Resection Of Retroperitoneal Sarcoma Research Articles

Preoperative nutritional support to tackle morbidity in multivisceral resection for retroperitoneal sarcoma. Early outcomes from a novel nutritional prehabilitation program in a prospective cohort

ObjectiveEvaluate the feasibility and outcomes of the implementation of a routinely prehabilitation nutritional program (PNP) in retroperitoneal sarcoma (RPS) patients. Summary background dataRate of preoperative malnutrition is scarcely evaluated in RPS patients and the efficacy of a PNP in detecting and reverting malnutrition has not been studied. MethodsProspective study in a high-volume reference center for RPS; adult patients with primary or persistent RPS deemed surgically resectable were enrolled in a PNP. Results119 patients underwent surgery for RPS at Fondazione IRCCS Istituto Nazionale dei Tumori in Milan, 73 (61.3 %) were enrolled in the PNP while the remaining served as control cohort. 43.8 % (32/73), 28.8 % (21/73), and 27.4 % (20/73) were classified as non-malnourished, moderately malnourished, and severely malnourished at diagnosis, respectively. Preoperative nutritional support was provided to 35 out of 73 patients (47.9 %). Among untreated patients 20 of 38 (52.6 %) experienced a preoperative worsening of their nutritional status, whereas among those in the prehabilitation program 16 of 35 (45.7 %) showed improvement.Surgical complications did not significantly differ between malnourished and non-malnourished patients, potentially due to increased use of diverting stomas in malnourished patients to prevent infectious complications. Reversal of initial malnutrition correlated with better postoperative outcomes, as evidenced by lower rates of severe complications (OR: 0.18, 95%CI 0.04–0.75, p = 0.02) and a lower Comprehensive Complication Index (OR: −0.28, 95%CI -0.51 to −0.06, p = 0.02) in multivariate analysis. ConclusionsThe implementation of a prehabilitation nutritional program brought relevant benefits in terms of postoperative morbidity.

Molecular markers of proliferation, DNA repair, and immune infiltration defines high-risk subset of resectable retroperitoneal sarcomas

IntroductionFor retroperitoneal sarcomas (RPS), aggressive surgical resection offers the only chance for a cure; however, 5-year survival remains below 65%. Therefore, there is a critical need to identify drivers of poor clinical outcomes. Materials and methodsTo identify biomarkers of tumors likely to recur following curative intent resection, we performed genomic and transcriptomic sequencing for 47 and 34 patients, respectively, with non-metastatic RPS at a single, high-volume sarcoma center. ResultsAt the DNA level, alterations in TERT were associated with poor disease-free survival (DFS) and overall survival (OS). Increased RNA expression of gene sets related to growth signaling and DNA repair were associated with poor DFS and OS. Infiltration of CD8+ T-Cells and activated dendritic cells were associated with poor DFS and OS. ConclusionThese findings may help to better identify and treat non-metastatic, high-risk RPS.

ASO Visual Abstract: 3D-SARC: A Pilot Study Testing the Use of a 3D Augmented Reality Model with Conventional Imaging as a Preoperative Assessment Tool for Surgical Resection of Retroperitoneal Sarcoma.

ASO Visual Abstract: 3D-SARC: A Pilot Study Testing the Use of a 3D Augmented Reality Model with Conventional Imaging as a Preoperative Assessment Tool for Surgical Resection of Retroperitoneal Sarcoma.

Impact of three-dimensional-printing technology guidance on surgical outcomes for retroperitoneal sarcoma: A propensity score-matched study.

The surgical treatment of retroperitoneal sarcoma (RPS) is highly challenging because of its complex anatomy. In this study, the authors compared the surgical outcomes of patients with RPS who underwent surgical resection guided by three-dimensional (3D) printing technology versus traditional imaging. This retrospective study included 251 patients who underwent RPS resection guided by 3D-printing technology or traditional imaging from January 2019 to December 2022. The main outcome measures were operative time, intraoperative blood loss, postoperative complications, and hospital stay. In total, 251 patients were enrolled in the study: 46 received 3D-printed navigation, and 205 underwent traditional surgical methods. Propensity score matching yielded 44 patients in the 3D group and 82 patients in the control group. The patients' demographics and tumor characteristics were comparable in the matched cohorts. The 3D group had significantly shorter operative time (median, 186.5 minutes [interquartile range (IQR), 130.0-251.3 minutes] vs. 210.0 minutes [IQR, 150.8-277.3 minutes]; p=.04), less intraoperative blood loss (median, 300.0 mL [IQR, 100.0-575.0 mL] vs. 375.0 mL [IQR, 200.0-925.0 mL]; p=.02), shorter postoperative hospital stays (median, 11.0 days [IQR, 9.0-13.0 days] vs. 14.0 days [IQR, 10.8-18.3 days]; p=.02), and lower incidence rate of overall postoperative complications than the control group (18.1% vs. 36.6%; p=.03). There were no differences with regard to the intraoperative blood transfusion rate, the R0/R1 resection rate, 30-day mortality, or overall survival. Patients in the 3D group had favorable surgical outcomes compared with those in the control group. These results suggest that 3D-printing technology might overcome challenges in RPS surgical treatment. The surgical treatment of retroperitoneal sarcoma (RPS) is highly challenging because of its complex anatomy. The purpose of this study was to investigate whether three-dimensional (3D) printing technology offers advantages over traditional two-dimensional imaging (such as computed tomography and magnetic resonance imaging) for guiding the surgical treatment of RPS. In a group of patients who had RPS, surgery guided by 3D-printing technology was associated with better surgical outcomes, including shorter operative time, decreased blood loss, shorter hospital stays, and fewer postoperative complications. These findings suggested that 3D-printing technology could help surgeons overcome challenges in the surgical treatment of RPS. 3D-printing technology has important prospects in the surgical treatment of RPS.

Surgical Approach to Retroperitoneal Sarcomas with Involvement of the Permeable Inferior Vena Cava: Use of the Femorojugular Bypass

Introduction: Retroperitoneal sarcomas with Inferior Vena Cava (IVC) involvement are rare cases and complex to manage. Radical surgical resection is the only potentially curative treatment and sometimes clamping of the IVC is necessary, which can cause hemodynamic alterations. In this study, we describe the use of femorojugular bypass with perfusion pump as a technique to optimize the hemodynamic situation during the resection of retroperitoneal sarcomas with IVC involvement. Methods: We collected data from patients presenting with retroperitoneal sarcomas with IVC involvement operated at the Hospital de la Santa Creu i Sant Pau (Barcelona), a sarcoma referral center, between March 2021 and May 2023. The technical details of the surgical procedures were analyzed, including the IVC involvement, surgical approach to treatment, and the use of femorojugular bypass. Postoperative complications and oncologic outcomes were also recorded. Results: A total of seven patients diagnosed with retroperitoneal sarcoma with IVC involvement were operated on. In two of the cases, a femorojugular bypass was performed prior to clamping the IVC. In five of the cases, radical resection of the tumor was achieved without leaving macroscopic disease. The mean estimated blood loss was 2.21 L and there was no postoperative mortality. Overall survival was 75% at 12 months with a mean follow-up of 11.86 months. Conclusion: The use of femorojugular bypass during the resection of retroperitoneal sarcomas with IVC involvement may improve the hemodynamic situation of the patient and allow for complete tumor resection. This multidisciplinary surgical approach in referral centers may be effective in the treatment of this rare disease. However, further studies are needed to confirm these results and to establish standardized management guidelines.

3D-SARC: A Pilot Study Testing the Use of a 3D Augmented-Reality Model with Conventional Imaging as a Preoperative Assessment Tool for Surgical Resection of Retroperitoneal Sarcoma.

Retroperitoneal sarcomas (RPSs) present a surgical challenge, with complex anatomic relationships to organs and vascular structures. This pilot study investigated the role of three-dimensional (3D) augmented reality (3DAR) compared with standard imaging in preoperative planning and resection strategies. For the study, 13 patients who underwent surgical resection of their RPS were selected based on the location of their tumor (right, left, pelvis). From the patients' preoperative computed tomography (CT) scans, 3DAR models were created using a D2P program and projected by an augmented-reality (AR) glass (Hololens). The 3DAR models were evaluated by three experienced sarcoma surgeons and compared with the baseline two-dimensional (2D) contrast-enhanced CT scans. Three members of the surgical team evaluated 13 models of retroperitoneal sarcomas, resulting in a total of 26 responses. When the surgical team was asked to evaluate whether the 3DAR better prepared the surgeon for planned surgical resection, 10 responses favored the 3DAR, 5 favored the 2D CT scans and 11 showed no difference (p = 0.074). According to 15 (57.6 %) of the 26 responses, the 3DAR offered additional value over standard imaging in the preoperative planning (median score of 4; range, 1-5). The median stated likelihood that the surgeons would consult the 3DAR was 5 (range, 2-5) for the preoperative setting and 3 (range, 1-5) for the intraoperative setting. This pilot study suggests that the use of 3DAR may provide additional value over current standard imaging in the preoperative planning for surgical resection of RPS, and the technology merits further study.

Radiation therapy for retroperitoneal sarcoma: practice patterns in North America

BackgroundThe addition of radiation therapy (RT) to surgery in retroperitoneal sarcoma (RPS) remains controversial. We examined practice patterns in the use of RT for patients with RPS over time in a large, national cohort.MethodsPatients in the National Cancer Database (2004–2017) who underwent resection of RPS were included. Trends over time for proportions were calculated using contingency tables with Cochran-Armitage Trend test.ResultsOf 7,485 patients who underwent resection, 1,821 (24.3%) received RT (adjuvant: 59.9%, neoadjuvant: 40.1%). The use of RT decreased annually by < 1% (p = 0.0178). There was an average annual increase of neoadjuvant RT by 13% compared to an average annual decrease of adjuvant RT by 6% (p < 0.0001). Treatment at high-volume centers (OR 14.795, p < 0.0001) and tumor > 10 cm (OR 2.009, p = 0.001) were associated with neoadjuvant RT. In contrast liposarcomas (OR 0.574, p = 0.001) were associated with adjuvant RT. There was no statistically significant difference in overall survival between patients treated with surgery alone versus surgery and RT (p = 0.07).ConclusionIn the United States, the use of RT for RPS has decreased over time, with a shift towards neoadjuvant RT. However, a large percentage of patients are still receiving adjuvant RT and this mostly occurs at low-volume hospitals.

A Systematic Review and Meta-Analysis of Surgery for Retroperitoneal Sarcoma With Vascular Resection.

This meta-analysis examines the outcomes of patients undergoing surgery with vascular resection for retroperitoneal sarcoma. A systematic literature search based on Preferred Reporting Items for Systematic Reviews and Meta-Analyses(PRISMA) guidelines was conducted, identifying five comparative retrospective cohort studies published from 2015 to 2021, with a total of 1,417 patients (180 in the vascular resection (VR)group and 1,237 in the control (no VR) group). The meta-analysis found that 30-day morbidity rates, as classified by Clavien-Dindo classification > 3, were higher in the VR group compared to the no VR group (46% versus 25%, odds ratio (OR): 1.84, 95% confidence interval (CI): 0.39-8.69, p=0.44). Local recurrence rates during the follow-up period were similar between the two groups (30% versus 30%, OR: 1.46, 95% CI: 0.50-4.25, p=0.49). However, distant recurrence was more frequent in the VR group (32% versus 8.5%, OR: 2.54, 95% CI: 1.05-6.13, p=0.04). In conclusion, although oncovascular procedures are feasible for patients with retroperitoneal sarcomas, the long-term outcomes appear to be worse when compared to procedures that do not involve vessel resections.

Data Dissemination of the Role of Neoadjuvant Radiation in Retroperitoneal Sarcoma: A CTOS and CSSO Survey.

Consensus guidelines call for complete resection of retroperitoneal sarcoma with consideration of neoadjuvant radiation for curative-intent treatment. The 15-month delay from the initial presentation of an abstract to the final publication of the STRASS trial results assessing the impact of neoadjuvant radiation led to a dilemma of how patients should be managed in the interim. This study aims to (1) understand perspectives regarding neoadjuvant radiation for RPS during this period; and (2) assess the process of integrating data into practice. A survey was distributed to international organizations including all specialties treating RPS. Eighty clinicians responded, including surgical (60.5%), radiation (21.0%) and medical oncologists (18.5%). Low kappa correlation coefficients on a series of clinical scenarios querying individual recommendations before and after initial presentation as an abstract indicate considerable change. Over 62% of respondents identified a practice change; however, most also noted discomfort in adopting changes without a manuscript available. Of the 45 respondents indicating discomfort with practice changes without a full manuscript, 28 (62%) indicated that their practice changed in response to the abstract. There was substantial variability in recommendations for neoadjuvant radiation between the presentation of the abstract and the publication of trial results. The difference in the proportion of clinicians describing comfort with changing practice based on the presentation of the abstract versus those that had done so shows that indications for proper integration of data into practice are not clear. Endeavors to resolve this ambiguity and expedite availability of practice-changing data are warranted.

Resection of Retroperitoneal Sarcomas Involving the Inferior Vena Cava With the Use of Veno-Veno Extracorporeal Perfusion: A Review of the First 20 Cases Performed at Sir Charles Gairdner Hospital, Perth, West Australia

Prolonged inferior vena cava (IVC) clamping during retroperitoneal sarcoma resection presents specific challenges requiring a multidisciplinary approach. Veno-veno bypass (VVB) drains blood from the IVC and returns it into the right atrium, allowing excellent surgical exposure. This institution has routinely used VVB for sarcoma resections involving the IVC since 2018. This review describes outcomes of the first 20 cases.

ASO Visual Abstract: SignificantPredictorsof Postoperative Morbidity After Radical Resection of Retroperitoneal Sarcoma in a TertiaryCenter.

ASO Visual Abstract: SignificantPredictorsof Postoperative Morbidity After Radical Resection of Retroperitoneal Sarcoma in a TertiaryCenter.

Significant Predictors of Postoperative Morbidity After Radical Resection of Retroperitoneal Sarcoma in a Tertiary Center.

The safety of multivisceral resection of retroperitoneal sarcoma is an issue. Previous reports have investigated its associations with the pattern of resection and factors recognized mostly per operatively. All consecutive RPS resections from May 2015 to April 2022 were studied retrospectively with respect to adverse events. Two univariate and multivariate logistic regression analyses were performed to investigate the associations between severe adverse events and factors recognized pre- and per operatively. Associations of adverse events with overall survival (OS) and local recurrence (LR) were investigated. A total of 265 surgical interventions corresponding to 251 patients were recorded(38 RPS surgeries/year). Severe postoperative adverse events (Clavien-Dindo ≥ 3) occurred in 50 patients (18.9%), 15 (5.6%) patients underwent an iterative laparotomy, and 6 patients (2.3%) died within 90 days. On multivariate analysis including all parameters known preoperatively, male sex, performance status, dedifferentiated liposarcoma histology, and low serum albumin level were found to be significant predictors of major complications, whereas the timing of surgery and preoperative treatment were not. On univariate analysis including all per operative parameters, transfusion requirement, operative time, number of digestive anastomoses, and pancreas and/or major arterial resection were found to entail higher operative risk. On multivariate analysis, only transfusion requirement was significant. There was no impact of postoperative adverse events on OS or LR. The recognition of preoperative parameters that impact safety could mitigate the extent of the surgery, specifically the resection of adherent organs not overtly invaded. For the best decision, this surgery should be performed in referral centers.

Complex Vascular Resections for Retroperitoneal Soft Tissue Sarcoma

Retroperitoneal sarcomas (RPSs) are locally aggressive tumors that can compromise major vessels of the retroperitoneum including the inferior vena cava, aorta, or main tributary vessels. Vascular involvement can be secondary to the tumor's infiltrating growth pattern or primary vascular origin. Surgery is still the mainstay for curing this disease, and resection of RPSs may include major vascular resections to secure adequate oncologic results. Our improved knowledge in the tumor biology of RPSs, in conjunction with the growing surgical expertise in both sarcoma and vascular surgical techniques, has allowed for major vascular reconstructions within multi-visceral resections for RPSs with good perioperative results. This complex surgical approach may include the combined work of various surgical subspecialties.

The Use of Extracorporeal Circulation to Facilitate the Resection of a Large Retroperitoneal Sarcoma With Major Vessel Involvement: A Single-Center Review of 20 Cases

To describe the introduction of extracorporeal corporeal oxygenation (ECMO) to facilitate the surgical resection of large retroperitoneal sarcomas involving major vessels and to report preliminary outcomes. A case series. At a tertiary university hospital and state sarcoma center. Patients undergoing retroperitoneal sarcoma resection requiring inferior vena cava (IVC) reconstruction between June 2018 and March 2022. ECMO for retroperitoneal tumor resection requiring IVC reconstruction. A total of 20 patients underwent ECMO-assisted retroperitoneal sarcoma resection and IVC reconstruction. The median age was 60.5 years (IQR 48-69); 15 women and 5 men. The median procedure and ECMO durations were 10.8 hours (IQR 8.5-12.4 hours) and 2.2 hours (IQR 62-218 minutes), respectively. The median intensive care unit and hospital lengths of stay were 4 days (IQR 3-5 days) and 21 days (IQR 14-31 days), respectively. All 20 patients received packed cell transfusions (median 8 per patient [IQR 4-14]); 11 patients required fresh frozen plasma, 6 required platelets, and 11 required fibrinogen supplementation. One patient required recombinant activated factor VII. Sixteen patients experienced acute kidney injury, with 12 patients progressing to chronic kidney disease. Three patients were required to return to the operating room within 7 days, with no returns within the first 24 hours. There was no in-hospital or 30-day mortality. Survival at 3 years was 84%. ECMO for resecting large retroperitoneal tumor resection was introduced successfully and facilitated satisfactory outcomes for many patients who might otherwise have been considered too high risk.

Delayed gastric emptying after aggressive surgery for retroperitoneal sarcoma - Incidence, characteristics, and risk factors.

Delayed gastric emptying (DGE) after aggressive resection of retroperitoneal sarcoma (RPS) has rarely been described. This study aimed to determine the incidence and characteristics of DGE after surgery for RPS and explore its potential risk factors. Patients with RPS who had undergone surgery between January 2010 and February 2021 were retrospectively analyzed. DGE was defined and graded according to the International Study Group of Pancreatic Surgery classification and classified as primary or secondary to other complications. Patients with clinically relevant DGE (crDGE, grade B+C) were compared to those with no or mild DGE (grade A). Multivariate logistic regression analysis of clinicopathological and surgical parameters was performed to identify risk factors for crDGE. Of the 239 patients studied, 69 (28.9%) had experienced DGE and 54 (22.6%) had experienced crDGE. Patients with primary and secondary DGE accounted approximately half and half. The most common concurrent complications included abdominal infection, postoperative pancreatic fistula, and abdominal bleeding. Patients with crDGE were more likely to have multifocal tumors and the liposarcoma subtype, with a larger tumor size, longer operating time, more resected organs, and a history of combined resection of the stomach, pancreas, small intestine, and/or colon. In multivariate analysis, the tumor size, operating time, and combined pancreatic resection were independent risk factors for crDGE. In conclusion, the current results indicated that approximately one-fourth of patients experienced DGE after aggressive surgery for RPS and that DGE was primary or secondary to other underlying conditions. A large tumor involving long, difficult surgery and combined pancreatic resection highly predicted the incidence of crDGE. The prevention and management of DGE remain challenging.

Management of Recurrent Retroperitoneal Sarcoma

Recurrence after resection of retroperitoneal sarcoma is common and varies by histological subtype. Pattern of recurrence is similarly affected by histology (e.g., well-differentiated liposarcoma is more likely to recur locoregionally, whereas leiomyosarcoma is more likely to develop distant metastases). Radiotherapy may provide effective locoregional control in limited circumstances and the data on the impact of chemotherapy are scant. Surgery for locally recurrent disease is associated with the greatest survival benefit; however, data are retrospective and from a highly selected subgroup of patients. Limited retrospective data have also suggested a survival association with the resection of limited distant metastases. Given the complexity of these patients, multidisciplinary evaluation at a high-volume sarcoma center is critical.

Replantation of solitary kidney in a patient with giant primary retroperitoneal sarcoma

Background. Surgery for non-organ malignant retroperitoneal tumors poses a serious challenge. Long-term asymptomatic course of the disease leads to a delayed diagnosis, when tumors can reach massive size with potential involvement of adjacent organs and critical structures. In most cases, nephrectomy is often required during resection of retroperitoneal sarcomas. Recently, there has been growing interest in nephronsaving surgery for large retroperitoneal tumors.Description of the clinical case. A 70-year-old patient was admitted to Irkutsk Regional Cancer Center with right-sided giant primary retroperitoneal tumor and grade 1 hydronephrosis of solitary right kidney. The patient underwent extended resection of primary retroperitoneal tumor with right-sided hemicolectomy and nephradrenalectomy. Extracorporeal resection of the solitary kidney was then performed. After obtaining negative kidney smears (imprints), the kidney was replanted in the pool of right iliac vessels. No complications were observed in the postoperative period. Histopathology examination revealed was welldifferentiated liposarcoma. On follow-up examination 38 months after surgery, there were no signs of local tumor recurrence, and renal function was satisfactory.Conclusion. Extracorporeal resection of the kidney with heterotopic replantation is an effective nephron-saving method in surgery for primary retroperitoneal sarcomas. The patient’s solitary kidney with primary retroperitoneal sarcoma is an absolute indication for kidney’s saving, including the use of transplant technologies.

Neoadjuvant radiotherapy for resectable retroperitoneal sarcoma: a meta-analysis

BackgroundNeoadjuvant radiotherapy (NRT) for resectable retroperitoneal sarcoma (RPS) has been shown to be systematically feasible. Whether NRT has equivalent or better clinical effects compared to surgery alone for RPS patients remains controversial.MethodsWe performed a systematic literature search of PubMed, Web of Science, Embase, ASCO s, and Cochrane library databases for studies in humans with defined search terms. Articles were independently assessed by 2 reviewers, and only randomized controlled trials and cohort studies were included. The hazard ratios (HRs) of overall survival (OS), recurrence-free survival (RFS), and local recurrence (LR) were extracted from included studies. Heterogeneity among study-specific HRs was assessed by the Q statistic and I2 statistic. Overall HR was assessed by random-effects or fixed-effects models. Publication bias was tested by Begg’s tests, and the quality of each study was assessed with the Newcastle Ottawa Scale.ResultsA total of 12 eligible studies with 7778 resectable RPS patients were finally included in this study. The pooled analysis revealed the distinct advantages of NRT as compared to surgery alone, including longer OS (HR = 0.81, P < 0.001), longer RFS (HR = 0.58, P = 0.04), and lower LR (HR = 0.70, P = 0.03). No evidence of publication bias was observed.ConclusionNRT is likely to be beneficial for resectable RPS patients in terms of OS and RFS. However, more multicenter clinical trials are needed to confirm these findings.

Short- and long-term surgical outcomes of pancreatic resection for retroperitoneal sarcoma: A long-term single-center experience of 90 cases.

Resection of retroperitoneal sarcoma (RPS) en bloc with pancreas is challenging and controversial. This single-center retrospective study aimed to analyze the impact of pancreatic resection (PR) and its different types on short- and long-term outcomes in patients with RPS. Data from 242 consecutive patients with RPS who underwent surgical treatment at the Peking University Cancer Hospital Sarcoma Center between January 2010 and February 2021 were analyzed. Out of these, 90 patients underwent PR, including pancreaticoduodenectomy (PD) in 31 and distal pancreatectomy (DP) in 59. Patients in the PR group had a higher major morbidity (37.8% vs. 14.5%) and mortality (8.9% vs. 1.3%) than those in the non-PR group, with a similar 5-year overall survival (OS) rate (46.9% vs. 53.6%). Patients in the PD and DP groups had a slight difference in major morbidity (48.4% vs. 32.2%), mortality (6.4% vs. 10.2%), and 5-year OS rates (43.3% vs. 49.3%). The PR type was not an independent risk factor for major morbidity or OS. PR in RPS resection was associated with increased morbidity and mortality with minimal influence on survival. Patients with RPS undergoing PD and DP showed slight differences in terms of safety and OS.

Prognostic factors in patients receiving surgery and radiation therapy for retroperitoneal sarcoma: A machine-learning analysis

BackgroundThe addition of radiation therapy to surgery for retroperitoneal sarcoma remains controversial. Improved patient selection may help identify optimal candidates for multimodality treatment. The aim of this analysis was to define prognostic factors among patients who receive radiation therapy and surgery to aid in patient selection for multimodal therapy. MethodsPatients who received radiation therapy and underwent curative-intent resection for retroperitoneal sarcoma between 2004 and 2016 were identified from a national cohort in the United States (National Cancer Database). A machine-based classification and regression tree model was used to generate similar groups of patients relative to overall survival based on preoperative factors. ResultsA total of 1,443 patients received radiation therapy in addition to surgery. Median age was 61 years old and 55.0% were female. Most patients (66%) received care at an academic or integrated network cancer program. With a median follow-up of 84 months, receipt of radiation therapy was not associated with improved overall survival (P = .81). Classification and regression tree analysis revealed a significant association between overall survival and American Joint Committee on Cancer stage group, age, tumor histology, and Charlson comorbidity score. Application of these parameters via machine learning stratified patients into 5 cohorts with distinct survival outcomes. In the most favorable cohort (Cohort 1: American Joint Committee on Cancer stage group ≤II, age ≤61, histology including fibrosarcoma, well differentiated liposarcoma, myxoid liposarcoma, and leiomyosarcoma), the 5-year overall survival was 81.7% and median overall survival was not reached; in the least favorable cohort (Cohort 6: American Joint Committee on Cancer stage group >II, age >68) where the 5-year survival was 41.3% and median overall survival was 45.2 months (P < .001 versus Cohort 1). ConclusionIn the absence of a defined survival benefit, patients with advanced American Joint Committee on Cancer stage group, older age, and medical comorbidities have relatively unfavorable overall survival after combined modality therapy and therefore stand the least to gain from the addition of radiation therapy to surgery. In contrast, younger patients with good performance status and retroperitoneal sarcoma histologies with a higher propensity for local recurrence may have the greatest opportunity to benefit from radiation therapy.