Kai Obayashi

Analysis of variation in bronchovascular pattern of the right middle and lower lobes of the lung using three-dimensional CT angiography and bronchography

ObjectivesGeneral thoracic surgeons must be familiar with anatomical variation in the pulmonary vessels and bronchi. Here, we analyzed the bronchovascular pattern of the right middle lobe (RML) and right lower lobe (RLL) of the lung using three-dimensional CT angiography and bronchography (3DCTAB).MethodsWe reviewed the anatomical patterns of the pulmonary vessels and bronchi in 270 patients using 3DCTAB images.ResultsThe branching patterns of vessels and bronchi of RML and S6 were classified according to the number of stems. The single-stem type was the most common, except in the artery of the RML, for which the two-stem type was the most common. The artery and bronchus of S*, which is an independent segment between S6 and S10, were observed in 20.4% of cases. The branching pattern of A7 (B7) was classified into four types. The A7a (B7a) type was observed in 74.8% of cases, and was the most common. The branching pattern of the artery and bronchus of S8−10 was classified into five and three types, respectively. The A8 and A9 + A10 type, and the B8 and B9 + B10 type, were observed in 68.1 and 80.4% of cases, respectively, and were the most common types. The branching pattern of V8−10 was more complex than that of A8−10 and B8−10.ConclusionWe explored the bronchovascular patterns of RML and RLL and their frequencies using a large number of 3DCTAB images. Our data can be used by thoracic surgeons to perform safe and precise lung resections.

Highly sensitive detection of a HER2 12-base pair duplicated insertion mutation in lung cancer using the Eprobe-PCR method

Somatic mutation in human epidermal growth factor receptor-related 2 gene (HER2) is one of the driver mutations in lung cancer. HER2 mutations are found in about 2% of lung adenocarcinomas (ADCs). Previous reports have been based mainly on diagnostic screening by Sanger sequencing or next-generation sequencing (NGS); however, these methods are time-consuming and complicated. We developed a rapid, simple, sensitive mutation detection assay for detecting HER2 12 base pair-duplicated insertion mutation based on the Eprobe-mediated PCR method (Eprobe-PCR) and validated the sensitivity of this assay system for clinical diagnostics. We examined 635 tumor samples and analyzed HER2 mutations using the Eprobe-PCR method, NGS, and Sanger sequencing. In a serial dilution study, the Eprobe-PCR was able to detect mutant plasmid DNA when its concentration was reduced to 0.1% by mixing with wild-type DNA. We also confirmed amplification of the mutated plasmid DNA with only 10 copies per reaction. In ADCs, Eprobe-PCR detected the HER2 mutation in 2.02% (9/446), while Sanger sequencing detected it in 1.57% (7/446). Eprobe-PCR was able to detect the mutation in two samples that were undetectable by Sanger sequencing. All non-ADC samples were wild-type. There were no discrepancies between frozen and formalin-fixed paraffin-embedded tissues in the nine samples. HER2 mutations detected by NGS data validated the high sensitivity of the method. Therefore, this new technique can lead to precise molecular-targeted therapies.

Impact of the Bim Deletion Polymorphism on Survival Among Patients With Completely Resected Non–Small-Cell Lung Carcinoma

Purpose A deletion polymorphism of the Bim gene has been reported to be a prognostic factor for patients with non–small-cell lung cancer (NSCLC) treated with epidermal growth factor receptor-tyrosine kinase inhibitors in the Asian population. We investigated the impact of the Bim deletion polymorphism on survival among patients with completely resected NSCLC. Patients and Methods The Bim polymorphism was detected by polymerase chain reaction analysis. We measured overall survival (OS) and recurrence-free survival rates in 411 patients and postrecurrence survival (PRS) in 94 patients who experienced recurrence and received additional anticancer therapy. Results The Bim deletion polymorphism was detected in 61 patients (14.8%). OS rates were significantly lower for patients with the Bim deletion polymorphism than for those with the wild-type sequence. On multivariable analysis, the Bim deletion polymorphism was identified as an independent prognostic factor for OS (hazard ratio, 1.98; 95% CI, 1.17 to 3.36; P = .011). Among the 94 patients who experienced recurrence and were treated with anticancer therapy, patients with the Bim deletion polymorphism showed significantly poorer PRS than those with the wild-type sequence (median, 9.8 months v 26.9 months, respectively; P < .001). Multivariable analysis revealed that the Bim deletion polymorphism was an independent predictor of PRS (hazard ratio, 3.36; 95% CI, 1.75 to 6.47; P < .001). This trend remained apparent in subgroup analyses stratified by EGFR status, histology, and therapeutic modality. Conclusion The Bim deletion polymorphism is a novel indicator of shortened PRS among patients with recurrent NSCLC treated with anticancer therapy in the Asian population.

The impact of histology and ground-glass opacity component on volume doubling time in primary lung cancer

Background Correlations between volume doubling time (VDT) of primary lung cancer (PLC), histology, and ground glass opacity (GGO) components remain unclear. The purpose of this study was to evaluate and compare VDT of PLC in terms of histology and presence or absence of GGO components. Methods A total of 371 surgically resected PLCs from 2003 to 2015 in our institute were retrospectively reviewed. The VDT was calculated both from the diameters of the entire tumor and of consolidation by using the approximation formula of Schwartz. Results The median VDTs of adenocarcinoma, squamous cell carcinoma, and others (large cell neuroendocrine carcinomas, small cell lung carcinomas, pulmonary pleomorphic carcinomas, and large cell carcinomas combined) were 261, 70, and 70 days, respectively; these differ significantly (P<0.001). All PLCs with GGO were adenocarcinomas. The VDT of adenocarcinomas with GGO was significantly longer than that of those without GGO (median VDT: 725 and 177 days, respectively), squamous cell carcinomas, and others. When the VDT calculated from the maximum diameter of consolidation component was compared, adenocarcinomas with GGO also showed significantly slower growth than those without GGO (median VDT: 248 versus 177 days, respectively, P=0.040). Conclusions The VDT of PLCs is longest for adenocarcinomas. VDT was significantly longer in adenocarcinomas with GGO components than in those without such components, irrespective of VDT calculated on the basis of either the entire tumor diameter or consolidation diameter.

Thoracoscopic Subsuperior Segment Segmentectomy

To date, anatomic subsuperior segment (S∗) segmentectomy has not yet been reported. Herein we report the technical details of thoracoscopic anatomic S∗ segmentectomy and the anatomic features of the S∗.

Thoracoscopic Medial-Basal Segment Segmentectomy

The technical details and anatomic features of medial-basal segment (S7) segmentectomy have not been reported. We report here thoracoscopic S7 segmentectomy and S7a subsegmentectomy and explain the anatomic knowledge necessary to perform S7 segmentectomy, especially the importance of recognizing bronchus (B7) branching patterns before surgery.

Anatomical segmentectomy of the lung: tip of identifying the intersegmental plane

A pulmonary segmentectomy requires identification of the segmental planes, making it technically more difficult than a lobectomy. Therefore, we present a selective segmental-inflation technique using a butterfly needle. This paper discusses anatomical segmenectomy with special reference to identifying the intersegmental plane. Methods First, the lung is deflated and the pulmonary vessels to the involved segment are divided. The segmental bronchus is divided using a stapling device or ligation. Then, using a butterfly needle, oxygen (approximately 1 L/min.) is instilled into the targeted bronchus to inflate the involved segment, and the involved segment is severed and removed using electrocautery or a stapling device. The raw surface is covered with an absorbable sealing material to prevent air leaks. Results Fifty-three (M:F = 33:33) patients underwent anatomical segmentectomy with the selective segmental-inflation technique using a butterfly needle. Their median age was 64.9 years. The diseases were malignant lung disease in 52 patients and benign lung disease in 14. The surgical procedure was segmentectomy only in 60 and segmentectomy combined with lobectomy in six. The median operating time was 170 min; the blood loss was 82 g; and the postoperative stay was 8 days. The duration of chest tube drainage was 3 days. No major complication occurred. Conclusions In summary, anatomical segmentectomy was performed successfully with the selective segmental-inflation technique using a butterfly needle. Advantages: Surgeons can control every manipulation. No special device is needed; a butterfly needle is sufficient. It is useful regardless of the situation of proximal bronchus. Ultraselective air instillation into the subsegmental bronchus depends on the needle direction. Disadvantages: The proximal site of the targeted bronchus must be identified. Care is needed to avoid systemic air embolism.