Physiology and morphology of projection neurons in the antennal lobe of the male moth Manduca sexta

1. We have used intracellular recording and staining, followed by reconstruction from serial sections, to characterize the responses and structure of projection neurons (PNs) that link the antennal lobe (AL) to other regions of the brain of the male sphinx moth Manduca sexta. 2. Dendritic arborizations of the AL PNs were usually restricted either to ordinary glomeruli or to the male-specific macroglomerular complex (MGC) within the AL neuropil. Dendritic fields in the MGC appeared to belong to distinct partitions within the MGC. PNs innervating the ordinary glomeruli had arborizations in a single glomerulus (uniglomerular) or in more than one ordinary glomerulus of one AL (multiglomerular) or in one case, in single glomeruli in both ALs (bilateral-uniglomerular). One PN innervated the MGC and many or all ordinary glomeruli of the AL. 3. PNs with dendritic arborizations in the ordinary glomeruli and PNs associated with the MGC typically projected both to the calyces of the ipsilateral mushroom body and to the lateral protocerebrum, but some differences in the patterns of termination in those regions have been noted for the two classes of PNs. One PN conspicuously lacked branches in the calyces but did project to the lateral protocerebrum. The PN innervating the MGC and many ordinary glomeruli projected to the calyces of the ipsilateral mushroom body and the superior protocerebrum. 4. Crude sex-pheromone extracts excited all neurons with arborizations in the MGC, although some were inhibited by other odors. One P(MGC) was excited by crude sex-pheromone extract and by a mimic of one component of the pheromone blend but was inhibited by another component of the blend. 5. PNs with dendritic arborizations in ordinary glomeruli were excited or inhibited by certain non-pheromonal odors. Some of these PNs also responded to mechanosensory stimulation of the antennae. 6. The PN with dendritic arborizations in the MGC and many ordinary glomeruli was excited by crude sex-pheromone extracts and non-pheromonal odors and also responded to mechanosensory stimulation of the antenna.

Heterogeneity of cancer-associated fibroblasts: Opportunities for precision medicine

Despite marked development in cancer therapies during recent decades, the prognosis for advanced cancer remains poor. The conventional tumor-cell-centric view of cancer can only explain part of cancer progression, and thus a thorough understanding of the tumor microenvironment (TME) is crucial. Among cells within the TME, cancer-associated fibroblasts (CAFs) are attracting attention as a target for cancer therapy. However, CAFs present a heterogeneous population of cells and more detailed classification of CAFs and investigation of functions of each subset is needed to develop novel CAF-targeted therapies. In this context, application of newly developed approaches to single-cell analysis has already made an impact on our understanding of the heterogeneity of CAFs. Here, we review the recent literature on CAF heterogeneity and function, and discuss the possibility of novel therapies targeting CAF subsets.

The Role of Surgery in Metastatic Bladder Cancer: A Systematic Review

CONTEXT

The role of surgery in metastatic bladder cancer (BCa) is unclear.

OBJECTIVE

In this collaborative review article, we reviewed the contemporary literature on the surgical management of metastatic BCa and factors associated with outcomes to support the development of clinical guidelines as well as informed clinical decision-making.

EVIDENCE ACQUISITION

A systematic search of English language literature using PubMed-Medline and Scopus from 1999 to 2016 was performed.

EVIDENCE SYNTHESIS

The beneficial role of consolidation surgery in metastatic BCa is still unproven. In patients with clinically evident lymph node metastasis, data suggest a survival advantage for patients undergoing postchemotherapy radical cystectomy with lymphadenectomy, especially in those with measurable response to chemotherapy (CHT). Intraoperatively identified enlarged pelvic lymph nodes should be removed. Anecdotal reports of resection of pulmonary metastasis as part of multimodal approach suggest possible improved survival in well-selected patients. Cytoreductive radical cystectomy as local treatment has also been explored in patients with metastatic disease, although its benefits remain to be assessed.

CONCLUSIONS

Consolidative extirpative surgery may be considered in patients with clinically evident pelvic or retroperitoneal lymph nodal metastases but only if they have had a response to CHT. Surgery for limited pulmonary metastases may also be considered in very selected cases. Best candidates are those with resectable disease who demonstrate measurable response to CHT with good performance status. In the absence of data from prospective randomized studies, each patient should be evaluated on an individual basis and decisions made together with the patient and multidisciplinary teams.

PATIENT SUMMARY

Surgical resection of metastases is technically feasible and can be safely performed. It may help improve cancer control and eventually survival in very selected patients with limited metastatic burden. In a patient who is motivated to receive chemotherapy and to undergo extirpative surgical intervention, surgery should be discussed with the patient among other consolidation therapies in the setting of multidisciplinary teams.

Dichotic listening in patients with situs inversus: brain asymmetry and situs asymmetry

In order to investigate the relation between situs asymmetry and functional asymmetry of the human brain, a consonant-vowel syllable dichotic listening test known as the Standard Dichotic Listening Test (SDLT) was administered to nine subjects with situs inversus (SI) that ranged in age from 6 to 46 years old (mean of 21.8 years old, S.D. = 15.6); the four males and five females all exhibited strong right-handedness. The SDLT was also used to study twenty four age-matched normal subjects that were from 6 to 48 years old (mean 21.7 years old, S.D. = 15.3); the twelve males and twelve females were all strongly right-handed and served as a control group. Eight out of the nine subjects (88.9%) with SI more often reproduced the sounds from the right ear than sounds from the left ear; this is called right ear advantage (REA). The ratio of REA in the control group was almost the same, i.e., nineteen out of the twenty-four subjects (79.1%) showed REA. Results of the present study suggest that the left-right reversal in situs inversus does not involve functional asymmetry of the brain. As such, the system that produces functional asymmetry in the human brain must independently recognize laterality from situs asymmetry.

CCM3 is a gatekeeper in focal adhesions regulating mechanotransduction and YAP/TAZ signalling

The YAP/TAZ transcriptional programme is not only a well-established driver of cancer progression and metastasis but also an important stimulator of tissue regeneration. Here we identified Cerebral cavernous malformations 3 (CCM3) as a regulator of mechanical cue-driven YAP/TAZ signalling, controlling both tumour progression and stem cell differentiation. We demonstrate that CCM3 localizes to focal adhesion sites in cancer-associated fibroblasts, where it regulates mechanotransduction and YAP/TAZ activation. Mechanistically, CCM3 and focal adhesion kinase (FAK) mutually compete for binding to paxillin to fine-tune FAK/Src/paxillin-driven mechanotransduction and YAP/TAZ activation. In mouse models of breast cancer, specific loss of CCM3 in cancer-associated fibroblasts leads to exacerbated tissue remodelling and force transmission to the matrix, resulting in reciprocal YAP/TAZ activation in the neighbouring tumour cells and dissemination of metastasis to distant organs. Similarly, CCM3 regulates the differentiation of mesenchymal stromal/stem cells. In conclusion, CCM3 is a gatekeeper in focal adhesions that controls mechanotransduction and YAP/TAZ signalling.

Physiology and morphology of descending neurons in pheromone-processing olfactory pathways in the male moth Manduca sexta

1. We have characterized the responses and structure of olfactory descending neurons (DNs) that reside in the protocerebrum (PC) of the brain of male sphinx moths Manduca sexta and project toward thoracic ganglia. 2. Excitatory responses of DNs to pheromone blends were of two general types: (a) brief excitation (BE) that recovered to background in less than 1 s after the stimulus, and (b) long-lasting excitation (LLE) that outlasted the stimulus by greater than or equal to 1 s and, in many cases, as long as 30 s. Individual pheromone components were ineffective in eliciting LLE. 3. Some neurons showing LLE also exhibited state-dependent responses to pheromonal stimuli. When such neurons were in a state of low background firing, stimulation with pheromone blend elicited LLE. When they were in a state of LLE, an identical stimulus reduced firing for 5-10 s after which firing gradually increased to the initial higher level. 4. Thirteen stained DNs were reconstructed from serial sections for detailed analysis of their morphology in the brain. DNs exhibiting LLE had neurites concentrated in the lateral accessory lobes (LALs) in the protocerebrum and adjacent neuropil. Most DNs exhibiting only BE to pheromonal stimuli and other DNs showing responses only to visual or mechanosensory stimuli did not have branches in the LALs.

A dual-channel FM transmitter for acquisition of flight muscle activities from the freely flying hawkmoth, Agrius convolvuli

Moths can perform various flight maneuvers by the contraction of some direct and indirect flight muscles. Multi-channel recording from these flight muscles and analysis of their interaction is very important for understanding insect flight motor system. In this study, we developed a dual-channel FM transmitter for acquisition of muscle potentials, with which a male hawkmoth (Agrius convolvuli) could fly freely and perform pheromone triggered zigzag flight in a wind tunnel. The transmitter weighs only 0.25 g including single battery, has a 5 m receivable range and works for more than 30 min. Doubling channels was achieved by providing two oscillators (the carrier frequencies were 82 and 85 MHz), and interference between them was overcome by buffer amplifiers and independent reference electrodes for each channel. With this transmitter, we could acquire muscle potentials from some direct and indirect muscles during free flight. Combined with simultaneous high-speed video analysis, we observed distinct changes of motor patterns during takeoff. Our radio-telemetric system allows acquisition of actual information from freely flying moths; such information will lead to further progress in the study of insect flight.

Physiology and morphology of protocerebral olfactory neurons in the male moth Manduca sexta

1. We have used intracellular recording and staining with Lucifer Yellow, followed by reconstruction from serial sections, to characterize the responses and structure of olfactory neurons in the protocerebrum (PC) of the brain of the male sphinx moth Manduca sexta. 2. Many olfactory protocerebral neurons (PCNs) innervate a particular neuropil region lateral to the central body, the lateral accessory lobe (LAL), which appears to be important for processing olfactory information. 3. Each LAL is linked by its constituent neurons to the ipsilateral lateral PC, where projection neurons from the antennal lobe terminate, as well as to other regions of the PC. The LALs are also linked to each other by bilateral neurons with arborizations in each LAL. 4. Some PC neurons showed long-lasting excitation (LLE) that outlasted the olfactory stimuli by greater than or equal to 1 s, and as long as 30 s in some preparations. LLE was more frequently elicited by the sex-pheromone blend than by individual pheromone components. All bilateral neurons that showed LLE had arborizations in the LALs. LLE responses were also recorded in a single local neuron innervating the mushroom body. 5. In some other PC neurons, pheromonal stimuli elicited brief excitations that recovered to background firing rates less than 1 s after stimulation.

Learning-stage-dependent, field-specific, map plasticity in the rat auditory cortex during appetitive operant conditioning

Cortical reorganizations during acquisition of motor skills and experience-dependent recovery after deafferentation consist of several distinct phases, in which expansion of receptive fields is followed by the shrinkage and use-dependent refinement. In perceptual learning, however, such non-monotonic, stage-dependent plasticity remains elusive in the sensory cortex. In the present study, microelectrode mapping characterized plasticity in the rat auditory cortex, including primary, anterior, and ventral/suprarhinal auditory fields (A1, AAF, and VAF/SRAF), at the early and late stages of appetitive operant conditioning. We first demonstrate that most plasticity at the early stage was tentative, and that long-lasting plasticity after extended training was able to be categorized into either early- or late-stage-dominant plasticity. Second, training-induced plasticity occurred both locally and globally with a specific temporal order. Conditioned-stimulus (CS) frequency used in the task tended to be locally over-represented in AAF at the early stage and in VAF/SRAF at the late stage. The behavioral relevance of neural responses suggests that the local plasticity also occurred in A1 at the early stage. In parallel, the tone-responsive area globally shrank at the late stage independently of CS frequency, and this shrinkage was also correlated with the behavioral improvements. Thus, the stage-dependent plasticity may commonly underlie cortical reorganization in the perceptual learning, yet the interactions of local and global plasticity have led to more complicated reorganization than previously thought. Field-specific plasticity has important implications for how each field subserves in the learning; for example, consistent with recent notions, A1 should construct filters to better identify auditory objects at the early stage, while VAF/SRAF contribute to hierarchical computation and storage at the late stage.

Outcome of surgical resection of pulmonary metastasis from urinary tract transitional cell carcinoma

There is little information on pulmonary metastasectomy of urinary tract transitional cell carcinoma (TCC). In this study, we examined the long-term outcome and the factors associated with long-term survival after pulmonary metastasectomy of urinary tract TCC based on a 20-year single center experience. Between 1984 and 2005, 18 patients (12 men, six women) underwent pulmonary metastasectomy of the urinary tract TCC in our hospital. The clinicopathological and surgical data of these patients obtained from the medical records were analyzed in this retrospective study. The time interval between lung resection and death, or latest follow-up ranged from two to 200 months (median 52). Survival analysis was conducted by the Kaplan-Meier method and log-rank test. The cumulative three- and five-year survival rates were 59.8% and 46.5%, respectively. The number of resected metastatic tumors (solitary vs. multiple) was associated with long-term survival (P<0.05). The five-year survival rate of patients with solitary metastasis was 85.7% while that of patients with multiple metastases was 20.0%. Pulmonary metastasectomy of urinary tract TCC is associated with a favorable outcome, and solitary metastasis is associated with long-term survival. Aggressive management of solitary pulmonary metastasis from a urinary tract TCC is feasible in selected patients.

Chemotherapy enhances programmed cell death 1/ligand 1 expression via TGF-β induced epithelial mesenchymal transition in non-small cell lung cancer

In cancer immunology, the programmed cell death 1-programmed cell death 1/ligand 1 (PD-1/PD-L1) pathway plays a major role. Anti-PD-1 and anti-PD-L1 antibodies provide reliable immunotherapy when given as treatment for various types of malignancy including lung cancer. PD-L1 expression in cancer cells has been reported to be a predictive factor for the therapeutic effects of immunotherapy. However, the mechanism of PD-L1 expression remains unclear. Another key process in cancer progression is epithelial-mesenchymal transition (EMT). In the present study, we investigated the mechanism of PD-L1 expression as well as changes in its expression during the EMT process in non-small cell lung cancer (NSCLC). In this study, A549 cells underwent EMT by treatment with TGF-β or chemotherapeutic agents and then PD-L1 expression was evaluated. The alterations of PD-L1 expression was also examined during the reverse EMT process; mesenchymal-epithelial transition (MET). The relationship between for PD-L1 expression and EMT status in clinical specimens with NSCLC after induction chemotherapy were analyzed by immunohistochemical staining. We found that PD-L1 expression was upregulated following TGF-β induction; in contrast, it was downregulated by TGF-β receptor-kinase inhibitors and the MET process. Furthermore, chemo-treatment increased TGF-β expression and enhances PD-L1 expression via autocrine TGF-β induced EMT. Analysis of clinical samples revealed a significant relationship between PD-L1 expression and EMT status (P<0.05). In conclusion, our results suggest that PD-L1 expression is regulated by TGF-β induced EMT and enhanced by chemo-treatment via the chemo-induced TGF-β signaling. The anti-PD-1/PD-L1 blockade may provide more effective anticancer activities in combination with chemotherapy in NSCLC.

Long-lasting excitation of protocerebral bilateral neurons in the pheromone-processing pathways of the male moth Bombyx mori

Intracellular recording and staining with Lucifer yellow were used to characterize the responses and structure of pheromone-processing bilateral neurons in the protocerebrum of the brain of the male silkworm moth Bombyx mori. Numerous olfactory bilateral neurons innervated a particular neuropil region lateral to the central body, the lateral accessory lobe (LAL). The LALs are linked to each other by bilateral neurons with arborizations in each LAL. The LAL appears to be important for collecting the olfactory information from both sides of the brain. Many of the bilateral neurons showed a characteristic long-lasting excitation (LLE) that outlasted the olfactory stimuli (1.5 s). In some preparations, the LLE lasted more than 20 s and the firing gradually decreased to the background level.

The prognostic impact of programmed cell death 1 and its ligand and the correlation with epithelial-mesenchymal transition in thymic carcinoma

Background

The significance of epithelial‐mesenchymal transition (EMT) and immune checkpoint proteins in thymic carcinoma remains unknown. We examined the clinical significance of EMT, tumor‐infiltrating lymphocytes expressing the immune checkpoint protein, programmed cell death 1 (PD‐1 + TILs), and the expression of PD‐1 ligand 1 (PD‐L1) in thymic carcinoma (TC). We also investigated the relationships between these immune checkpoint proteins and the EMT status and examined the impact of induction chemotherapy on patients with tumors that express these proteins.

Methods

The relationship between PD‐1 + TILs/PD‐L1 and clinicopathological findings including EMT was investigated by immunohistochemistry (IHC) of surgically resected samples from 43 patients with TC. In 15 patients receiving induction therapy (IT), those factors were compared before and after IT.

Results

With IHC, 26 cases (60.5%) were positive for PD‐L1, and 19 cases were positive for PD‐1 + TILs (44.2%). The disease‐free survival rate in patients showing EMT and who were PD‐1/PD‐L1 positive was significantly worse compared to negative cases (EMT; P = 0.0095, PD‐1; P = 0.001, PD‐L1; P = 0.0037). We found a significant relationship between PD‐L1 and EMT status (P = 0.01). In patients who received IT, PD‐L1 increased, and the change was strongly correlated with EMT status (P = 0.01).

Conclusion

Epithelial‐mesenchymal transition, PD‐L1, and PD‐1 + TILs have prognostic impact, and PD‐L1 is correlated with EMT status. PD‐L1 expression after IT was significantly higher compared to before IT and was correlated with the EMT change. Thus, PD‐L1 may be upregulated during EMT, and anti‐PD‐1/PD‐L1 immunotherapy may provide reliable treatment of TC in combination with chemotherapy.

Descending protocerebral neurons related to the mating dance of the male silkworm moth

Descending protocerebral neurons in the male silkworm moth brain responding to the sexual pheromone (Bombykol) were identified. The neurons responded well with a tonic type of response and the high-frequency spikes evoked continued even after the end of the stimulus. Characteristics of the dose-response curves of the neurons to the pheromone remarkably resembled those of the wing vibration which is one of the mating behavioral components of the male moths.

Clinical application of the AMOY 9-in-1 panel to lung cancer patients

INTRODUCTION

To investigate the clinical performance of the AMOY 9-in-1 kit (AMOY) in comparison with a next-generation sequencing (NGS) panel in lung cancer patients.

METHODS

Lung cancer patients enrolled in the LC-SCRUM-Asia program at a single institution were analyzed for the success rate of AMOY analysis, the detection rate of targetable driver mutations, the turn around time (TAT) from specimen submission to the result reporting, and the concordance rate of results with the NGS panel.

RESULTS

Of the 406 patients included in the analysis, 81.3% had lung adenocarcinoma. The success rates of AMOY and NGS were 98.5% and 87.8%, respectively. With AMOY, genetic alterations were detected in 54.9% of cases. Of the 42 cases in which NGS analysis failed, targetable driver mutations were detected by AMOY in ten cases through analysis of the same sample. Of the 347 patients for whom the AMOY and NGS panels were successful, 22 showed inconsistent results. In four of the 22 cases, the mutation was detected only in the NGS panel because AMOY did not cover the EGFR mutant variant. Mutations were detected only by AMOY in five of the six discordant pleural fluid samples, with AMOY having a higher detection rate than NGS. The TAT was significantly shorter five days after AMOY.

CONCLUSION

AMOY had a higher success rate, shorter turnaround time, and higher detection rate than NGS panels. Only a limited number of mutant variants were included; thus be careful not to miss promising targetable driver mutations.

Podocalyxin influences malignant potential by controlling epithelial-mesenchymal transition in lung adenocarcinoma

Epithelial-mesenchymal transition (EMT) plays an important role in the progression of lung carcinoma. Podocalyxin (PODXL), which belongs to the CD34 family and regulates cell morphology, has been linked to EMT in lung cancer, and PODXL overexpression is associated with poor prognosis in several different classes of cancers. The aim of this study was to clarify the role of PODXL overexpression in EMT in lung cancer, and to determine the prognostic value of PODXL overexpression in tumors from lung cancer patients. The morphology, EMT marker expression, and migration and invasion abilities of engineered A549 PODXL-knockdown (KD) or PODXL-overexpression (OE) lung adenocarcinoma cells were examined. PODXL expression levels were assessed by immunohistochemistry in 114 human clinical lung adenocarcinoma specimens and correlated with clinical outcomes. PODXL-KD cells were epithelial in shape, whereas PODXL-OE cells displayed mesenchymal morphology. Epithelial markers were upregulated in PODXL-KD cells and downregulated in PODXL-OE cells, whereas mesenchymal markers were downregulated in the former and upregulated in the latter. A highly selective inhibitor of phosphatidylinositol 3-kinase-Akt signaling attenuated EMT of PODXL-OE cells, while a transforming growth factor inhibitor did not, suggesting that PODXL induces EMT of lung adenocarcinoma cells via the phosphatidylinositol 3-kinase pathway. In lung adenocarcinoma clinical specimens, PODXL expression was detected in minimally invasive and invasive adenocarcinoma, but not in non-invasive adenocarcinoma. Disease free survival and cancer-specific survival were significantly worse for patients whose tumors overexpressed PODXL. PODXL overexpression induces EMT in lung adenocarcinoma and contributes to tumor progression.

Ectopic Hepatocellular Carcinoma Arising in the Left Triangular Ligament of the Liver

Hepatocellular carcinoma (HCC) rarely originates in extrahepatic liver tissue. Laparoscopic resection is widely used to treat HCC. This report presents a case of a patient with ectopic HCC arising in the left triangular ligament of the liver that was successfully treated by laparoscopic resection. A 59-year-old female presented with an elevated serum alpha-fetoprotein (AFP) level (2,508 ng/ml). Dynamic computed tomography demonstrated a tumor measuring 20 mm in diameter below the left diaphragm just adjacent to the spleen. The tumor showed contrast enhancement in the hepatic arterial phase and became less dense than the liver parenchyma in the portal phase. The patient was diagnosed with ectopic HCC arising in the left diaphragm and laparoscopic surgery was performed. The tumor was located in the left triangular ligament of the liver and had a stalk between the tumor and the liver. The tumor was resected, and the final diagnosis was moderately differentiated ectopic HCC arising in the left triangular ligament of the liver. The patient had an uneventful postoperative recovery and has experienced no recurrence over 18 months after the operation.

Odour-tracking capability of a silkmoth driving a mobile robot with turning bias and time delay

The reconstruction of mechanisms behind odour-tracking behaviours of animals is expected to enable the development of biomimetic robots capable of adaptive behaviour and effectively locating odour sources. However, because the behavioural mechanisms of animals have not been extensively studied, their behavioural capabilities cannot be verified. In this study, we have employed a mobile robot driven by a genuine insect (insect-controlled robot) to evaluate the behavioural capabilities of a biological system implemented in an artificial system. We used a male silkmoth as the 'driver' and investigated its behavioural capabilities to imposed perturbations during odour tracking. When we manipulated the robot to induce the turning bias, it located the odour source by compensatory turning of the on-board moth. Shifting of the orientation paths to the odour plume boundaries and decreased orientation ability caused by covering the visual field suggested that the moth steered with bilateral olfaction and vision to overcome the bias. An evaluation of the time delays of the moth and robot movements suggested an acceptable range for sensory-motor processing when the insect system was directly applied to artificial systems. Further evaluations of the insect-controlled robot will provide a 'blueprint' for biomimetic robots and strongly promote the field of biomimetics.

Air leak pattern shown by digital chest drainage system predict prolonged air leakage after pulmonary resection for patients with lung cancer

Background

A common cause of complications after a pulmonary resection procedure is prolonged air leakage. Recently introduced digital drainage systems provide accurate recording of air leak data for later review. We investigated the clinical usefulness of the continuous stream of data recorded by such a device.

Methods

We analyzed data obtained from 299 patients with pulmonary malignancy who underwent a pulmonary resection procedure for lung cancer patients with use of a digital chest drainage system. Postoperative air leak patterns were divided into 4 groups and their correlation with prolonged air leakage after pulmonary resection was evaluated.

Results

The incidence of prolonged air leak was 10% (30/299). The postoperative air leak patterns noted in the present patients were divided into none (n=217, 73%), intermittent (n=21, 7%), decrease (n=40, 13%), and variable (n=21, 7%). The incidence of prolonged air leak in each group was 0.5% (1/217) in the none group, 24% (5/21) in the intermittent group, 20% (8/40) in the decrease group, and 76% (16/21) in the variable group. The amount of air leakage immediately after surgery was highest in the variable group. Patients in the intermittent and variable groups had longer durations of air leakage and chest tube placement. The frequency of postoperative interventional treatment was significantly higher in the variable group as compared to the others. Chest tube reinsertion for pneumothorax and increased subcutaneous emphysema after the initial chest tube removal was only seen in the intermittent group.

Conclusions

Advantages of digital drainage system use are continuous monitoring and recording capabilities, which show the detailed air leak pattern after pulmonary resection. That pattern can be used to predict the durations of air leakage and chest tube drainage, as well as for producing an air leak management algorithm.

Long-Term Outcomes After Surgical Resection for Pleural Dissemination of Thymoma

BACKGROUND

Cases of thymoma with pleural dissemination are occasionally encountered, and their management is difficult. Some reports have noted that surgical treatment for dissemination is effective, although the long-term results and clinical course details remain unclear. The current study investigated the short- and long-term outcomes of surgical resection of pleural dissemination.

METHODS

A retrospective review examined the medical records for 38 patients who underwent surgical resection for pleural dissemination occurring synchronously with a primary thymoma or metachronously after complete surgical resection of a primary thymoma between 1996 and 2017 at the authors' institution. Clinical characteristics and prognostic factors were analyzed.

RESULTS

The patients were classified into synchronous (n = 21) and metachronous (n = 17) groups. The 10-year overall survival rate was 59% for the synchronous group and 88% for the metachronous group. The median follow-up period for all the patients was 61 months (range 4-225 months). No perioperative deaths occurred. For all the patients, the 5- and 10-year overall survival rates were respectively 91% and 82%, and the 5- and 10-year relapse-free survival rates were respectively 29% and 19%. A significantly worse prognosis was observed for patients 50 years of age or older than for those younger than 50 years (p = 0.02). For 13 patients who underwent repeat resection for pleural dissemination, the prognosis was better than for those without repeat resection (p < 0.01).

CONCLUSION

Surgical resection of thymoma with pleural disseminated nodules can be safely performed and provides a favorable long-term outcome. Repeat resection is considered to be effective for achieving a good prognosis.