Application of carbon nanoparticles in lymph node dissection and parathyroid protection during thyroid cancer surgeries: a systematic review and meta-analysis

PURPOSE To investigate whether carbon nanoparticles (CNs) are helpful in identifying lymph nodes and metastatic lymph nodes and in parathyroid protection during thyroid cancer surgery. METHODS English and Chinese literature in PubMed, Cochrane Database of Systematic Reviews, EMBASE, ClinicalTrials.gov, China Biology Medicine Database, China National Knowledge Infrastructure, China Master's and Doctoral Theses Full-Text Database, Wanfang database, and Cqvip database were searched (till March 22, 2016). Randomized controlled trials (RCTs) that compared the use of CNs with a blank control in patients undergoing thyroid cancer surgery were included. Quality assessment and data extraction were performed, and a meta-analysis was conducted using RevMan 5.1 software. The primary outcomes were the number of retrieved central lymph nodes and metastatic lymph nodes, and the rate of accidental parathyroid removal. RESULTS We obtained 149 relevant studies, and only 47 RCTs with 4,605 patients (CN group: n=2,197; blank control group: n=2,408) met the inclusion criteria. Compared with the control group, the CN group was associated with more retrieved lymph nodes/patient (weighted mean difference [WMD]: 3.39, 95% confidence interval [CI]: 2.73-4.05), more retrieved metastatic lymph nodes (WMD: 0.98, 95% CI: 0.61-1.35), lower rate of accidental parathyroid removal, and lower rates of hypoparathyroidism and hypocalcemia. However, the total metastatic rate of the retrieved lymph nodes did not differ between the groups (odds ratio: 1.13, 95% CI: 0.87-1.47, P=0.35). CONCLUSION CNs can improve the extent of neck dissection and protect the parathyroid glands during thyroid cancer surgery. And the number of identified metastatic lymph nodes can be simultaneously increased.