Near-Infrared Fluorescence Guided Robotic Pulmonary Segmentectomy for Early Stage Lung Cancer

Near-Infrared Fluorescence Guided Robotic Pulmonary Segmentectomy for Early Stage Lung Cancer: Analysis of Accuracy and Added Value

Lungs are made up of individual lobes. When a lung cancer tumour is detected in one of these lobes, surgeons typically perform a Lobectomy. A Lobectomy is the surgery most commonly done to treat early-stage lung cancer and requires removal of an entire lobe of the lung, which removes a large amount of lung tissue For patients with small tumours saving as much healthy lung tissue as possible is important. Each lobe of the lung has smaller sections called segments. When a lung cancer is in one of these segments, it is possible to remove that segment, without removing the entire lobe. This surgery is called a segmentectomy. Compared to a lobectomy, a segmentectomy saves a larger amount of healthy lung tissue. With the advances in screening technology for lung cancer tumours, an increasing amount of very small lung cancer tumours are being found, and the demand for segmentectomy is increasing. A segmentectomy is a hard surgery to perform robotically because it is difficult to view the tissue lines that separate each segment within the lobe. As a result, it is difficult for the surgeon to see exactly which pieces of tissue should be removed. Because of these challenges, many patients having robotic surgery will have a lobectomy, even if a full lobectomy is not needed. Near-Infrared Fluorescence (NIF) using indocyanine green (ICG) fluorescent dye is a recent advancement in the robotic platform of robotic surgery. The surgeon will view the CT scan to determine which segment the tumour is located in. Once identified, the surgeon will isolate the segment by cutting off the blood supply to that segment. Then ICG will be injected into a vein. It is expected that the entire lung, except the isolated segment, which will remain 'dark' as it was isolated from blood supply, will fluoresce, giving off a green hue when viewed with the da Vinci Firefly camera. The surgeon will identify 'dark' segment, and will remove it. A pathologist will examine the excised tissue to ensure that the tumour was removed in its entirety. Once confirmed, the surgeon will end the procedure. If the pathologist determines that the segment removed did not contain the entire tumour, then the surgeon will perform a routine lobectomy. This ensures patient safety and confirms that all participants will have the entire tumour removed from their lung.

lung cancer, segmentectomy, robotic surgery, near-infrared fluorescent, IC-GREEN, indocyanine green, early-stage lung cancer

ICG will be prepared as a sterile solution (2.5 mg/10mL) for injection. After vascular ligation, a 6 to 8mL bolus of ICG solution will be injected into the peripheral vein catheter, followed by a 10mL saline solution bolus. The Firefly camera will then be used for the NIF imaging. It is expected that the entire lung, except the segment which was previously isolated from blood supply, will fluoresce within 30-40 seconds, exhibiting a green hue. The surgeon will perform the pulmonary resection and the resected 'dark' lung segment will be immediately evaluated by a pathologist, depending on the pathologist findings the operation may be concluded or the patient will receive a pulmonary lobectomy.

Feasibility of using NIF-guidance in robotic pulmonary segmentectomy for early-stage lung cancer will be evaluated using items 1, 2, and 3 of a 7-item binary rating scale. An score of 3/7 for these items will indicate success.

Item 1: Visualization of fluoresced lung by NIF imaging; Item 2:Demarcation of a dark segment and inter-segmental plane; Item 3: Completion of segmental resection along the borders of the dark-segmental plane.

Safety will be measured by the rate of adverse reactions to ICG dye as defined by the Ottawa Thoracic Morbidity and Mortality classification

Safety will also be measured by the rate of perioperative complications as defined by the Ottawa Thoracic Morbidity and Mortality classification

Anatomical accuracy will be evaluated using items 4, 5, and 6 of the Indocyanine Green Segmentectomy 7-Item Binary Scale. A score of 3/7 on these items will indicate success of anatomical accuracy

Item 4: Ex-vivo localization of lesions; Item 5: Ex-vivo confirmation of tumor-free margins around lesion; Item 6: Ex-vivo confirmation of adequate anatomical inter-segmental.

Added value of ICG-guidance will be evaluated using Item 7 of the 7-item binary rating scale. A score of 1/7 will indicate added value of ICG-guidance

Overall success of the intervention will be evaluated using Items 1-7 of the binary rating scale, only an aggregate score of 7/7 will be considered a success

Partial success of the intervention will be measured by scores between 1/5 and 4/5 on the 7-item binary scale

Length of time of the procedure will be measured by collecting the procedure start and procedure start time

Length of time of the operation will be measured by collecting the time the patient entered the operating room until the time the patient left the operating room

Rate of conversions to lobectomy will be measured by collecting the proportion of conversions to lobectomy or thoracotomy

Rate of conversion to thoracotomy will be measured by collecting the proportion of conversions to thoracotomy

Duration the patient had chest tubes in situ will be measured by collecting the date of surgery and the date the chest tube was removed

Duration of hospital length of stay will be measured by collecting the data of admission and the date of discharge

Learning curve will be evaluated during the analysis of the data using Items 1-7 of the 7-item binary rating scale, particularly the measured difference (millimeters) in the predicted cautery-marked intersegmental planes delineated prior to using ICG and the true anatomical intersegmental planes delineated with ICG and NIF.

Inclusion Criteria: Age > 18 years Tumor size <3 cm Clinical Stage 1 Non-Small Cell Lung Cancer (NSCLC) CT-imaging confirming that the tumour is confined to the one broncho-pulmonary segment, rendering the patient a candidate for segmental resection. Exclusion Criteria: Hypersensitivity or allergy to ICG, sodium iodide or iodine Women who are currently pregnant or are breast feeding; or women of child bearing potential who are not currently taking adequate birth control.

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