Precise and Safe Lung Segmentectomy Enabled by Dual-Channel Near-Infrared Fluorescence Tumor and Pleural Demarcation

Lung cancer is a leading cause of cancer-related deaths globally. Since the introduction of computed tomography screening, the early detection rate of lung cancer has greatly increased, significantly reducing mortality rates. Studies have shown that the incidence of early-stage non-small cell lung cancer (NSCLC) has risen significantly in recent years, with the three-year survival rate increasing from 21% to 31%. For patients with early-stage NSCLC or impaired cardiopulmonary function, precise limited resection surgery such as segmentectomy can not only improve overall survival but also better preserve lung function. The key to successful segmentectomy is the intraoperative identification of both the tumor tissue and segmental plane. However, accurate identification of the surgical margins remains challenging due to high background signals and poor serum stability of imaging probes.

This study investigated a novel approach using dual-channel near-infrared fluorescence imaging technology, which employs a clearable renal fluorescent dye with good physicochemical stability and a tumor-targeting fluorescent dye to clearly distinguish the tumor and lung segmental plane in different colors during surgery, enabling precise segmentectomy. The article was published in the International Journal of Surgery, and the research was conducted in collaboration by researchers from the Department of Thoracic Surgery at Guro Hospital, Korea University, the Center for Systems Biology at Massachusetts General Hospital in Boston, Shenyang Pharmaceutical University, and other institutions. The primary authors include Ok Hwa Jeon, Kai Bao, Kyungsu Kim, and others, with Hak Soo Choi from Harvard Medical School and Hyun Koo Kim from Korea University as the corresponding authors.

Background and Purpose

Segmentectomy, a limited resection procedure recommended for very early-stage lung cancer or functionally impaired patients, aims to minimize the removal of normal tissue. However, precisely detecting the tumor and simultaneously identifying the lung segmental plane during surgery is extremely challenging. The authors of this study aimed to develop a novel dual-channel near-infrared fluorescence imaging technique that provides clear visualization of different colors during surgery, thereby addressing this challenge, increasing the success rate of the procedure, and reducing recurrence rates.

Research Methods

Study Design

The study employed tumor animal models in mice, rabbits, and dogs, developed two near-infrared fluorescent dyes emitting at 700 nm and 800 nm, and evaluated their biodistribution, tumor-targeting ability, and optical and biological properties both in vitro and in vivo. The research was divided into the following steps:

1. Fluorescent Dye Development and Characterization:

   • The conjugate of crgdyk and zw800-PEG (crgd-zw800-PEG) was synthesized using conventional N-hydroxysuccinimide ester chemistry and evaluated for its physicochemical properties, plasma protein-binding affinity, and cytotoxicity.
   • The 700 nm emitting zw700-1c was developed and used in combination with the 800 nm fluorescent dye.

2. Cell Experiments:

   • The cell-targeting ability and internalization of the fluorescent dyes were evaluated in NSCLC cell lines, and the expression levels of integrin αvβ3 in tumor and control tissues were assessed.

3. Animal Experiments:

   • In tumor animal models, the biodistribution, pharmacokinetics, and clearance characteristics of crgd-zw800-PEG were evaluated after intravenous injection.
   • Optimal drug dosage and time points were optimized for tumor location and different doses, and the ability to identify the segmental plane was finally evaluated in a canine model.

Study Subjects

• Cell Samples: NSCLC cell lines were used for in vitro cell experiments, and the expression of integrin αvβ3 in patient cancer and normal control tissues was analyzed to validate the targeting ability.
• Animal Samples: Mice, rabbits, and dogs were used as in vivo experimental models to evaluate the targeting ability and biodistribution of the fluorescent dyes.

Results

Physicochemical and Optical Properties

• The chemically synthesized crgd-zw800-PEG exhibited excellent water solubility and serum stability, and its optical emission wavelength was red-shifted, making it suitable for near-infrared fluorescence imaging systems used in operating rooms.
• crgd-zw800-PEG demonstrated superior tumor signal (TBR) and target specificity. Compared to the FDA-approved near-infrared fluorescent probe ICG (indocyanine green), crgd-zw800-PEG exhibited higher targeting ability and better solubility in most solvents.

Cell Experiment Results

• In vitro cell experiments showed that crgd-zw800-PEG exhibited superior targeting ability in integrin αvβ3-overexpressing NSCLC cells and low toxicity in non-tumor cells.
• The results indicated that integrin αvβ3 was significantly overexpressed in cancer tissues compared to normal tissues in 61 NSCLC patient samples, with high expression observed in both lung adenocarcinoma and squamous cell carcinoma, suggesting the effective targeting ability and clinical applicability of crgd-zw800-PEG.

Animal Experiment Results

• In a mouse tumor model, crgd-zw800-PEG exhibited superior tumor-targeting signals and clearance characteristics after injection, with significantly higher TBR values compared to ICG and zw800-PEG, as well as a longer blood half-life.
• In a rabbit VX2 tumor model, a dose of 0.1 mg/kg crgd-zw800-PEG achieved optimal tumor-targeting signals while exhibiting high TBR values.
• In a canine model, intravenous injection of 0.3 mg/kg zw700-1c and zw800-PEG enabled effective identification of the lung segmental plane, with longer signal duration suitable for surgical guidance.

Research Conclusions

This study developed a novel dual-channel near-infrared fluorescence imaging technique that combines the blood pool agent zw700-1c and the tumor-targeting agent crgd-zw800-PEG to simultaneously identify the tumor and lung segmental plane in different colors, providing a new approach for precise and safe segmentectomy. This method not only reduces surgical time and recurrence rates but also improves the survival rate of cancer patients. It may have significant clinical application value, particularly in image-guided precise resection for lung cancer surgery.

Significance and Application Value

This research not only addresses the challenge of simultaneously identifying the tumor and lung segmental plane during segmentectomy but also demonstrates, for the first time, higher tumor-targeting ability and longer signal duration achieved through dual-channel near-infrared fluorescence imaging, providing a new perspective and technology for future clinical intraoperative image navigation.

With the technique developed in this study, intraoperative visualization of the tumor and lung segment can significantly enhance the precision and safety of surgery, reducing postoperative recurrence rates and improving patient survival. Furthermore, as dual-channel near-infrared fluorescence imaging has broad application prospects, it can be applied not only in lung cancer surgery but also in other types of surgical procedures.