Comparison of Preoperative CT Scan Guided and Intraoperative Hybrid DynaCT Scan-Guided Small Lung Tumor Localization

Overview

It is well known that video-assisted thoracoscopic surgery(VATS) is preferred to open surgery for lung resection because of the use of smaller incisions and optimized postoperative recovery, including a shorter length of hospitalization. Studies have shown decreased operative and post-operative morbidity with decreased operative times. However, for small nodules (i.e. lesions \<1 cm or those at a distance more than 1.5cm from the lung periphery), adequate identification of the target nodule has been be difficult by VATS, and a more significant resection or conversion to thoracotomy is occasionally needed to ensure complete resection. In order to improve nodule localization, a variety of preoperative localization methods such as CT-guide hook wire or methyl blue dye localization have been proposed and described to mark lung nodules for easier identification of small nodules and help guide resection during VATS. However, there are certain concerns. First, there are the difficult logistics in minimizing the time between the localization procedure and the subsequent surgery. Second, there is concern for patient safety, in particular pneumothorax, during transfer to and from the ward to the radiology department and in the frequent delays and waiting in reception areas prior to transfer to operating heaters. Finally, interdepartmental transfers and delays can also increase the risk of hook-wire dislodgement. Theoretically, the aforementioned disadvantage could be solved by performing the localization procedure and the lung surgery in the same hybrid operating room environment. In the current study, the investigators will perform intraoperative lung tumor localization in CGMH hybrid operation room (Room 51) equipped with the Siemens Artis Zeego system with DynaCT imaging capabilities. The system provides images equivalent to a 16-slice spiral CT scanner in a single 6-s sweep. Through a randomized study design, the advantages, disadvantages, and important considerations of this combined approach will be compared with traditional preoperative CT scan guided localization protocol.

Lung Cancer continues to have high morbidity and mortality, and it is estimated that in 2014 in Taiwan there were approximately 11692 new cases and 9167 deaths from lung cancer, which was the first leading cause of cancer deaths. Because 70% of lung cancer patients in Taiwan were diagnosed at late stage, only palliative treatment could be given and prognosis was poor. Owing so, screening and early detection of early stage lung cancer is of paramount importance. In 2012, the National Lung Screening Trial demonstrated that screening for lung cancer with chest computed tomography (CT) results in a 20% reduction in mortality. Low dose CT(LDCT) has been acknowledged as the most powerful tool for early lung cancer detection. With the increasing use of CT, it is expected that many patients with small lesions (\< 2 cm), enlarging lesions, and partially solid lesions that are suspicious for cancer will be discovered and will require surgical resection. It is well known that video-assisted thoracoscopic surgery(VATS) is preferred to open surgery for lung tumor resection because of the use of smaller incisions and optimized postoperative recovery, including a shorter length of hospitalization. Studies have shown decreased operative and post-operative morbidity with decreased operative times. While this procedure speeds up recovery and potentially reduces complications, the loss of natural vision and tactile sensing makes it difficult for the surgeon to locate the nodules, especially in cases of non-superficial, ground-glass opaque, and small lesions. The yield rate for nodules \< 1 cm can be below 40% as studies show. And a more significant resection (more healthy tissue is resected than actually necessary in order to avoid missing the lesion.) or conversion to thoracotomy is occasionally needed to ensure complete resection. In order to improve nodule localization, a variety of methods have been proposed and described to mark lung nodules for easier identification of small nodules and help guide resection during VATS. These ranged from percutaneous image guided injection of a dye (methylene blue) or radio-opaque material such as barium sulphate, to percutaneously placed hookwires and micro-coils in the radiology suite prior to surgery. All these preoperative CT scan guided localization procedures were carried out "outside" operation room and under local anesthesia. However, there remain certain concerns. First, there are the difficult logistics in minimizing the time between the hookwire procedure and the subsequent surgery. Second, there is concern for patient safety, in particular pneumothorax, during transfer to and from the ward to the radiology department and in the frequent delays and waiting in reception areas prior to transfer to operating theaters. Finally, interdepartmental transfers and delays can also increase the risk of hookwire dislodgement. Theoretically, the aforementioned disadvantage could be solved by performing the localization procedure and the lung surgery in the same hybrid operating room environment(i.e. Hybrid OR). A hybrid operating room is a surgical theatre that is equipped with advanced medical imaging devices such as fixed C-Arms, CT scanners or MRI scanners. These imaging devices enable minimally-invasive surgery, which is less traumatic for the patient. Hybrid operating rooms are currently used mainly in cardiac, vascular and neuro-surgery, and could be suitable for a number of other surgical disciplines, such as thoracic surgery. Using advanced intra-operative imaging in the OR helps to precisely locate and resect the lesion in a potentially tissue-sparing and quick fashion. In order to be able to use image guidance during VATS, rotational angiography has to be performed before the introduction of ports, thus before the lobe in question deflates. This way the lesion is visible through the natural contrast of air. In a second step, hook wires, thread needles, or contrast agent (Lipiodol, Iopamidol) are introduced into or next to the lesion to ensure visibility on the angiogram after lung deflation. Then, the conventional part of VATS starts with the introduction of thoracoscope. The imaging system is used in fluoroscopic mode now, where both the inserted instruments and the previously marked lesion are well visible. A precise resection is now possible. In case contrast agent has been used to mark the lesion, it will also drain into the regional lymph nodes, which then can be resected within the same procedure. Reviewing the literature, there are several studies reporting the efficacy of Hybrid OR in localization of the lung nodule with good result and acceptable radiation exposure. However, there was no study so far comparing the efficacy of intraoperative localization and preoperative CT guided localization. In the current study, the investigators will perform intraoperative lung tumor localization in CGMH hybrid OR(Room 51) equipped with the Siemens Artis Zeego system with DynaCT imaging capabilities. The system provides images equivalent to a 16-slice spiral CT scanner in a single 6-s sweep. Through a randomized study design, the advantages, disadvantages, and important considerations of this combined approach will be compared with traditional preoperative CT scan guided localization protocol.