Native lung surgery after single lung transplantation: clinical characteristics and outcomes.

PURPOSE: Single lung transplantation (SLT) is a viable option for patients with end-stage pulmonary parenchymal and vascular diseases. However, various diseases can occur in native lungs after SLT. METHODS: Between January 2000 and December 2021, 35 patients underwent cadaveric SLT and survived for more than 30 days in our hospital. Among these 35 patients, 10 required surgery for diseases that developed in their native lungs. The clinical characteristics of these 10 patients and the outcomes of native lung surgery (NLS) were investigated. RESULTS: Among these ten patients, the indications for lung transplantation were chronic obstructive pulmonary disease and idiopathic interstitial pneumonia in three patients each, and lymphangioleiomyomatosis and collagen vascular disease-related interstitial pneumoniain two patients each. The causes of NLS included pneumothorax (n = 4), primary lung cancer (n = 2), native lung hyperinflation (n = 2), and pulmonary aspergilloma (n = 2). The surgical procedures were pneumonectomy (n = 7), lobectomy (n = 2), and alveolar-pleural fistula repair (n = 1). Only one postoperative complication, empyema, was treated with antibiotics. The 5-year overall survival rates after transplantation with and without NLS were 70.0% and 80.0%, respectively, and did not differ to a statistically extent (p = 0.56). CONCLUSION: NLS is an effective treatment option for diseases that develop in the native lungs after SLT.

Surgery for pulmonary lesions in patients with a history of urinary tract transitional cell carcinoma.

BACKGROUND: There has been little information on the actual diagnosis of pulmonary lesions in patients with a history of urinary tract transitional cell carcinoma (TCC) and short- and long- outcomes of pulmonary resection for these patients. METHODS: In the present study, the data of 37 consecutive patients with a history of TCC who underwent pulmonary resection for solitary pulmonary lesions were reviewed, and the clinical factors and short- and long-term outcomes were analyzed. RESULTS: The study population included 35 male patients, and 2 female patients. The mean age was 72.5 years. Twenty patients (80%) were smokers and showed a high incidence of chronic obstructive pulmonary disease. Pulmonary lesions and primary TCC were detected simultaneously in 5 patients and metachronously in 32 patients. The median interval between treatment for primary TCC and the detection of pulmonary lesion was 43 months. The mean tumor diameter was 23 mm. The types of resection included lobectomy (n = 19), segmentectomy (n = 8), and partial resection (n = 10). Twelve of 37 patients (32%) developed postoperative complications. The pathological diagnoses included primary lung cancer (n = 28), pulmonary metastasis from TCC (n = 7), and others (n = 2). The 5-year overall survival rate for all patients was 72%. The 5-year overall survival rate of patients with primary lung cancer was 74%, while that of patients with pulmonary metastasis from TCC was 57%. CONCLUSIONS: Surgery can be proactively considered for treating pulmonary lesions in patients with a previous history of TCC, as it provides favorable long-term outcomes.

A Novel Peroxisome Proliferator-Activated Receptor Gamma/Nuclear Factor-Kappa B Activation Pathway is Involved in the Protective Effect of Adipose-Derived Mesenchymal Stem Cells Against Ischemia-Reperfusion Lung Injury.

BACKGROUND: Adipose-derived stem cells (ADSCs) are well-recognized for their remarkable ability to suppress ischemia-reperfusion lung injury (IRLI). The primary objective of this investigation was to elucidate the underlying mechanism through which ADSCs exert protective effects against IRLI. METHODS: A warm hilar occlusion model in C57BL6J mice was used. Hilar occlusion was achieved for 1 hour (ischemic), and after 1 hour the occlusion was released (reperfusion) to recover for 3 hours. RNA sequencing, the physiological function, pathway activation, and expression of inflammatory cytokines were evaluated. RESULTS: Lung gas exchange and pulmonary edema were significantly improved in the IRLI/ADSCs group compared with the IRLI group. RNA sequencing results suggested that the peroxisome proliferator-activated receptor gamma (PPARγ)/nuclear factor-kappa B (NF-κB) pathway was involved in the effect of the ADSCs. Administration of a PPARγ antagonist in the IRLI/ADSC group resulted in the deterioration of the physiological function. Furthermore, the PPARγ protein expression level decreased, the NF-κB protein expression level increased, and inflammatory cytokine parameters from lung tissue and blood sample worsened in the PPARγ antagonist-administered group. CONCLUSION: Administration of ADSCs exerted a significant protective effect against IRLI in mice, and the effect is attributed to the activation of the PPARγ/NF-κB pathway.

Association of the psoas muscle index with the survival of patients on a waiting list for lung transplantation: a Japanese single-institution study.

PURPOSES: Some predictive markers of death have been reported for patients on the waiting list for lung transplantation (LTx). We assessed whether or not the preoperative psoas muscle index (PMI) correlates with waitlist mortality. METHODS: In 81 patients with end-stage lung disease on the waiting list for LTx between 2011 and 2020 at Osaka University Hospital, we examined the association between baseline characteristics, including the diagnosis, respiratory function test results, blood collection items, steroid use, and psoas muscle mass on computed tomography, and survival during the waiting period using Kaplan-Meier curves and Cox proportional hazard regression models. RESULTS: Thirty-three patients (41%) died during follow-up. Univariate and multivariate analyses showed that patients with a low PMI had a higher rate of death during follow-up than those with a high PMI (p < 0.0001 and 0.0002, respectively). In addition, a diagnosis of interstitial pneumonia (hazard ratio 3.30, 95% confidence interval 1.52-7.17, p = 0.0025) and low albumin level (hazard ratio 2.21, 95% confidence interval 1.02-4.80, p = 0.0449) were also significant predictors of survival. CONCLUSION: A low PMI at registration is associated with a decreased survival time among LTx candidates and it may be a predictive factor of mortality in patients waiting for LTx.

Integrated cardiothoracic team approach for complex lung transplantation procedures in Japan-current status and future direction.

The first lung transplant procedure in the world was performed in 1983, while in Japan that was first accomplished in 1998. Over the following 25 years, lung transplantation has become a viable treatment option for Japanese patients with a variety of end-stage lung diseases. Seventy cadaveric-donor lung (41 single, 29 bilateral), 11 bilateral living-donor lobar lung, and three heart-lung transplants have been performed with use of an integrated cardiothoracic team approach at medical facilities associated with Osaka University. Extremely advanced clinical and surgical skill sets are required to complete a lung transplant procedure, including surgical knowledge and techniques, as well as management of cardiovascular surgery, especially in regard to mechanical circulatory support (MCS), vascular anastomosis in difficult cases, and concomitant cardiac surgery. We have found that a collaborative effort by general thoracic and cardiac surgeons is an important key for success with lung transplantation. Complex lung transplant surgery and management in Japan are performed by use of an integrated cardiothoracic team approach, which has led to a synergistic impact on successful lung transplantation cases by capitalizing greatly on the experiences, techniques, and expertise of cardiac and thoracic experts. The present review is focused on the role of cardiac surgeons from the viewpoint of our experience with these cases.

Evaluation of LAT1 Expression in Patients With Lung Cancer and Mediastinal Tumors: 18F-FBPA PET Study With Immunohistological Comparison.

PURPOSE OF THE REPORT: L-type amino acid transporter-1 (LAT1) is a tumor-specific transporter expressed in various tumor types, with minimal expression in normal organs. We previously demonstrated 18F-fluoro-borono-phenylalanine (18F-FBPA) as a selective PET probe for LAT1 in a preclinical study. Herein, we evaluated LAT1 expression in preoperative patients with lung or mediastinal tumors using 18F-FBPA PET and immunofluorescence staining. PATIENTS AND METHODS: The study population included patients with histopathological diagnosis (n = 55): primary lung cancers (n = 21), lung metastases (n = 6), mediastinal tumors (n = 15), and benign lesion (n = 13). PET scanning was performed 1 hour after the injection of 18F-FBPA (232 ± 32 MBq). Immunofluorescence staining was performed on the resected tumor sections using LAT1 antibody. LAT1 staining was graded on a 4-grade scale and compared with the SUVmax on 18F-FBPA PET. RESULTS: A positive correlation was observed between the SUVmax of 18F-FBPA PET and LAT1 expression by immunofluorescence staining (r = 0.611, P < 0.001). The SUVmax of 18F-FBPA was 3.92 ± 1.46 in grade 3, 3.21 ± 1.82 in grade 2, 2.33 ± 0.93 in grade 1, and 1.50 ± 0.39 in grade 0 of LAT1 expression. Although 18F-FBPA PET showed variable uptake in lung cancers and mediastinal tumors, benign lesions showed significantly lower SUVmax than those in malignant lesions (P < 0.01). CONCLUSIONS: Uptake on 18F-FBPA PET reflected the expression level of LAT1 in lung and mediastinal tumors. It was suggested that 18F-FBPA PET can be used for the precise characterization of the tumor in pretreatment evaluation.

A case of alpha-fetoprotein-positive thymic small cell carcinoma: a case report.

BACKGROUND: An alpha-fetoprotein (AFP)-positive neuroendocrine tumor of the thymus is a rare thoracic malignancy. Few cases of AFP-positive thymic large cell neuroendocrine carcinoma have been reported, with no known previous report of an AFP-positive thymic small cell carcinoma. We encountered a patient with an AFP-positive small cell carcinoma and report here the clinical course. CASE PRESENTATION: A 40-year-old man was transferred to our hospital for a large anterior mediastinal tumor and showed an elevated serum AFP level. Computed tomography-guided biopsy results led to diagnosis of small cell carcinoma. Induction chemoradiotherapy was performed before surgery because of pulmonary artery invasion. The response to Induction chemoradiotherapy varied among sites, with the main tumor showing shrinkage and the metastasis site growth. This discrepancy suggested a histologic type unresponsive to or cancer cells potentially resistant to chemotherapy, thus a surgical re-biopsy was performed and histological findings revealed AFP-positive small cell carcinoma. Additional chemotherapy was performed, though could not control cancer progression, and the patient died 8 months after the first medical examination. CONCLUSIONS: Our present clinical experience indicates the importance of histological examination for determining AFP-positive anterior mediastinal tumor treatment. Although AFP-positive neuroendocrine tumor of the thymus is relatively rarer than germ cell carcinoma, differential diagnosis with use of a histological examination should be considered because of the potentially poorer prognosis. The present clinical findings for an AFP-positive neuroendocrine tumor of the thymus case are considered useful for establishing an optimal treatment strategy in the future.

Perceptions and attitudes of users and non-users of mental health services concerning mental illness and services in Japan.

Objectives: There is a global movement to develop and implement community-based integrated mental health systems. The present study attempted to clarify the perceptions and attitudes of users and non-users of mental health services concerning mental illness and services in Japan. Methods: A new questionnaire was developed for this internet survey. Data from 500 outpatients with depression and 500 healthy subjects were sampled according to the demographics of the Japanese population. Results: Over 90% of healthy subjects and over 70% of patients were unaware of the common age of onset or lifetime prevalence of mental illness. Over 90% of the healthy subjects and about 70% of the patients could not describe any services where they would feel comfortable discussing mental health problems. In both groups, "adolescents and young adults" were ranked first as a target population for mental health and illness policies. The top requirement for the integrated care systems was the promotion and awareness of correct knowledge of mental illness in both the healthy subjects and patients. Conclusion: Societal requirements could include disseminating correct knowledge, awareness-raising actions for society, and implementing services where people, especially young people, can easily consult and receive support in the community.

T cell immunity in interstitial lung disease with non-small cell lung cancer patients.

OBJECTIVES: Limited treatment options are available for non-small cell lung cancer (NSCLC) patients with interstitial lung disease (ILD). The rationale for immunotherapy and its adverse events for NSCLC with ILD remains unclear. In this study, we examined T cell profiles and functions in the lung tissues of NSCLC patients with or without ILD to provide evidence for the potential mechanism of immune checkpoint inhibitor (ICI)-related pneumonitis in NSCLC patients with ILD. MATERIAL AND METHODS: We investigated T cell immunity in the lung tissues of NSCLC patients with ILD to support the application of immunotherapy for these patients. We analyzed T cell profiles and functions in surgically resected lung tissues from NSCLC patients with and without ILD. The T cell profiles of infiltrating cells in lung tissues were analyzed by flow cytometry. T cell functions were measured based on cytokine production by T cells stimulated with phorbol 12-myristate 13-acetate and ionomycin. RESULTS: The percentages of CD4+ T cells expressing immune checkpoint molecules (Tim-3, ICOS, and 4-1BB), CD103+CD8+ T cells, and regulatory T (Treg) cells were higher in NSCLC patients with than in those without ILD. A functional analysis of T cells in lung tissues indicated that CD103+CD8+ T cells positively correlated with IFNγ production, whereas Treg cells negatively correlated with IFNγ and TNFα production. Cytokine production by CD4+ and CD8+ T cells did not significantly differ between NSCLC patients with and without ILD, except for TNFα production by CD4+ T cells being lower in the former than in the latter. CONCLUSION: In NSCLC patients with ILD stable for surgery, T cells were active participants and balanced in part by Treg cells in lung tissues, suggesting the potential development of ICI-related pneumonitis in NSCLC patients with ILD.

Significance of the Surgical Treatment with Lymph Node Dissection for Neuroendocrine Tumors of Thymus.

BACKGROUND: Neuroendocrine tumors of a thymus (NETTs) are rare, accounting for approximately 2-5% of all thymic epithelial tumors, and have a poor prognosis due to frequent lymph nodes or distant metastasis. METHODS: We retrospectively reviewed the clinicopathological background and outcomes of 40 patients who underwent resection or surgical biopsy with histologically diagnosed NETTs from 1986 to 2022. RESULTS: The most common pathological type was atypical carcinoid. Surgical resection was performed in 35 patients, with lymph node dissection in 33 and surgical biopsy in five. The overall survival (OS) rate for all patients was 81.4% and 52.3% at 5 and 10 years, respectively. The 2-year survival rate was 20% for the biopsy group, which was significantly worse than that of the resected group (p < 0.001). The relapse-free survival rates were 61.7% and 37.6% at 5 and 10 years, respectively, in 34 patients with complete resection. The univariate analysis revealed better the OS rate in the resected cases but with no significant differences between histological grade, lymph node metastasis, tumor size, or Ki67 index. CONCLUSIONS: Surgical complete resection is considered to improve prognosis regardless of histologic type. NETTs frequently develop lymph node metastasis, thus, lymph node dissection seems necessary for complete resection.

MGIT-seq for the Identification of Nontuberculous Mycobacteria and Drug Resistance: a Prospective Study.

Because nontuberculous mycobacterial pulmonary disease is a considerable health burden, a simple and clinically applicable analytical protocol enabling the identification of subspecies and drug-resistant disease is required to determine the treatment strategy. We aimed to develop a simplified workflow consisting only of direct sequencing of mycobacterial growth indicator tube cultures (MGIT-seq). In total, 138 patients were prospectively enrolled between April 2021 and May 2022, and culture-positive MGIT broths were subjected to sequencing using MinION, a portable next-generation sequencer. Sequence analysis was conducted to identify species using core genome multilocus sequence typing and to predict macrolide and amikacin (AMK) resistance based on previously reported mutations in rrl, rrs, and erm(41). The results were compared to clinical tests for species identification and drug susceptibility. A total of 116 patients with positive MGIT cultures were included in the analysis. MGIT-seq yielded 99.1% accuracy in species-level identification and identified 98 isolates (84.5%) at the subspecies level. Macrolide and AMK resistance were detected in 19.4% and 1.9% of Mycobacterium avium complex (MAC) and Mycobacterium abscessus isolates. The predicted macrolide and AMK resistance was consistent with the results of conventional drug susceptibility tests, with specificities of 97.6% and 100.0%, respectively. Direct MGIT-seq has achieved comprehensive identification and drug resistance detection of nontuberculous mycobacteria, which could be applicable to determine the treatment strategy by a single test in clinical practice.

[Ingenuities of Segmentectomy for Small Lung Cancer in Uniportal Video-assisted Thoracic Surgery].

Our department has been performing uniportal thoracoscopic lobectomy since April 2019 and now also performs segmentectomy for small malignant tumors. A skin incision of approximately 4 cm is created between the anterior fifth intercostal space on the left and right sides. Based on our experience, uniportal segmentectomy does not follow the learning curve unique to segmentectomy. For dissection of segmental surface, an automatic suture is used to prevent pulmonary fistulas. If the cutting line between the segments is straight, dissection can be performed easily even in uniportal surgery, in which the automatic suturing device is inserted from one direction. For inter-area identification, we use an air-containing collapsed line with normal ventilation, after which thoracoscopic indocyanine green( ICG) imaging is introduced. However, there have been cases in which a difference in inter-area identification occurred between ICG identification and the air-containing collapsed line. As such, it is better to utilize both methods in cases with masses close to the inter-areas.

Therapeutic Targeting of Cancer-Associated Fibroblasts in the Non-Small Cell Lung Cancer Tumor Microenvironment.

Lung cancer is the most frequently diagnosed cancer and the leading cause of cancer death worldwide. The most common lung cancer is non-small cell lung cancer (NSCLC), with an overall 5-year survival rate of around 20% because NSCLC is a metastatic disease. A better understanding of the mechanism underlying lung cancer metastasis is therefore urgently needed. The tumor microenvironment involves different types of stromal cells and functions as key components in the progression of NSCLC. Through epithelial-mesenchymal transition (EMT), in which epithelial cells lose their polarity and acquire mesenchymal potential, cancer cells acquire metastatic abilities, as well as cancer stem-cell-like potential. We previously reported that cancer-associated fibroblasts (CAFs) interact with lung cancer cells to allow for the acquisition of malignancy and treatment resistance by paracrine loops via EMT signals in the tumor microenvironment. Furthermore, CAFs regulate the cytotoxic activity of immune cells via various cytokines and chemokines, creating a microenvironment of immune tolerance. Regulation of CAFs can therefore affect immune responses. Recent research has shown several roles of CAFs in NSCLC tumorigenesis, owing to their heterogeneity, so molecular markers of CAFs should be elucidated to better classify tumor-promoting subtypes and facilitate the establishment of CAF-specific targeted therapies. CAF-targeted cancer treatments may suppress EMT and regulate the niche of cancer stem cells and the immunosuppressive network and thus may prove useful for NSCLC treatment through multiple mechanisms.

Protective Effect of Calpain Inhibition During Cold Ischemia on Ischemia-reperfusion Injury After Lung Transplantation.

BACKGROUND: Necroptosis, one of the types of regulated necrosis, causes ischemia-reperfusion (IR) lung injury. N-acetyl-leucyl-leucyl-norleucinal (ALLN), a calpain inhibitor, is known to attenuate necroptosis and apoptosis, and the purpose of this study was to evaluate the protective effect of ALLN during cold ischemia against IR injury in a rat lung transplant model. METHODS: Male Lewis rats (250-350 g) were divided into 3 groups: sham group (n = 4), nontransplantation; control group (n = 8), transplantation with IR lung injury; and ALLN group (n = 8), transplantation with IR lung injury/ALLN. Rats in the sham group underwent a simple thoracotomy, and the remaining 2 groups of rats underwent an orthotopic left lung transplant. Cold ischemic time was 15 h. After 2 h of reperfusion, physiological function, inflammatory cytokine expression, pathway activation, and the degrees of necroptosis and apoptosis were evaluated. RESULTS: Lung gas exchange (PaO 2 /FiO 2 ) was significantly better, and pulmonary edema was significantly improved in the ALLN group compared with the control group ( P = 0.0009, P = 0.0014). Plasma expression of interleukin-1ß was significantly lower in the ALLN group than in the control group ( P = 0.0313). The proportion of necroptotic and apoptotic cells was significantly lower in the ALLN group than in the control group ( P = 0.0009), whereas the proportion of apoptotic cells remained unchanged ( P = 0.372); therefore, the calpain inhibitor was thought to suppress necroptosis. CONCLUSIONS: The administration of ALLN during cold ischemia appears to improve IR lung injury in a lung transplant animal model via the inhibition of necroptosis.

The Mental Health of Young Return Migrants with Ancestral Roots in Their Destination Country: A Cross-Sectional Study Focusing on the Ethnic Identities of Japanese-Brazilian High School Students Living in Japan.

BACKGROUND: The number of young Japanese Brazilians, who are return migrants with Japanese ancestral roots, is increasing rapidly in Japan. However, the characteristics of their mental health and the relation between mental health and a complex ethnic identity remains unclear. METHODS: This cross-sectional study compared 25 Japanese-Brazilian high school students with 62 Japanese high school students living in the same area. Research using self-report questionnaires on mental health, help-seeking behavior tendencies, and ethnic identity was conducted. The Japanese-Brazilian group was also divided into high and low ethnic identity groups, and their mental health conditions were compared. RESULTS: The Japanese-Brazilian group had significantly poorer mental health conditions and lower ethnic identities than the Japanese group and were less likely to seek help from family members and close relatives. Among the Japanese Brazilians, those with low ethnic identity had significantly poorer mental health than those with high ethnic identity. CONCLUSIONS: Young Japanese Brazilians may face conflicts of ethnic identity that can disturb their mental health. To build an inclusive society, the establishment of community services to support mental health and to help return migrants develop their ethnic identity is essential.

Clinicopathological analysis of a superior sulcus tumor treated by salvage surgery after concurrent definitive chemoradiotherapy followed by durvalumab: A case report.

Surgical treatment of superior sulcus tumors (SSTs) is clinically challenging. Definitive chemoradiotherapy (CRT) is a standard treatment for SST. In operable cases, multimodal therapy (CRT followed by surgery) is another option, at least for experienced institutions. Immune checkpoint inhibitors (ICIs) have recently been developed, and several clinical trials have investigated definitive CRT followed by ICIs for consolidation or maintenance therapy of unresectable local advanced non-small cell lung cancer (NSCLC), including SSTs. Clinical studies of salvage surgery after CRT followed by ICIs are also ongoing. However, the clinical outcomes of salvage surgery after multimodal therapies and histopathological analyses of surgical specimens after such treatments remain unclear. Here, we report the case of a patient with SST comprising squamous cell carcinoma with invasion of the second to third rib and vertebrae who underwent salvage surgery after concurrent definitive CRT followed by the ICI durvalumab, and show the results of clinicopathological analyses of the resected specimen.

Utility of the surgical Apgar score for predicting the short- and long-term outcomes in non-small-cell lung cancer patients who undergo surgery.

OBJECTIVES: The surgical Apgar score (SAS) is a simple score that predicts postoperative complications based on 3 intraoperative valuables. The present study evaluated the association between the SAS and postoperative outcomes in non-small-cell lung cancer patients who underwent surgery. METHODS: A total of 585 patients who underwent lung resection were enrolled in the present study. We calculated the SAS of each patient and investigated its influence on the short- and long-term outcomes. RESULTS: Postoperative complications of any grade were detected in 164 cases (28%). The morbidity rate increased with decreasing SAS. When all the patients were divided into 2 groups (SAS <7 vs ≥7), postoperative complications were observed more frequently in the SAS <7 group than in the SAS ≥7 group (41% vs 25%, P < 0.001). In the multivariate analysis, the SAS was an independent risk factor for postoperative complications (odds ratio: 1.64 [1.03-2.61], P = 0.036). In terms of long-term outcomes, the 5-year disease-free survival (54.1% vs 73.2%, P < 0.001) and overall survival (73.8% vs 83.0%, P = 0.031) were significantly worse in the SAS <7 group than in the SAS ≥7 group. In a multivariate analysis, however, the SAS was not found to be an independent prognostic factor for either disease-free survival (hazard ratio: 1.39 [0.97-2.00], P = 0.075) or overall survival (hazard ratio: 0.90 [0.57-1.42], P = 0.642). CONCLUSIONS: The SAS reflected preoperative and intraoperative characteristics and was able to stratify the morbidity rate, suggesting it to be a useful predictor of short-term outcomes in non-small-cell lung cancer patients who undergo surgery.

Usefulness of positron-emission tomography for predicting the World Health Organization grade of thymic epithelial tumors.

BACKGROUND: It is often difficult to distinguish between thymoma and thymic carcinoma by preoperative radiological tests. While there have been some reports that the maximum standardized uptake value (SUVmax ) in positron emission tomography-computed tomography (PET-CT) is useful to this end, no large-scale analysis has been performed. We therefore analyzed the usefulness of the SUVmax and tumor size (TS) for differentiating thymic epithelial tumors. METHODS: From 2011 to 2019, 129 patients with thymic epithelial tumor who underwent PET-CT before surgical treatment were enrolled. The relevance of the SUVmax to the World Health Organization (WHO) histological type was assessed. To reduce the impact of the TS, the ratio of the SUVmax to the TS was also investigated. RESULTS: A total of 99 thymoma cases and 30 thymic carcinoma cases were enrolled into the study. The SUVmax and SUVmax /TS of thymic carcinoma were significantly higher than those of thymoma (SUVmax : 7.7 ± 3.4 vs. 3.3 ± 1.3, p < 0.01; SUVmax /TS: 1.5 ± 0.7 vs. 0.6 ± 0.4, p < 0.01). Focusing on the patients with a moderate SUVmax of ≤5 (84 thymoma and 4 thymic carcinoma), the SUVmax /TS values of thymic carcinoma were still significantly higher than those of thymoma (1.6 ± 0.8 vs. 0.6 ± 0.4, p < 0.01). CONCLUSIONS: PET-CT might provide significant information for differentiating images of thymoma and thymic carcinoma. We experienced several cases of thymic carcinoma with a moderate SUVmax of ≤5, and SUVmax /TS was considered a useful parameter for differentiating such cases.

Prognostic Impact of Number of Organ Invasions in Patients with Surgically Resected Thymoma.

PURPOSE: This study aimed to explore the clinical implications and prognostic value of the number of organ/structure invasions (NOI) in patients with thymoma after curative surgical resection. METHODS: We retrospectively analyzed 306 consecutive Japanese patients with thymoma who underwent curative surgical resection. Tumor invasions of pericardium, mediastinal pleura, phrenic nerve, lung, and venous structures were examined histopathologically. Cases were classified into four subgroups according to NOI: group 0, no tumor invasion; group 1, tumor invasion into single organ/structure; group 2, tumor invasion of two organs/structures; group 3, invasion of three or more organs/structures. Associations with NOI and several clinical characteristics and their prognostic significance were analyzed. RESULTS: Pleural invasion was found in 100 cases (32.7%), lung invasion in 48 cases (15.7%), pericardial invasion in 46 cases (15%), phrenic nerve invasion in 29 (9.5%), and venous invasion in 22 cases (7.2%). NOI was classed as group 0 in 201 cases (65.0%), group 1 in 42 cases (13.7%), group 2 in 20 cases (6.5%), and group 3 in 43 cases (14.1%). Cases with higher NOI showed significantly worse relapse-free survival (RFS) and overall survival (OS). Cox's proportional hazard model analysis also identified NOI as a prognostic factor affecting RFS and OS. CONCLUSIONS: Cases with higher NOI of thymoma after radical surgical resection showed significantly worse recurrence rates and survival.