Combined surgeries for retroperitoneal tumors.

e23579 Background: Retroperitoneal tumors are rare heterogeneous malignant tumors. Due to their poor response to chemoradiotherapy, surgery is the main treatment option. Currently, there is little data on treatment outcomes in patients who underwent en block resection of retroperitoneal tumors and major vessels. Our purpose was to analyze surgical and oncological results in patients with retroperitoneal tumors and major blood vessel involvement. Methods: 27 patients received surgery for retroperitoneal tumors with major vessel resection in 2015-2019. Results: The mean tumor diameter was 17 cm (11-39 cm). The most frequent histological types were moderately differentiated liposarcoma (33.4%), well differentiated (18.5%), poorly differentiated sarcoma (18.5%), pleomorphic liposarcoma (22.2%), leiomyosarcoma (7.4%). Resection of the suprarenal inferior vena cava (IVC) with prosthetics was performed in 4 cases, resection of its renal segment with renal vein reimplantation - 1, resection of the infrarenal IVC with prosthetics - 8. PTFE prostheses were used as a conduit in all cases. Marginal excision of the suprarenal IVC was performed in one patient, that of the infrarenal IVC - in 5 patients; resection of the infrarenal IVC without the reconstruction - in one case. The iliac venous segment resection was required in 6 patients, in one case – with the iliac arterial segment resection and prosthetics. Macroscopic complete resection (R0-R1) was achieved in 92.6%. The postoperative morbidity was 25.9%, with no fatal outcomes. Despite the anticoagulant therapy, the frequency of thrombosis of the venous reconstruction area in the early postoperative period (1 month) was 7.4%. The median relapse-free survival was 14 months; the median overall survival was not achieved. Conclusions: Combined surgeries with simultaneous removal of retroperitoneal tumor and angioplasty demonstrate an acceptable level of morbidity and mortality. Radical removal of tumors with major blood vessel involvement allows increasing the survival in patients often considered inoperable.