Association of surgeon and hospital volume with postoperative mortality after total gastrectomy for gastric cancer: data from 71,307 Japanese patients collected from a nationwide web-based data entry system

Background: Despite interest in surgeon and hospital volume effects on total gastrectomy (TG), clinical significance has not been confirmed in a large-scale population. This study aimed at clarifying the association of surgeon and hospital volume on postoperative mortality after TG for gastric cancer among Japanese patients in National Clinical Database (NCD). Methods: Between 2011 and 2015, we retrospectively extracted data on TG for gastric cancer from the NCD. The primary outcome was operative mortality. We divided surgeon volume as the number of TGs performed by a patient’s surgeon in the previous year: S1 (0–2 cases), S2 (3–9), S3 (10–25), S4 (26–79) and hospital volume by the number of TGs performed in the previous year: H1 (0–11 cases), H2 (12–26), H3 (27–146). We calculated the 95% confidence interval (CI) for the mortality rate based on odds ratios (OR) estimated from a hierarchical logistic regression model. Results: We analyzed 71,307 patients at 2051 institutions. Low-volume surgeons and hospitals had significantly older and poorer-risk patients with various comorbidities. The operative mortality rate decreased with surgeon volume, 2.5% in S1 and 0.6% in S4. The operative mortality was 3.1% in H1, 1.7% in H2, and 1.2% in H3. After risk adjustment for surgeon, hospital volume and patient characteristics, hospital volume was significantly associated with operative morality (H3: OR = 0.53, 95% CI 0.43–0.63). Conclusions: We demonstrate hospital volume has an impact on postoperative mortality after TG in a nationwide population study. These findings suggest centralization may improve outcomes after TG.