Post-thoracotomy pain syndrome in the era of minimally invasive thoracic surgery.

Post-thoracotomy pain syndrome (PTPS) is defined as pain around the wound that persists for more than 2 months after surgery. Persistent pain not only increases the use of analgesics and their side effects but also causes many social problems, such as decreased activities of daily living, decreased quality of life, and increased medical costs. In particular, thoracic surgery is associated with a higher frequency and severity of chronic pain than is surgery for other diseases. The basic principles of postoperative pain treatment, not limited to thoracic surgery, are multimodal analgesic methods (using combinations of several drugs to minimize opioid use) and around-the-clock treatment (administering analgesics at a fixed time and in sufficient doses). Thoracic surgeons must always be aware of the following three points: acute severe postoperative pain is a major risk factor for chronic pain; neuropathic pain due to intercostal nerve injury is a major cause of postoperative pain after thoracic surgery, and its presence must not be overlooked from the acute stage; and analgesics must be administered in sufficient quantities according to dosage and volume. The frequency of PTPS has decreased compared with that in the standard thoracotomy era because of the development of analgesia and the widespread use of minimally invasive procedures such as thoracoscopic surgery and robot-assisted surgery. However, no consistently effective prevention or treatment strategies for PTPS have yet been established. In this review, we focus on PTPS in the era of minimally invasive surgery and discuss the role of thoracic surgeons in its management.

Designer umbilical cord-stem cells induce alveolar wall regeneration in pulmonary disease models.

Background: Researchers are focusing on cellular therapy for chronic obstructive pulmonary disease (COPD) using mesenchymal stem cells (MSCs), with human bone marrow-derived MSCs (hBM-MSCs) leading the way. However, BM-MSCs may not be as optimal as therapeutic cells owing to their low growth potential, invasive harvesting, and high expression of aging-related genes with poor differentiation potential. Consequently, umbilical cord-derived MSCs (hUC-MSCs), which have many excellent features as allogeneic heterologous stem cells, have received considerable attention. Allogeneic and heterologous hUC-MSCs appear to be promising owing to their excellent therapeutic properties. However, MSCs cannot remain in the lungs for long periods after intravenous infusion. Objective: To develop designer hUC-MSCs (dUC-MSCs), which are novel therapeutic cells with modified cell-adhesion properties, to aid COPD treatment. Methods: dUC-MSCs were cultured on type-I collagen gels and laminin 411, which are extracellular matrices. Mouse models of elastase-induced COPD were treated with hUC-MSCs. Biochemical analysis of the lungs of treated and control animals was performed. Results: Increased efficiency of vascular induction was found with dUC-MSCs transplanted into COPD mouse models compared with that observed with transplanted hUC-MSCs cultured on plates. The transplanted dUC-MSCs inhibited apoptosis by downregulating pro-inflammatory cytokine production, enhancing adhesion of the extracellular matrix to alveolar tissue via integrin ß1, promoting the polarity of M2 macrophages, and contributing to the repair of collapsed alveolar walls by forming smooth muscle fibers. dUC-MSCs inhibited osteoclastogenesis in COPD-induced osteoporosis. hUC-MSCs are a promising cell source and have many advantages over BM-MSCs and adipose tissue-derived MSCs. Conclusion: We developed novel designer cells that may be involved in anti-inflammatory, homeostatic, injury repair, and disease resistance processes. dUC-MSCs repair and regenerate the alveolar wall by enhancing adhesion to the damaged site. Therefore, they can contribute to the treatment of COPD and systemic diseases such as osteoporosis.

Curved Axillary Incision with Video-Assisted Thoracoscopic Surgery: An Alternative Approach for Teenage Female with Large Apical Chest Wall Tumor.

Primary chest wall tumors are rare, their common clinical features are not well known, and surgical resection remains the main treatment. Apical chest wall tumors require large skin incisions and dissection of the chest wall muscles, making it difficult to maintain cosmetic appearance, respiratory function, and support of the upper extremity. There are few treatment options and no studies have reported on thoracotomy that spares muscles and preserves cosmetic superiority. However, in benign chest wall tumors in young patients, it is necessary to consider radicality, cosmetic superiority, and muscle sparing. We used a combined axillary incision and thoracoscopic approach to treat a massive myxoid neurofibroma at the apical chest wall in a 14-year-old female and were able to preserve the chest wall, upper limb function, and cosmetic aspects. This report provides a detailed description of the combined axillary incision and thoracoscopic approach for apical chest wall tumors.

Does the human leukocyte antigen's relatively homogeneous genetic background relate to better lung transplantation outcomes in Japan?

The outcomes of lung transplantation in Japan are better than in other countries; however, the reasons for this are unclear. While the genetic background of the Japanese may be relatively homogeneous compared with those of other countries, whether this genetic similarity is related to better lung transplantation outcomes is an interesting question. We reviewed the literature to define the relationship between genetic similarity and better lung transplantation outcomes. However, it is still difficult to directly describe the relationship between genetic background and lung transplantation outcomes. As another approach, racial match or mismatch lung transplantation helps investigate whether genetic background similarity contributes to better outcomes of lung transplantation. Some reports have evaluated the impact of donor/recipient race-matching, which does not sufficiently influence patient outcomes to factor into organ transplant offers. Matching is not beneficial for African American lung transplant recipients. This may indicate that other factors influence the outcomes of these transplants. However, to discuss racial mismatch transplantation, racial disparities in organ transplantation need to be understood because the outcomes of organ transplantation differ between recipients of different races regardless of mismatched or matched organ transplantation. This makes it difficult to understand the outcome of a racially matched or mismatched lung transplantation. Meanwhile, in cadaveric liver and kidney transplantations, there is no difference in the outcomes in Japan and in other countries. In conclusion, it remains difficult to determine whether similarity in genetic backgrounds is related to better lung transplantation outcomes in Japan.

Timing of Mesenchymal Stromal Cell Therapy Defines its Immunosuppressive Effects in a Rat Lung Transplantation Model.

Cell therapy using mesenchymal stromal cells (MSCs) is being studied for its immunosuppressive effects. In organ transplantation, the amount of MSCs that accumulate in transplanted organs and other organs may differ depending on administration timing, which may impact their immunosuppressive effects. In vitro, adipose-derived mesenchymal stem cells (ADMSCs) suppress lymphocyte activation under cell-to-cell contact conditions. However, in vivo, it is controversial whether ADMSCs are more effective in accumulating in transplanted organs or in secondary lymphoid organs. Herein, we aimed to investigate whether the timing of ADMSC administration affects its immunosuppression ability in a rat lung transplantation model. In the transplantation study, rats were intramuscularly administered half the usual dose of tacrolimus (0.5 mg/kg) every 24 h after lung transplantation. ADMSCs (1 × 106) were administered via the jugular vein before (PreTx) or after (PostTx) transplantation. Cell tracking using quantum dots was performed. ADMSCs accumulated predominantly in the lung and liver; fewer ADMSCs were distributed in the grafted lung in the PreTx group than in the PostTx group. The rejection rate was remarkably low in the ADMSC-administered groups, particularly in the PostTx group. Serum tumor necrosis factor-α (TNF-α), interferon-γ, and interleukin (IL)-6 levels showed a greater tendency to decrease in the PreTx group than in the PostTx group. The proportion of regulatory T cells in the grafted lung 10 days after transplantation was higher in the PostTx group than in the PreTx group. PostTx administration suppresses rejection better than PreTx administration, possibly due to regulatory T cell induction by ADMSCs accumulated in the transplanted lungs, suggesting a mechanism different from that in heart or kidney transplantation that PreTx administration is more effective than PostTx administration. These results could help establish cell therapy using MSCs in lung transplantation.

A novel ex vivo lung cancer model based on bioengineered rat lungs.

Introduction: Two-dimensional cell cultures have contributed substantially to lung cancer research, but 3D cultures are gaining attention as a new, more efficient, and effective research model. A model reproducing the 3D characteristics and tumor microenvironment of the lungs in vivo, including the co-existence of healthy alveolar cells with lung cancer cells, is ideal. Here, we describe the creation of a successful ex vivo lung cancer model based on bioengineered lungs formed by decellularization and recellularization. Methods: Human cancer cells were directly implanted into a bioengineered rat lung, which was created with a decellularized rat lung scaffold reseeded with epithelial cells, endothelial cells and adipose-derived stem cells. Four human lung cancer cell lines (A549, PC-9, H1299, and PC-6) were applied to demonstrate forming cancer nodules on recellularized lungs and histopathological assessment were made among these models. MUC-1 expression analysis, RNA-seq analysis and drug response test were performed to demonstrate the superiority of this cancer model. Results: The morphology and MUC-1 expression of the model were like those of lung cancer in vivo. RNA sequencing revealed an elevated expression of genes related to epithelial-mesenchymal transition, hypoxia, and TNF-α signaling via NF-κB; but suppression of cell cycle-related genes including E2F. Drug response assays showed that gefitinib suppressed PC-9 cell proliferation equally well in the 3D lung cancer model as in 2D culture dishes, albeit over a smaller volume of cells, suggesting that fluctuations in gefitinib resistance genes such as JUN may affect drug sensitivity. Conclusions: A novel ex vivo lung cancer model was closely reproduced the 3D structure and microenvironment of the actual lungs, highlighting its possible use as a platform for lung cancer research and pathophysiological studies.

Spontaneous pleural aspergillosis in an immunocompetent young adult treated with minimally invasive surgery.

Spontaneous cases of pleural aspergillosis in healthy adults are rare, and the optimal therapeutic approach has not been established. Here we report a rare case of spontaneous pleural aspergillosis in an otherwise healthy young adult. Two-stage surgery with decortication and cavernostomy, followed by systemic antifungal therapy, finally resulted in a successful resolution of his empyema without any serious complications. In young patients with good pulmonary compliance, less invasive procedures, such as thoracoscopic decortication and/or carvernotomy, is a potential treatment option.

Adipose-Derived Mesenchymal Stem Cells Attenuate Immune Reactions Against Pig Decellularized Bronchi Engrafted into Rat Tracheal Defects.

Decellularized scaffolds are promising biomaterials for tissue and organ reconstruction; however, strategies to effectively suppress the host immune responses toward these implants, particularly those without chemical crosslinking, remain warranted. Administration of mesenchymal stem cells is effective against immune-mediated inflammatory disorders. Herein, we investigated the effect of isogeneic abdominal adipose-derived mesenchymal stem/stromal cells (ADMSCs) on xenogeneic biomaterial-induced immunoreactions. Peripheral bronchi from pigs, decellularized using a detergent enzymatic method, were engrafted onto tracheal defects of Brown Norway (BN) rats. BN rats were implanted with native pig bronchi (Xenograft group), decellularized pig bronchi (Decellularized Xenograft), or Decellularized Xenograft and ADMSCs (Decellularized Xenograft+ADMSC group). In the latter group, ADMSCs were injected intravenously immediately post implantation. Harvested graft implants were assessed histologically and immunohistochemically. We found that acute rejections were milder in the Decellularized Xenograft and Decellularized Xenograft+ADMSC groups than in the Xenograft group. Mild inflammatory cell infiltration and reduced collagen deposition were observed in the Decellularized Xenograft+ADMSC group. Additionally, ADMSC administration decreased CD8+ lymphocyte counts but increased CD163+ cell counts. In the Decellularized Xenograft+ADMSC group, serum levels of vascular endothelial growth factor and IL-10 were elevated and tissue deposition of IgM and IgG was low. The significant immunosuppressive effects of ADMSCs illustrate their potential use as immunosuppressive agents for xenogeneic biomaterial-based implants.

Donor and Recipient Adipose-Derived Mesenchymal Stem Cell Therapy for Rat Lung Transplantation.

BACKGROUND: Mesenchymal stem cells (MSCs) are beginning to be proven as immunosuppressant in the field of organ transplantation. However, the effects of MSC origin (donor or recipient) on immunosuppression are not clear. Hence, we investigated the effects of recipient and donor adipose-derived MSCs (ADMSCs) on immunosuppression in a rat lung transplantation model. METHODS: Subjects were divided into no treatment, tacrolimus administration, recipient ADMSC administration, donor ADMSC administration, and mixed donor and recipient ADMSC administration groups. ADMSC-administered groups were also treated with tacrolimus. Histologic study, immunofluorescence, immunohistochemistry, enzyme-linked immunosorbent assay, and polymerase chain reaction were used for various analyses. RESULTS: Fluorescently labeled ADMSCs were predominant in the grafted donor lung, but not in the recipient lung, on day 5. On day 7, the pathologic rejection grades of the grafted donor lung were significantly lower in the ADMSC-administered groups (P < .05) and did not differ among these groups. Although serum hepatocyte growth factor and vascular endothelial growth factor levels did not differ among the groups, interleukin 10 level was slightly higher in the ADMSC-administered groups. The numbers of infiltrating regulatory T cells in the grafted lung were significantly higher in the ADMSC-administered groups (P < .05) but did not differ with cell origin. Transcriptional analysis suggested interleukin 6 suppression to be the main overlapping immunosuppressive mechanism, regardless of origin. Therefore, a donor or recipient origin may not influence the immunosuppressive efficacy of ADMSCs in our rat lung transplantation model. CONCLUSIONS: Collectively, the results indicate that allogenic ADMSCs, regardless of their origin, may exert similar immunosuppressive effects in clinical organ transplantation.

Preoperative respiratory intervention eliminated the operation cancelations of lobectomy surgery.

In Nagasaki University Hospital, the patients undergoing surgery with abnormal respiratory function have been automatically referred to specialized clinic by Medical Support Center (MSC) since July 2016 to reduce surgery cancellations due to insufficient preoperative evaluation. Whether the MSC system decreased post-hospital surgery cancellation, variance rate, or length of hospital stays in patients received "lobectomy" were retrospectively compared between Period A (n = 264, before MSC introduction) and Period B (n = 264, after MSC introduction). Four patients' operations were cancelled after hospitalization in Period A, while 0 patients in Period B (p < 0.05). The length of hospital stay, operation time, anesthesia time, and postoperative extubation oxygen administration time were all shorten in Period B significantly. "Period B", "operation time", and "postoperation oxygenation time" were independent factors for "hospital days", but chronic obstructive pulmonary disease or age were not. The preoperative intervention eliminated the operation cancellation. Preoperative MSC interventions may have contributed to the reduction in hospital days even for the patients with pulmonary dysfunction.

[Airway Complications after Lung Transplantation].

Lung transplantation is the only option for patients with end-stage pulmonary diseases. During recent years, satisfactory results in terms of long-term survival and quality of life have been achieved with improvements in perioperative management, surgical technique, and immunosuppression. Airway complications after lung transplantation are associated with significant morbidity and mortality. Common airway complications after lung transplantation include anastomotic granulation, airway stenosis, bronchomalacia, fistulas, and anastomotic infection. These airway complications often result in repeated hospitalisations and interventions. If bronchoscopic interventions are not effective, other alternatives like surgical intervention or re-transplantation become necessary. While numerous strategies for airway complications have been proven effective, there are still some issues that to be solved. Further research is necessary to reduce mortality and improve quality of life of these patients.

Successful pulmonary artery stenting for occlusion at a constructed pericardial conduit after right upper double sleeve lobectomy.

The patient was a 53-year-old man. His chief complaint was a cough and dyspnea on exertion. Computed tomography (CT) showed a 3-cm-diameter tumor in the right upper lobe with invasion from hilar lymph nodes to the superior vena cava, right main bronchus, and pulmonary artery. After being diagnosed with non-small cell lung cancer, the patient underwent preoperative induction radiochemotherapy. At surgery, right upper double sleeve lobe lobectomy was performed. The right main pulmonary artery was reconstructed using a pericardial conduit. CT 1 week after surgery showed impaired blood flow in the right pulmonary artery. A metal vascular stent was inserted into the narrow part of the constructed pulmonary artery in the hybrid operating room because thrombectomy was unsuccessful. After surgery, contrast CT showed that blood flow was maintained. The patient is currently well without any recurrence 3 years after surgery.

Anticancer agent α-sulfoquinovosyl-acylpropanediol enhances the radiosensitivity of human malignant mesothelioma in nude mouse models.

Malignant pleural mesothelioma (MPM) is a highly malignant disease that develops after asbestos exposure. Although the number of MPM cases is predicted to increase, no effective standard therapies have been established. The novel radiosensitizer α-sulfoquinovosyl-acylpropanediol (SQAP) enhances the effects of γ-radiation in human lung and prostate cancer cell lines and in animal models. In this study, we explored the radiosensitizing effect of SQAP and its mechanisms in MPM. The human MPM cell lines MSTO-211H and MESO-4 were implanted subcutaneously into the backs and thoracic cavities of immunodeficient KSN/Slc mice, then 2 mg/kg SQAP was intravenously administered with or without irradiation with a total body dose of 8 Gy. In both the orthotopic and ectopic xenograft murine models, the combination of irradiation plus SQAP delayed the implanted human MSTO-211H tumor growth. The analysis of the changes in the relative tumor volume of the MSTO-211H indicated a statistically significant difference after 8 Gy total body combined with 2 mg/kg SQAP, compared to both the untreated control (P = 0.0127) and the radiation treatment alone (P = 0.0171). After the treatment in each case, immunostaining of the harvested tumors revealed decreased cell proliferation, increased apoptosis and normalization of tumor blood vessels in the SQAP- and irradiation-treated group. Furthermore, hypoxia-inducible factor (HIF) 1 mRNA and protein expression were decreased, indicating reoxygenation in this group. In conclusion, SQAP improved hypoxic conditions in tumor tissue and may elicit a radiosensitizing effect in malignant mesothelioma models.

Mirogabalin treatment of postoperative neuropathic pain after thoracic surgery: study protocol for a multicenter, randomized, open-label, parallel-group, interventional trial.

BACKGROUND: Intercostal nerve damage due to thoracotomy or thoracoscopic manipulation is a major contributor to chronic postsurgical pain after pulmonary resection. Chronic postsurgical pain may last for months or years and can negatively impair physical functioning and daily activities. Global consensus on severe postoperative pain management is lacking, and chronic pain incidence after thoracic surgery remains high. Many patients report neuropathic pain, which can be difficult to treat with currently available therapies. The efficacy and safety of mirogabalin have been demonstrated for other types of neuropathic pain; thus, this study was planned to investigate the efficacy and safety of mirogabalin to treat neuropathic pain after thoracic surgery. METHODS: In this multicenter, randomized, open-label, parallel-group, interventional study, patients who are diagnosed with neuropathic pain following removal of a chest drain after lung resection will receive conventional therapy (non-steroidal anti-inflammatory drugs and/or acetaminophen) with or without the addition of a clinical dose of mirogabalin for 8 weeks. For patient stratification, a visual analog scale pain intensity score at baseline of <60 vs. ≥60 mm will be used. Treatment efficacy and safety with and without the addition of mirogabalin will be assessed using a questionnaire evaluating postoperative changes in pain severity and activity. The primary study endpoint is the change in pain intensity from baseline to Week 8, measured by the visual analog scale. Additionally, the presence of chronic pain at 12 weeks after enrollment in each treatment group will be recorded. DISCUSSION: This protocol has been reviewed and approved by the Clinical Research Review Board of Nagasaki University. Study data will be published in the Japan Registry of Clinical Trials database and peer-reviewed journals. Mirogabalin is already approved for the treatment of other types of neuropathic pain. It is anticipated that this study will provide data to elucidate the impact of mirogabalin treatment, in combination with conventional therapy, to benefit patients with neuropathic pain following thoracic surgery. TRIAL REGISTRATION: Japan Registry of Clinical Trials Identifier: jRCTs071200053.

Increased In Vitro Intercellular Barrier Function of Lung Epithelial Cells Using Adipose-Derived Mesenchymal Stem/Stromal Cells.

With the emergence of coronavirus disease-2019, researchers have gained interest in the therapeutic efficacy of mesenchymal stem/stromal cells (MSCs) in acute respiratory distress syndrome; however, the mechanisms of the therapeutic effects of MSCs are unclear. We have previously reported that adipose-derived MSCs (AD-MSCs) strengthen the barrier function of the pulmonary vessels in scaffold-based bioengineered rat lungs. In this study, we evaluated whether AD-MSCs could enhance the intercellular barrier function of lung epithelial cells in vitro using a transwell coculture system. Transepithelial electrical resistance (TEER) measurements revealed that the peak TEER value was significantly higher in the AD-MSC coculture group than in the AD-MSC non-coculture group. Similarly, the permeability coefficient was significantly decreased in the AD-MSC coculture group compared to that in the AD-MSC non-coculture group. Immunostaining of insert membranes showed that zonula occuldens-1 expression was significantly high at cell junctions in the AD-MSC coculture group. Moreover, cell junction-related gene profiling showed that the expression of some claudin genes, including claudin-4, was upregulated in the AD-MSC coculture group. Taken together, these results showed that AD-MSCs enhanced the barrier function between lung epithelial cells, suggesting that both direct adhesion and indirect paracrine effects strengthened the barrier function of lung alveolar epithelium in vitro.

Primary mucinous adenocarcinoma of the thymus; a rare type of thymic carcinoma. Case Report.

Mucinous adenocarcinoma of the thymus is a particularly rare type among thymic carcinomas. Here, we report a patient who underwent complete surgical resection of the primary mucinous adenocarcinoma of the thymus. She was 74 years old and presented with a 60-mm multilocular cystic tumor in her right anterior mediastinum. We performed extended thymo-thymectomy with partial resection of the right upper lobe and pathologically diagnosed the patient with Masaoka stage II mucinous adenocarcinoma of the thymus. Immunohistochemistry showed the absence of PD-L1, suggesting that immune check point inhibitors targeting PD-1/PD-L1 might not be effective in this case. The increased preoperative serum levels of CA19-9 decreased after the operation. CA19-9 is a biomarker for disease status. Future reports should help elucidate the pathogenesis of this disease.

A randomized phase II study of S-1 monotherapy versus cisplatin with vinorelbine for completely resected stage II/IIIA non-small cell lung cancer: rationale and study protocol design for the LOGIK1702 study.

BACKGROUND: The current standard postoperative treatment for stage II-IIIA non-small cell lung cancer (NSCLC) is a regimen of platinum doublet adjuvant chemotherapy. These regimens, which are the same as for solid NSCLC tumors, often cause severe adverse reactions in the treated patients. Therefore, an effective treatment regimen with fewer side effects is needed. METHODS/DESIGN: The purpose of this study is to evaluate the effectiveness and safety of S-1 monotherapy (80 mg/m2 orally administrated twice daily, at day 1-14, 16 cycles) and cisplatin with vinorelbine combination therapy (cisplatin 80 mg/m2 at day 1,vinorelbine 25 mg/m2 at day 1, 8, 4 cycles) in patients with II/IIIA stage non-small-cell lung cancer who underwent a total resection. In addition, we will also evaluate the level of treatment side effects by assessing quality of life (QOL), work productivity and activity performance. The primary endpoint is a 2-year relapse free survival (RFS) and the second primary endpoints are 2-year overall survival (OS), rate of treatment completion, safety, work productivity and activity, and quality of adjusted life years (QALY). At the same time, we aim to obtain precise information required to perform future phase 3 randomized controlled trials. The study is designed to estimate the primary endpoint with accuracy determined as the width of its 95% confidence interval to be less than 20%. Recruitment started in May 2017 and is ongoing. DISCUSSION: This study has been conceived to establish a superior regimen for completely resected NSCLC based on efficacy, safety and QOL. TRIAL REGISTRATION: Registry number: UMIN000027435 . Registered May 22, 2017.

Preoperative tracheal resection and reconstruction simulations with patient-specific three-dimensional models.

Three-dimensional (3D) printers are increasingly being used for a variety of applications. In the surgical field, patient-specific organ models are increasingly being used as preoperative simulators for complicated surgeries. In this study, we describe the use of patient-specific 3D models for tracheal resection. We performed preoperative simulations for two patients diagnosed with tracheal ganglioneuroma and adenoid cystic carcinoma; the mimic operations suggested the necessity of a short cuff intubation tube across the surgical field, indicating the recommended amount of dissection around the trachea and bilateral hilum prior to tracheal reconstruction. The postoperative courses were free from any anastomotic or pulmonary complications. We described the availability of preoperative simulations for complicated tracheal resection and reconstruction using patient-specific 3D printed models. Mimic operations using the 3D printed models allowed accurate preparation and confidence in selection of the optimal surgical strategy.

Enhanced airway stenting using a preoperative, three-dimensionally printed airway model simulation.

Three-dimensionally printed organ models that facilitate preoperative simulations have the potential to improve outcomes of surgical procedures. Here, we report a case involving a 54-year-old man diagnosed with lung cancer of the right upper bronchus that was invading the right main bronchus. A right upper lobectomy with carinoplasty was performed. Although complete excision of the tumor was achieved, exertional dyspnea redeveloped 4 months post-surgery. Chest computed tomography revealed that airway stenosis caused by granulation had deformed the airway. Ablation of the granulation and airway stenting was required to improve the patient's symptoms. Prior to performing airway stenting, a three-dimensionally printed airway model was constructed, and the Y-shaped silicone stent used was modified in accordance with the model. After stenting, both the right and left bronchi were preserved, and the patient's symptoms improved. The three-dimensional printed airway model enhanced the accuracy and safety of the airway stenting procedure performed.

Surgery or stereotactic body radiotherapy for metachronous primary lung cancer? A propensity score matching analysis.

OBJECTIVE: We compared outcomes after surgery or stereotactic body radiotherapy (SBRT) among patients with metachronous primary lung cancer (MPLC). METHODS: Patients with MPLC were treated with either surgery (2008-2018) or SBRT (2010-2018). We used propensity score matching (PSM) to reduce bias from various clinicopathological factors. MPLC was defined by the Martini and Melamed criteria. RESULTS: Of 77 patients, 51 underwent surgery and 26 received SBRT. Most median clinicopathological characteristics did not significantly differ between the surgery and SBRT groups (male sex: 67% vs 65%; age: 73 vs 77 years; time after first surgery: 6.2 vs 4.7 years; lobectomy as first procedure: 82% vs 85%; second tumor size: 11 vs 12 mm; clinical stage I: 96% vs 100%; CEA: 2.9 vs 3.0 ng/ml). However, the surgery group had significantly more ipsilateral second tumors (n = 71, 58%, P = 0.003), better performance status (P = 0.03), and preserved lung function (P = 0.02). Surgery, thus, tended to be selected for patients with good physical function and for the MPLC in the contralateral side. Five-year overall survival did not significantly differ between the surgery and SBRT groups, either before PSM (86.5% vs 65.8%, P = 0.24, log-rank) or after PSM (100% vs 84.4%, P = 0.73). CONCLUSIONS: Surgery and SBRT for MPLC patients are safe and feasible treatments with similar outcomes. However, this finding should be verified by a random controlled trial with a larger study cohort.