Assessment of Carbon Nanoparticle Suspension Lymphography–Guided Distal Gastrectomy for Gastric Cancer

IMPORTANCE: Carbon nanoparticle suspension injection (CNSI) can be used to visualize lymph node (LN) drainage in gastric cancer. The tracing and diagnostic value of carbon nanoparticle suspension lymphography-guided distal gastrectomy for gastric cancer has not been thoroughly reported. OBJECTIVE: To compare the number of lymph nodes identified in patients with gastric cancer receiving a CNSI vs no injection. DESIGN, SETTING, AND PARTICIPANTS: This is a retrospective cohort study including patients with clinical T1 to T4 disease who underwent laparoscopic or robotic distal gastrectomy. Data from a cohort of 1225 patients at the Fourth Hospital of Hebei Medical University (Shijiazhuang, China) from November 2019 to February 2021 were analyzed. Patients were divided into the CNSI group and conventional group after 1:1 propensity matching analysis. The mean number of LNs detected was compared between groups, and the diagnostic role of CNSI was analyzed in the CNSI group. Statistical analysis was performed from May to July 2021. EXPOSURE: CNSI was peritumorally injected under an endoscope 1 day before surgery in the CNSI group, and the conventional group did not receive any treatment before surgery. MAIN OUTCOMES AND MEASURES: The main outcome was the number of LNs detected. Gastrectomy with systematic D1+ (ie, stations 1, 3, 4sb, 4d, 5, 6, and 7) or D2 (ie, all D1 stations, plus 8a, 9, 11p, and 12a) lymphadenectomy was performed. Black-stained LNs and nonblack-stained LNs were examined separately in the CNSI group. RESULTS: A total of 312 consecutive patients (mean [SD] age, 56.7 [10.4] years; 216 [69.2%] men) who underwent distal gastrectomy were enrolled, including 78 patients in the CNSI group, and another 78 patients determined from 1:1 propensity score matching, making an overall cohort size of 156 patients. The mean (SD) number of LNs detected in the CNSI group was 59.6 (21.4), which was significantly higher than that in the conventional group (30.0 [11.3] LNs; P < .001). In the CNSI group, the mean (SD) number of LNs detected at black-stained LN stations was significantly higher than that at nonstained LN stations (9.2 [6.1] LNs per station vs 3.5 [3.2] LNs per station; P < .001). For black-stained LN stations, the sensitivity was 97.8% (95% CI, 91.6%-99.6%), specificity was 38.1% (95% CI, 34.2%-42.3%), positive predictive value was 20.1% (95% CI, 16.6%-24.2%), and negative predictive value was 99.1% (95% CI, 96.4%-99.8%); for the black-stained LNs, sensitivity was 97.6% (95% CI, 95.3%-98.8%), specificity was 35.4% (95% CI, 33.9%-36.8%), positive predictive value was 11.6% (95% CI, 10.5%-12.8%), and negative predictive value was 99.4% (95% CI, 98.8%-99.7%). CONCLUSIONS AND RELEVANCE: These findings suggest that CNSI was associated with facilitating the dissection of all positive LNs, which could improve surgical quality. Carbon nanoparticle suspension-guided lymphography may be an alternative to conventional systematic lymphadenectomy for distal gastrectomy.