Surgical outcomes of major vascular resection for retroperitoneal liposarcoma from a high‑volume sarcoma center: a propensity score matching analysis

Multi-visceral resection of RLPS may necessitate vascular resection and reconstruction(Tzanis et al. 2018). Vascular invasion can be a sign of intrinsic biological aggressiveness (Devaud et al. 2023). In our cohort, the 5-year LRFS and OS rates were similar between patients with and without the vascular resection. This reflects that major vascular involvement does not represent a contraindication for curative resection of RLPS. To our knowledge, the present study is one of the largest studies solely focused on homogeneous RLPS to assess surgical outcomes of major vascular resection by using a propensity score matching analysis.

Liposarcoma and leiomyosarcoma represent the predominant histologic subtypes of RPS (de Bree et al. 2023). Major vascular resection in surgery for RLPS is less infrequent compared with retroperitoneal leiomyosarcoma (Devaud et al. 2023). Thanks to the improvements in the surgical techniques and perioperative management, en-bloc resections with the invaded vessels are no longer a contraindication to surgery for RLPS (Fiore et al. 2012). As one of the largest specialized sarcoma centers in China, we have performed 42 (21%) major vessel resection for RLPS in 199 patients. The frequency was similar to that reported by the University of Heidelberg (17.7%) (Schwarzbach et al. 2006), but is higher than those reported by Spolverato et al. (5%) (Spolverato et al. 2021). This could be attributed to the fact that the decision to perform major vessel resection may be affected by various factors, including different surgical strategies and the surgeon’s familiarity with the technique of vascular resection. In our study, patients with recurrent tumors underwent previous simple resection instead of the extended resection in other hospitals, nearly all of which were not high-volume centers. Previous studies have shown that re-resection for tumor residue after initial inadequate resection could provide a similar overall survival compared to complete primary resection (Nizri et al. 2019). Therefore, we performed relatively aggressive surgical treatment for patients with recurrent tumors after the initial simple resection. This is the reason why 48% of the patients had recurrent tumors and 33% presented with multifocality in the vascular resection group. In the present study, vascular infiltration was confirmed in 27 (64%) patients and R0 resection was achieved in 80.4% of the patients. This is in line with the vascular infiltration rate (70%) reported by Fairweather et al. (Fairweather et al. 2018). Therefore, adjacent major vessels should be resected when they are widely encased or frankly infiltrated.

Different reconstructive techniques have been developed over the past decades and are not standardized (Dull et al. 2013). The inferior vena cava and iliac vessels were the most commonly involved vessels in RPS resection (Quinones-Baldrich et al. 2012). Moreover, both venous and arterial resection were commonly required in cases of RPS involving iliac vessels (Radaelli et al. 2016). The methods of reconstruction include partial resection, primary repair, transplantation, and ligation (Quinones-Baldrich and Farley 2013). Reconstructions with PTFE grafts are the most reported reconstructive technique in published articles (Blair et al. 2018; Quinones-Baldrich et al. 2012). Similarly, PTFE grafts were used in the majority of the patients in our cohort. Of note, the graft patency rates (86%) were comparable to those in other studies that reported a graft patency of 80-90% (Kieffer et al. 2006; Shafique et al. 2024). Previous reports have associated a higher risk of VTE with vascular reconstruction (Blair et al. 2018). Indeed, VTE (14.3%) was the leading cause of major morbidity and reoperations in the vascular resection group, followed by postoperative abdominal bleeding and abdominal infection.

Vascular resection increases the complexity of the operation, which involve high risk (Devaud et al. 2023). Different retrospective studies have confirmed that risk of RPS surgery are higher in patients who underwent major vascular resection, with the major morbidity and mortality rates of approximately 18-50% and 0-21% (Devaud et al. 2023), respectively. In a France study analyzing 31 patients with RPS who received oncovascular surgery, the reoperation rate was 16% (Bertrand et al. 2016), which is consistent with our current finding of a reoperation rate of 19%. In another retrospective analysis, the major morbidity and mortality rates of surgery for PRS involving major vessels were 36% and 4%, respectively (Schwarzbach et al. 2006). Similarly, in this series of 42 patients with en-bloc vascular resection, the major complication and mortality rates were 38% and 7.1%, respectively. Given the great number of organs resected, intrinsic aggressiveness, and malnutrition, the high morbidity, reoperation and mortality rates were feasible in the vascular resection cohort. Thus, meticulous preoperative planning and resection policy should be adopted when major vascular structures are involved in patients with RLPS.

In terms of the high morbidity and mortality after extensive resections with the invaded vessels, downstaging RPS with neoadjuvant therapy to facilitate adequate resection is crucial. But the role of perioperative therapy remains controversial for RPS (de Bree et al. 2023). The global randomized trial (STRASS) to evaluate the role of surgery with and without preoperative RT for patients with RPS, did not demonstrate a significant overall benefit (Bonvalot et al. 2020). RLPS was less sensitive to conventional doxorubicin-based chemotherapy (Italiano et al. 2012). The benefit of neoadjuvant chemotherapy remains unclear from retrospective data and await confirmation by the ongoing STRASS2 randomized controlled trial (Lambdin et al. 2023). Due to the unsatisfactory effect of perioperative therapy seen in the most RPS cases, administration of systemic therapies or radiotherapy in neoadjuvant and adjuvant setting is not the current standard of care (de Bree et al. 2023). Further randomised trials are warranted to identify the definite role of systemic therapies or radiotherapy in the multimodality treatment of RPS.

Studies have shown that survival rates of patients who underwent major vascular resection are comparable to those without vascular involvement (Blair et al. 2018; Poultsides et al. 2015). Our study showed similar 5-year LRFS and OS rates between patients with and without the vascular resection in the matched cohort (LRFS: P = 0.74, OS: p = 0.12, respectively). This finding was comparable to those reported by Hu et al. (Hu et al. 2023) and Blair et al. (Blair et al. 2018). Vascular resection was also not an independent predictor influencing LRFS and OS in patients with RLPS. Multivariate analyses confirmed that larger tumor size and higher numbers of organs resected are independent adverse prognostic factors of OS. It could be inferred that the necessity of increased number of organs resected may imply more aggressive tumor behavior and high difficulty of tumor removal. As aforementioned, the need of vascular resection for RLPS is not associated with a worse oncological prognosis.

Taken together, the study offers a valuable perspective for the role of major vascular resection in the surgical management of RLPS. Nevertheless, our study had several limitations. First, this study was performed retrospectively and the inherent selection bias could not be avoided. Second, the sample size of patients undergoing vascular resection was limited and the criteria for vascular resection was not prospectively selected. Finally, the assessment of long-term vascular patency was insufficient and longer follow-up is needed. Further studies from multi-institutional and international collaborations are needed to verify these results over a longer time span.