Protocol for the VAL-MAP 2.0 trial: a multicentre, single-arm, phase III trial to evaluate the effectiveness of virtual-assisted lung mapping by bronchoscopic dye injection and microcoil implementation in patients with small pulmonary nodules in Japan

Prospective Exploratory Phase I Clinical Trial Assessing the Safety of Preoperative Marking for Small Liver Tumors

Background Small tumors in liver cirrhosis are difficult to distinguish using intraoperative ultrasonography. In addition, preoperative chemotherapy for metastatic liver cancer may diminish tumor size, thus making tumors difficult to identify intraoperatively. To address such difficulties, we devised a method to mark liver tumors preoperatively to facilitate intraoperative identification. This study aimed to investigate the safety of a preoperative liver tumor marking method. Methodology This exploratory prospective clinical trial included patients with liver tumors measuring ≤20 mm requiring resection. Preoperative marking was performed by placing a coil for embolization of blood vessels near the tumor using either the transcatheter or percutaneous approach. The tumor was identified and resected by intraoperative ultrasonography based on the marker. The study was registered in the University Hospital Medical Information Network Clinical Trials Registry (UMIN000028608). Results Overall, 19 patients (9 with primary liver cancer and 10 with metastatic tumors) were recruited. The transcatheter and percutaneous methods were used in 13 and 6 patients, respectively. Marking was not possible in two patients in the transcatheter group because the catheter could not be guided to the vicinity of the tumor. There were no marking-related complications. Hepatectomy was performed in all but one patient who was not fit for hepatectomy owing to the development of a metastatic liver tumor. The markers were adequately identified during hepatectomy. Additionally, there were no difficulties in the surgical procedure or postoperative complications. Conclusions Preoperative marking with embolization coils can be performed safely for intraoperative identification of liver nodules.

Expert consensus on indocyanine green fluorescence imaging for thoracoscopic lung resection (The Version 2022)

The use of the white-light thoracoscopy is hampered by the low contrast between oncologic margins and surrounding normal parenchyma. As a result, many patients with in situ or micro-infiltrating adenocarcinoma have to undergo lobectomy due to a lack of tactile and visual feedback in the resection of solitary pulmonary nodules. Near-infrared (NIR) guided indocyanine green (ICG) fluorescence imaging technique has been widely investigated due to its unique capability in addressing the current challenges; however, there is no special consensus on the evidence and recommendations for its preoperative and intraoperative applications. This manuscript will describe the development process of a consensus on ICG fluorescence-guided thoracoscopic resection of pulmonary lesions and make recommendations that can be applied in a greater number of centers. Specifically, an expert panel of thoracic surgeons and radiographers was formed. Based on the quality of evidence and strength of recommendations, the consensus was developed in conjunction with the Chinese Guidelines on Video-assisted Thoracoscopy, and the National Comprehensive Cancer Network (NCCN) guidelines on the management of pulmonary lesions. Each of the statements was discussed and agreed upon with a unanimous consensus amongst the panel. A total of 6 consensus statements were developed. Fluorescence-guided thoracoscopy has unique advantages in the visualization of pulmonary nodules, and recognition and resection of the anterior plane of the pulmonary segment. The expert panel agrees that fluorescence-guided thoracoscopic surgery has the potential to become a routine operation for the treatment of pulmonary lesions.

Computed Tomography-Guided Localization and Extended Segmentectomy for Non-Small Cell Lung Cancer

Background: Lung cancer is one of the most devastating cancers. Low-dose computed tomography (LDCT) can detect lung cancer at an early stage of the disease when a minimally invasive surgical procedure using video-assisted thoracoscopic surgery is the best strategy. Herein, we discuss the treatment of deep lung tumors between segments or lesions located near the margin of a segment. Patients and Methods: This was a retrospective study conducted from January 2013 to January 2020 using the National Taiwan University Hospital data bank. We included early-stage non-small cell lung cancer (NSCLC) patients who underwent lung surgery and screened out those who received CT-guided localization for extended segmentectomy. Outcome measurements were safety margin, complication rate, and postoperative course. Results: During the study period, 68 patients with early-stage NSCLC received CT-guided localization followed by extended segmentectomy. The mean surgery time was 92.1 ± 30.3 min, and the mean blood loss was 32.8 mL. Mean drainage time was 2.3 ± 1 days, and the total hospital stay was 4.9 ± 1.1 days. Pathological reports showed tumor-free resection margins >2 cm. Sixty-one patients had adenocarcinoma at stage IA and two patients at stage IB. One patient had squamous cell carcinoma at stage IA. Conclusion: CT-guided localization followed by extended segmentectomy allows lung volume preservation with clean safety margins and good clinical outcomes.

Novel Intraoperative CT-Guided Marking Using O-arm System in Video-Assisted Thoracoscopic Surgery: An Easy, Safe, Time-Saving, Practical Method

OBJECTIVE

With the increased frequency of small lung tumor detection, there has been a similar increase in limited surgery, such as wedge resection. To identify such small lung tumors, we use a computed tomography (CT)-guided intraoperative marking method using the O-arm Surgical Imaging System. We retrospectively investigated its usefulness.

METHODS

Of 1,043 cases of thoracic surgery performed at our department between May 2017 and June 2021, O-arm System marking was used in 30 cases (2.9%), totaling 39 lesions. Tumor location was predicted preoperatively based on 3-dimensional CT and anatomic positioning. Visceral pleura near the tumor was marked with a metal clip, and the O-arm System was brought to the surgical site. CT was taken after the tumor side lung was fully re-expanded and clamped. After confirming the tumor and the clip locations, the clip was repositioned as necessary and marked in the same way. If the marking was successful, the clips were used as markers when performing lung resection.

RESULTS

Marking was successful in all cases. The average number of targets was 1.3, the average number of O-arm insertions was 1.3, and the average total number of marking clips was 2.6. In all cases, we checked the specimens, and if the tumor was palpable, the resection margin was also checked. No intraoperative or postoperative complications were observed in any patients.

CONCLUSIONS

If the O-arm System is available, this technique is a noninvasive, simple, and useful method that could be widely used in clinical practice with a low dose of radiation.

Risk factors for invisible intraoperative markings after virtual-assisted lung mapping

BACKGROUND

Virtual-assisted lung mapping (VAL-MAP) is a preoperative bronchoscopic multi-spot dye-marking technique, which can be combined with bronchoscopic placement of a microcoil (VAL-MAP 2.0). VAL-MAP can identify unpalpable pulmonary lesions; however, the markings are occasionally deemed invisible intraoperatively. We investigated preoperative risk factors for invisible markings after VAL-MAP.

METHODS

We prospectively performed preoperative VAL-MAP in patients at the University of Tokyo between January 2014 and June 2020. Data of 219 patients (257 lesions) and 857 markings were retrospectively reviewed. Dye markings were categorized as Grade 0 (invisible) or 1-5 (visible). The risk factors for Grade 0 markings were assessed using multiple logistic regression analysis. Subsegments of the bronchus showing Grade 0 markings were also evaluated for 133 lesions and 504 markings without missing data for the target segment.

RESULTS

Sixty-one of the 257 lesions (24%) displayed >1 Grade 0 markings. Seventy-six (8.9%) of the 857 markings were Grade 0 intraoperatively. VAL-MAP 1.0 was performed for 202 (79%) and 25 lesions (10%) without and with electromagnetic navigation bronchoscopy, and VAL-MAP 2.0 with a microcoil was performed for 30 lesions (11%). Upper lobe markings were associated with a significantly increased risk of invisible markings. There was no significant difference in the frequency of Grade 0 markings among the VAL-MAP methods. Among all bronchi subsegments, left B1+2c exhibited the highest rate of Grade 0 markings.

CONCLUSIONS

Markings placed using VAL-MAP are more likely to be invisible for upper lobe pulmonary lesions. Injecting markings for lesions in the left S1+2c thus require caution.

The role of virtual-assisted lung mapping 2.0 combining microcoils and dye marks in deep lung resection

OBJECTIVES

Virtual-assisted lung mapping 2.0 is a novel preoperative bronchoscopic lung mapping technique combining the multiple dye marks of conventional virtual-assisted lung mapping with intrabronchial microcoils to navigate thoracoscopic deep lung resection. This study's purpose was to evaluate the feasibility of virtual-assisted lung mapping 2.0 in resecting deeply located pulmonary nodules with adequate margins.

METHODS

A multicenter, prospective single-arm study was performed from 2019 to 2020 in 8 institutions. The selection criteria were barely identifiable nodules requiring sublobar lung resections, nodules requiring resection lines reaching the inner 2/3 of the pulmonary lobe on computed tomography images in wedge resection, or the nodule center located in the inner 2/3 of the pulmonary lobe in wedge resection or segmentectomy. Resection margins larger than 2 cm or the nodule diameter were considered successful resection. Bronchoscopic placement of multiple dye marks and microcoil(s) was conducted 0 to 2 days before surgery.

RESULTS

We analyzed 65 lesions in 64 patients. The diameter and depth of the targeted nodules and the minimum required resection depth reported as median (interquartile range) were 9 (7-13) mm, 11 (5-15) mm, and 30 (25-35) mm, respectively. Among 60 wedge resections and 5 segmentectomies, successful resection was achieved in 64 of 65 resections (98.5%; 95% confidence interval, 91.7-100). Among 75 microcoils placed, 3 showed major displacement after bronchoscopic placement. There were no severe adverse events associated with the virtual-assisted lung mapping procedure.

CONCLUSIONS

This study demonstrated that virtual-assisted lung mapping 2.0 can facilitate successful resections for deep pulmonary nodules, overcoming the limitations of conventional virtual-assisted lung mapping.

Managing screening-detected subsolid nodules-the Asian perspective

The broad application of low-dose computed tomography (CT) screening has resulted in the detection of many small pulmonary nodules. In Asia, a large number of these detected nodules with a radiological ground glass pattern are reported as lung adenocarcinomas or premalignant lesions, especially among female non-smokers. In this review article, we discuss controversial issues and conditions involving these subsolid pulmonary nodules that we often face in Asia, including a lack or insufficiency of current guidelines; the roles of preoperative biopsy and imaging; the location of lesions; appropriate selection of localization techniques; the roles of dissection and sampling of frozen sections and lymph nodes; multifocal lesions; and the roles of non-surgical treatment modalities. For these complex issues, we have tried to present up-to-date evidence and our own opinions regarding the management of subsolid nodules. It is our hope that this article helps surgeons and physicians to manage the complex issues involving ground glass nodules (GGNs) in a balanced manner in their daily practice and provokes further discussion towards better guidelines and/or algorithms.

The efficacy of transbronchial indocyanine green instillation for fluorescent-guided wedge resection

 

OBJECTIVES

The purpose of this study was to investigate the feasibility of lung wedge resection by combining 3-dimensional (3D) image analysis with transbronchial indocyanine green (ICG) instillation, in order to delineate the intended area for resection.

METHODS

From December 2017 to July 2020, 28 patients undergoing wedge resection (17 primary lung cancers, 11 metastatic lung tumours) were enrolled, and fluorescence-guided wedge resection was attempted. Virtual sublobar resections were created preoperatively for each patient using a 3D Image Analyzer. Surgical margins were measured in each sublobar resection simulation in order to select the most optimal surgical resection area. After transbronchial instillation of ICG, near-infrared thoracoscopic visualization allowed matching of the intended area for resection to the virtual sublobar resection area. To investigate the effectiveness of ICG instillation, the clarity of the ICG-florescent border was evaluated, and the distance from the true tumour to the surgical margins was compared to that of simulation.

RESULTS

Mean tumour diameter was 12.4 ± 4.3 mm. The entire targeted tumour was included in resected specimens of all patients (100% success rate). The shortest distances to the surgical margin via 3D simulation and by actual measurement of the specimen were11.4 ± 5.4 and 12.2 ± 4.1 mm, respectively (P = 0.285) and were well correlated (R2 = 0.437). While all specimens had negative malignant cells at the surgical margins, one loco-regional recurrence was observed secondary to the dissemination of neuroendocrine carcinoma.

CONCLUSIONS

ICG-guided lung wedge resection after transbronchial ICG instillation and preoperative 3D image analysis allow for adequate negative surgical margins, providing decreased risk of local recurrence.

Strategies to improve the accuracy of lung stapling in uniportal and multiportal thoracoscopic sublobar lung resections

The challenges in video-assisted thoracic surgery for sublobar lung resection include difficulty in tumour localization by palpation and difficulty in determining appropriate resection lines. Virtual-assisted lung mapping (VAL-MAP), a bronchoscopic preoperative multispot lung dye-marking technique, allows for both tumour localization and determination of resection lines. To facilitate stapler-based resection, the AMAGAMI or 'incomplete grasping' stapler technique is useful to adjust the alignment of the stapler and resection lines. However, when the lung tissue to be stapled is thick, there is unavoidable uncertainty in the staple line inside the lung. We experimentally demonstrated that up to 1 cm of slippage of lung parenchyma occurs at stapling when the stapled lung tissue is >1 cm thick. VAL-MAP 2.0 is a new generation of VAL-MAP combining multispot dye markings with intrabronchial microcoil placement, allowing for 3-dimensional lung mapping and intraoperative navigation using fluoroscopy. The uncertainty of stapling in the lung parenchyma can be partly overcome by VAL-MAP 2.0.