[Introduction of Robot-assisted Lung Segmentectomy].

Robot-assisted lung segmentectomy will be covered by insurance starting 2020. The results of the Japan Clinical Oncology Group( JCOG) 0802 trial have been reported, and the use of robot-assisted lung segmentectomy is expected to increase in the future. We present an introduction to robot-assisted lung segmentectomy at our institution using actual cases. Our facility constructs vascular three-dimensional (3D) images from computed tomography( CT) images as a preoperative simulation. Robot-assisted surgery is performed with the da Vinci Xi, using four arms with carbon dioxide insufflation through an assist hole in the anterior thoracic region of the fifth intercostal space, with a focus on the eighth intercostal space. The port placement and forceps used are the same as for lobectomy. Interdigitations are identified with intravenous indocyanine green after dissecting the pulmonary arteriovenous veins. After that, the da Vinci Xi firefly is activated, and the non-resected lungs are fluorescently stained to identify the inter-areas, and the inter-areas which are separated with an automatic suture device.

[Robot-assisted Thoracoscopic Surgery for Mediastinal Tumor in Our Department].

In 2019, our facility introduced robot-assisted surgery for mediastinal tumors using da Vinci Si, which was upgrade to da Vinci X and Xi in 2021. Initially, the unilateral thoracic cavity approach was used for robot-assisted surgeries. The unilateral approach has the advantage of facilitating the anatomical recognition of either the left or right side, with the side used selected depending on the location of the lesion. Notably, challenges such as difficulty in recognizing objects were still encountered. To compensate for these shortcomings, our hospital introduced robotic subxiphoid-optical thymectomy, a subxiphoid approach, which has been used for all robot-assisted mediastinal tumor surgeries since its introduction under the guidance of Kyoto Prefectural University of Medicine. Additionally, extended thymectomy, which has been covered by insurance since 2020 and used as the standard surgical procedure for robot-assisted mediastinal tumor surgery at our department, can be performed using the same approach.

[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.

Association of the prognostic model iSEND with PD-1/L1 monotherapy outcome in non-small-cell lung cancer.

BACKGROUND: Accessible biomarkers are needed for immunotherapy in advanced non-small-cell lung cancer (NSCLC). We previously described a multivariate risk prediction model, the iSEND, which categorises advanced NSCLC patients treated with nivolumab into Good, Intermediate or Poor groups. This model was developed by using only clinical and analytical variables (sex, ECOG-performance status, neutrophil-to-lymphocyte ratio [NLR] and post-treatment delta NLR). METHODS: An international database of 439 patients who received post-platinum PD-1/L1 monotherapies was collected for validation. Performance of the iSEND to different PD-L1 groups was compared by using time-dependent positive predictive value (PPV) for their mortality events. RESULTS: Median follow-up was 18.2 months (95% CI: 15.9-19.6). The overall survival of the iSEND Good (HR = 0.31, 95% CI: 0.22-0.43, p < 0.0001) was superior to the iSEND Poor. Time-dependent PPV for mortality of iSEND Poor was superior to PD-L1 = 0% group at 12 (75 vs. 53%, p = 0.01) and 18 months (85 vs. 46%, p = 0.03). However, female gender did not independently associate with better outcome in the validation cohort. CONCLUSION: The iSEND model is associated with the outcome of post-platinum PD-1/L1 monotherapy in advanced NSCLC patients. The iSEND Poor demonstrated a superior performance to PD-L1 = 0% in negative prognostication. Prospective investigation and modelling with other significant parameters in a larger cohort are warranted.

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.

Current status of intensity-modulated radiation therapy for prostate cancer: History, clinical results and future directions.

External beam radiotherapy has changed dramatically over several decades with the improvement of computer hardware and software, and machinery developments. Intensity-modulated radiation therapy is the most sophisticated technique for all cancer treatment with radiation therapy, and is widely disseminated and available for daily use in many countries. Several retrospective and prospective studies have shown that intensity-modulated radiation therapy reduces the radiation dose in the organs at risk with diminished rates of acute and late toxicity, even with higher doses (>74 Gy). An important technique for the clinical use of intensity-modulated radiation therapy is image-guided radiation therapy. The clinical benefit for prostate image-guided radiation therapy has been assessed by comparing the outcomes of patients with either the image-guided radiation therapy or non-image-guided radiation therapy technique. These studies have shown that image-guided radiation therapy significantly decreases acute and late rectal and bladder toxicities. Randomized trials and meta-analysis have shown that higher doses result in better biochemical control. More recently, hypofractionated radiation therapy comparing hypofractionated radiation therapy versus conventional fractionated radiation therapy have shown that hypofractionated radiation therapy produces biochemical control and toxicity rated similar to those produced by conventional fractionated radiation therapy. The clinical use of ultrahypofractionated radiation therapy and simultaneous integrated boost technique is necessary to evaluate its further safety and benefits. Intensity-modulated radiation therapy is also widely accepted in the field of salvage therapy and for the patients with distant oligometastases. The purpose of the present review is to summarize the history of intensity-modulated radiation therapy, new techniques for intensity-modulated radiation therapy, hypofractionation and future directions for prostate cancer.

Quantitative T-cell repertoire analysis of peripheral blood mononuclear cells from lung cancer patients following long-term cancer peptide vaccination.

Therapeutic cancer peptide vaccination is an immunotherapy designed to elicit cytotoxic T-lymphocyte (CTL) responses in patients. A number of therapeutic vaccination trials have been performed, nevertheless there are only a few reports that have analyzed the T-cell receptors (TCRs) expressed on tumor antigen-specific CTLs. Here, we use next-generation sequencing (NGS) to analyze TCRs of vaccine-induced CTL clones and the TCR repertoire of bulk T cells in peripheral blood mononuclear cells (PBMCs) from two lung cancer patients over the course of long-term vaccine therapy. In both patients, vaccination with two epitope peptides derived from cancer/testis antigens (upregulated lung cancer 10 (URLC10) and cell division associated 1 (CDCA1)) induced specific CTLs expressing various TCRs. All URLC10-specific CTL clones tested showed Ca2+ influx, IFN-γ production, and cytotoxicity when co-cultured with URLC10-pulsed tumor cells. Moreover, in CTL clones that were not stained with the URLC10/MHC-multimer, the CD3 ζ chain was not phosphorylated. NGS of the TCR repertoire of bulk PBMCs demonstrated that the frequency of vaccine peptide-specific CTL clones was near the minimum detectable threshold level. These results demonstrate that vaccination induces antigen-specific CTLs expressing various TCRs at different time points in cancer patients, and that some CTL clones are maintained in PBMCs during long-term treatment, including some with TCRs that do not bind peptide/MHC-multimer.

Garcin syndrome caused by sphenoid bone metastasis of lung cancer: a case study.

BACKGROUND: Garcin syndrome, which consists of unilateral palsies of almost all cranial nerves without either sensory or motor long-tract disturbances or intracranial hypertension, can be caused by malignant tumors at the skull base. The case of a patient with lung cancer that metastasized to the sphenoid bone and resulted in Garcin syndrome is presented. CASE PRESENTATION: A 76-year-old woman was diagnosed as having non-small cell lung cancer with pericardial and diaphragmatic infiltration, cT4N1M0, stage 3A. The left lower lobectomy with concomitant resection of the pericardium and diaphragm was performed. The pathological diagnosis was pleomorphic carcinoma, pT2bN0M0, stage 1B. She was then followed in the surgery clinic, and 2 months after surgery, she visited an emergency room complaining of headache and diplopia. Neurological examination showed the left IV, V1, and VI cranial nerve palsies. Metastatic tumor with bone destruction was found in the left sphenoid sinus on head computed tomography (CT) and contrast magnetic resonance imaging (MRI), and she was diagnosed with Garcin syndrome caused by sphenoid bone metastasis of lung cancer. Irradiation was performed as palliative treatment, but her neurological findings did not improve. Her general condition gradually worsened, and she died 5 months after surgery. CONCLUSIONS: Bone metastasis of lung cancer occurs frequently, but sphenoid bone metastasis is extremely rare. In this case report, Garcin syndrome caused by lung cancer is discussed in the context of the few previous reports.

[Two cases of thymic carcinoid treated with octreotide long-acting repeatable].

Thymic carcinoid is a rare disease that accounts for 3.1% of thymic tumors and 1.8-6% of all carcinoid tumors in Japan. Advanced thymic carcinoid has a 5-year survival rate of 28-31%.Compared with carcinoid tumors that arise in other organs, thyroid carcinoid tumors carry a relatively worse prognosis, and the most effective therapeutic strategy is thought to be surgical resection.However, for patients with recurrence and distant metastases, multimodal therapy including radiotherapy and/or chemotherapy is usually applied.No chemotherapy treatment regimen has been established in Japan, although the National Comprehensive Cancer Network Guidelines proposed the application of octreotide long-acting repeatable(LAR).In this report, we present two cases of thymic carcinoid that were treated with octreotide LAR and achieved long-term survival.

Association between specific human leukocyte antigen alleles and development of thyroid immune-related adverse event.

Aim: Inherent variations in human leukocyte antigen (HLA) alleles have been revealed epidemiologically to influence the development of autoimmune diseases. HLA alleles may thus also be associated with the development of immune-related adverse events (irAEs), such as thyroid irAE. Materials & methods: In this case-control study, 71 cancer patients who received immune checkpoint inhibitors were enrolled and HLA-genotyped and the frequency of HLA alleles was compared. Results: A*26:01, DPA1*01:03 and DPB1*02:01 were significantly more frequent in patients with thyroid irAE than in patients without any irAEs (35.0 vs 3.2% [p = 0.004], 80.0 vs 45.2% [p = 0.020] and 55.0 vs 25.8% [p = 0.044], respectively). Conclusion: A*26:01, DPA1*01:03 and DPB1*02:01 appear to be associated with thyroid irAE.

Everyone has a unique combination of human leukocyte antigens (HLAs) in their body that help the immune system identify threats. HLAs were named from the fact that they were first identified on the surface of human leukocytes. Afterward, HLAs were also found on all human cells. HLAs present antigens to immune cells. These HLAs also influence how the immune system attacks cancer cells. Immune checkpoint inhibitors are drugs that can help the immune system fight cancer, but they sometimes cause severe adverse events. In this study, we investigated whether specific HLA genes are related to the development of an adverse event that affects the thyroid in cancer patients treated with immune checkpoint inhibitors. We found an association between three HLA genes (A*26:01, DPA1*01:03 and DPB1*02:01) and the development of the thyroid adverse event. However, larger studies are needed to confirm and generalize these initial exploratory findings.

Multiple therapeutic peptide vaccines consisting of combined novel cancer testis antigens and anti-angiogenic peptides for patients with non-small cell lung cancer.

BACKGROUND: Vaccine treatment using multiple peptides derived from multiple proteins is considered to be a promising option for cancer immune therapy, but scientific evidence supporting the therapeutic efficacy of multiple peptides is limited. METHODS: We conducted phase I trials using a mixture of multiple therapeutic peptide vaccines to evaluate their safety, immunogenicity and clinical response in patients with advanced/recurrent NSCLC. We administered two different combinations of four HLA-A24-restricted peptides. Two were peptides derived from vascular endothelial growth factor receptor 1 (VEGFR1) and 2 (VEGFR2), and the third was a peptide derived from up-regulated lung cancer 10 (URLC10, which is also called lymphocyte antigen 6 complex locus K [LY6K]). The fourth peptide used was derived from TTK protein kinase (TTK) or cell division associated 1 (CDCA1). Vaccines were administered weekly by subcutaneous injection into the axillary region of patients with montanide ISA-51 incomplete Freund's adjuvant, until the disease was judged to have progressed or patients requested to be withdrawn from the trial. Immunological responses were primarily evaluated using an IFN-gamma ELiSPOT assay. RESULTS: Vaccinations were well tolerated with no severe treatment-associated adverse events except for the reactions that occurred at the injection sites. Peptide-specific T cell responses against at least one peptide were observed in 13 of the 15 patients enrolled. Although no patient exhibited complete or partial responses, seven patients (47%) had stable disease for at least 2 months. The median overall survival time was 398 days, and the 1- and 2-year survival rates were 58.3% and 32.8%, respectively. CONCLUSION: Peptide vaccine therapy using a mixture of four novel peptides was found to be safe, and is expected to induce strong specific T cell responses. TRIAL REGISTRATION: These studies were registered with ClinicalTrials.gov NCT00633724 and NCT00874588.

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.

Novel quantitative immunohistochemical analysis for evaluating PD-L1 expression with phosphor-integrated dots for predicting the efficacy of patients with cancer treated with immune checkpoint inhibitors.

Introduction: Programmed cell death ligand 1 (PD-L1) expression in tumor tissues is measured as a predictor of the therapeutic efficacy of immune checkpoint inhibitors (ICIs) in many cancer types. PD-L1 expression is evaluated by immunohistochemical staining using 3,3´-diaminobenzidine (DAB) chronogenesis (IHC-DAB); however, quantitative and reproducibility issues remain. We focused on a highly sensitive quantitative immunohistochemical method using phosphor-integrated dots (PIDs), which are fluorescent nanoparticles, and evaluated PD-L1 expression between the PID method and conventional DAB method. Methods: In total, 155 patients with metastatic or recurrent cancer treated with ICIs were enrolled from four university hospitals. Tumor tissue specimens collected before treatment were subjected to immunohistochemical staining with both the PID and conventional DAB methods to evaluate PD-L1 protein expression. Results: PD-L1 expression assessed using the PID and DAB methods was positively correlated. We quantified PD-L1 expression using the PID method and calculated PD-L1 PID scores. The PID score was significantly higher in the responder group than in the non-responder group. Survival analysis demonstrated that PD-L1 expression evaluated using the IHC-DAB method was not associated with progression-free survival (PFS) or overall survival (OS). Yet, PFS and OS were strikingly prolonged in the high PD-L1 PID score group. Conclusion: Quantification of PD-L1 expression as a PID score was more effective in predicting the treatment efficacy and prognosis of patients with cancer treated with ICIs. The quantitative evaluation of PD-L1 expression using the PID method is a novel strategy for protein detection. It is highly significant that the PID method was able to identify a group of patients with a favorable prognosis who could not be identified by the conventional DAB method.

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.

Large cell neuroendocrine carcinoma of the lung controlled for 4 years by a single administration of pembrolizumab: A case report.

Large cell neuroendocrine carcinoma of the lung (LCNEC) is a rare and highly progressive tumor with a poor prognosis. Although immune checkpoint inhibitors have been approved for treatment of both small cell and non-small cell lung cancers, their role in the treatment of LCNEC is unclear. We describe a patient with postoperative recurrence of LCNEC who maintained complete remission for 4 years after a single administration of pembrolizumab. A 68-year-old Japanese man underwent thoracoscopic right lower lobectomy for LCNEC (pathological stage pT1bN0M0, stage IA2). Epidermal growth factor receptor and anaplastic lymphoma kinase were negative, and the programmed death ligand 1 expression rate in tumor cells was 5% (clone 22C3). Eight months later, the patient developed recurrence with mediastinal lymph node metastasis and pleural dissemination. Therefore, chemotherapy with cisplatin and etoposide was administered. However, relapse occurred 6 months later. Pembrolizumab was administered as second-line chemotherapy, which was discontinued after first dose because of interstitial pneumonia 1 month later. Thereafter, however, both the lymph node metastasis and pleural dissemination disappeared and did not relapse for 4 years. Pembrolizumab may be used as a treatment option for pulmonary LCNEC.