Image-Guided Platform-Assisted Sentinel Lymph Node Retrieval in Early Gastric Cancer

Sentinel lymph node navigation surgery provides an individualized approach to lymph node assessment in patients with early gastric cancer. However, the identification and retrieval of sentinel lymph nodes (SLNs) from resected sentinel lymphatic basin (SLB) tissue remain largely dependent on visual inspection and manual palpation by experienced physicians. This process can be time-consuming and operator-dependent and may result in missed lymph nodes (LNs), particularly small or visually inconspicuous nodes.

This study is a single-center, prospective, randomized, superiority-controlled trial designed to evaluate an Image-Guided Platform assisted by a deep learning model for intraoperative and postoperative SLN retrieval in patients with early gastric cancer undergoing laparoscopic-endoscopic cooperative surgery combined with sentinel lymph node navigation surgery (LECS-SNNS). Eligible participants will be randomly assigned in a 1:1 ratio to either the Image-Guided Platform group or the Traditional Palpation group. Randomization will be performed using a computer-generated random sequence with allocation concealment.

All participants will undergo a standardized LECS-SNNS procedure. Indocyanine green (ICG) will be injected endoscopically around the gastric lesion for near-infrared fluorescence lymphatic mapping. Fluorescent SLBs will be identified and resected en bloc. Fluorescent SLNs identified by visual inspection and fluorescence imaging will initially be retrieved and designated as SBNs. In the Image-Guided Platform group, the remaining SLB tissue will be placed on the Image-Guided Platform for radiographic and optical imaging. The acquired images will be analyzed using a deep learning model to identify and localize suspected LNs. Physicians will subsequently retrieve suspected LNs according to the image-guided and model-generated localization results. After image-guided LN retrieval, supplementary visual inspection and manual palpation will be performed to identify any additional LNs when appropriate. In the Traditional Palpation group, the remaining SLB tissue will be systematically examined by experienced physicians using standardized dissection, visual inspection, and manual palpation to identify and retrieve suspected LNs without image-guided or deep learning-assisted localization.

All retrieved SLNs will undergo intraoperative frozen-section pathological examination according to standardized institutional procedures. Permanent pathological examination will subsequently be performed to confirm the pathological findings and to identify any additional LNs that were not retrieved during the intraoperative LN retrieval process. This approach will allow assessment of retrieved LNs, additional LNs identified during permanent pathological examination, and the overall LN harvest from the SLB specimen.

Data Collection and Assessments

Study data will include a broad range of demographic, clinical, diagnostic, surgical, pathological, technical, imaging-related, and perioperative information relevant to early gastric cancer, sentinel lymph node navigation surgery, LN retrieval, and pathological assessment. Data collection may include baseline demographic and clinical characteristics; medical and treatment history; preoperative laboratory, endoscopic, imaging, and clinical staging information; tumor-related characteristics; intraoperative and surgical variables; fluorescence mapping and SLB characteristics; LN retrieval and specimen-handling information; Image-Guided Platform-related parameters; radiographic and optical image-related parameters; deep learning model-related parameters; intraoperative frozen-section findings; permanent pathological findings; LN-related characteristics; perioperative recovery and safety information; and other clinically relevant variables collected according to the study protocol and case report forms. Derived variables, composite variables, subgroup classifications, technical performance measures, image- or specimen-level parameters, and exploratory clinical or pathological variables may also be generated from the collected data according to prespecified or exploratory statistical analyses. The collected information will be used to compare the effectiveness, efficiency, and diagnostic performance of Image-Guided Platform-assisted LN retrieval and Traditional Palpation, and to explore factors potentially associated with LN retrieval, total LN harvest, pathological assessment, technical performance, and other relevant clinical outcomes.

Inclusion criteria

• Age between 18 and 80 years, inclusive.
• Eastern Cooperative Oncology Group (ECOG) performance status of 0-2 and considered able to tolerate surgery and anesthesia.
• Histologically confirmed gastric adenocarcinoma based on preoperative endoscopic biopsy.
• Clinical stage cT1N0M0 based on multidisciplinary evaluation and appropriate preoperative examinations, including endoscopy and imaging, or patients after non-curative endoscopic submucosal dissection (ESD) who are considered appropriate candidates for further surgical treatment.
• Adequate hepatic, renal, cardiac, pulmonary, and bone marrow function to tolerate the planned surgical and perioperative management.
• Considered clinically suitable for laparoscopic-endoscopic cooperative surgery combined with sentinel lymph node navigation surgery (LECS-SNNS).
• Able to understand the study procedures and provide written informed consent voluntarily.

Exclusion criteria

• Patients who meet the absolute indications for endoscopic submucosal dissection according to the applicable Chinese gastric cancer treatment guidelines.
• Contraindications to the use of the lymphatic tracer or to endoscopic examination.
• Unable to undergo ESD or failure of ESD treatment.
• Inability to determine the extent of tracer staining or fluorescence mapping.
• Contraindications to surgery, including clinically significant coagulation disorders or severe cardiopulmonary dysfunction.
• Previous gastrointestinal surgery, chemotherapy, or radiotherapy.
• Preoperative imaging indicating bulky, conglomerated, or markedly enlarged metastatic lymph nodes.
• Concurrent malignancy involving another organ system, or intraoperative confirmation of metastatic gastric cancer or a non-gastric primary malignancy.
• Pregnancy or breastfeeding.
• Psychiatric disorders, cognitive impairment, or other conditions that impair the ability to provide informed consent or comply with study procedures.
• Any other condition that, in the investigator's judgment, makes the individual unsuitable for participation in the study.