Stage III-IV thymic squamous cell carcinoma in complete pathological remission achieved with thymic cancer resection after immunotherapy combined with chemotherapeutic conversion therapy: a report of two cases from real-world data

Background

Thymic carcinoma, a rare malignancy in the mediastinum, currently lacks standardized treatment options. Although surgery remains a crucial component among traditional therapeutic approaches, the potential benefits of radiotherapy and chemotherapy remain controversial. Nevertheless, a substantial number of patients are diagnosed with advanced tumor growth, posing challenges for achieving complete resection through surgical intervention and resulting in a poor prognosis. In light of the promising antitumor effects demonstrated by immunotherapy in various prevalent cancers, certain studies have shown favorable efficacy in advanced or recurrent thymic cancer cases. However, the incidence of adverse effects induced by immunotherapy in thymic cancer is notably higher compared to other tumor types, with severe and fatal complications being particularly significant. Consequently, there is an urgent need to address the crucial issue of patient selection for immunotherapy in thymic cancer.

Case Description

In this study, we report on the treatment with programmed cell death protein 1 (PD-1) inhibitor therapy combined with chemotherapy conversion therapy for two patients diagnosed with stage III-IV thymic squamous cell carcinoma according to the Masaoka-Koga staging system. The aim of this study was to assess the effectiveness and safety of PD-1 inhibitor combined with chemotherapy conversion therapy in patients with thymic squamous cell carcinoma. Two patients in this cohort, one with stage III and another with stage IV disease, were deemed ineligible for upfront surgical resection. Puncture pathology confirmed the diagnosis of thymic squamous cell carcinoma. Both patients underwent transformation therapy using a combination of PD-1 inhibitors and chemotherapy. Tumor shrinkage was observed in both patients, enabling successful completion of surgery. Postoperative pathology revealed no residual tumor cells, indicating complete pathological remission. Notably, none of the patients experienced grade 3 or higher immunotherapy-related adverse reactions following immunotherapy.

Conclusions

A combination of PD-1 inhibitors and chemotherapy followed by surgery demonstrated improved efficacy and enhanced safety for treating patients with Masaoka-Koga stage III-IV thymic squamous carcinoma and represents a potential novel therapeutic alternative for this disease.

Prospective Observation Study for Primary Spontaneous Pneumothorax: Incidence of and Risk Factors for Postoperative Neogenesis of Bullae

PURPOSE

Details of the neogenesis of bullae (NOB), which causes recurrent primary spontaneous pneumothorax (PSP) following bullectomy, have not been reported and risk factors for NOB remain unclear. We aimed to clarify the details of NOB.

METHODS

We conducted a prospective study using three computed tomography (CT) examinations performed 6, 12, and 24 months after bullectomy to identify the incidence of and risk factors for NOB. We enrolled 50 patients who underwent bullectomy for PSP.

RESULTS

After excluding 11 patients who canceled the postoperative CT examination at 6 months after bullectomy, only 39 patients were analyzed. The incidence of NOB at 6, 12, and 24 months after bullectomy was 38.5%, 55.2%, and 71.2%, respectively. The rate of NOB in the operated lung was almost 2 times higher than that in the contralateral nonoperative lung. Male sex, multiple bullae on preoperative CT, long stapling line (≥7 cm), deep stapling depth (≥1.5 cm), and heavier resected sample (≥5 g) were suggested to be risk factors for NOB.

CONCLUSIONS

We recognized a high incidence of postoperative NOB in PSP patients. Bullectomy itself seems to promote NOB. Postoperative NOB occurs frequently, especially in patients who require a large-volume lung resection with a long staple line.

Prognostic impact of highly solid component in early-stage solid lung adenocarcinoma

Background

Based on computed tomography (CT) findings of lung cancer, solid nodules have a much worse prognosis than subsolid nodules, even if the nodules are subcentimeter in size. There is, however, no systematic method for determining the prognosis of solid tumors on CT. This study aimed to discover the prognostic factor of early-stage solid lung adenocarcinoma using three-dimensional CT volumetry.

Methods

Patients with pathological stage I solid lung adenocarcinoma who underwent complete resection between 2007 and 2012 were selected in this retrospective study. Clinicopathological data and preoperative multidetector CT findings, such as tumor size on the two-dimensional axial image, three-dimensional tumor volume between -600 and 199 HU, and three-dimensional solid volume between 0 and 199 HU, which corresponded to highly solid components, were compared between recurrence and non-recurrence. Furthermore, these radiological values were compared to pathological invasive volume (PIV).

Results

During this time, 709 patients had their lung cancer completely removed. From this cohort, 90 patients with pathological stage I solid lung adenocarcinoma were selected. In addition, recurrence was found in 26 patients (28.9%). Although two-dimensional axial image, serum carcinoembryonic antigen (CEA) level, and SUVmax on 18F fluorodeoxyglucose positron emission tomography/computed tomography (FDG-PET/CT) did not differ statistically between recurrent and non-recurrent patients, three-dimensional tumor and solid tumor volume did. Multivariate analysis indicated that three-dimensional solid tumor volume [hazard ratio: 2.440; 95% confidence interval (CI): 1.110-5.361, P=0.026] and epidermal growth factor receptor (EGFR) mutation (hazard ratio: 4.307; 95% CI: 1.328-13.977, P=0.015) were significantly associated with disease-free survival (DFS). When three-dimensional tumor and solid tumor volume were compared to PIV, three-dimensional solid tumor volume (3,091 mm3 on average) showed a highly similar value with PIV (2,930 mm3 on average), whereas three-dimensional tumor volume (6,175 mm3 on average) was significantly larger than PIV (P<0.001).

Conclusions

In patients with early-stage solid lung adenocarcinoma, the measurement of three-dimensional solid tumor volume, which is correlated with PIV, accurately predicted the postoperative outcome.

Marginal calcification of thymoma: differences in the location of calcification indicate differences in the characteristics of thymomas

BACKGROUND

Thymic epithelial tumors (TETs) are the most common tumors located in the anterior mediastinum. Calcification is sometimes observed in thymomas, especially in thymomas, and has been reported to be an indicator of the invasive behavior of thymomas. However, whether or not all calcification indicates invasive behavior is unclear. The present study therefore analyzed the location, size, and patterns of thymoma calcification and the relationships between calcification and clinicopathological factors and prognosis.

METHODS

We conducted a retrospective study among 77 thymoma patients who underwent surgery between January 2012 and May 2022 and analyzed the relationship between the location of calcification and clinicopathological findings. The patients were categorized into three groups: those with inner calcification of the tumor (group I), those with marginal calcification (group M), and those without any calcification (group N).

RESULTS

Calcification was identified in 13 thymomas (16.9%) in group I (n=8) and group M (n=5). Group M included significantly more low-risk thymomas than the other groups (P=0.030). In low-risk thymomas, especially type AB thymoma, marginal calcification was observed more frequently than in other lesions. There were significant differences in age (P=0.024) and Masako-Koga stage (P=0.020) among the groups. In group I, younger patients and patients with advanced-stage disease were included. There were no significant differences in the rates of recurrence or the recurrence-free period among the groups. However, recurrence was not recognized in any members of group M.

CONCLUSIONS

The location of calcification should be a point of focus in thymomas, and differences in the location of calcification indicate differences in the characteristics of thymomas.

Impact of Pleural Thickness on Occurrence of Postoperative Complications in Patients with Malignant Pleural Mesothelioma

OBJECTIVES

The rates of postoperative mortality and morbidity are high in patients with malignant pleural mesothelioma (MPM). Therefore, it is important to identify variables that increase the risk of postoperative complications. Pleural thickness has recently been identified as a prognostic indicator in patients with MPM. The aim of this study was to investigate clinical variables, including pleural thickness, that contribute to postoperative complications in patients with MPM.

PATIENTS AND METHODS

A total of 47 patients who underwent surgical excision of MPM between 2005 and 2021 were enrolled in this study. Correlations between postoperative complications within 90 days of surgery and preoperative clinical factors were investigated.

RESULTS

A total of 27 patients underwent extrapleural pneumonectomy (EPP), and the remaining 20 underwent pleurectomy/decortication (P/D). Macroscopic complete resections were obtained in all but three patients. Of the 47 patients, 23 (49%) experienced postoperative complications of grade 3 or worse. The major complication in patients with EPP was respiratory failure (n = 6), whereas the major complication in patients with P/D was prolonged air leakage (n = 7). Univariate logistic regression analysis found a correlation between postoperative complications and age, surgical side, and pleural thickness, while multivariate logistic regression analysis found surgical side (p = 0.04, 95% Cl 1.10-21.71, OR 4.90) and pleural thickness (p = 0.03, 95% Cl 1.21-23.00, OR 5.26) to significantly influence the occurrence of postoperative complications.

CONCLUSIONS

Pleural thickness has a significant effect on the occurrence of postoperative complications. Patients with thick pleura on the right side are at greater risk of postoperative complications.

Real-world evidence of safety and influence for lung cancer surgery under COVID-19 pandemic in Japan

Background

The COVID-19 pandemic has affected the clinical practice of lung cancer surgery in Japan, but few studies have revealed the real situation of surgical practice for lung cancer in this country. This latest information will help us to decide the future direction of lung cancer surgery under pandemic circumstances.

Methods

We collected data from patients with primary lung cancer who underwent thoracic surgery between 2018 and 2021. To investigate the impact of the COVID-19 pandemic on lung cancer surgery, we compared between 2018-2019 (prepandemic group) and 2020-2021 (pandemic group) in the respect of patient characteristics, pathological findings, and short-term outcome after lung cancer resection by Mann-Whitney and Fisher's exact tests. Moreover, the monthly number of surgeries for lung cancer in our institution during 2020-2021 was compared with the number of newly diagnosed COVID-19 patients in Japan by Spearman correlation analysis.

Results

From 2018 through 2021, 936 patients with primary lung cancer underwent surgical intervention in our institute and were included in this study. The number of surgeries did not decrease in the pandemic group (n=443) compared with that in the prepandemic group (n=493). Tumor and invasive size in stage I which was measured by pathologist were significantly larger in the pandemic group than in the prepandemic group (tumor size: P=0.031, invasive size: P<0.001). In terms of postoperative short-term outcome, the median hospital stay was 6 days, 30-day mortality was 2, and morbidity was around 20% in both groups. Only one patient suffered from COVID-19 infection 5 months after right upper lobectomy. An increased ratio of newly diagnosed COVID-19 cases in Japan was negatively correlated with the number of surgeries for lung cancer in our institution in the next month (r=-0.393, P=0.007), although there was no correlation in the present or the month after next.

Conclusions

Even during the COVID-19 pandemic period, lung cancer surgery could be performed safely and in a sustainable manner. However, pathological findings of lung cancer tended to be progressive in early-stage lung cancer.

Postoperative empyema complicated with descending necrotizing fasciitis: a case report

Background

Empyema is a serious complication of lung surgery.

Case presentation

We report a case of Streptococcus anginosus empyema complicated by descending necrotizing fasciitis after surgery. Ten days after the initial surgery, the patient presented with arrhythmia and hypotension with septic shock. Pleural fluid analysis led to the diagnosis of empyema, and surgical debridement (second surgery) was performed. One week after the emergency surgery, a palpable pink erythematous skin change was observed on the ipsilateral iliac crest. Hence, the second emergency surgery (third surgery) was performed to debride the subcutaneous and intramuscular abscesses.

Conclusions

The possibility of descending abscess and necrotizing fasciitis should be considered when Streptococcus anginosus is detected.

Video-assisted thoracoscopic surgery for pleuroperitoneal communication

Here we report the cases of five patients on continuous ambulatory peritoneal dialysis (CAPD) who developed hydrothorax because of pleuroperitoneal communication. Preoperative computed tomography (CT) peritoneography revealed penetrated sites on the diaphragm in all patients. All patients underwent video-assisted thoracoscopic surgery (VATS), and a dialysate containing indigo carmine was injected intraperitoneally through a CAPD catheter to confirm the fistula. In all patients, a thinned bleb was found at the center of the diaphragmatic tendon consistent with that noted on preoperative CT peritoneography. The bleb was resected using a surgical stapler in four patients, and the pleuroperitoneal communication did not recur. However, in one patient, the bleb was only covered with reinforcement agents and the hydrothorax recurred after CAPD. This study demonstrates that VATS treatment for pleuroperitoneal communication is safe and effective but that lesion resection would be more useful for preventing hydrothorax recurrence in patients undergoing CAPD.

Skeletal muscle and related protein expression as prognostic factors in thymic squamous cell carcinoma

Background

Sarcopenia and its marker, the psoas muscle index (PMI), have attracted attention as prognostic factors for various types of cancers. The fragile X-related 1 (FXR1) gene is highly expressed in myocytes, and FXR1 overexpression is a candidate biomarker for poor survival in several types of cancers. Thymic squamous cell carcinoma (TSQCC) is rare, and no studies assessing its prognostic factors, particularly in terms of skeletal muscle mass and FXR1 expression, are available.

Methods

We retrospectively investigated the prognostic significance of PMI in 34 patients who underwent TSQCC resection, considering the status of FXR1 and tumor programmed death-ligand 1 (PD-L1). PMI was calculated from the bilateral psoas muscle using preoperative computed tomography (CT). Patients were divided into two groups: low PMI (<58.2%, n=17) and normal PMI (≥58.2%, n=17). Immunohistochemical analysis was performed to determine the FXR1 and PD-L1 expression levels.

Results

Low PMI was significantly associated with worse overall survival (OS) (5-year survival rate; 86% vs. 100%; P=0.026) and marginally associated with worse disease-free survival (DFS) (5-year survival rate; 39% vs. 66%; P=0.090) compared with normal PMI. The immunohistochemical analysis revealed that the FXR1 intensity score (0-1+: 6% vs. 0%; 2+-3+: 94% vs. 100%; P=0.31), median FXR1 distribution (95% vs. 90%; P=0.63), and PD-L1 status (high: 47% vs. 59%; P=0.49) were not significantly different between the two groups.

Conclusions

Our findings suggest that PMI might be considered as a potential prognostic factor in TSQCC and that FXR1 is widely expressed regardless of the PMI status. Skeletal muscle mass may play a role in the prognosis of TSQCC.

Challenges in left sleeve pneumonectomy in the left lateral decubitus position

We report the case of a 20-year-old woman with carinal adenoid cystic carcinoma who underwent left sleeve pneumonectomy in the left lateral decubitus position, during which severe desaturation was encountered. After transecting the left main bronchus, the left lung was selectively intubated and ventilated. However, oxygenation was inadequate. Hence, venoarterial extracorporeal membrane oxygenation (ECMO) was introduced. Initially, Barclay's procedure was planned to preserve the left lung, but this plan was altered due to the extent of the tumor and unstable ventilation. After the lesion was removed, the trachea and right main bronchus were anastomosed end-to-end. During left pneumonectomy, the right lung was selectively ventilated, but oxygen saturation (SpO₂) dropped to <70% despite ECMO. SpO₂ improved on additionally ventilating the left lung using another breathing circuit. Temporary right chest closure was performed with ventilation of the left lung across the thoracotomy wound. The patient was turned to the semi-supine position, and tolerated selective right lung ventilation with ECMO. Subsequently, left thoracotomy and pneumonectomy were successfully performed. Careful management is required for desaturation in left sleeve pneumonectomy in the left lateral decubitus position.

Chest three-dimensional-computed tomography imaging data analysis for the variation of exercise capacity after lung lobectomy

BACKGROUND

Postoperative loss of exercise capacity and pulmonary function is a major concern among lung cancer patients. In this study, the time for a stair-climbing to 12-m height was used to investigate whether preoperative chest 3D-computed tomography (CT) could be a useful tool for predicting postoperative variations in exercise capacity and pulmonary function.

METHODS

Seventy-eight patients undergoing lobectomy for suspected stage I lung cancer were prospectively enrolled. Preoperatively, lobe volume and low attenuation volume (LAV) were evaluated using the SYNAPSE VINCENT system. Preoperative data on stair-climbing time, spirometry, and diffusing capacity of the lung for carbon monoxide (DL_CO ) at baseline and 6-month postoperative data were used to evaluate variations in exercise capacity and pulmonary function. Maximal oxygen uptake (VO₂ t) was evaluated based on the stair-climbing time.

RESULTS

Significant differences in the variation of exercise capacity at 6 months postoperatively were found between the groups categorized by target lobe volume and LAV status: The large volume/LAV (+) group had a greater decline in VO₂ t. Mean loss of VO₂ t was -6.2%, -1.4%, -1.6%, and -0.1% in the large volume/LAV (+), large volume/LAV (-), small volume/LAV (+), and small volume/LAV (-) groups, respectively. The large volume/LAV (-) group had a greater decline in forced expiratory volume in 1 s. The small volume/LAV (+) group showed a reduced decline in the DL_CO .

CONCLUSIONS

Analysis of chest 3D-CT scans is a potential tool for predicting the loss of exercise capacity and pulmonary function after lung lobectomy. This article is protected by copyright. All rights reserved.

Removal of hematoma due to massive hemoptysis after transbronchial biopsy: a case report

Background

Massive hemoptysis is a life-threatening complication after transbronchial biopsy (TBB). Reports on massive hemoptysis occurring several days after TBB are scarce.

Case presentation

A 62-year-old man presented with massive hemoptysis and was admitted to hospital as an emergency on the eighth day after TBB. On the 12th day after TBB, computed tomography showed complete atelectasis of the right middle and lower lobes. The patient underwent emergent right upper lobectomy. The right upper lobe bronchus was separated with a scalpel, the hematoma was pulled out with forceps, and the bronchus subsequently sutured shut. The patient was discharged from the hospital uneventfully.

Conclusions

We experienced a case of massive hemoptysis on the eighth day after TBB, which required emergency surgery due to persistent bleeding into the airway and airway obstruction during follow-up. Postoperative pneumonia and atelectasis could be prevented by manual removal of the residual hematoma.

Pleural Invasion Depth of Disseminated Nodules in Patients with Stage IVa or Recurrent Thymoma: Assessment, Curative Impact, and Surgical Outcomes

BACKGROUND

Thymoma patients with pleural dissemination are difficult to manage, and their treatment strategy remains undefined. This study aimed to investigate the clinicopathologic features of these patients, focusing on the association between the depth of pleural invasion and prognosis.

METHODS

Between 2003 and 2019, the study identified 120 disseminated lesions in 20 thymoma patients. Seven patients had de novo stage IVa thymoma and 13 were recurrent cases. Extrapleural pneumonectomy was performed for 8 patients and debulking surgery for 12 patients. Invasion depth of pleural tumors was classified into two groups: when the disseminated tumors invaded the pleura beneath the elastic layer, the tumor was diagnosed as Da, and when the disseminated tumors invaded the pleura beyond the elastic layer, the tumor was diagnosed as Db.

RESULTS

Of 120 nodules, 31 (26%), found in eight patients with recurrent malignancies, were classified as Db. The pathologic status of the surgical margin (PSM) was positive in eight patients, seven of whom had Db nodules. The 5-year overall survival (OS) rate was 100% in the Da group and 75% in the Db group (P = 0.02). The 5-year progression-free survival (PFS) rate was 66.7% in the Da group and 25% in the Db group (P = 0.02). Cox univariate analysis showed that PFS was significantly influenced by the depth of invasion (P = 0.04) and PSM (P = 0.03).

CONCLUSION

Depth of pleural invasion may influence survival outcomes for thymoma patients with pleural dissemination. The patients in this study with Da-disseminated nodules had an increased probability of a longer OS and PFS and tended to achieve negative PSM compared with the patients with Db.

Diagnostic utility of metabolic parameters on FDG PET/CT for lymph node metastasis in patients with cN2 non-small cell lung cancer

Background

The aim of this study was to assess the diagnostic utility of metabolic parameters on fluorine-18-fluoro-2-deoxy-D-glucose-positron emission tomography (FDG-PET)/computed tomography (CT) for predicting lymph node (LN) metastasis in patients with cN2 non-small cell lung cancer (NSCLC).

Methods

We retrospectively reviewed patients who underwent surgery for cN2 NSCLC between 2007 and 2020. Those who had clinically diagnosed positive hilar and mediastinal LNs by routine CT and PET/CT imaging were investigated. To measure the metabolic parameters of LNs, the data according to maximum standardized uptake value (SUVmax), metabolic tumor volume (MTV), total lesion glycolysis (TLG), and LN-to-primary tumor ratio of SUVmax (LPR) were examined. The diagnosis of each retrieved LN was confirmed based on histopathological examination of surgical tissue specimens. Receiver operating characteristics (ROC) curves with area under the curve (AUC) calculations and multivariate analysis by logistic regression were performed.

Results

Forty-five patients with 84 clinically diagnosed positive hilar or mediastinal LNs were enrolled in the present study. Of the 84 LNs, 63 LNs were pathologically proven as positive (75%). The SUVmax, MTV, TLG, and LPR of LN metastasis were significantly higher than those of benign nodes. In the ROC analysis, the AUC value of LPR [AUC, 0.776; 95% confidence interval (CI), 0.640–0.913] was higher than that of LN SUVmax (AUC, 0.753; 95% CI, 0.626–0.880) or LN TLG3.5 (AUC, 0.746; 95% CI, 0.607–0.885). Using the optimal LPR cutoff value of 0.47, the sensitivity, specificity, positive predictive value, negative predictive value, and accuracy were 84.1, 66.7, 88.3, 58.3, and 79.8%, respectively. Multivariate analysis by logistic regression showed that LPR was an independent predictor for LN metastasis (odds ratio, 6.45; 95% CI, 1.785–23.301; P = 0.004). In the subgroup analysis of adenocarcinoma patients (n = 18; 32 LNs), TLG3.5 was a better predictor (AUC, 0.816; 95% CI, 0.639–0.985) than LPR (AUC, 0.792; 95% CI, 0.599–0.986) or LN SUVmax (AUC, 0.792; 95% CI, 0.625–0.959).

Conclusions

Our findings suggest that LPR on FDG-PET is a useful predictor for LN metastasis in patients with cN2 NSCLC. TLG can be a good predictor for LN metastasis in patients with adenocarcinoma.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12885-021-08688-6.

Prognostic value of uncertain resection for overall survival in non-small cell lung cancer

BACKGROUND

In this study, we aimed to evaluate the R(un) category proposed by the International Association for the Study of Lung Cancer (IASLC) for non-small cell lung cancer (NSCLC).

METHODS

We retrospectively reviewed the medical records of patients with NSCLC who underwent segmentectomy or lobectomy between 2014 and 2015 at our institution. Residual tumor (R) status was reclassified from the Union for International Cancer Control designation to the IASLC-proposed R classification [R0 and R(un)]. The underlying reasons for the R(un) reclassification were analyzed according to pathological stage, lymph node status, and resected lobe. A Cox proportional hazard model was used to evaluate the impacts of R(un) categorization on overall survival.

RESULTS

Of 355 cases, 44.5% were reclassified as R(un). The most common reason for the reclassification was insufficient number of harvested lymph nodes or no station 7 lymph nodes. When stratified by tumor location, the absence of station 7 lymph nodes was especially prominent in both the right and left upper lung resections. In the multivariate Cox regression model, IASLC R classification was associated with poor overall survival in node-positive cases (hazard ratio: 2.657; P =.016).

CONCLUSIONS

Various factors resulted in reclassification to R(un) because the R(un) group was highly heterogeneous. Careful consideration is required to determine whether R(un) classification can be used as an indicator of lymph node dissection quality. For advanced cases, the R(un) definition may be useful in predicting poor prognosis.

Preoperative paraspinous muscle sarcopenia and physical performance as prognostic indicators in non-small-cell lung cancer

BACKGROUND

Despite the associations of both preoperative sarcopenia and physical performance with post-operative mortality in non-small-cell lung cancer (NSCLC), there have been no comprehensive studies of the impact of physical status on prognosis. This study was performed to investigate the prognostic significance of preoperative sarcopenia and physical performance in NSCLC.

METHODS

This retrospective cohort study was performed in NSCLS patients undergoing curative lung resection at a university hospital between January 2014 and December 2017. The patients were divided into four groups according to the skeletal muscle index [sarcopenia (lowest sex-specific tertile) and non-sarcopenia] and 6 min walking distance (6MWD) [short distance (<400 m) and long distance (≥400 m)]. Sarcopenia was assessed by preoperative cross-sectional areas of right and left paraspinous muscles at the level of the 12th thoracic vertebra from computed tomography images, and physical performance was determined by preoperative 6MWD. The primary and secondary endpoints were post-operative overall survival (OS) and disease-free survival (DFS).

RESULTS

The 587 patients [mean age: 68.5 ± 8.8 years, 399 men (68%)] included in the study were divided into the non-sarcopenia/long-distance group (58%), sarcopenia/long-distance group (26%), non-sarcopenia/short-distance group (9%), and sarcopenia/short-distance group (7%). A total of 109 (18.6%) deaths and 209 (35.6%) combined endpoints were observed over a mean follow-up of 3.1 ± 1.3 years. After adjusting for other covariates, the sarcopenia/short-distance group showed significant associations with shorter OS (hazard ratio, 3.38; 95% confidence interval, 1.79-6.37; P < 0.001) and DFS (hazard ratio, 2.11; 95% confidence, 1.27-3.51; P = 0.004) compared with the non-sarcopenia/long-distance group on multivariate analyses. Although not significant, adding skeletal muscle index and 6MWD to the pre-existing risk model increased the area under the curve on time-dependent receiver operating characteristic curve analysis for OS and DFS, except within 2 years of surgery.

CONCLUSIONS

The presence of both preoperative paraspinous muscle sarcopenia and short distance in 6MWD had an adverse effect on post-operative prognosis in patients with NSCLC, suggesting that preoperative assessment of thoracic sarcopenia and physical performance may be useful for risk stratification of surgical candidates with potential for targeted interventions.

Current trends in thoracic surgery

Thoracic surgery has evolved drastically in recent years. Although thoracic surgeons mainly deal with tumorous lesion in the lungs, mediastinum, and pleura, they also perform lung transplantation surgery in patients with end-stage lung disease. Herein, we introduce various major current topics in thoracic surgery. Minimally invasive surgical procedures include robot-assisted thoracic surgery and uniportal video-assisted thoracic surgery. Novel techniques for sublobar resection include virtual-assisted lung mapping, image-guided video-assisted thoracic surgery, and segmentectomy using indocyanine green. Three-dimensional (3D) computed tomography (CT) simulation consists of surgeon-friendly 3D-CT image analysis systems and new-generation, dynamic 3D-CT imaging systems. Updates in cadaveric lung transplantation include use of marginal donors, including donation after circulatory death, and ex vivo lung perfusion for such donors. Topics in living donor lobar lung transplantation include size matching, donor issues, and new surgical techniques. During routine clinical practice, thoracic surgeons encounter various pivotal topics related to thoracic surgery, which are described in this report.

Left brachiocephalic vein aneurysm: a case report

Background

Aneurysm of the left brachiocephalic vein is a very rare clinical disease and only 40 cases have been reported so far.

Case presentation

The patient was a 61-year-old woman with no related medical history. She underwent CT to investigate the cause of a cough and a mass was noted in the anterior mediastinum. Dynamic computed tomography with contrast medium injected into the left basilic vein demonstrated the venous aneurysm with blood flow to the left brachiocephalic vein. The patient had no symptoms, but because of the risk of pulmonary infarction and aneurysm rupture, the aneurysm was surgically resected. A median sternotomy was a reasonable approach because of the fragility of the venous aneurysm wall with little working space in the anterior mediastinum.

Conclusions

We diagnosed an aneurysm of the left brachiocephalic vein on preoperative imaging and excised it through a median sternotomy. The venous wall was thin and fragile in some areas and so this approach was appropriate in view of the possibility of intraoperative injury.

Differential impacts of postoperative complications on patients' survival in completely resected non-small-cell lung cancer

OBJECTIVE

The aim of this study was to investigate the effects of inflammatory respiratory complications on long-term survival in patients with resected non-small cell lung cancer. We defined inflammatory respiratory complications to include the following six conditions: pneumonia, empyema, bronchial fistula, respiratory dysfunction, acute interstitial pneumonia, and atelectasis.

METHODS

Part of the National Clinical Database was linked to our prospective database from 2014 to 2017. Linkage was achieved for 866 patients. The Kaplan-Meier method was used to evaluate the overall, relapse-free, and cancer-related survival. The Cox proportional hazard model was used to analyze the impact of each complication.

RESULTS

Of the 736 patients included in the study, 149 had complications. The 5-year overall and cancer-specific survival rates were significantly lower in patients with inflammatory respiratory complications. The Cox proportional hazard model showed that the inflammatory respiratory complications had a significant impact on overall survival (hazard ratio 2.48, 95% confidence interval 1.41-4.38) but not air leak (hazard ratio 1.38, 95% confidence interval 0.70-2.70).

CONCLUSIONS

Our study shows the differential impact of each complication on the survival of patients with non-small cell lung cancer. The presence of inflammatory respiratory complications was the only predictor of poor overall survival.

Micro-computed tomography images of lung adenocarcinoma: detection of lepidic growth patterns

Micro-computed tomography (µCT) provides extremely high-resolution images of samples and can be employed as a non-destructive inspection tool. Using µCT, we can obtain images comparable with microscopic images. In this work, we have attempted to take high-resolution images of the human lung using µCT. Compared to clinical high-resolution computed tomography (HRCT) images of living body (in-vivo imaging), we can obtain extremely high-resolution images by µCT of ex-vivo tissues (resected lungs) as three-dimensional data. The purpose of this study was to distinguish between areas of normal lung and lung cancer by µCT images in order to study the feasibility of cancer diagnosis using this novel radiological image modality. Ten resected human lungs containing primary cancer were fixed by Heitzman's methods to obtain high-resolution µCT images. After fixation of the lung, images of the specimens were taken by µCT between January 2016 and November 2017. The imaging conditions were tube voltage: 90 kV and tube current: 110 µA. To compare details of images gained by conventional HRCT and µCT, we measured the thickness of the alveolar walls of the normal lung area and the cancer area of which alveoli might be replaced by tumor cells, and compared their appearance by means of histopathological images. All the nodules were diagnosed as adenocarcinoma. The median whole tumor size was 18 mm (9 mm-24 mm). Each specimen was clearly divided into areas of normal alveolar wall and of thickened alveolar wall on µCT 'visually'. Median thickness of alveolar walls of the normal lung was 0.037 mm (0.034 mm-0.048 mm), and that of the cancer area was 0.084 mm (0.074 mm-0.094 mm); there was a statistically significant difference between both thicknesses by Student's t-test (P < 0.01). The area of thickened alveolar walls on µCT corresponded well with the area of microscopically lepidic growth patterns of adenocarcinoma. We found that µCT images could be correctly divided by alveolar walls into normal lung area and lung cancer area. Further detailed investigations with regard to µCT are needed to make comparable histological diagnoses using µCT images with conventional microscopic methods of pathological diagnoses.

Thymic lipofibroadenoma accompanied with largish calcifications

Thymic lipofibroadenomas are extremely rare; their radiological features have never been reported. We report the first case of a lipofibroadenoma with some largish calcifications mimicking a teratoma. A 28-year-old man had an anterior mediastinal tumor with some calcifications on preoperative computed tomography, which was suspected to be a mature teratoma and resected through robot-assisted thoracic surgery. This tumor had strands of epithelial cells separated by abundant fibrous stroma containing fat cells and was thus diagnosed as a lipofibroadenoma. He was well without any recurrence 6 months postoperatively. Largish calcifications on preoperative computed tomography make distinguishing between teratomas and lipfibroadenomas difficult.

Prognostic factors of stage I thymic epithelial tumors

OBJECTIVE

According to the tumor-node-metastasis classification for thymic malignancies, the proportion of patients diagnosed with stage I is expected to increase significantly. However, whether those patients have homogenous clinicopathological features and survival has not been fully evaluated.

METHODS

We reviewed 153 consecutive patients with stage I thymic epithelial tumors (133 thymomas, 15 thymic carcinomas, and 5 neuroendocrine tumors) who underwent complete resection at our institution between 2001 and 2016 and evaluated the prognostic significance of their clinicopathological factors.

RESULTS

The stage I patients accounted for 78% of all thymic epithelial tumors. The 5-year overall survival and recurrence-free survival rates of the 153 patients were 94% and 80%, respectively. The patients with the histology of thymic carcinoma or neuroendocrine tumor and with a tumor larger than 5.0 cm showed significantly worse recurrence-free survival in multivariate analysis (p = 0.027 and 0.038, respectively). Only the tumor size was revealed as a significant prognostic factor for recurrence-free survival when limited in the 133 cases of thymoma (p = 0.048).

CONCLUSIONS

Patients with large tumors showed significantly worse recurrence-free survival than those with small tumors both in stage I thymic epithelial tumors and thymomas.

Clinical application of a surgical navigation system based on virtual thoracoscopy for lung cancer patients: real time visualization of area of lung cancer before induction therapy and optimal resection line for obtaining a safe surgical margin during surgery

Background

We have developed a surgical navigation system that presents virtual thoracoscopic images using computed tomography (CT) image data, as if you are observing intra-thoracic cavity in synchronization with the real thoracoscopic view. Using this system, we made it possible to simultaneously visualize the ‘area of lung cancer before induction therapy’ and the ‘optimal resection line for obtaining a safe surgical margin’ as a virtual thoracoscopic view. We applied this navigation system in the clinical setting in operations for lung cancer patients with chest wall invasion after induction chemoradiotherapy.

Methods

The proposed surgical navigation system consisted of a three-dimensional (3D) positional tracker and a virtual thoracoscopy system. The 3D positional tracker was used to recognize the positional information of the real thoracoscope. The virtual thoracoscopy system generated virtual thoracoscopic views based on CT image data. Combined with these two technologies, patient-to-image registration was performed in two patients, and the results generated a virtual thoracoscopic view that was synchronized with the real thoracoscopic view.

Results

The operations were started with video-assisted thoracic surgery (VATS), and the navigation system was activated at the same time. The virtual thoracoscopic view was synchronized with the real thoracoscopic view, which also simultaneously indicated the ‘area of lung cancer before induction therapy’ and the ‘optimal resection lines for obtaining a safe surgical margin’. We marked the optimal lines using an electric scalpel, and then performed lobectomy and chest wall resection with a sufficient surgical margin using these landmarks. Pathological examinations confirmed that the surgical margin was negative. No complications related to the navigation system were encountered during or after the procedures.

Conclusions

Using this proposed navigation system, we could obtain a ‘CT-derived virtual intra-thoracic 3D view of the patient’ that was aligned with the thoracoscopic view during surgery. The accurate identification of areas of cancer invasion before induction therapy using this system might be a useful for determining optimal surgical resection lines.

Psoas muscle mass in patients undergoing lung cancer surgery: a prognostic difference between squamous cell carcinoma and adenocarcinoma

BACKGROUND

Psoas muscle mass is a surrogate marker for sarcopenia: a depletion of skeletal muscle mass. This study was conducted to elucidate the prognostic significance of the psoas muscle index (PMI: cross-sectional area of the bilateral psoas muscle at the umbilical level on computed tomography/height² [cm²/m²]) in patients undergoing surgery for lung squamous cell carcinoma (SCC) and lung adenocarcinoma (ADC).

METHODS

One hundred and sixty-five patients with SCC and 556 patients with ADC who underwent R0 resection between 2007 and 2014 were reviewed for analysis. In SCC patients, the mean value (standard deviation) of the PMI was 6.15 (1.49) in men and 4.65 (1.36) in women. Among ADC patients, the PMI was 7.12 (1.60) in men and 5.29 (1.22) in women. Clinicopathological characteristics as well as the survival were evaluated.

RESULTS

The PMI was associated with the age, body mass index (BMI), and serum albumin. In the multivariable Cox regression analysis, after adjusting for age, BMI, serum albumin, sex, pathological stage, and diffusing capacity for carbon monoxide, the PMI showed a significant association with the overall survival (OS) and disease-free survival (DFS) in SCC patients (hazard ratios 0.50 and 0.56, 95% confidence intervals 0.39-0.65 and 0.45-0.71, respectively). On the other hand, in ADC patients, the PMI had no impact on the OS or DFS.

CONCLUSIONS

The PMI was significantly associated with the survival of lung SCC patients, but not of lung ADC patients, suggesting the presence of a previously unidentified relationship between skeletal muscle and lung SCC progression.

Primary peritoneal carcinoma with late-phase pulmonary metastases: a case report

Background

Primary peritoneal carcinoma (PPC) is a very rare and aggressive type of malignancy with a poor prognosis.

Case presentation

A 66-year-old woman was referred to our hospital with two pulmonary nodules that developed after PPC resection and postoperative adjuvant chemotherapy administered 5 years earlier. Computed tomography revealed a 1.3-cm-sized nodule in the left lung with a small airspace in the posterior basal segment and a 0.9-cm-sized solid nodule in the apico-posterior segment that grew slightly within a 2-month period. 18F-Fluorodeoxyglucose-positron emission tomography of these lesions revealed respective maximum standardized uptake values of 7.11 and 2.46. Her serum cancer antigen-125 level remained within the normal range, despite elevation before the first surgery. The posterior basal segment and superior division were subjected to anatomical segmentectomy. An intraoperative frozen section examination could not distinguish metastatic PPC from primary lung cancer. Immunopathologically, the two nodules were identified as metastatic PPC.

Conclusions

Our findings suggest that PPC patients may develop late-phase thoracic recurrence that is difficult to diagnose clinically after initial treatment in a potentially resectable setting.

Hydrogen water alleviates obliterative airway disease in mice

OBJECTIVE

Bronchiolitis obliterans syndrome arising from chronic airway inflammation is a leading cause of death following lung transplantation. Several studies have suggested that inhaled hydrogen can protect lung grafts from ischemia-reperfusion injury via anti-inflammatory and -oxidative mechanisms. We investigated whether molecular hydrogen-saturated water can preserve lung allograft function in a heterotopic tracheal allograft mouse model of obliterative airway disease METHODS: Obliterative airway disease was induced by heterotopically transplanting tracheal allografts from BALB/c donor mice into C57BL/6 recipient mice, which were subsequently administered hydrogen water (10 ppm) or tap water (control group) (n = 6 each) daily without any immunosuppressive treatment. Histological and immunohistochemical analyses were performed on days 7, 14, and 21.

RESULTS

Hydrogen water decreased airway occlusion on day 14. No significant histological differences were observed on days 7 or 21. The cluster of differentiation 4/cluster of differentiation 3 ratio in tracheal allografts on day 14 was higher in the hydrogen water group than in control mice. Enzyme-linked immunosorbent assay performed on day 7 revealed that hydrogen water reduced the level of the pro-inflammatory cytokine interleukin-6 and increased that of forkhead box P3 transcription factor, suggesting an enhancement of regulatory T cell activity.

CONCLUSIONS

Hydrogen water suppressed the development of mid-term obliterative airway disease in a mouse tracheal allograft model via anti-oxidant and -inflammatory mechanisms and through the activation of Tregs. Thus, hydrogen water is a potential treatment strategy for BOS that can improve the outcome of lung transplant patients.

Evaluation of intra-tumoral blood feeding to predict the effect of induction therapy in patients with locally advanced lung cancer

There is little known about predictors of the effects of induction therapy in locally advanced lung cancer, including superior sulcus tumors. We analyzed whether intra-tumoral blood feeding could predict a pathologic complete response (pCR). Patients who underwent induction therapy followed by surgery for locally advanced lung cancer were retrospectively reviewed. The intra-tumoral blood feeding was defined by the CT value (HU, Hounsfield unit), which was calculated by subtracting the non-enhanced value from the contrast-enhanced value (divided into the early and delayed phase) at the maximum diameter of the tumor on dynamic CT. The cases were classified, according to the efficacy of induction therapy, into the pCR and residual tumor (pRT) group. There were 38 cases of T3 and 12 of T4; the induction therapy consisted of chemoradiotherapy in 39 patients, chemotherapy in 6, and radiotherapy in 5. A pCR was obtained in 15 (30%) patients. The mean CT values of the early and delayed phases in the pCR group were 14.8 and 30.7 HU, while those in the pRT were 15.3 and 32.2 HU, respectively. A logistic regression analysis revealed that a smaller tumor size (< 42 mm) was a non-significant predictor of a pCR (p = 0.09); the maximum standardized uptake value on FDG-PET and the CT values on the early and delayed phases of dynamic CT were not associated with the achievement of a pCR. In conclusion, intra-tumoral blood feeding of the locally advanced lung cancer did not predict the effects of induction therapy, whereas smaller sized tumors tended to show a better response.

The tumor doubling time is a useful parameter for predicting the histological type of thymic epithelial tumors

PURPOSE

We assessed the utility of the tumor doubling time (TDT) for predicting the histological type of thymic epithelial tumors.

METHODS

We retrospectively reviewed 130 patients with thymic epithelial tumors who underwent computed tomography two or more times before surgery. The patients were divided into low-risk thymoma (types A, AB and B1), high-risk thymoma (types B2 and B3) and thymic carcinoma (thymic carcinoma and thymic neuroendocrine tumor) groups. In the 96 patients who showed tumor enlargement, the relationship between the histological type and the TDT of the tumor was investigated.

RESULTS

The study population included 55 men and 41 women from 26 to 82 years of age. The TDT of the thymic carcinoma group (median 205 days) was significantly shorter in comparison to the low-risk thymoma (median 607 days) and high-risk thymoma (median 459 days) groups. No significant differences were observed between the low-risk thymoma and high-risk thymoma groups. When we set the cutoff time for differentiating thymic carcinoma group from thymoma at 313 days, the sensitivity and specificity were 83.8% and 82.1%, respectively.

CONCLUSIONS

The TDT is a useful parameter for differentiating between thymoma and thymic carcinoma group.

Verification of T descriptor with consolidation size for sub-centimeter non-small cell lung cancer

PURPOSE

In the most recent (eighth) edition of the TNM classification, the clinical T descriptor has been adapted to measure the consolidation size of sub-solid lung cancer. Sub-centimeter non-small cell lung cancer (NSCLC) has thereby been subclassified into three groups: Tis, T1mi, and T1a; however, the revision has not been validated well. Thus, we investigated the clinicopathological characteristics and long-term oncological outcomes of sub-centimeter NSCLCs based on the solid size.

METHODS

The subjects of this retrospective review were 99 patients who underwent complete resection for NSCLC with ≤ 1 cm in consolidation size on computed tomography (CT). Survival was reanalyzed after reclassification according to the new TNM classification.

RESULTS

This cohort consisted of 14 patients with cTis tumors, 18 with cT1mi tumors, and 67 with cT1a tumors. Among the patients with tumors classified as cT1a, two had lymph node metastasis and two had vascular invasion. The cumulative incidences of recurrence at 5 and 10 years were 0% for cTis/cT1mi tumors, and 4.5% and 6.1% for cT1a tumors, respectively.

CONCLUSIONS

There may be pathological and survival differences between cTis/cT1mi tumors and cT1a tumors, but not between cTis tumors and cT1mi tumors.

Clinicopathologic Features of Thymoma With the Expression of Programmed Death Ligand 1

BACKGROUND

Programmed death ligand 1 (PD-L1) is reportedly expressed in various malignancies and is considered a prognostic factor. We attempted to reveal the usefulness of the PD-L1 expression as a prognostic factor in patients with thymoma.

METHODS

Eighty-one patients with thymoma who underwent surgical resection between 2004 and 2015 were retrospectively reviewed. The PD-L1 expression was evaluated by immunohistochemistry and stratified by the proportion of positive tumor cells. Strong membranous reactivity of the PD-L1 antibody in 1% or more of tumor cells was considered "positive." The association between the PD-L1 expression and the clinicopathologic features was investigated.

RESULTS

The PD-L1 expression was positive in 22 patients (27%) and negative in 59 patients (73%). The PD-L1 positivity was significantly associated with type B2 and B3 thymoma (p < 0.001) and stage III and IV disease (p = 0.048). In addition, PD-L1 positive tumors showed a significantly higher maximum standardized uptake value than PD-L1 negative tumors (p = 0.026). The 5-year disease-free survival rate was 82% in PD-L1 positive patients and 88% in PD-L1 negative patients, showing no significant difference (p = 0.57). Furthermore, PD-L1 positivity was not an independent prognostic factor for the disease-free survival on a Cox proportional hazards analysis (p = 0.59).

CONCLUSIONS

A strong expression of PD-L1 in thymoma was significantly associated with type B2 and B3 and higher pathologic stages. In addition, PD-L1 positivity was associated with an increased maximum standardized uptake value of the tumor. However, patients with PD-L1 positive thymomas did not show a significantly worse prognosis than patients with PD-L1 negative tumors.

Prognostic impact of tumour size in completely resected thymic epithelial tumours

OBJECTIVES

The T descriptor of thymic epithelial tumours proposed by the International Association for the Study of Lung Cancer and the International Thymic Malignancy Interest Group as well as the Masaoka-Koga system is defined by the anatomical extent of primary tumours, regardless of their size. However, the prognostic significance of tumour size in thymic epithelial tumours has not been fully elucidated.

METHODS

We evaluated the prognostic significance of tumour size in 154 consecutive patients with thymic epithelial tumours including 124 thymomas, 21 thymic carcinomas and 9 neuroendocrine tumours, who underwent complete resection between 2001 and 2014.

RESULTS

Among all tumours, the median tumour size was 4.9 cm. The median thymoma, thymic carcinoma and neuroendocrine tumour sizes were 4.8, 5.7 and 5.8, respectively, although the differences were not significant. In survival analysis, the 5- and 10-year overall survival (OS) and recurrence-free survival (RFS) rates for all patients were 91 and 81%, and 80 and 69%, respectively. Under the stratification of tumour size, no trend was observed for OS, whereas RFS showed stepwise deterioration as tumour size increased. For 119 patients with Stage I disease, RFS showed deterioration as tumour size increased. Multivariate analysis revealed that tumour size >4.0 cm was an independent prognostic factor for worsening RFS (P = 0.03).

CONCLUSIONS

Patients with tumours >4.0 cm showed significantly worse outcomes in RFS compared with those with smaller tumours. This relationship was also noted in patients with Stage I disease.

Collaborative operation with cardiovascular surgeons in general thoracic surgery

OBJECTIVES

The aim of this study was to investigate the feasibility and safety of our surgical experiences conducted in collaboration with cardiovascular surgeons at our institution.

METHODS

From May 2002 to December 2015, among 3595 general thoracic surgeries, 75 (2.1%) operations were carried out collaboratively with cardiovascular surgeons at Nagoya University Hospital. We investigated the surgical procedures, manipulated organs, morbidity and mortality, completeness of surgical resection, and prognosis of these 75 cases.

RESULTS

The study cohort consisted of 56 males and 19 females, ranging in age from 18 to 79 years (median 60 years). Fifty-eight patients had a malignant disease, and 17 had a benign disease. Out of 75 collaborative surgeries, 53 (71%) were scheduled cases (cardiovascular surgeons' support was considered to be necessary preoperatively), and 22 (29%) were emergent cases (cardiovascular surgeons' support was considered to be necessary intraoperatively). No 30- or 90-day mortality was observed. Respiratory failure, defined as the requirement of mechanical ventilation or non-invasive positive pressure ventilation for ≥5 days, was the most common morbidity (n = 14, 18%). Forty-three patients (78%) out of 55 with thoracic neoplasms achieved microscopic complete resection. The resection status of the remaining 12 (22%) was microscopic residual tumor.

CONCLUSION

Collaborative surgeries with cardiovascular surgeons at our institution were feasible. High-quality surgeries with a good balance between safety and completeness of resection are important not only for treatment, but also in terms of education for general thoracic surgeons.

Marginal pulmonary function is associated with poor short- and long-term outcomes in lung cancer surgery

We sought to determine the short- and long-term prognoses among ‘marginal-risk’ non-small cell lung cancer patients who have a predicted postoperative- (ppo) forced expiratory volume in the first second (FEV₁) of 30–60% and/or a ppo-diffusing capacity of the lung for carbon monoxide (DL_CO) of 30–60%. The present study included 73 ‘marginal-risk’ and 318 ‘normal-risk’ patients who underwent anatomical resection for clinical stage I lung cancer between 2008 and 2012. The rates of postoperative morbidity, prolonged hospital stay, and overall survival were assessed. Postoperative morbidity occurred in 35 (48%) ‘marginal-risk’ patients and 66 (21%) ‘normal-risk’ patients, and 17 (23%) ‘marginal-risk’ patients and 20 (6%) ‘normal-risk’ patients required a prolonged hospital stay. The three- and five-year survival rates were 79% and 64% in the ‘marginal-risk’ patients and 93% and 87% in the ‘normal-risk’ patients, respectively. A ‘marginal-risk’ status was a significant factor in the prediction of postoperative morbidity (odds ratio [OR] 2.97, p < 0.001), the rate of prolonged hospital stay (OR 3.83, p < 0.001), and overall survival (hazard ratio 2.07, p = 0.028). In conclusion, ‘Marginal-risk’ patients, who are assessed based on ppo-values, comprise a subgroup of patients with poorer short- and long-term postoperative outcomes.

Pulmonary metastasis from urothelial carcinoma of the upper urinary tract 29 years after nephrectomy

Background

Late pulmonary metastasis from urothelial carcinoma (UC) of the upper urinary tract is extremely rare.

Case presentation

A 76-year-old man was referred to our hospital due to an abnormal shadow on chest X-ray. He had a history of left nephrectomy with a diagnosis of UC in the renal pelvis 29 years previously. Computed tomography showed a mass lesion in the right middle lobe of the lung that measured 4.9 cm in diameter. A transbronchial biopsy revealed the tumor to be metastatic pulmonary UC, and he underwent right middle lobectomy of the lung.

Conclusion

Long-term postoperative follow-up of patients with UC might be necessary after radical nephrectomy.

Monoiodoacetic acid induces arthritis and synovitis in rats in a dose- and time-dependent manner: proposed model-specific scoring systems

OBJECTIVE

In a rat monoiodoacetic acid (MIA)-induced arthritis model, the amount of MIA commonly used was too high, resulting in rapid bone destruction. We examined the effect of MIA concentrations on articular cartilage and infrapatellar fat pad (IFP). We also established an original system for "macroscopic cartilage and bone score" and "IFP inflammation score" specific to the rat MIA-induced arthritis model.

DESIGN

Male Wistar rats received a single intra-articular injection of MIA in the knee. The amount of MIA was 0.1, 0.2, 0.5, and 1 mg respectively. Articular cartilage was evaluated at 2-12 weeks. IFP was also observed at 3-14 days.

RESULTS

Macroscopically, low MIA doses induced punctate depressions on the cartilage surface, and cartilage erosion proceeded slowly over 12 weeks, while higher MIA doses already induced cartilage erosion at 2 weeks, followed by bone destruction. MIA macroscopic cartilage and bone score, OARSI histological score, and Mankin score increased in a dose- and time-dependent manner. The IFP inflammation score peaked at 5 days in low dose groups, then decreased, while in high dose groups, the IFP score continued to increase over 14 days due to IFP fibrosis.

CONCLUSIONS

Punctate depressions, cartilage erosion, and bone destruction were observed in the MIA-induced arthritis model. The macroscopic cartilage and bone scoring enabled the quantification of cartilage degeneration and demonstrated that MIA-induced arthritis progressed in a dose- and time-dependent manner. IFP inflammation scores revealed that 0.2 mg MIA induced reversible synovitis, while 1 mg MIA induced fibrosis of the IFP body.

Not single but periodic injections of synovial mesenchymal stem cells maintain viable cells in knees and inhibit osteoarthritis progression in rats

OBJECTIVE

We investigated the effects of single or repetitive intra-articular injections of synovial mesenchymal stem cells (MSCs) on a rat osteoarthritis (OA) model, and elucidated the behaviors and underlying mechanisms of the stem cells after the injection.

DESIGN

One week after the transection of the anterior cruciate ligament (ACL) of wild type Lewis rats, one million synovial MSCs were injected into the knee joint every week. Cartilage degeneration was evaluated with safranin-o staining after the first injection. To analyze cell kinetics or MSC properties, luciferase, LacZ, and GFP expressing synovial MSCs were used. To confirm the role of MSCs, species-specific microarray and PCR analyses were performed using human synovial MSCs.

RESULTS

Histological analysis for femoral and tibial cartilage showed that a single injection was ineffective but weekly injections had significant chondroprotective effects for 12 weeks. Histological and flow-cytometric analyses of LacZ and GFP expressing synovial MSCs revealed that injected MSCs migrated mainly into the synovium and most of them retained their undifferentiated MSC properties though the migrated cells rapidly decreased. In vivo imaging analysis revealed that MSCs maintained in knees while weekly injection. Species-specific microarray and PCR analyses showed that the human mRNAs on day 1 for 21 genes increased over 50-fold, and increased the expressions of PRG-4, BMP-2, and BMP-6 genes encoding chondroprotective proteins, and TSG-6 encoding an anti-inflammatory one.

CONCLUSION

Not single but periodic injections of synovial MSCs maintained viable cells without losing their MSC properties in knees and inhibited osteoarthritis (OA) progression by secretion of trophic factors.

Clinical evaluation of a new tumour-node-metastasis staging system for thymic malignancies proposed by the International Association for the Study of Lung Cancer Staging and Prognostic Factors Committee and the International Thymic Malignancy Interest Group

OBJECTIVES

The tumour-node-metastasis classification has been widely used as a guide for estimating prognosis, and is the basis for treatment decisions in patients with malignant tumours. The International Association for the Study of Lung Cancer Staging and Prognostic Factors Committee and the International Thymic Malignancy Interest Group have proposed a new staging system for thymic malignancies. However, its validity has not been fully established. In this study, we assessed the system's utilities and drawbacks.

METHODS

We reviewed 154 consecutive patients with thymic epithelial tumours who underwent complete resection at our institution, and compared their characteristics and outcomes when classified according to the proposed system with those when classified under the Masaoka-Koga system.

RESULTS

The proportion of patients with Stage I disease increased remarkably to 77.3% when using the proposed system because of the reclassification of Masaoka-Koga stages II and III diseases. Among 69 patients with Type A, AB or B1 thymoma, 68 tumours (98%) were reclassified as Stage I disease. Moreover, the proportion of Stage III and IV tumours increased in concordance with Types B2, B3 thymomas and thymic carcinoma. Under the proposed new system, the recurrence-free survival rates showed significant deterioration with increasing stage, while the overall survival curves did not.

CONCLUSIONS

The newly proposed classification for thymic malignancies does not serve as a prognostic prediction model for overall survival but served as a significant imbalance of stage distribution in our cohort. However, it appears to be beneficial, especially in clinical settings and recurrence-free survival analysis.