UK guidelines for the management of soft tissue sarcomas.

Soft tissue sarcomas (STS) are rare tumours arising in mesenchymal tissues and can occur almost anywhere in the body. Their rarity, and the heterogeneity of subtype and location, means that developing evidence-based guidelines is complicated by the limitations of the data available. This makes it more important that STS are managed by expert multidisciplinary teams, to ensure consistent and optimal treatment, recruitment to clinical trials, and the ongoing accumulation of further data and knowledge. The development of appropriate guidance, by an experienced panel referring to the evidence available, is therefore a useful foundation on which to build progress in the field. These guidelines are an update of the previous versions published in 2010 and 2016 [1, 2]. The original guidelines were drawn up by a panel of UK sarcoma specialists convened under the auspices of the British Sarcoma Group (BSG) and were intended to provide a framework for the multidisciplinary care of patients with soft tissue sarcomas. This iteration of the guidance, as well as updating the general multidisciplinary management of soft tissue sarcoma, includes specific sections relating to the management of sarcomas at defined anatomical sites: gynaecological sarcomas, retroperitoneal sarcomas, breast sarcomas, and skin sarcomas. These are generally managed collaboratively by site specific multidisciplinary teams linked to the regional sarcoma specialist team, as stipulated in the recently published sarcoma service specification [3]. In the UK, any patient with a suspected soft tissue sarcoma should be referred to a specialist regional soft tissues sarcoma service, to be managed by a specialist sarcoma multidisciplinary team. Once the diagnosis has been confirmed using appropriate imaging and a tissue biopsy, the main modality of management is usually surgical excision performed by a specialist surgeon, combined with pre- or post-operative radiotherapy for tumours at higher risk for local recurrence. Systemic anti-cancer therapy (SACT) may be utilised in cases where the histological subtype is considered more sensitive to systemic treatment. Regular follow-up is recommended to assess local control, development of metastatic disease, and any late effects of treatment.

Risk Factors for the Development of Early Recurrence in Patients with Primary Retroperitoneal Sarcoma.

BACKGROUND: Disease recurrence after retroperitoneal sarcoma (RPS) surgery is common, and resection may offer no benefit for patients who experience recurrence early. This study examined the incidence of early recurrence (EREC) in RPS patients, and the association between EREC and prognosis, aiming to identify the factors associated with EREC. METHODS: Patients undergoing surgery for primary RPS from 2008 to 2019 at two tertiary RPS centers were analyzed. The study defined EREC as any evidence of local recurrence and/or distant metastases on the CT scan up to 6 months after surgery. Overall survival (OS) was calculated using the Kaplan-Meier method. A multivariable analysis was performed to identify independent predictors of EREC. RESULTS: Of the 692 patients who underwent surgery during the study period, 657 were included in the analysis. Sixty-five of these patients (9.9%; 95% confidence interval [CI], 7.7-12.4%) developed EREC. Five-year OS was 3% for the patients with EREC versus 76% for those without EREC (p < 0.001). Patient characteristics were compared between the EREC and non-EREC patients, and EREC was found to be significantly associated with Eastern Cooperative Oncology Group (ECOG) performance status (p = 0.006), tumor histology (p = 0.002), tumor grading (p < 0.001), radiotherapy (p = 0.04), and postoperative complications measured as a comprehensive complications index value (p = 0.003). However, the only significant independent predictor of EREC in the multivariable analysis was grade 3 tumors, with an odds ratio of 14.8 (95% CI, 4.44-49.2; p < 0.001). CONCLUSION: Early recurrence is associated with a poor prognosis, and a high tumor grade is an independent predictor for the development of EREC. Patients with EREC may benefit the most from new therapeutic options such as neoadjuvant chemotherapy.

Assessment of inter-centre agreement across multidisciplinary team meetings for patients with retroperitoneal sarcoma.

BACKGROUND: Decision-making in the management of patients with retroperitoneal sarcoma is complex and requires input from a number of different specialists. The aim of this study was to evaluate the levels of agreement in terms of resectability, treatment allocation, and organs proposed to be resected across different retroperitoneal sarcoma multidisciplinary team meetings. METHODS: The CT scans and clinical information of 21 anonymized retroperitoneal sarcoma patients were sent to all of the retroperitoneal sarcoma multidisciplinary team meetings in Great Britain, which were asked to give an opinion about resectability, treatment allocation, and organs proposed to be resected. The main outcome was inter-centre reliability, which was quantified using overall agreement, as well as the chance-corrected Krippendorff's alpha statistic. Based on the latter, the level of agreement was classified as: 'slight' (0.00-0.20), 'fair' (0.21-0.40), 'moderate' (0.41-0.60), 'substantial' (0.61-0.80), or 'near-perfect' (>0.80). RESULTS: Twenty-one patients were reviewed at 12 retroperitoneal sarcoma multidisciplinary team meetings, giving a total of 252 assessments for analysis. Consistency between centres was only 'slight' to 'fair', with rates of overall agreement and Krippendorff's alpha statistics of 85.4 per cent (211 of 247) and 0.37 (95 per cent c.i. 0.11 to 0.57) for resectability; 80.4 per cent (201 of 250) and 0.39 (95 per cent c.i. 0.33 to 0.45) for treatment allocation; and 53.0 per cent (131 of 247) and 0.20 (95 per cent c.i. 0.17 to 0.23) for the organs proposed to be resected. Depending on the centre that they had attended, 12 of 21 patients could either have been deemed resectable or unresectable, and 10 of 21 could have received either potentially curative or palliative treatment. CONCLUSIONS: Inter-centre agreement between retroperitoneal sarcoma multidisciplinary team meetings was low. Multidisciplinary team meetings may not provide the same standard of care for patients with retroperitoneal sarcoma across Great Britain.

Primary retroperitoneal sarcoma: A comparison of survival outcomes in specialist and non-specialist sarcoma centres.

BACKGROUND: Consensus guidelines outline that patients with primary retroperitoneal sarcoma (RPS) should be managed within specialist sarcoma centres (SSC). There is, however, a paucity of population-based data detailing incidence and outcomes in these patients. Hence, we aimed to evaluate patterns of care among RPS patients in England and compare outcomes for those undergoing surgery in high-volume specialist sarcoma centres (HV-SSC), low-volume SSC (LV-SSC), and non-SSC (N-SSC). METHODS: Data on patients diagnosed with primary RPS between 2013 and 2018 were extracted from NHS Digital's National Cancer Registration and Analysis Service using the national cancer registration dataset. Diagnostic pathways, treatment, and survival outcomes were compared between HV-SSC, LV-SSC, and N-SSC. Uni- and multivariate analyses were calculated. RESULTS: Of 1878 patients diagnosed with RPS, 1120 (60%) underwent surgery within 12 months of diagnosis, with 847 (76%) operated on at SSC; of these, 432 patients (51%) were operated on in HV-SSC, and 415 (49%) in LV-SSC. One- and 5-year estimated overall survival (OS) rates for patients undergoing surgery in N-SSC were 70.6% (95% confidence interval [CI]: 64.8-75.7) and 42.0% (CI: 35.9-47.9), compared to 85.0% (CI: 81.1-88.1) and 51.7% (CI: 46.6-56.6) in LV-SSC (p < 0.01), and 87.4% (CI: 83.9-90.2) and 62.8% (CI: 57.9-67.4) in HV-SSC, (p < 0.01). After adjusting for patient- and treatment-related factors, patients treated in HV-SSC were found to have significantly longer OS than those treated at LV-SSC, with an adjusted hazard ratio of 0.78 (CI: 0.62-0.96, p < 0.05). CONCLUSION: Patients with RPS undergoing surgery in HV-SSC have significantly better survival outcomes than those treated in N-SSC and L-SSC.

Dealing with malignancy involving the inferior vena cava in the 21st century.

INTRODUCTION: Malignancies involving the inferior vena cava (IVC) have historically been considered not amendable to surgery. More recently, involvement of the IVC by neoplastic processes in the kidney, liver or in the retroperitoneum can be managed successfully. EVIDENCE ACQUISITION: In this systematic review we summarize the current evidence regarding the surgical management of the IVC in cases of involvement in neoplastic processes. Current literature was searched, and studies selected on the base of the PRISMA guidelines. Evidence was synthesized in narrative form due to heterogeneity of studies. EVIDENCE SYNTHESIS: Renal cell carcinoma accounts for the greatest proportion of studied patients and can be managed with partial or complete vascular exclusion of the IVC, thrombectomy and direct closure or patch repair with good oncological prognosis. Hepatic malignancies or metastases may involve the IVC, and the joint expertise of hepatobiliary and vascular surgeons has developed various strategies, according to the location of tumor and the need to perform a complete vascular exclusion above the hepatic veins. In retroperitoneal lymph node dissection, the IVC can be excised en-block to guarantee better oncological margins. Also, in retroperitoneal sarcomas not arising from the IVC a vascular substitution may be required to improve the overall survival by clearing all the neoplastic cells in the retroperitoneum. Leiomyoma can have a challenging presentation with involvement of the IVC requiring either thrombectomy, partial or complete substitution, with good oncological outcomes. CONCLUSIONS: A multidisciplinary approach with specialist expertise is required when dealing with IVC involvement in surgical oncology. Multiple techniques and strategies are required to deliver the most efficient care and achieve the best possible overall survival. The main aim of these procedures must be the complete clearance of all neoplastic cells and achievement of a safe margin according to the perioperative treatment strategy.

Emergency multivisceral resection for spontaneous haemorrhage rupture of huge solid pseudopapillary neoplasm of the pancreas during pregnancy†.

Solid pseudopapillary neoplasm (SPN) of the pancreas is a rare malignancy with a low malignant potential and strong female preponderance. Diagnosis during pregnancy is extraordinary, and management must consider the risks to the mother and foetus of tumour growth and rupture. A large 35-cm SPN was identified on magnetic resonance imaging (MRI) in a 24-year-old woman at 6 weeks of gestation following presentation with an abdominal mass. Surgery was delayed to allow the foetus to reach as close to term as possible because surveillance MRIs showed incremental mass growth. Emergency c-section was undertaken at 35 weeks of gestation due to persistent tachycardia and suspected haemorrhage into the tumour. A Hb of 70 g/l post-delivery despite four units of RBCs and an albumin of 11 g/l necessitated urgent multivisceral surgery. Surgical resection is the mainstay of treatment for SPN. However, the strategy of choice during pregnancy remains undetermined, with more recent reports delaying surgery until post-partum.

Evaluation of outcomes in the management of primary sporadic desmoid-type fibromatosis at a specialist soft tissue sarcoma unit.

BACKGROUND: Desmoids are rare fibroblastic tumours whose treatment in any individual case presents a persistent challenge. We endeavoured to evaluate various clinicopathological factors contributing to tumour behaviour. METHODS: This is a retrospective review of 95 primary truncal sporadic fibromatosis managed between 2011 and 2020. We studied progression rate for wait and watch (WW) and recurrence rate for the surgically treated group as adverse events. Relevant event-free survivals and potential risk factors were analysed over a median follow-up of 27 months. RESULTS: 66 patients (69.5%) received watchful surveillance and 28 upfront surgery. 2-year progression-free survival in WW group (88.9%) was higher than RFS in the surgical group (77.1%) p = 0.02. Adverse event rate compared favourably, 28.8% in WW and 28.6% in surgical group. At final follow-up, rate of stable disease for WW was 47%, and the regression rate was 24.2%. On Cox regression analysis, meantime to progress was 14 ± 2.0 months, with larger tumour size as a significant prognostic indicator (p = 0.05). Surgical group's mean time to recurrence was 13.8 ± 2.76 months, with tumour location a significant contributing factor (p = 0.05). CONCLUSIONS: This study confirms to the safety of both treatment approaches. Adverse event rates remained comparable, but event-free survival was longer for the watchful surveillance group.

Association Between Ageing and Short-Term Survival Outcomes in Patients Undergoing Surgery for Primary Retroperitoneal Sarcoma.

BACKGROUND: As the population ages, more elderly patients are receiving surgery for retroperitoneal sarcoma (RPS). However, high-quality data investigating associations between ageing and prognosis are lacking. Our study aimed to investigate whether ageing is associated with inferior short-term survival outcomes after RPS surgery. PATIENTS AND METHODS: Patients undergoing surgery for primary RPS between 2008 and 2019 at two tertiary sarcoma centres were analysed. The primary outcome was 1-year mortality, and the primary explanatory variable was patient age, classified as: < 55, 55-64, 65-74 or 75+ years. RESULTS: The 692 patients undergoing surgery (mean age 60.8 ± 13.8 years) had a 1-year mortality rate of 9.4%, which differed significantly by age (p < 0.001), with rates of 7.2%, 6.9%, 8.7% and 22.8% for the < 55, 55-64, 65-74 and 75+ years groups, respectively. The distribution of causes of death also differed significantly by age (p = 0.023), with 22% and 28% of deaths in the 65-74 and 75+ years groups caused by post-operative complications, versus none in the < 55 and 55-64 years groups. On multivariable analysis, age of 75+ years (versus < 55 years) was a significant independent predictor of 1-year mortality [odds ratio (OR) 7.05, 95% confidence interval (CI) 2.63-18.9, p < 0.001]; no significant increase in risk was observed in the 55-64 (OR 0.72, 95% CI 0.28-1.87) or 65-74 (OR 0.89, 95% CI 0.37-2.15) years groups. CONCLUSIONS: Post-operative complications are an important cause of deaths in elderly patients. These findings are relevant to decision-making and counselling when surgery is considered for patients with RPS.

Management of Locally Recurrent Retroperitoneal Sarcoma in the Adult: An Updated Consensus Approach from the Transatlantic Australasian Retroperitoneal Sarcoma Working Group.

BACKGROUND: Surgery is the mainstay of treatment for retroperitoneal sarcoma (RPS), but local recurrence is common. Biologic behavior and recurrence patterns differ significantly among histologic types of RPS, with implications for management. The Transatlantic Australasian RPS Working Group (TARPSWG) published a consensus approach to primary RPS, and to complement this, one for recurrent RPS in 2016. Since then, additional studies have been published, and collaborative discussion is ongoing to address the clinical challenges of local recurrence in RPS. METHODS: An extensive literature search was performed, and the previous consensus statements for recurrent RPS were updated after review by TARPSWG members. The search included the most common RPS histologic types: liposarcoma, leiomyosarcoma, solitary fibrous tumor, undifferentiated pleomorphic sarcoma, and malignant peripheral nerve sheath tumor. RESULTS: Recurrent RPS management was evaluated from diagnosis to follow-up evaluation. For appropriately selected patients, resection is safe. Nomograms currently are available to help predict outcome after resection. These and other new findings have been combined with expert recommendations to provide 36 statements, each of which is attributed a level of evidence and grade of recommendation. In this updated document, more emphasis is placed on histologic type and clarification of the intent for surgical treatment, either curative or palliative. Overall, the fundamental tenet of optimal care for patients with recurrent RPS remains individualized treatment after multidisciplinary discussion by an experienced team with expertise in RPS. CONCLUSIONS: Updated consensus recommendations are provided to help guide decision-making for treatment of locally recurrent RPS and better selection of patients who would potentially benefit from surgery.

Overall survival in abdominal wall sarcoma treated with curative intent surgery: A retrospective study from two European referral centres.

INTRODUCTION: Primary abdominal wall sarcomas are rare, heterogeneous tumours. The mainstay of management is surgery, although local recurrences (LR) and distant metastases (DM) are common. OBJECTIVES: Overall survival (OS) and disease-free survival (DFS) were primary outcomes; factors associated with prognosis secondary outcomes. MATERIALS AND METHODS: Patients undergoing surgery of primary abdominal wall sarcomas between April 2008 and May 2018 were identified at two referrals centres for sarcoma surgery. Patient demographics, tumour and treatment-related characteristics were recorded and analysed. RESULTS: A cohort of 65 patients underwent surgical resection with a median follow-up of 56 months, 5-year OS and DFS were 69% and 71%, respectively. Eleven patients (16.9%) experienced a recurrence event: 6 LR (9.2%), 10 DM (15.4%) and 5 both (7.7%). At univariate analysis, size (p = 0.03), grade (p = 0.001) and depth (p = 0.04) were associated with OS while size (p = 0.02) was associated with DFS. No significant relationship with tumour depth, type of surgery, surgical margin status or neo-/adjuvant treatment was demonstrated. CONCLUSION: Recurrence events are less common following treatment of abdominal wall sarcomas if compared to extremities STSs, but size (≥5 cm), high malignancy grade (FNCLCC 3) and depth are associated with worse OS.

Comparison of comprehensive complication index and Clavien-Dindo classification in patients with retroperitoneal sarcoma.

BACKGROUND: Our study aimed to compare the comprehensive complication index (CCI) to the conventional Clavien-Dindo classification (CDC) in patients undergoing surgery for primary retroperitoneal sarcoma (RPS). METHODS: Data were collected for patients who underwent surgery from 2008 to 2019 at a tertiary institution. The length of hospital stay (LOS) was used as a surrogate marker for clinical outcomes, and associations with CDC and CCI were assessed. RESULTS: Data were available for 191 patients, with the highest CDC Grade of I, II, III, and IV in 18.3%, 41.9%, 17.8%, and 4.2%, respectively; the 30-day postoperative mortality (CDC Grade V) was 1.6% (N = 3). Whilst both classification systems were significantly correlated with LOS, this association was significantly stronger for CCI (Spearman's ρ: 0.768 vs. 0.648, p < 0.001). Increasing Charlson Comorbidity Index, tumor size, and organ weighted resection scores were independently associated with longer LOS. However, the association between LOS and both the CDC and CCI remained significant, even after adjusting for these factors (both p < 0.001). CONCLUSION: The CCI is more strongly associated with LOS than the CDC, and represents a useful tool to quantify the total burden of postoperative complications after surgery for RPS.

The molecular landscape of well differentiated retroperitoneal liposarcoma.

Well differentiated liposarcoma (WD-LPS) is a relatively rare tumour, with fewer than 50 cases occurring per year in the UK. These tumours are both chemotherapy- and radiotherapy-resistant and present a significant treatment challenge requiring radical surgery. Little is known of the molecular landscape of these tumours and no current targets for molecular therapy exist. We aimed to carry out a comprehensive molecular characterisation of WD-LPS via whole genome sequencing, RNA sequencing, and methylation array analysis. A recurrent mutation within exon 1 of FOXD4L3 was observed (chr9:70,918,189A>T; c.322A>T; p.Lys108Ter). Recurrent mutations were also observed in Wnt signalling, immunity, DNA repair, and hypoxia-associated genes. Recurrent amplification of HGMA2 was observed, although this was in fact part of a general amplification of the region around this gene. Recurrent gene fusions in HGMA2, SDHA, TSPAN31, and MDM2 were also observed as well as consistent rearrangements between chromosome 6 and chromosome 12. Our study has demonstrated a recurrent mutation within FOXD4L3, which shows evidence of interaction with the PAX pathway to promote tumourigenesis. © 2021 The Authors. The Journal of Pathology published by John Wiley & Sons, Ltd. on behalf of The Pathological Society of Great Britain and Ireland.

Cumulative Burden of Postoperative Complications in Patients Undergoing Surgery for Primary Retroperitoneal Sarcoma.

BACKGROUND: Correlations between postoperative complications and oncological outcomes have been reported in several malignancies, but their impact in retroperitoneal sarcoma (RPS) is unclear. Our study aimed to evaluate the association between postoperative complications and prognosis in patients with RPS. METHODS: Patients undergoing surgery for primary RPS from 2008 to 2019 at a sarcoma center were evaluated. The cumulative burden of postoperative complications was quantified using the Comprehensive Complication Index (CCI), and associations with local recurrence (LR), distant metastases (DM) and overall survival (OS) were assessed. RESULTS: Data were available for 191 patients, of whom 160 (82.9%) developed at least one postoperative complication, with a median CCI of 20.9 (interquartile range 8.7-33.5). After postoperative deaths were excluded (n = 3, 1.6%), the remaining patients were divided into those with a CCI of 0-20.9 (n = 97) and > 20.9 (n = 91). Patients with a CCI >20.9 had significantly shorter OS than those with a CCI of 0-20.9 (43.3% vs. 69.5% at 5 years; p = 0.005), and this difference remained significant after multivariable adjustment for patient- and treatment-related factors [hazard ratio (HR) 2.31, 95% confidence interval (CI) 1.30-4.09; p = 0.004]. However, CCI > 20.9 was not found to be a significant independent predictor of either LR (HR 1.30, 95% CI 0.76-2.23; p = 0.333) or DM (HR 1.08, 95% CI 0.61-1.93; p = 0.786). CONCLUSION: Increasing complication burden, as quantified by the CCI, is a significant independent predictor of OS; however, there is no evidence of a significant association with either LR or DM, which may be more related to tumor biological factors.

Management of Primary Retroperitoneal Sarcoma (RPS) in the Adult: An Updated Consensus Approach from the Transatlantic Australasian RPS Working Group.

BACKGROUND: Retroperitoneal soft tissue sarcomas comprise a heterogeneous group of rare tumors of mesenchymal origin that include several well-defined histologic subtypes. In 2015, the Transatlantic Australasian RPS Working Group (TARPSWG) published consensus recommendations for the best management of primary retroperitoneal sarcoma (RPS). Since then, through international collaboration, new evidence and knowledge have been generated, creating the need for an updated consensus document. METHODS: The primary aim of this study was to critically evaluate the current evidence and develop an up-to-date consensus document on the approach to these difficult tumors. The resulting document applies to primary RPS that is non-visceral in origin, with exclusion criteria as previously described. The relevant literature was evaluated and an international group of experts consulted to formulate consensus statements regarding the best management of primary RPS. A level of evidence and grade of recommendation were attributed to each new/updated recommendation. RESULTS: Management of primary RPS was considered from diagnosis to follow-up. This rare and complex malignancy is best managed by an experienced multidisciplinary team in a specialized referral center. The best chance of cure is at the time of primary presentation, and an individualized management plan should be made based on the 29 consensus statements included in this article, which were agreed upon by all of the authors. Whenever possible, patients should be enrolled in prospective trials and studies. CONCLUSIONS: Ongoing international collaboration is critical to expand upon current knowledge and further improve outcomes of patients with RPS. In addition, prospective data collection and participation in multi-institution trials are strongly encouraged.

Perioperative blood transfusion is not an independent predictor for worse outcomes in retroperitoneal sarcoma surgery.

BACKGROUND: Surgery for retroperitoneal soft tissue sarcoma (RPS) is technically challenging, often requiring perioperative red blood cell transfusion (PBT). In other cancers, controversy exists regarding the association of PBT and oncologic outcomes. No study has assessed this association in primary RPS, or identified factors associated with PBT. METHODS: Data was collected on all resected primary RPS between 2006 and 2020 at The Ottawa Hospital (Canada) and University Hospital Birmingham (United Kingdom). 'PBT' denotes transfusion given one week before surgery until discharge. Multivariable regression (MVA) identified clinicopathologic factors associated with PBT and assessed PBT association with oncologic outcomes. Surgical complexity was measured using resected organ score (ROS) and patterns of resection. RESULTS: 192 patients were included with 98 (50.8%) receiving PBT. Median follow-up was 38.2 months. High tumour grade (OR 2.20, P = 0.048), preoperative anemia (OR 2.78, P = 0.020), blood loss >1000 mL (OR 4.89, P = 0.004) and ROS >2 (OR 2.29, P = 0.026) were associated with PBT on MVA. A direct linear relationship was observed between higher ROS and increasing units of PBT (ß = 0.586, P = 0.038). Increasingly complex patterns of resection were associated with increasing odds of PBT. PBT was associated with severe post-operative complications (P = 0.008) on MVA. Univariable association between PBT and 5-year disease-free or overall survival was lost upon MVA. CONCLUSIONS: Surgical complexity and high tumour grade are potentially related to PBT. Oncologic outcomes are not predicted by PBT but are better explained by tumour grade which subsequently may increase surgical complexity. Strategies to reduce PBT should be considered in primary RPS patients.

Primary mesenteric sarcomas: Collaborative experience from the Trans-Atlantic Australasian Retroperitoneal Sarcoma Working Group (TARPSWG).

BACKGROUND: Primary mesenteric soft tissue sarcomas (STS) are rare and limited evidence is available to inform management. Surgical resection is challenging due to the proximity of vital structures and a need to preserve enteric function. OBJECTIVES: To determine the overall survival (OS) and recurrence-free survival (RFS) for patients undergoing primary resection for mesenteric STS. METHODS: The Trans-Atlantic Australasian Retroperitoneal Sarcoma Working Group (TARPSWG) is an intercontinental collaborative comprising specialist sarcoma centers. Data were collected retrospectively for all patients with mesenteric STS undergoing primary resection between 2000 and 2019. RESULTS: Fifty-six cases from 15 institutions were included. The spectrum of pathology was similar to the retroperitoneum, although of a higher grade. R0/R1 resection was achieved in 87%. Median OS was 56 months. OS was significantly shorter in higher-grade tumors (p = .018) and extensive resection (p < .001). No significant association between OS and resection margin or tumor size was detected. Rates of local recurrence (LR) and distant metastases (DM) at 5 years were 60% and 41%, respectively. Liver metastases were common (60%), reflecting portal drainage of the mesentery. CONCLUSION: Primary mesenteric sarcoma is rare, with a modest survival rate. LR and DM are frequent events. Liver metastases are common, highlighting the need for surveillance imaging.