reaction of ß,γ-unsaturated α-ketoesters with allylsilanes is described. Chiral copper(II) catalysts successfully activate the ß,γ-unsaturated α-ketoesters and promote the reaction with allylsilanes with excellent enantioselectivities. This process represents a new entry to chiral oxanes.

Clinical, Genomic, and Transcriptomic Featurses of Lung Adenocarcinoma With Uncommon EGFR Mutation.

PURPOSE: The purpose of this study is to identify the clinical, genomic, and transcriptomic features of patients with lung adenocarcinoma (LUAD) harboring uncommon epidermal growth factor receptor (EGFR) mutations (UCM) compared with common EGFR mutations (CM). MATERIALS AND METHODS: In this multicenter retrospective cohort study, clinicopathological data were collected from 1047 consecutive patients who underwent complete surgical resection for LUAD, as well as EGFR mutation analysis, between 2005 and 2012 at 4 institutions. Differences in postoperative overall survival (OS) and recurrence-free survival (RFS) according to EGFR mutation status were evaluated. For the genomic and transcriptomic analyses, 5 cohorts from public databases were evaluated. RESULTS: Of 466 eligible patients, 415 (89.1%) and 51 (10.9%) had CM and UCM, respectively. The 5-year OS and RFS rates in the CM/UCM groups were 86.8%/77.0% and 74.8%/59.0%, respectively. OS and RFS were significantly shorter in the UCM than CM group (both P < .01). Multivariable analysis of OS showed that UCM was an independent prognostic factor (hazard ratio 1.72, 95% confidential interval 1.01-2.93). According to the genomic analysis, tumors with UCM had a significantly higher tumor mutation burden and TP53 mutation frequency. Transcriptomic analysis showed that the T-cell-inflamed gene signature, a biomarker of the treatment for immunotherapy, was significantly associated with tumors with UCM. CONCLUSION: UCM were associated with a poor prognosis in patients with surgically resected EGFR-mutated LUAD. Tumors with UCM had unique genomic and transcriptomic features suggestive of a tumor microenvironment responsive to immunotherapy.

Automated immunoassay of serum NY-ESO-1 and XAGE1 antibodies for predicting clinical benefit with immune checkpoint inhibitor (ICI) in advanced non-small cell lung cancer.

BACKGROUND: NY-ESO-1 and XAGE1 cancer/testis antigens elicit humoral and cellular immune responses in NSCLC patients. We aimed to predict clinical benefit with ICI monotherapy, using an automated immunoassay of NY-ESO-1/XAGE1 antibodies (Abs). METHODS: This study enrolled 99 NSCLC patients who received nivolumab after chemotherapy, including 21 patients harboring EGFR, ALK, or KRAS alterations. The cutoff value (10 units/mL) of NY-ESO-1 and XAGE1 Ab was determined based on Ab levels in non-malignant controls, and NY-ESO-1/XAGE1 Abs in NSCLC were measured before nivolumab. Differences in PFS and OS between the Ab-positive and Ab-negative groups were retrospectively analyzed using Cox regression analysis after applying inverse probability of treatment weighting (IPTW). RESULTS: NY-ESO-1/XAGE1 Abs were positive in 28 NSCLC, who responded more highly to nivolumab than the Ab-negatives (response rate 50.0% vs. 15.5 %, p < 0.0007). The IPTW-adjusted positives and negatives for NY-ESO-1/XAGE1 Abs were 24.5 and 70.2, respectively. The Ab-positives showed longer IPTW-adjusted PFS (HR = 0.59, 95 % CI: 0.39-0.90, p = 0.014) and IPTW-adjusted OS (HR = 0.51, 95 % CI: 0.32-0.81, p = 0.004) than the Ab-negatives. Among NSCLC harboring driver genes, the Ab-positives (n = 10) showed longer PFS (HR = 0.34, 95 % CI: 0.13-0.89, p = 0.029) and OS (HR = 0.27, 95 % CI: 0.098-0.75, p = 0.012) than the Ab-negatives (n = 11). CONCLUSION: Our immunoassay of NY-ESO-1/XAGE1 Abs is probably useful for predicting the clinical benefit with nivolumab in NSCLC, including those harboring driver genes. These results suggest that our immunoassay may be useful in ICI monotherapy for NSCLC.

Long-term follow-up of a consecutive cohort validating an epidermal growth factor receptor mutation as an independent risk factor for postoperative recurrence in lung adenocarcinoma.

OBJECTIVES: Third-generation epidermal growth factor receptor (EGFR) tyrosine kinase inhibitors were recently reported to be effective as adjuvant therapy for resected lung adenocarcinoma (ADC) harbouring common EGFR mutations. However, whether the EGFR mutation is a direct risk factor for postoperative recurrence remains unknown. Therefore, we conducted a multi-institutional observational study to compare postoperative survival according to EGFR mutation status. METHODS: We collected the medical records of consecutive patients who underwent surgical resection for ADC between 2005 and 2012 at 4 participating institutions. Recurrence-free survival (RFS) and overall survival (OS) associated with EGFR mutation status were evaluated. We further analysed survival after pair-matching patients' clinicopathological characteristics. RESULTS: EGFR mutations were harboured by 401 of 840 (48%) enrolled patients. The number of patients with an EGFR mutation (M group) differed from that with the EGFR wild-type sequence (W group) in terms of sex, smoking history and pathological stage. The median follow-up period was 85 months. The five-year RFS/OS rates of the M and W groups were 70%/85% and 61%/75%, respectively (P < 0.001 for both groups). However, multivariable analysis revealed that EGFR mutation status was not independently related with both RFS and OS. In pair-matched analysis, the RFS and OS curves of the patients with an EGFR mutation and wild-type sequence were not statistically different, either. CONCLUSIONS: Long-term follow-up of consecutive patients did not show that a common EGFR mutation was an independent risk factor of recurrence or prognostic factor for completely resected lung ADC.

Efficacy of platinum-based adjuvant chemotherapy for epidermal growth factor receptor-mutant lung adenocarcinoma.

Background: The ADAURA trial reported that osimertinib improved overall survival (OS) as an adjuvant chemotherapy for pathological stage IB-IIIA epidermal growth factor receptor (EGFR) mutant lung cancer compared with a placebo. Currently, platinum-based adjuvant chemotherapy is the standard treatment for patients with or without EGFR mutations. This study aimed to evaluate the efficacy of platinum-based adjuvant chemotherapy in patient with stage II-IIIA EGFR mutant lung adenocarcinoma. Methods: We collected the medical records of consecutive patients who underwent surgical resection for lung adenocarcinoma between 2005 and 2012 at the four participating institutions. The data of 173 patients with different EGFR mutation status were retrospectively evaluated to determine the efficacy of platinum-based adjuvant chemotherapy for OS and recurrence-free survival (RFS). We further analyzed OS using the inverse probability of treatment weighting method with propensity scores. Results: The median age was 69 years (range, 45-85 years); 95 (54.9%) were male and 74 (42.8%) had EGFR mutations. A total of 43 patients with EGFR mutants (58.1%) and 43 patients with wild-type EGFR tumors (43.4%) received platinum-based adjuvant chemotherapy. No differences in RFS and OS were observed between EGFR mutant and wild-type EGFR in lung adenocarcinoma without adjuvant therapy. However, wild-type EGFR showed an improvement in OS with platinum-based adjuvant chemotherapy in inverse probability of treatment weighting analysis, whereas those with EGFR mutations showed no significant difference in OS between the surgery-only group and the adjuvant group. The deletion of exon 19 and exon 21 L858R point mutation showed no significant differences in OS between the surgery-only group and the adjuvant group, respectively. The hazard ratio (HR) exceeded 1 for uncommon EGFR mutations. Conclusions: Platinum-based adjuvant chemotherapy may be less effective for EGFR-mutant lung adenocarcinoma, regardless of the mutation type.

Wnt/ß-Catenin Signaling and Resistance to Immune Checkpoint Inhibitors: From Non-Small-Cell Lung Cancer to Other Cancers.

Lung cancer is the leading cause of cancer-related deaths worldwide. The standard of care for advanced non-small-cell lung cancer (NSCLC) without driver-gene mutations is a combination of an anti-PD-1/PD-L1 antibody and chemotherapy, or an anti-PD-1/PD-L1 antibody and an anti-CTLA-4 antibody with or without chemotherapy. Although there were fewer cases of disease progression in the early stages of combination treatment than with anti-PD-1/PD-L1 antibodies alone, only approximately half of the patients had a long-term response. Therefore, it is necessary to elucidate the mechanisms of resistance to immune checkpoint inhibitors. Recent reports of such mechanisms include reduced cancer-cell immunogenicity, loss of major histocompatibility complex, dysfunctional tumor-intrinsic interferon-γ signaling, and oncogenic signaling leading to immunoediting. Among these, the Wnt/ß-catenin pathway is a notable potential mechanism of immune escape and resistance to immune checkpoint inhibitors. In this review, we will summarize findings on these resistance mechanisms in NSCLC and other cancers, focusing on Wnt/ß-catenin signaling. First, we will review the molecular biology of Wnt/ß-catenin signaling, then discuss how it can induce immunoediting and resistance to immune checkpoint inhibitors. We will also describe other various mechanisms of immune-checkpoint-inhibitor resistance. Finally, we will propose therapeutic approaches to overcome these mechanisms.

Morphophenotypic characteristics of intralymphatic cancer and stromal cells susceptible to lymphogenic metastasis.

The intravessel microenvironment has significant effects on cancer metastasis. The aim of the present study was to determine how the morphologic and immunophenotypic features of cancer cells and infiltrating stromal cells within the permeated lymphatic vessels are associated with lymphogenic metastasis. A total of 137 primary lung adenocarcinoma patients with extratumoral lymphatic permeations were examined. Morphologically, the floating cancer nests within the permeated lymphatic vessels were divided into two types: Type A, consisting of a single large cancer nest; and Type B, consisting of multiple small cancer nests. We compared the clinicopathologic characteristics and the immunophenotypes of the cancer cells and infiltrating stromal cells between the Type A and Type B nests. Eleven of 54 Type A patients (20%) had intrapulmonary metastases, compared with 36 of 83 Type B patients (43%; P = 0.006). Immunohistochemically, Type B cancer cells expressed significantly higher levels of CD44 than Type A cancer cells (mean scoresAUTHOR: Scores - what is this score? Is it the number of cells expressing CD44 or the concentration of CD44 or some other type of scoring system? 43.0 vs 20.5, respectively) and E-cadherin (60.5 vs 31.5, respectively), but lower levels of Geminin (11.9% vs 20.3%, respectively) and cleaved caspase 3 (2.4% vs 7.8%AUTHOR: 11.9% vs 20.3%, respectively) and cleaved caspase 3 (2.4% vs 7.8%, - what do the percentages here refer to? The number of cells expressing geminin and caspase 3? The levels of these factors? Please clarify., respectively). Moreover, a significantly larger number of CD204-positive macrophages were present within the cancer-permeated lymphatic vessels in Type B patients than in Type A patients (mean number 9.5 vs 4.6, respectively). The present study reveals that intralymphatic cancer cell and stromal cell phenotypes are susceptible to lymphogenic metastasis, suggesting that lymphogenic metastasis may be affected by the intralymphatic microenvironment they create.

The recurrence of malignant pleural mesothelioma 14 years after extrapleural pneumonectomy: possible histological transformation.

A 56-year-old man underwent extrapleural pneumonectomy for malignant pleural mesothelioma (MPM). The histological diagnosis was epithelioid mesothelioma with T2N0M0, and no sarcomatoid component was observed. Subsequently, 14 years after complete resection, screening computed tomography detected a rapidly growing right thoracic mass, which was diagnosed as a recurrence of MPM on resection. However, it was composed of both epithelioid (50%) and sarcomatoid (50%) components, suggesting possible histological transformation. Although there have been some previous reports on the recurrence of MPM, to the best of our knowledge, this is the first clinical case which indicated that histological transformation of MPM might occur.

Lateral- or prone-position video-assisted thoracic surgery for dumbbell-type posterior mediastinal tumors: pros and cons.

Surgery for dumbbell-type posterior mediastinal tumors (D-PMTs) is difficult because surgeons should confirm the tumor's extension into the spinal cord and pay attention to the Adamkiewicz artery. We describe two patients of D-PMTs who underwent lateral- or prone-position video-assisted thoracic surgery (VATS). In patient 1 (a 70-year-old woman), the tumor extended to the spinal canal through the fourth thoracic intervertebral foramen. After hemi-laminectomies, she was moved to the lateral position, and the tumor was resected. In patient 2 (a 16-year-old boy), the tumor extended to the spinal canal through the seventh thoracic intervertebral foramen. Additionally, 320-row high-resolution computed tomography showed Adamkiewicz arteries running through the sixth and eighth thoracic intervertebral foramina. After laminectomy, the tumor was resected without repositioning. Prone-position VATS is a useful approach for D-PMTs because it provides a better view of the vertebrae compared with the lateral position. We discuss the advantages and disadvantages of both approaches. Supplementary Information: The online version contains supplementary material available at 10.1007/s12055-022-01343-0.

Thoracoscopic resection of posterior mediastinal paraganglioma: perioperative management and surgical tips.

Posterior mediastinal paraganglioma (PM-PGL) is a rare disease that is difficult to diagnose. If PM-PGL is misdiagnosed preoperatively, surgeons may encounter severe tachycardia and hypertension and easy bleeding from the tumor during the operation. Therefore, it is essential to include PGL as a differential diagnosis for mediastinal tumors. We herein describe a 73-year-old Japanese man with a PM-PGL that was diagnosed preoperatively and resected safely by video-assisted thoracic surgery. Preoperative management of hypertension with doxazosin mesylate, soft coagulation of the peritumor area, and careful clipping of feeding arteries were effective for hemostasis. The patient's vital signs were stable during and after the operation.