Diagnostic Value Of Optical Imaging Combined With Indocyanine Green Guided Sentinel Lymph Node Biopsy In Gastric Cancer:a Meta-analysis

Gastric cancer（GC）is one of the main causes of the most common cancer-related deaths in China,and surgical treatment is one of the most important therapies.The postoperative complications owing to unnecessary lymph node dissection will be reduced if the lymph node metastasis（LNM）can be real-time and accurately evaluated in surgery.The sentinel lymph node（SLN）is defined as the group of lymph nodes（which may be one or more lymph nodes）that first receive regional lymphatic drainage.In malignant tumors,it is the first station of lymph nodes that tumor cells will reach.Since the 21^st century,novel methods optical imaging（such as near-infrared or fluorescent imaging）combined with indocyanine green（ICG）guided sentinel lymph node biopsy（SLNB）in GC have been reported with satisfactory results.These studies have shown good application perspectives,however the results of each research are inconsistent:large fluctuation range in sensitivity and specificity.Therefore,we conducted a meta-analysis for the diagnostic value of optical imaging combined with ICG-guided SLNB,aiming to provide guidance for the treatment of gastric cancer.Objective:This meta-analysis was performed to evaluate the diagnostic value of optical imaging combined with indocyanine green（ICG）guided sentinel lymph node biopsy（SLNB）in gastric cancer,and to identify potential factors that would influence diagnostic accuracy.Methods:Clinical studies were searched in electronic database of Pubmed,Embase,Medline,Web of science,and the Cochrane Library.The meta-analysis was performed in the Stata12.0 software using the"bivariate mixed-effects model"combined with the"midas"command to pool the data.Information such as true positive value,false positive value,false negative value,and true negative value of each included articles were extracted.The literature quality assessment map was drawn to describe the overall quality of the articles;the heterogeneity analysis was performed with the forest map,P<0.01 was considered statistically significant;the funnel plot was used to describe the publication bias,P<0.1 was considered statistically significant;Area under curve（AUC）of summary receiver operator characteristic curve（SROC）was used to describe the diagnostic accuracy.The closer the（SROC）AUC get to 1,the higher the diagnostic accuracy will be.If there was heterogeneity（I²>50%）between studies,then regression analysis and subgroup analysis were performed,P<0.05 was considered statistically significant.Results:A total of 15 studies（1016 patients）were included.The optical imaging contained near-infrared（NIR）imaging and fluorescent imaging（FI）.The pooled sensitivity was 0.95（95%CI:0.82⁰.99）,specificity was 1.00（95%CI:0.92¹.00）,positive likelihood ratio was 30.39（95%CI:9.14¹01.06）,negative likelihood ratio was 0.05（95%CI:0.01⁰.20）,and diagnostic odds ratio was 225.54（95%CI:88.81⁵72.77）.Meta-subgroup analysis indicated that NIR imaging,optical imaging performed 20 min after ICG injection,mean number of SLN≥4,stained with IHC（+HE）,submucosa injection,early stage（cT₁）,study size>26,and publication year≥2010 were contributed to more satisfactory sensitivity.With respect to ICG concentration,the diluted ICG group（0.5 or 0.05 mg/ml vs 5 mg/ml）showed higher sensitivities.However,there were no statistical differences in gastrectomy,lymphadenectomy,and tumor diameter.Conclusion:Optical imaging combined with ICG guided sentinel lymph node biopsy（SLNB）in gastric cancer is clinically feasible,and especially suitable for early gastric cancer.Higher sensitivity was found for NIR imaging when compared with FI method,and an excessive ICG concentration may be used in current clinical studies.