Patients meeting the following criteria were enrolled:

1. Aged 18–75 years; 2. Body mass index (BMI) between 17–24 kg/m²; 3. Preoperative pathological confirmation of primary gastric adenocarcinoma located in the middle or lower third of the stomach; 4. Preoperative assessment indicating a tumor diameter ≤5 cm; 5. No evidence of distant metastasis (e.g., liver, lung) on contrast-enhanced CT; 6. Eastern Cooperative Oncology Group (ECOG) performance status of 0-1; 7. Clinical stage cT1-4aN0-3M0 (AJCC 8th edition TNM staging) with planned R0 resection via totally laparoscopic radical distal gastrectomy; 8. Early GC deemed unsuitable for endoscopic resection upon preoperative evaluation, or patients/families opting against endoscopic treatment.

Patients were excluded if they met any of the following: 1. Previous upper abdominal surgery (except cholecystectomy) or requirement for multi-organ resection; 2. Conversion to five-port laparoscopic distal gastrectomy (FPLDG) or open surgery during three-port totally laparoscopic distal gastrectomy (TPLDG); 3. Emergency surgery due to complications (bleeding, perforation, obstruction); 4. Non-compliance with postoperative adjuvant chemotherapy; 5. Severe systemic comorbidities contraindicating laparoscopic surgery (additional criteria detailed in the clinical trial registry). This study was approved by the Medical Ethics Committee of the First Affiliated Hospital of Air Force Medical University (Approval No. KY20212225-C-1). All participants provided written informed consent. The trial was registered at www.chictr.org.cn (ChiCTR2200060322). By April 2024, 416 patients were initially enrolled. Exclusions included: 8 cases: occult metastasis detected intraoperatively; 3 cases: conversion to open surgery; 15 cases: conversion from 3-port to 5-port laparoscopy; 5 cases: multi-organ resection; 12 cases: non-compliance with adjuvant chemotherapy; 18 cases: incomplete data or loss to follow-up; Final cohort: 355 patients (see Figure 1 for recruitment flowchart).

For patients in the FPLDG group, they are placed in a supine position with legs abducted. A 10 mm Trocar is inserted through a small incision below the umbilicus as the observation port. After exploring the abdominal and pelvic organs to confirm the absence of distant metastasis, a 12 mm Trocar is inserted below the costal margin at the left anterior axillary line as the main operation port, and a 5 mm Trocar is inserted at the umbilical level on the left midclavicular line as the auxiliary port. The placement on the right side is the opposite of that on the left side. The chief surgeon stands on the left side of the patient, the assistant stands on the right side of the patient, and the scope holder stands between the patient’s legs. For the TPTLDG group, on the basis of the control group, the two Trocar ports on the right side (assistant’s position) are removed, and the other layout is consistent with that of the FPLDG group (14).

The technical details of the three-port laparoscopic gastrectomy for GC with the left-side standing position have been described in previous reports (14). Briefly, the patient is placed in a supine position with the head elevated and the feet lowered. An observation port and two operation ports are created at the umbilicus and on the left and right sides of the patient respectively. The operation is performed without the assistance of an assistant. The surgical operation techniques, including gastric resection and lymph node dissection, follow the principles of the guidelines for the treatment of GC, which are consistent with those of traditional laparoscopic gastrectomy for GC. D2 lymph node dissection is performed for all tumors. After the gastric body is transected by a laparoscopic stapler, the 10 mm Trocar port below the umbilicus is enlarged to 3–4 cm to remove the specimen. Depending on the location of the tumor, Billroth-I anastomosis or Billroth-II posterior gastric wall anastomosis is selected, and Braun anastomosis is completed at the umbilical incision. The surgeon evaluates whether to place a drainage tube according to the completion of the operation and records the placement situation. No nasogastric tube is placed in all patients. The urinary catheter is removed immediately after the patient wakes up from anesthesia. For other management, multimodal analgesia, early mobilization, and early oral feeding are carried out with reference to the consensus guidelines of enhanced recovery after surgery for GC.

Postoperative inflammatory and nutritional indicators: preoperative and postoperative levels of high-sensitivity C-reactive protein (hs-CRP), interleukin-6 (IL-6), white blood cell count (WBC), and albumin (Alb).

Postoperative complication rate and mortality: defined as any complication or death occurring within 30 days postoperatively. The severity of complications was classified according to the Clavien-Dindo grading system (15).

Long-term survival outcomes: follow-up was conducted via hospitalization records, outpatient visits, WeChat, or telephone to assess complications within 30 days postoperatively, as well as 30-day and 90-day readmission rates. Follow-up continued until March 2025.Overall survival (OS): Defined as the time from surgery to death from any cause. Disease-free survival (DFS): Defined as the time from surgery to death or disease recurrence. Postoperatively, patients were followed up every 6 or 12 months for 5 years, including chest and abdominal computed tomography (CT) and endoscopic examinations. Patients with pathological stage II-III received guideline-recommended chemotherapy regimens.

Normally distributed continuous variables were expressed as mean ± standard deviation ( x ¯ ± s) and compared using Student’s t-test. Categorical variables were compared using the χ² test or Fisher’s exact test, as appropriate. Non-normally distributed continuous variables were expressed as median (Q1, Q3) and compared using the Mann-Whitney U test. Count data were presented as absolute numbers. Kaplan-Meier analysis was used to assess survival rates. All statistical analyses were performed using SPSS 22.0, and a P-value < 0.05 was considered statistically significant.

No significant differences were observed between the two groups regarding age, BMI, sex, ASA classification, tumor stage, histological type, or Lauren classification ( Table 1 ). The operative time was 140 (125, 160) minutes in the TPLDG group versus 135 (120, 150) minutes in the FPLDG group (p=0.068). Estimated blood loss was 80 (50, 100) mL and 100 (125, 160) mL, respectively(p=0.128). The numbers of total retrieved lymph nodes were 22(19,27) in the TPLDG group and 22(18,27)in the FPLDG group (p=0.696).The two groups showed comparable results in postoperative complication rates, mortality, and 30-/90-day readmission rates. ( Table 2 ).

The TPLDG group showed earlier time to first flatus[2(2,3) vs. 3(2,3) day, Z=-4.067, p<0.001], shorter hospital stay [4(3,5) vs. 5.2(4.2,6.3) day, Z=-7.719, p<0.001]), higher tubeless rate, and lower total hospitalization costs in terms of postoperative recovery.( Table 2 )To further compare the differences in postoperative recovery between the two groups, we analyzed inflammatory markers on postoperative day 3. The results demonstrated that the TPLDG group had significantly lower levels of C-reactive protein (CRP) and interleukin-6 (IL-6) compared to the FPLDG group ( Table 3 ).

The 3-year DFS rates were 85.4% for the TPLDG group and 85.8% for the FPLDG group (p=0.85, Figure 2A ), while the 3-year OS rates were 89.4% and 89.2%, respectively (p=0.70, Figure 2D ). Given the significant influence of disease stage on prognosis, we performed a stratified survival analysis. As shown in Figures 2B, C, E, F , the survival curves were compared between the two groups across different pathological stages. No significant differences in DFS were observed in either stage I (p=0.31, Figure 2B ) or stages II–III (p=0.62, Figure 2C ). Similarly, OS did not differ significantly between the groups for stage I (p=0.79, Figure 2E ) or stages II–III (p = 0.55, Figure 2F ).