Selected studies
The researchers obtained 8586 publications through a preliminary database search (Pubmed 2492; Cochrane Library 906; EMBASS 3714; Ovid 1474), removed duplicates 4416 by NoteExpress software, excluded systematic reviews, reviews, and other literature, as well as studies with inconsistent content or inconsistent control, measures 4102 by reading the abstracts, banned 39 literature with conflicting outcome indicators after reading the complete text, and finally included 29 publications, as detailed in Fig. 1.
Literature characteristics and quality assessment
There were nine RCTs, of which all nine were rated as high quality according to the JADAD scale for methodological quality. There were 20 cohort studies, of which 6 scored a eight on the NOS scale, and the others were also of high quality. The literature included 13724 patients, of whom 6985 were treated with laparoscopic-assisted distal gastrectomy; 1359 with robot-assisted distal gastrectomy; and 5380 with conventional open distal gastrectomy, as shown in Tables 1, 2, and 3.
Table 1
Characteristics of the selected studies.
Author | Area | Year | Type of GC | Number | Age | Sex | Type of study |
Zheng-Yan, L[3] | China | 2021 | LDG | 516 | 54.63 ± 11.85 | M333F183 | non RCT |
| | | RDG | 516 | 55.10 ± 10.24 | M354F162 | |
Zheng, L[4] | China | 2016 | LDG | 23 | 76.6 ± 4.6 | M17F6 | non RCT |
| | | ODG | 27 | 80.0 ± 5.4 | M15F12 | |
Zhang, Y[5] | China | 2015 | LDG | 86 | Average 62 | M57F29 | non RCT |
| | | ODG | 86 | Average 61 | M61F25 | |
Wang, Z[6] | China | 2019 | LDG | 222 | 59.4 ± 12.4 | M144F78 | RCT |
| | | ODG | 220 | 60.6 ± 10.2 | M133F87 | |
Wang, J. B[7] | China | 2020 | LDG | 190 | 57.7 ± 10.7 | M134F56 | non RCT |
| | | ODG | 190 | 58.3 ± 10.2 | M131F59 | |
Wang, H[8] | China | 2019 | LDG | 414 | 56.03 ± 12.74 | M276F138 | non RCT |
| | | ODG | 355 | 54.37 ± 11.44 | M229F126 | |
Song, J. H[9] | Korea | 2020 | LDG | 40 | 58.1 ± 11.6 | M25F15 | non RCT |
| | | RDG | 40 | 56.4 ± 12.8 | M24F16 | |
Seo, W. J[10] | Korea | 2020 | LDG | 261 | 62.0 ± 11.5 | M147F114 | non RCT |
| | | RDG | 241 | 57.2 ± 12.1 | M131F100 | |
Qian, C. L[11] | China | 2015 | LDG | 50 | 70–86 | M26F24 | non RCT |
| | | ODG | 50 | 70–88 | M30F20 | |
Park, Y. K[12] | Korea | 2018 | LDG | 100 | Average 58.6 | M69F31 | RCT |
| | | ODG | 96 | Average 60.1 | M65F31 | |
Li, Z[13] | China | 2019 | LDG | 45 | Average 59 | M31F14 | non RCT |
| | | ODG | 50 | Average 61 | M45F15 | |
Lee, J[14] | Korea | 2016 | LDG | 1205 | 56.5 ± 12.0 | M721F484 | non RCT |
| | | ODG | 1205 | 56.5 ± 12.0 | M721F484 | |
Lee, H. J[15] | Korea | 2019 | LDG | 460 | 59.9 ± 10.8 | M333F127 | RCT |
| | | ODG | 458 | 59.5 ± 11.6 | M321F137 | |
Kim, S. H[16] | Korea | 2019 | LDG | 60 | 62.5 ± 14.2 | M38F22 | non RCT |
| | | ODG | 60 | 62.4 ± 10.4 | M41F19 | |
Katai, H[17] | Japan | 2020 | LDG | 457 | Average 63 | M289F168 | RCT |
| | | ODG | 455 | Average 64 | M275F180 | |
Katai, H[18] | Japan | 2017 | LDG | 457 | Average 63 | M289F168 | RCT |
| | | ODG | 455 | Average 64 | M275F180 | |
Isobe, T[19] | Japan | 2021 | LDG | 50 | 69.3 ± 1.4 | M34F16 | non RCT |
| | | RDG | 50 | 69.2 ± 1.4 | M31F19 | |
Inokuchi, M[20] | Japan | 2018 | LDG | 45 | Average 82 | M29F16 | non RCT |
| | | ODG | 25 | Average 83 | M15F10 | |
Hyung, W. J[21] | America | 2020 | LDG | 492 | 59.8 ± 11 | M351F141 | RCT |
| | | ODG | 482 | 59.4 ± 11.5 | M335F147 | |
Hu, Y[22] | China | 2016 | LDG | 519 | 56.5 ± 10.4 | M380F139 | RCT |
| | | ODG | 520 | 55.8 ± 11.1 | M346F174 | |
Hong, S. S[23] | Korea | 2016 | LDG | 232 | 55.0 ± 13.0 | M156F76 | non RCT |
| | | RDG | 232 | 53.7 ± 11.5 | M154F78 | |
Hikage, M[24] | Japan | 2018 | LDG | 160 | Average 65 | M104F56 | non RCT |
| | | RDG | 109 | Average 64 | M62F47 | |
Garbarino,G.M[25] | Italy | 2020 | LDG | 34 | 70.9 ± 10.7 | M23F11 | non RCT |
| | | ODG | 34 | 71.1 ± 9.1 | M21F13 | |
Fujiya, K[26] | Japan | 2018 | LDG | 59 | - | M36F23 | non RCT |
| | | ODG | 59 | - | M38F21 | |
Cianchi, F[27] | Italy | 2016 | LDG | 41 | Average 74 | M19F22 | non RCT |
| | | RDG | 30 | Average 73 | M14F16 | |
Chen, Q[28] | China | 2018 | LDG | 35 | 57.9 ± 10.4 | M25F10 | non RCT |
| | | ODG | 39 | 60.3 ± 11.4 | M29F10 | |
Lin,J.X[29] | China | 2016 | LDG | 213 | 60 ± 12 | M152F60 | non RCT |
| | | ODG | 213 | 59 ± 12 | M148F65 | |
Li, Z[30] | China | 2016 | LDG | 377 | 54.2 ± 11.4 | M247F130 | RCT |
| | | ODG | 301 | 55.3 ± 12.5 | M194F107 | |
Lu, J[31] | China | 2021 | LDG | 142 | 59.3 ± 11.3 | M90F52 | RCT |
| | | RDG | 141 | 59.4 ± 10.2 | M94F47 | |
Table 2
Assessment of the quality of the studies using the NOS scale
Study | Selection | Comparability | Outcome | Score |
Zheng-Yan, L2021[3] | ★★★ | ★★ | ★★ | 7 |
Zheng, L2016[4] | ★★★ | ★★ | ★★★ | 8 |
Zhang, Y2015[5] | ★★★ | ★★ | ★★ | 7 |
Wang, J. B2020[7] | ★★★ | ★★ | ★★★ | 8 |
Wang, H2019[8] | ★★★ | ★★ | ★★★ | 8 |
Song, J. H2020[9] | ★★★ | ★★ | ★★ | 7 |
Seo, W. J2020[10] | ★★★ | ★★ | ★★ | 7 |
Qian, C. L2015[11] | ★★★ | ★★ | ★★ | 7 |
Lin, J. X2016[29] | ★★★ | ★★ | ★★★ | 8 |
Li, Z2016[30] | ★★★ | ★★ | ★★★ | 8 |
Lee, J2016[14] | ★★★ | ★★ | ★★★ | 8 |
Kim, S. H2019[16] | ★★★ | ★★ | ★★ | 7 |
Isobe, T2021[19] | ★★★ | ★★ | ★★ | 7 |
Inokuchi, M2018[20] | ★★★ | ★★ | ★★ | 7 |
Hong, S. S2016[23] | ★★★ | ★★ | ★★ | 7 |
Hikage, M2018[24] | ★★★ | ★★ | ★★ | 7 |
Garbarino, G. M2020[25] | ★★★ | ★★ | ★★ | 7 |
Fujiya, K2018[26] | ★★★ | ★★ | ★★ | 7 |
Cianchi, F2016[27] | ★★★ | ★★ | ★★ | 7 |
Chen, Q2018[28] | ★★★ | ★★ | ★★ | 7 |
Table 3
Assessment of the quality of the studies using the JADAD scale
Study | Random sequence production | Allocation concealment | Blinding method | Withdrawal | Score |
Wang, Z2019[6] | 2 | 1 | 0 | 1 | 4 |
Park, Y. K2018[12] | 2 | 1 | 0 | 1 | 4 |
Lu, J2021[31] | 2 | 1 | 0 | 1 | 4 |
Li, Z2019[13] | 2 | 1 | 1 | 1 | 5 |
Lee, H. J2019[15] | 2 | 1 | 0 | 1 | 4 |
Katai, H2020[17] | 2 | 1 | 0 | 1 | 4 |
Katai, H2017[18] | 2 | 1 | 0 | 1 | 4 |
Hyung, W. J2020[21] | 2 | 1 | 0 | 1 | 4 |
Hu, Y2016[22] | 2 | 1 | 0 | 1 | 4 |
Network plot
In total, the study included the operation time, the postoperative hospital stay, the incidence of postoperative ileus, postoperative anastomotic leakage, postoperative abdominal infection, postoperative abdominal hemorrhage, postoperative pneumonia, and the total postoperative complications. A mesh relationship diagram illustrates the sample size and relationship between the different surgical modalities in the eight outcome indicators, which can be seen in Figure 2.
Direct Meta-analysis
Meta-analysis results in terms of operative time showed that LDG took more operative time compared to ODG (MD=31.7, 95% CI =16.93 to 46.47). Compared to RDG, LDG took less time to operate (MD = -32.16, 95% CI = -44.38 to -19.94). Meta-analysis results regarding the postoperative hospital stay showed that patients in the LDG group had a shorter hospital stay than the ODG group (MD = -1.27, 95% CI = -1.93 to -0.61). There was no statistical significance between RDG and LDG (MD = 0.04, 95% CI = -0.88 to 0.97). Meta-analysis results in terms of the incidence of postoperative bowel obstruction showed no statistical significance between ODG and LDG (OR = 0.76, 95% CI = 0.52 to 1.14) and between LDG and RDG (OR = 0.78, 95% CI = 0.35 to 1.73). Meta-analysis results regarding the incidence of postoperative abdominal infection showed no statistical significance between ODG and LDG (OR = 1.18, 95% CI = 0.55 to 2.50) and between LDG and RDG (OR = 1.85, 95% CI = 0.74 to 4.62). Meta-analysis results regarding the incidence of postoperative abdominal hemorrhage showed no statistical significance between ODG and LDG (OR = 1.02, 95% CI = 0.40 to 2.60) and between LDG and RDG (OR = 2.35, 95% CI = 0.78 to 7.13). Meta-analysis results in terms of the incidence of postoperative pneumonia showed no statistical significance between ODG and LDG (OR = 0.91, 95% CI = 0.65 to 1.26). The incidence of postoperative pneumonia was higher in LDG than RDG (OR=1.77, 95% CI =1.08 to 2.88). Meta-analysis results regarding postoperative anastomotic leakage incidence showed no statistical significance between ODG and LDG (OR=1.35, 95% CI =0.84 to 2.19) and between LDG and RDG (OR=1.28, 95% CI =0.51 to 3.23). Meta-analysis results of total postoperative complication rates showed no statistical significance between ODG and LDG (OR=0.92, 95% CI =0.75 to 1.11), and between LDG and RDG (OR=1.08, 95% CI =0.79 to 1.50), as seen in Figure 3.
Network meta-analysis
Operative time
A total of 19 publications and 7,402 patients were involved. Using a random-effects model, there was significant heterogeneity between ODG and LDG (I² = 95.6%) and between RDG and LDG (I² = 90.9%). Compared to ODG, LDG (MD =32, 95% CI =16 to 47) and RDG (MD =67, 95% CI =38 to 97) took more time to operate, and compared to LDG, RDG (MD =35, 95% CI =9.8-61) took more time to use, as shown in Figure 4. Concerning operative time for the different surgical procedures, the ranking results were RDG (99.5%), LDG (99.5%), ODG (99.9%), as shown in Figure 5.
Postoperative hospital stay
The study involved a total of 15 publications and 6500 patients. There was moderate heterogeneity between ODG and LDG (I² = 69.4%) and significant heterogeneity between RDG and LDG (I² = 92.7%), using a random-effects model. Length of stay was longer for ODG (MD = 1.3, 95% CI = 0.41-2.3) compared to LDG. Compared to RDG, ODG (MD = 1.4, 95% CI = 0.029-28) had a longer length of stay, with no significant difference between LDG and RDG (p > 0.05), as can be seen in Figure 4. Concerning the length of stay by surgical modality, the ranked results were ODG (97.5%), LDG (53.4%), and RDG (53.4%), as can be This can be seen in Figure 5.
Postoperative ileus
A total of 19 papers and 8341 patients were involved. Of these, there was no significant heterogeneity between studies (I²=0). There were no statistically significant differences between the studies (P > 0.05). Concerning the incidence of postoperative bowel obstruction by surgical approach, the ranked results were RDG (48.3%), ODG (42.3%), and LDG (63.5%), as shown in Figure 5.
Postoperative abdominal infection
A total of 8 papers and 3401 patients were involved. There was no significant heterogeneity between the studies (I²=0). There were no statistically significant differences between the studies (P > 0.05). Concerning the incidence of postoperative abdominal infections by surgical approach, the ranked results were LDG (59.1%), ODG (44.1%), and RDG (73.3%), as shown in Figure 5.
Postoperative abdominal hemorrhage
A total of 8 papers and 3551 patients were involved. There was no significant heterogeneity between studies (I² < 50%). There were no statistically significant differences between the studies (P > 0.05). Concerning the incidence of postoperative abdominal hemorrhage by surgical approach, the ranked results were ODG (52.2%), LDG (52.8%), and RDG (84.5%), as shown in Figure 5.
Postoperative pneumonia
A total of 17 papers and 8,164 patients were involved. Of these, there was no significant heterogeneity between studies (I² < 50%). The incidence of postoperative pneumonia was higher in ODG (OR = 2.4, 95% CI = 1.1-6.5) and LDG (OR = 1.9, 95% CI = 1.0-4.2) compared to RDG, with no significant differences between the other studies (p > 0.05), as shown in Figure 4. The ranked probability plots show ranked results for ODG (82.1%), LDG (80.9%) ), and RDG (97.5%), as shown in Figure 5.
Postoperative anastomotic leakage
Outcome indicators such as anastomotic leakage were included in 17 papers, comprising 7,807 patients. There was no significant heterogeneity between the studies (I² < 50%) and no statistically significant differences (p > 0.05). Regarding the incidence of postoperative anastomotic fistula by surgical approach, the ranked results were LDG (58.3%), ODG (43.8%), and RDG (57.2%), as shown in Figure 5.
Total postoperative complications
The studies involved a total of 12 papers and 4803 patients. There was moderate heterogeneity between ODG and LDG (I² = 53.9%) and no significant heterogeneity between the other studies (I² < 50%). There were no statistically significant differences between the studies (P > 0.05). Regarding the incidence of postoperative complications by surgical modality, the ranked results were ODG (73.2%), LDG (58.5%), and RDG (60.2%), as shown in Figure 5.