Koichiro Kajiura

Fluoroscopy-assisted thoracoscopic resection after computed tomography-guided bronchoscopic metallic coil marking for small peripheral pulmonary lesions

OBJECTIVES To re-evaluate the efficacy of fluoroscopy-assisted thoracoscopic resection after computed tomography (CT)-guided bronchoscopic metallic coil marking (FATS-CM), which was our original method for small peripheral pulmonary lesions. METHODS Fifty-eight patients with 63 lesions underwent FATS-CM. A metallic coil was installed in the bronchus nearest to the lesion under CT fluoroscopic guidance with ultrathin bronchoscopy. The virtual bronchoscopic navigation (VBN) system was used in 14 cases. Afterwards, we basically performed wide wedge resection (WWR) using a C-arm-shaped roentgenographic fluoroscope during thoracoscopic surgery initially, and then the final procedure was determined by intraoperative histological diagnosis. Moreover, we prospectively treated ground-glass opacity (GGO) lesions of <20 mm diameter according to our treatment protocol from September 2004. RESULTS We could install coils in the objective bronchi in all cases. The average time required for the marking procedure was 38.9 (15-120) min. Pneumothorax was recognized in 1 (1.7%) case as a complication, but no fatal complications occurred. We could also install coils for each lesion in 4 cases (9 lesions) with multiple lesions. In 14 cases with the VBN system, the examination time and CT number were significantly reduced (P < 0.05 and <0.001, respectively), compared with those of 40 cases without the VBN system. The average interval between the CM and the operation was 5.6 (0-30) days. We never experienced a case of migration preoperatively. Sixty-two (98.4%) lesions were definitively identified, and WWRs were performed using three trocars in 58 (92.1%) cases during thoracoscopic surgery. Lobectomy was initially performed in only 1 case owing to coil migration. Thirty-seven of 40 cases (92.5%) were in line with the treatment protocol. There were no local-regional recurrences in all cases undergoing WWR. CONCLUSIONS We could prospectively show that our method was suitable to perform WWR with a sufficient margin for small GGO lesions of <20 mm. Moreover, we reconfirmed that the advantages of our method were safety, permitting flexibility in scheduling operations and a high ability to deal with multiple lesions. Additionally, our method became a minimally invasive and mature technique by using a new VBN system.

18F-fluorodeoxyglucose positron emission tomography/computed tomography and the relationship between fluorodeoxyglucose uptake and the expression of hypoxia-inducible factor-1α, glucose transporter-1 and vascular endothelial growth factor in thymic epithelial tumours.

OBJECTIVES The objective of this study was to evaluate the usefulness of (18)F-fluorodeoxyglucose positron emission tomography/computed tomography (FDG-PET/CT) and the relationships among the expressions of hypoxia-inducible factor-1α (HIF-1α), glucose transporter-1 (Glut-1) and vascular endothelial growth factor (VEGF), histological type, other clinical factors and FDG uptake in thymic epithelial tumours. METHODS Thirty-three patients who underwent FDG-PET/CT before treatment were reviewed. All types of tumours were reclassified into three subgroups: low-risk thymomas (types A, AB and B1), high-risk thymomas (types B2 and B3) and thymic carcinomas. Tumour contour, pattern of FDG uptake, tumour size and maximum standardized uptake value (SUVmax) were obtained. Expressions of HIF-1α, Glut-1 and VEGF were analysed immunohistochemically, and these expressions were evaluated using grading scales. RESULTS FDG uptake was visually recognized in all (100%) tumours. A homogeneous pattern of FDG uptake was increasingly observed in the order of low-risk thymomas to high-risk thymomas to thymic carcinomas (P = 0.016). SUVmax for thymic carcinomas was significantly higher than that for thymomas (P = 0.008). With the optimal cut-off value of SUVmax of 5.6, the sensitivity, specificity and accuracy for diagnosing thymic carcinoma were 0.75, 0.80 and 0.79, respectively. Regarding the mean scoring of HIF-1α, Glut-1 and VEGF, increasing trends were observed in the order of low-risk thymomas to high-risk thymomas to thymic carcinomas. Tumour size revealed a significant correlation with SUVmax (r = 0.60, P < 0.001), and the expression of HIF-1α showed a moderate association, but the expression of Glut-1 showed no correlation with SUVmax. Regarding correlations between the expression of the three markers, there were moderate associations between HIF-1α and Glut-1, and HIF-1α and VEGF, and a significant correlation between Glut-1 and VEGF (r = 0.60, P < 0.001). In type B1 thymoma, HIF-1α and Glut-1 were partly expressed in non-neoplastic immature lymphocytes. CONCLUSIONS FDG-PET/CT should be performed in patients with tumours in the anterior mediastinum because the pattern of FDG uptake and SUVmax are useful in the differential diagnosis of thymic epithelial tumours. Furthermore, the expressions of HIF-1α, Glut-1 and VEGF might be associated with malignancy of thymic epithelial tumours. In contrast, FDG uptake might be dependent on tumour size rather than Glut-1 overexpression.

Methylation and expression profiles of MGMT gene in thymic epithelial tumors

OBJECTIVES A key challenge in diagnosis and treatment of thymic epithelial tumors (TET) is in improving our understanding of the genetic and epigenetic changes of these relatively rare tumors. METHODS Methylation specific PCR (MSP) and immunohistochemistry were applied to 66 TET to profile the methylation status of DNA repair gene O6-methylguanine DNA methyltransferase (MGMT) and its protein expression in TET to clarify the association between MGMT status and clinicopathological features, response to chemotherapy and overall survival. RESULTS MGMT methylation was significantly more frequent in thymic carcinoma than in thymoma (17/23, 74% versus 13/44, 29%; P<0.001). Loss of expression of MGMT protein was significantly more frequent in thymic carcinoma than in thymoma (20/23, 87% versus 10/44, 23%; P<0.0001). There is a significant correlation between of MGMT methylation and loss of its protein expression (P<0.0003). MGMT methylation and loss of expression were significantly more frequent in advanced thymic epithelial tumors (III/IV) than in early tumors (I/II). CONCLUSION MGMT methylation plays a soul role in development of TET, especially in thymic carcinoma. Therefore, translation of our results from basic molecular research to clinical practice may have important implication for considering MGMT methylation as a marker and a target of future therapies in TET.

Computed tomography lymphography by transbronchial injection of iopamidol to identify sentinel nodes in preoperative patients with non–small cell lung cancer: A pilot study

OBJECTIVE The objective of the present study was to assess the safety and feasibility of computed tomography lymphography by transbronchial injection of a water-soluble extracellular computed tomography contrast agent. METHODS From April 2010 to May 2011, patients with clinical stage I non-small cell lung cancer who were candidates for lobectomy were enrolled in the present study. An ultrathin bronchoscope was inserted to the target bronchus under the guidance of virtual bronchoscopic navigation images. Computed tomography images of the chest were obtained 0.5 and 5 minutes after 2 or 3 mL of iopamidol was injected through a microcatheter. Sentinel nodes were identified when the maximum computed tomography attenuation value of the lymph nodes on the postcontrast computed tomography images increased by 30 Hounsfield units or more compared with the precontrast images. Patients underwent lobectomy with standard lymph node dissection. RESULTS The ultrathin bronchoscope could access the targeted bronchus, and iopamidol was delivered into the peritumoral area in all 13 patients without any complications. Sentinel nodes were identified in 12 (92.3%) of the 13 patients. The average number of sentinel nodes was 1.5 (range, 1-2). Pathologic examination revealed metastatic lymph nodes in 2 patients. Metastatic nodes were included with the sentinel nodes. CONCLUSIONS Computed tomography lymphography by transbronchial injection of iopamidol was a safe and feasible method to identify the sentinel nodes in patients with clinical stage I non-small cell lung cancer.

Frequent silencing of the candidate tumor suppressor TRIM58 by promoter methylation in early-stage lung adenocarcinoma

In this study, we aimed to identify novel drivers that would be epigenetically altered through aberrant methylation in early-stage lung adenocarcinoma (LADC), regardless of the presence or absence of tobacco smoking-induced epigenetic field defects. Through genome-wide screening for aberrantly methylated CpG islands (CGIs) in 12 clinically uniform, stage-I LADC cases affecting six non-smokers and six smokers, we identified candidate tumor-suppressor genes (TSGs) inactivated by hypermethylation. Through systematic expression analyses of those candidates in panels of additional tumor samples and cell lines treated or not treated with 5-aza-deoxycitidine followed by validation analyses of cancer-specific silencing by CGI hypermethylation using a public database, we identified TRIM58 as the most prominent candidate for TSG. TRIM58 was robustly silenced by hypermethylation even in early-stage primary LADC, and the restoration of TRIM58 expression in LADC cell lines inhibited cell growth in vitro and in vivo in anchorage-dependent and -independent manners. Our findings suggest that aberrant inactivation of TRIM58 consequent to CGI hypermethylation might stimulate the early carcinogenesis of LADC regardless of smoking status; furthermore, TRIM58 methylation might be a possible early diagnostic and epigenetic therapeutic target in LADC.

Non-invasive monitoring of anticancer effects of cisplatin on lung cancer in an orthotopic SCID mouse model using [18F] FDG PET-CT

Positron emission tomography-computed tomography (PET-CT) with [18F] fluorodeoxyglucose (FDG) has recently been applied for evaluating tumor response to anticancer therapy. The aim of the present study was to evaluate the utility of FDG PET-CT in monitoring non-invasively and repeatedly the inhibitory effect of cisplatin (CDDP) on an orthotopic lung cancer model. Validation of in vivo FDG uptake in human lung cancer Ma44-3 cell line in an orthotopic SCID mouse model was carried out. Next, we assessed the use of FDG PET-CT to monitor the response of orthotopic lung cancer to the anticancer effect of CDDP. SCID mice were divided into the CDDP group (7 mg/kg single dose intraperitoneally) and the control group. Tumor volume and maximal standardized uptake value (SUV max) were calculated for all mice. All mice were sacrificed for histopathologic analysis. Validation of FDG PET-CT showed that tumor volume and SUV max were significantly correlated with postmortem tumor length measured in specimens (P=0.023) and (P=0.012), respectively, and there was a significant correlation between SUV max and tumor volume (P=0.048). Response monitoring showed that significant growth inhibition by CDDP in the form of SUV max of the CDDP group was significantly lower than that of the control group on day 8 (P=0.02) and on day 13 (P=0.003). Tumor volume of the CDDP group was significantly lower than that of the control group on day 13 (P=0.03). The present study supports using FDG PET-CT in monitoring tumor progression and therapeutic response of lung cancer in an orthotopic model non‑invasively and repeatedly.

Autofluorescence for the diagnosis of visceral pleural invasion in non-small-cell lung cancer

OBJECTIVES This study was conducted to evaluate the accuracy of autofluorescence as a mode of diagnosis for visceral pleural invasion of non-small-cell lung cancer compared with white-light by means of clinical questions to several thoracic surgeons. METHODS Eight independent thoracic surgeons evaluated visceral pleural invasion in 25 cases of non-small-cell lung cancer attached to the visceral pleura on lung windows of preoperative computed tomography images. At the first study meeting to evaluate the accuracy of visceral pleural invasion diagnosis using conventional white-light images, the surgeons diagnosed visceral pleural invasion based on information in preoperative computed tomography images, histological types and videos recorded with white-light mode using a thoracoscope. At the second study meeting to evaluate the accuracy of visceral pleural invasion diagnosis using autofluorescence, the same surgeons diagnosed visceral pleural invasion based on information in 2 videos recorded in white-light mode and in autofluorescence mode using the thoracoscope. RESULTS The overall average sensitivity, specificity and accuracy of visceral pleural invasion diagnosis by white-light versus autofluorescence mode were 64.6% vs 83.3%, 53.9% vs 73.7% and 56.5% vs 76.0%, respectively. CONCLUSIONS The sensitivity, specificity and accuracy of visceral pleural invasion diagnosis was improved through the additional use of the autofluorescence mode compared with the white-light mode alone.

Frequent silencing of RASSF1A by DNA methylation in thymic neuroendocrine tumours

OBJECTIVES Aberrant methylation of promoter CpG islands (CGIs) of tumour suppressor genes is a common epigenetic mechanism underlying cancer pathogenesis. The methylation patterns of thymic tumours have not been studied in detail since such tumours are rare. Herein, we sought to identify genes that could serve as epigenetic targets for thymic neuroendocrine tumour (NET) therapy. MATERIALS AND METHODS Genome-wide screening for aberrantly methylated CGIs was performed in three NET samples, seven thymic carcinoma (TC) samples, and eight type-B3 thymoma samples. The methylation status of thymic epithelial tumours (TETs) samples was validated by pyrosequencing in a larger cohort. The expression status was analysed by quantitative polymerase chain reaction (PCR) and immunohistochemistry. RESULTS We identified a CGI on a novel gene, RASSF1A, which was strongly hypermethylated in NET, but not in thymic carcinoma or B3 thymoma. RASSF1A was identified as a candidate gene statistically and bibliographically, as it showed frequent CGI hypermethylation in NET by genome-wide screening. Pyrosequencing confirmed significant hypermethylation of a RASSF1A CGI in NET. Low-grade NET tissue was more strongly methylated than high-grade NET. Quantitative PCR and immunohistochemical staining revealed that RASSF1A mRNA and protein expression levels were negatively regulated by DNA methylation. CONCLUSIONS RASSF1A is a tumour suppressor gene epigenetically dysregulated in NET. Aberrant methylation of RASSF1A has been reported in various tumours, but this is the first report of RASSF1A hypermethylation in TETs. RASSF1A may represent an epigenetic therapeutic target in thymic NET.

Indocyanine Green Fluorescence Intraoperative Imaging for Hepatic Hydrothorax With a Small Diaphragmatic Defect

Fluorescence imaging revealed the passage of a small Hepatic hydrothorax is defined as a pleural effusion in a patient with cirrhosis who does not have any other detectable cause for the effusion. The most likely etiology is leakage of ascites from the peritoneal cavity into the pleural cavity through diaphragmatic defects. These defects are almost always very small, making them difficult to detect during thoracoscopic surgery. Here we report the use of indocyanine green (ICG) fluorescence imaging combined with pneumoperitoneum for the detection of a diaphragmatic defect in a patient with hepatic hydrothorax. amount of dye through the diaphragm.