Safety and Short-term Outcomes of Modular Robotic System for Siewert II/III Gastroesophageal Junction Cancer (ROBOT-GEJ)

A Prospective Single-arm Study Evaluating the Safety and Short-term Outcomes of Modular Robotic System for Siewert II/III Gastroesophageal Junction Cancer

Siewert type II/III gastroesophageal junction (GEJ) adenocarcinoma is a challenging malignancy located at the anatomical transition between the esophagus and stomach. Due to its complex anatomical location and mixed biological characteristics of esophageal and gastric cancers, the optimal surgical strategy remains controversial. Current surgical approaches vary in terms of operative access, extent of resection, and lymph node dissection. Although minimally invasive laparoscopic and integrated robotic surgery have demonstrated potential advantages in improving perioperative outcomes, limitations remain when managing complex procedures involving both abdominal and mediastinal fields.

Split-type robotic surgical systems, characterized by independently movable robotic carts, provide greater flexibility in robotic arm positioning and may overcome some limitations associated with conventional integrated robotic platforms, particularly in extensive multi-quadrant procedures requiring simultaneous abdominal and mediastinal lymph node dissection. However, clinical evidence regarding the safety and effectiveness of split-type robotic surgery for Siewert type II/III GEJ cancer remains limited.

This prospective single-arm clinical study aims to evaluate the feasibility, safety, and short-term surgical outcomes of split-type robotic radical surgery for patients with Siewert type II/III GEJ adenocarcinoma. The study will assess perioperative outcomes, including operative characteristics, postoperative complications, lymph node dissection quality, and short-term recovery parameters. The findings of this study are expected to provide preliminary clinical evidence regarding the application of split-type robotic technology in complex GEJ cancer surgery and support future large-scale clinical investigations.

Study Overview

• Status: Recruiting
• Conditions: Siewert Type II/III Gastroesophageal Junction Adenocarcinoma
• Intervention / Treatment: Procedure: Robotic-assisted radical resection for Siewert type II/III gastroesophageal junction cancer

Detailed Description

Siewert type II/III gastroesophageal junction (GEJ) adenocarcinoma represents a unique clinical entity located at the junction between the distal esophagus and proximal stomach. According to the Siewert classification, type II tumors are defined as tumors with their epicenter located from 1 cm above to 2 cm below the esophagogastric junction, whereas type III tumors extend from 2 cm to 5 cm below the junction. Due to their distinct anatomical characteristics and lymphatic drainage patterns, these tumors present unique challenges in surgical management.

Siewert type II tumors have a relatively increased risk of mediastinal lymph node metastasis, while Siewert type III tumors primarily involve abdominal lymphatic pathways. Consequently, significant controversy remains regarding the optimal surgical approach, including the choice between transthoracic and transabdominal approaches, esophagectomy versus gastrectomy, and the appropriate extent of lymphadenectomy. In particular, the management of Siewert type II tumors remains debated because of their overlapping features between esophageal and gastric cancers. Currently, Siewert type III tumors are generally treated according to gastric cancer principles, with total gastrectomy and D2 lymphadenectomy being widely accepted surgical strategies.

Minimally invasive surgery has increasingly been applied in GEJ cancer treatment. Previous studies have demonstrated that laparoscopic surgery may provide advantages in reducing surgical trauma and improving short-term postoperative recovery compared with open surgery. However, existing evidence is primarily derived from retrospective studies, with considerable heterogeneity and limited long-term oncological outcome data.

Robotic-assisted surgery has emerged as an advanced minimally invasive approach, offering three-dimensional visualization, enhanced instrument dexterity, motion scaling, and improved ergonomics. Small retrospective series using the da Vinci integrated robotic platform for Siewert type II/III GEJ cancer surgery have demonstrated acceptable perioperative safety and feasibility. However, conventional integrated robotic systems have limitations in complex procedures requiring extensive operative fields. Due to restricted robotic arm mobility and fixed configuration, procedures involving both thoracic and abdominal regions may require intraoperative redocking, which may interrupt surgical workflow, prolong operative time, and reduce procedural efficiency.

The split-type robotic surgical system provides an alternative robotic platform design consisting of multiple independently movable robotic carts. This configuration allows more flexible arrangement of robotic arms according to surgical requirements and may be particularly advantageous for Siewert type II/III GEJ cancer surgery, where both mediastinal and abdominal lymph node dissection may be required. Compared with integrated robotic systems, split-type robotic platforms may reduce the need for intraoperative redocking, maintain procedural continuity, decrease mechanical interference, and improve surgical efficiency during complex multi-quadrant operations.

The Carina™ Split-type Surgical Robotic System and compatible surgical instruments developed by Ruilong Nuofu (Shanghai) Medical Technology Co., Ltd. have obtained approval from the National Medical Products Administration (NMPA) of China. The system has fulfilled regulatory requirements for investigator-initiated clinical studies according to relevant medical device regulations and clinical trial quality management principles. Previous clinical applications of the Carina™ system in multiple surgical specialties, including gastrointestinal surgery, have demonstrated acceptable safety profiles and perioperative outcomes.

Nevertheless, despite these theoretical advantages, clinical evidence regarding the application of split-type robotic systems in radical surgery for Siewert type II/III GEJ cancer remains lacking. In particular, whether split-type robotic surgery can improve operative efficiency, facilitate lymph node dissection, reduce surgical interruptions, and maintain acceptable perioperative safety has not been prospectively evaluated.

Therefore, this prospective single-arm clinical study is designed to investigate the feasibility, safety, and short-term outcomes of split-type robotic radical surgery for patients with Siewert type II/III GEJ adenocarcinoma. The study will evaluate perioperative parameters, including operative time, intraoperative blood loss, conversion rate, postoperative complications, recovery indicators, pathological outcomes, and lymph node dissection results.

The results of this study will provide preliminary clinical evidence regarding the role of split-type robotic technology in complex GEJ cancer surgery. These findings may serve as a foundation for future multicenter clinical trials, optimization of robotic surgical strategies, establishment of standardized surgical protocols, and improvement of clinical outcomes for patients with Siewert type II/III GEJ adenocarcinoma.

• Study Type: Interventional
• Enrollment (Estimated): 25
• Phase: Not Applicable

Contacts and Locations

• Study Contact: Name: Quan Wang; Phone Number: +86 15843073207; Email: wquan@jlu.edu.cn

Study Locations

• China
  • Jilin
    • Changchun, Jilin, China, 130021
      • Recruiting
      • First Hospital of Jilin Universiry
      • Contact: Quan Wang; Phone Number: +86 15843073207; Email: wquan@jlu.edu.cn

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult; Older Adult
• Accepts Healthy Volunteers: No

Description

Inclusion Criteria:

1. Age between 18 and 80 years, inclusive, regardless of sex.
2. Histologically and/or cytologically confirmed Siewert type II or type III gastroesophageal junction tumor, with clinical staging according to AJCC 8th edition TNM classification indicating suitability for curative surgical resection.
3. Adequate organ function as assessed by the investigator before surgery.
4. Provision of written informed consent and willingness to participate in the study.
5. Ability and willingness to comply with study procedures and follow-up requirements.
6. ECOG performance status of 0-1.
7. Absence of distant metastasis confirmed by preoperative thoracoabdominal and pelvic CT or PET-CT.

Exclusion Criteria:

1. Patients with body mass index (BMI) <18.5 kg/m² or BMI ≥35 kg/m².
2. Patients with severe cardiac, pulmonary, neurological, hepatic, or renal diseases that may prevent tolerance of surgery or anesthesia.
3. Patients unable to tolerate pneumoperitoneum or considered by the investigator to have extensive intra-abdominal adhesions or other conditions preventing safe establishment of pneumoperitoneum.
4. Patients with severe coagulation disorders that contraindicate minimally invasive surgery.
5. Patients with active pulmonary tuberculosis.
6. Patients with severe uncontrolled diseases, acute infections, severe physical deterioration, massive ascites, active intra-abdominal bleeding, or shock.
7. Patients with metastatic lymph nodes fused together or encasing major blood vessels, making curative resection infeasible.
8. Patients with previous abdominal/pelvic surgery, radiotherapy, or chemotherapy that may affect the feasibility of laparoscopic or robotic surgery.
9. Pregnant or breastfeeding women.
10. Patients currently participating in other clinical trials involving investigational drugs or medical devices.
11. Patients considered unsuitable for this study by the investigator.

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Treatment
• Allocation: N/A
• Interventional Model: Single Group Assignment
• Masking: None (Open Label)

Number of Arms

1

Arms and Interventions

Participant Group / Arm

Intervention / Treatment

Experimental: Carina Robotic Surgery Group; Patients with Siewert type II/III gastroesophageal junction adenocarcinoma who undergo radical surgical resection assisted by the Carina modular surgical robotic system. All participants will receive the same robotic surgical intervention, and perioperative safety, surgical outcomes, pathological outcomes, and short-term postoperative recovery will be evaluated prospectively.

Procedure: Robotic-assisted radical resection for Siewert type II/III gastroesophageal junction cancer; Patients will undergo totally robotic-assisted radical surgery for Siewert type II/III gastroesophageal junction cancer. The surgical procedure includes robotic-assisted tumor resection and lymph node dissection according to standard oncologic principles.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Rate of Successful Completion of Robotic Surgery Without Conversion	The proportion of patients who successfully complete radical resection using the Carina modular robotic surgical system without conversion to conventional laparoscopy or open surgery. Conversion includes unplanned transition to another surgical approach due to technical difficulties, intraoperative complications, or inability to complete the planned robotic procedure.	Intraoperatively
Incidence of Perioperative Complications (Clavien-Dindo Classification)	The incidence and severity of postoperative complications occurring within 30 days after surgery, classified according to the Clavien-Dindo grading system. Complications include surgical and medical adverse events occurring during the perioperative period.	Within 30 days after surgery

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Achievement Rate of D2 Lymphadenectomy	The proportion of patients achieving complete D2 lymph node dissection according to the Japanese Gastric Cancer Treatment Guidelines. The adequacy of lymphadenectomy will be assessed based on intraoperative findings and postoperative pathological examination.	Perioperative/Periprocedural
Number and Metastatic Rate of Lymph Nodes in the Lower Mediastinal and Suprapancreatic Regions	The number of harvested lymph nodes and the proportion of metastatic lymph nodes in specific anatomical regions, including lower mediastinal lymph nodes and suprapancreatic lymph nodes, will be evaluated based on postoperative pathological examination.	Within 14 days after surgery (pathological assessment)
Postoperative Pathological Stage (pTNM Classification)	The pathological tumor stage will be determined according to the 8th edition of the American Joint Committee on Cancer (AJCC) TNM staging system.	Within 14 days after surgery
R0 Resection Rate	The proportion of patients achieving complete tumor resection with microscopically negative margins (R0 resection) according to postoperative pathological examination.	Within 14 days after surgery
Proximal and Distal Resection Margin Distance	The length of proximal and distal surgical margins measured from the tumor edge to the resection margin based on pathological examination.	Within 14 days after surgery
Incidence of Specific Postoperative Complications	The incidence of specific postoperative complications within 30 days after surgery, including: Anastomotic leakage Bleeding requiring blood transfusion Chylothorax Surgical site infection Pulmonary complications Deep venous thrombosis	Within 30 days after surgery
Estimated Intraoperative Blood Loss	Estimated Intraoperative Blood Loss	During the index operation
Device- and Instrument-related Adverse Events	The incidence of adverse events related to the Carina™ split-type robotic surgical system and associated instruments, including device malfunction, instrument failure, or unexpected technical issues.	From surgery initiation to 30 days after surgery
Type of Gastrointestinal Reconstruction	The type of gastrointestinal reconstruction performed after tumor resection will be recorded based on operative records, including the reconstruction method and type of esophagojejunostomy or other gastrointestinal reconstruction techniques.	During surgery
30-day Postoperative Mortality	The proportion of patients who die from any cause within 30 days after surgery.	Within 30 days after surgery
30-day Hospital Readmission Rate	The proportion of patients requiring unplanned hospital readmission within 30 days after surgery.	Within 30 days after surgery
ICU Admission Rate and Duration of ICU Stay	The proportion of patients admitted to the intensive care unit after surgery and the duration of ICU stay.	From surgery until hospital discharge
Postoperative Hospital Stay	The duration of hospitalization after surgery.	From postoperative day 1 until hospital discharge
System Preparation Time	Time required for preparation, setup, and initialization of the split-type robotic surgical system before surgery.	Perioperative/Periprocedural
Robotic Arm Docking Time	Time required to complete initial docking of robotic carts and robotic arms before surgical operation.	During surgery preparation
Robot-assisted Operative Time	Duration of robotic-assisted surgical operation from initiation of robotic manipulation to completion of robotic procedures.	During surgery
Total Operative Time	Total duration from skin incision to completion of surgical closure.	During surgery
Redocking Events and Duration	Number of intraoperative robotic redocking events and cumulative duration required for robotic repositioning.	Perioperative/Periprocedural
Surgical Interruption Events and Duration	Number and duration of unplanned surgical interruptions caused by robotic system setup, instrument issues, robotic arm collision, or other technical factors.	Perioperative/Periprocedural
Time to First Ambulation	Time interval from completion of surgery to first postoperative mobilization.	From completion of surgery until first postoperative ambulation
Time to First Postoperative Flatus	Time interval from surgery completion to first passage of gas.	From completion of surgery until first postoperative flatus
Time to Initiation of Liquid Diet	Time interval from surgery completion to initiation of oral liquid intake.	From completion of surgery until initiation of oral liquid intake
Postoperative Pain Score	Postoperative pain intensity will be assessed using the Visual Analog Scale (VAS), a 10-cm continuous scale ranging from 0 (no pain) to 10 (worst imaginable pain). Pain scores will be recorded at predefined postoperative time points to evaluate postoperative pain recovery.	Postoperative days 1-7
Surgeon Physical Workload Assessed by the Local Experienced Discomfort Scale	The intraoperative physical workload of the primary surgeon will be assessed using the Local Experienced Discomfort (LED) scale. Physical discomfort is rated from 0 to 10 for each assessed body region, where 0 indicates no discomfort and 10 indicates extreme discomfort. Higher scores indicate greater physical discomfort and a higher physical workload.	Immediately after surgery
Surgeon Mental Workload Assessed by the Subjective Mental Effort Questionnaire	The intraoperative mental workload of the primary surgeon will be assessed using the Subjective Mental Effort Questionnaire (SMEQ). The SMEQ ranges from 0 to 150 points, with higher scores indicating greater subjective mental effort and a higher mental workload.	Immediately after surgery

Collaborators and Investigators

• Sponsor: The First Hospital of Jilin University

Study record dates

Study Major Dates

• Study Start (Estimated): August 20, 2026
• Primary Completion (Estimated): February 20, 2027
• Study Completion (Estimated): February 20, 2027

Study Registration Dates

• First Submitted: August 20, 2026
• First Submitted That Met QC Criteria: August 25, 2026
• First Posted (Actual): August 27, 2026

Study Record Updates

• Last Update Posted (Actual): September 2, 2026
• Last Update Submitted That Met QC Criteria: August 29, 2026
• Last Verified: August 1, 2026

More Information

Terms related to this study

• Keywords: Lymph Node Dissection; Minimally Invasive Surgery; Gastroesophageal Junction Adenocarcinoma; Siewert Type II/III; Modular Robotic Surgery
• Other Study ID Numbers: Carina-GEJ-1

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO
• IPD Plan Description: Individual participant data will not be shared. The study involves a relatively small patient population, and participant privacy and confidentiality considerations limit the sharing of individual-level data. Data may be available from the corresponding investigator upon reasonable request and subject to institutional and ethical approval.

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No