Diagnostic value of near-infrared or fluorescent indocyanine green guided sentinel lymph node mapping in gastric cancer: A systematic review and meta-analysis.

BACKGROUND: This meta-analysis was conducted to evaluate the diagnostic value of near-infrared (NIR) or fluorescent indocyanine green (ICG) guided sentinel lymph node (SLN) mapping in gastric cancer (GC).

METHODS: This meta-analysis was registered at the PROSPERO. Clinical studies were retrieved from the electronic database Pubmed, Embase, Medline, Web of science, and the Cochrane Library. Quality assessment was conducted by an adapted checklist of QUADAS-2. A bivariate mixed-effects model was used to pool the data. Evaluation of articles quality, analysis for publication bias, summary receiver operator characteristic (SROC) curves, and meta-regression were also performed. Subgroup analysis was used to explain the heterogeneities.

RESULTS: A total of 13 clinical studies (971 patients) were included. The NIR or fluorescent imaging (FI) involved infrared ray electronic endoscopy (IREE), infrared ray laparoscopic system (IRLS), and FI system. Significant evidence of heterogeneity was found for sensitivity and specificity (I 2  = 91.1% and I 2  = 98.2%), respectively. The pooled SLN sensitivity (Sen), specificity (Spe), positive likelihood ratio (PLR), negative likelihood ratio (NLR), and diagnostic odds ratio (DOR) were 0.94(95%CI: 0.80-0.99), 1.00(95%CI: 0.60-1.00), 34.0(95%CI: 9.25-125.29), 0.06(95%CI:0.02-0.22), and 252.50(95%CI: 94.93-671.61), respectively. Area under curve (AUC) of SROC curve was 1.00 (95%CI: 0.99-1.00), and the summary operating point (cut-off value) was SENS = 0.94(95%CI: 0.80-0.99) and SPEC = 1.00(95%CI: 0.60-1.00). Subgroup analysis showed that NIR imaging, imaging performed 20 minutes after intraoperative injection, preoperative injection (especially for FI imaging), stained with immunohistochemistry (IHC) (+hematoxylin-eosin [HE]), cT1 stage, submucosa injection (especially for cT1), mean number of SLN ≥ 5, study size > 26 were associated with higher SLN sensitivity. In terms of ICG concentration, diluted ICG concentration that 0.5 mg/mL (compared with 5 mg/mL) in NIR imaging and 0.05 mg/mL (compared with 0.5 mg/mL) in FI system showed higher sensitivities. However, the differences in tumor diameter (≤30 mm vs >30 mm), gastrectomy methods (opening vs laparoscopy), lymphadenectomy methods (LBD vs pick-up), and publication year (≥2010 vs <2010) did not achieve statistical significance.

CONCLUSION: ICG combined with NIR or FI guided SLN mapping is technically feasible for GC. Based on the small sample size evidence, the IREE and IRLS devices may have higher sensitivity than FI in current clinical studies; and there may be an excessive ICG concentration used for current SLN mapping in GC. However, well-designed further studies with large sample size are needed to confirm the best procedure and suitable criteria.

MINI-ABSTRACT: This meta-analysis was registered at PROSPERO. Clinical studies on this topic were retrieved from the electronic database Pubmed, Embase, Medline, Web of Science, and the Cochrane Library. The NIR or FI involved IREE, IRLS, and FI techniques. A total of 13 clinical studies (971 patients) were included. Based on the small sample size evidence, NIR or FI ICG guided SLN mapping in GC is technically feasible.