Short-term perioperative safety and long-term follow-up after robotic-assisted resection of non-renal, non-adrenal retroperitoneal tumors: a 10-year retrospective cohort study.

Background: Open surgery remains the conventional approach for large retroperitoneal tumors because of limited operative space, complex vascular anatomy, potential bleeding risk, and oncological concerns. However, evidence regarding robotic-assisted laparoscopic resection for retroperitoneal tumors larger than 10 cm remains limited. This study aimed to evaluate the feasibility, safety, perioperative outcomes, and follow-up results of robotic-assisted laparoscopic resection for non-renal and non-adrenal retroperitoneal tumors, with particular focus on tumors larger than 10 cm. Methods: We retrospectively reviewed patients who underwent robotic-assisted laparoscopic resection of retroperitoneal tumors at our institution between November 2015 and November 2024. Tumors of renal or adrenal origin were excluded based on postoperative pathological diagnosis. Patients were stratified according to maximum tumor diameter into three groups: >10, >6 to <10, and <6 cm. Baseline characteristics, operative variables, perioperative outcomes, pathological findings, and follow-up results were compared among the three groups. The primary descriptive endpoints were conversion, estimated blood loss, transfusion, postoperative intensive care unit admission, operative time, and postoperative hospital stay. Comparisons were exploratory and unadjusted. Results: A total of 207 patients were included, comprising 27 patients in the >10 cm group, 52 in the >6 to <10 cm group, and 128 in the <6 cm group. There were no significant differences among the groups in age, body mass index, sex distribution, American Society of Anesthesiologists grade, transfusion rate, conversion rate, postoperative intensive care unit admission, or follow-up duration.  Two procedures (1.0%) were converted to open surgery. After inclusion of the 3,000 mL bleeding conversion, mean blood loss in the >10 cm group was 300.42±658.94 mL (F=6.4952, P=0.002). Operative time and postoperative hospital stay were longer in the >10 cm group. Malignancy was more frequent in tumors larger than 6 cm than in tumors smaller than 6 cm. In the >10 cm group, liposarcoma, ganglioneuroma, and paraganglioma were the most common pathological diagnoses. In the liposarcoma-specific review, 14 patients underwent 18 robotic procedures; six developed local recurrence, and one died of metastatic disease during follow-up. Conclusions: Robotic-assisted laparoscopic resection was technically feasible in this selected cohort for selected non-renal and non-adrenal retroperitoneal tumors larger than 10 cm when performed in experienced centers. Although larger tumors were associated with longer operative time and postoperative hospital stay, conversion and transfusion rates were low, one major bleeding conversion illustrates an important limitation. For large benign tumors, perioperative outcomes were broadly comparable with those of smaller tumors. For large malignant tumors, robotic surgery may represent a minimally invasive option with acceptable perioperative outcomes; however, careful patient selection and long-term oncological surveillance remain essential. These findings do not establish oncological equivalence to open surgery, particularly for retroperitoneal sarcoma.