Trends of Oncological Quality of Robotic Gastrectomy for Gastric Cancer in the United States

Background: Robotic gastrectomy (RG) has been increasingly used for treatment of gastric cancer in the United States. However, it is unknown if there has been a nationwide improvement of short-term safety outcomes and oncological quality metrics over time. Methods: We used the National Cancer Database to identify patients who underwent major gastrectomy from 2010 through 2018. The shortterm safety outcomes and oncological metrics were compared between cases of open gastrectomy (OG), laparoscopic gastrectomy (LG), and RG. We also compared the indications and outcomes of RG between the three periods (2010-2012, 2013-2015, and 2016-2018). Results: Of the 22,445 patients included, 1,867 (8%) underwent RG. Number of RG continued to increase from only 37 cases performed in 2010 to 412 cases performed in 2018. The number of lymph nodes (LNs) examined (OG, 16; LG, 17; and RG, 19) and the R0 rate (OG, 88%; LG, 92%; and RG 94%) were better for RG than for OG or LG (P < 0.001). In the RG group, the number of LNs examined (first period, 15; third period, 18; P < 0.001), R0 rate (first period, 88.6%; third period, 91.1%; P < 0.001), length of hospital stay (first period, 9 days; third period, 8 days; P < 0.001), 30-day readmission rate (first period, 10.1%; third period, 7.9%; P < 0.001), and 90-day mortality (first period, 7.3%; third period, 6.0%; P = 0.003) continued to improve cohort over time. The ratio of the robotic cases performed in academic institutions gradually increased (first period, 48.6%; third period, 54.3%; P < 0.001). In multivariable analyses, RG was associated with more than 15 LNs being examined (OR, 1.49; 95% CI, 1.34 - 1.65; P < 0.001). The indications for RG appeared expanding to include more advanced stage, high comorbidity, and patients who underwent preoperative therapy. Conclusions: RG has been increasingly performed in the past decade. Although its indication was expanded to include more advanced tumors, we found that the oncological quality metrics and safety outcomes of RG have improved over time and were better than those of OG or LG.