Real‐World Data of Retroperitoneal Tumor Surgeries Performed by Gastroenterological Surgeons in Japan: Analysis Based on the National Clinical Database

ABSTRACT Background Retroperitoneal tumors (RPTs) are rare and anatomically complex neoplasms, for which surgery remains the mainstay of treatment. However, real‐world data on their surgical management in Japan have been limited. Objective To describe the clinical characteristics and short‐term outcomes of patients undergoing resection for RPTs in Japan, based on data from gastroenterological surgical practice. Methods This study analyzed data from the Japanese National Clinical Database (NCD) for gastroenterological surgery. A total of 4948 patients with RPT who underwent surgery between 2019 and 2021 were included. Results There were 2360 men (47.7%) and 2588 women (52.3%), with a median age of 66 years. RPTs were histologically classified as malignant in 75.3% and benign in 24.7% of cases. The median operative time was 205 min, and the median blood loss was 150 mL. Postoperative complications occurred in 23.9% of patients, with 7.5% experiencing severe complications (Clavien–Dindo grade III or higher). The 30 day postoperative mortality rate was 0.5%, and the perioperative mortality rate was 1.0%. Conclusion This analysis demonstrates that a substantial number (approximately 1650 per year) of RPTs surgeries are performed annually by gastrointestinal surgeons in Japan, and that the short‐term surgical outcomes are acceptable. These data provide an important reference to exhibit the current surgical practice in Japan and to develop future strategies for RPTs.