Phase I trial of preoperative concurrent doxorubicin and radiation therapy, surgical resection, and intraoperative electron-beam radiation therapy for patients with localized retroperitoneal sarcoma

Dose-Escalated Preoperative Proton Therapy for Retroperitoneal Sarcomas: Initial Outcomes of a New Treatment Paradigm

Purpose

Retroperitoneal sarcomas (RPS) have varied treatment practices with regard to the use of radiation therapy (RT). Preoperative RT ∼50 Gy is commonly used, but the Surgery With or Without Radiation Therapy in Untreated Nonmetastatic Retroperitoneal Sarcoma (STRASS-1) randomized trial demonstrated no improvement in abdominal recurrence-free survival with preoperative RT. Dose escalation has been proposed to improve the efficacy of preoperative RT. We analyzed RPS treated with preoperative intensity modulated proton therapy (IMPT) to an escalated dose of 63 Gy at a single institution.

Methods and Materials

Patients who received preoperative RT with IMPT with RPS between January 2015 and October 2021 were reviewed. IMPT 63 Gy in 28 fractions to the clinical target volume high-risk and 50.4 Gy in 28 fractions to clinical target volume low-risk was used. Patient baseline characteristics, RT dose parameters, toxicities, margin status, and recurrence patterns were recorded. Local control was computed by Fine-Gray analysis and overall survival by Kaplan-Meier analysis.

Results

Sixteen patients met the study criteria (n = 16): 12 primary and 4 isolated local recurrences. Median age was 62 years (IQR, 43.5-66 years) and 62.5% were male; 10 were liposarcoma. The median maximum tumor diameter was 19.9 cm (IQR, 12-24 cm). With a median follow-up of 18 months (IQR, 11.5-37 months), the estimated 3-year freedom from local failure rate was 68.2% (95% CI, 41.7%-94.7%); 3-year overall survival (OS) rate was 68.8% (95% CI, 41.9%-95.8%). No Radiation Therapy Oncology Group grade ≥3 acute or late toxicities were noted.

Conclusions

In our RPS cohort, preoperative dose-escalated RT to 63 Gy demonstrated comparable local control without G3 acute toxicities. Given the high local recurrence rates of RPS, this approach warrants further study to validate these results and identify patients most likely to benefit from therapy.

Progress in Retroperitoneal Sarcoma Management: Surgical and Radiotherapy Approaches

Surgical resection is the cornerstone of curative treatment for retroperitoneal sarcomas (RPS), aiming for complete excision, yet the complexity of RPS with its proximity to vital structures continues to lead to high local recurrence rates after surgery alone. Thus, the role of radiotherapy (RT) continues to be refined to improve local control, which remains an important goal to prevent RPS recurrence. The recently completed global randomized trial to evaluate the role of surgery with and without preoperative RT - STRASS1, did not demonstrate a significant overall benefit for neoadjuvant RT based on the pre-specified definition of abdominal recurrence-free survival, however, sensitivity analysis using a standard definition of local recurrence and analysis of outcomes by compliance to the RT protocol suggests histology-specific benefit in well- and some de-differentiated liposarcomas. Ultimately, multidisciplinary collaboration and personalized approaches that consider histological sarcoma types and patient-specific factors are imperative for optimizing the therapeutic strategy in the management of RPS.

Neoadjuvant Chemotherapy in Retroperitoneal Sarcoma: A National Cohort Study

INTRODUCTION

Management of retroperitoneal sarcoma (RPS) remains controversial, with the mainstay of treatment being surgery. While neoadjuvant radiation demonstrated no improvement in recurrence-free survival in a prospective randomized trial (STRASS), the role of neoadjuvant chemotherapy (NCT) remains unknown and is the subject of ongoing study (STRASS2).

METHODS

Patients who underwent surgical resection of high-grade RP leiomyosarcoma (LMS) or dedifferentiated liposarcoma (DDLS) were identified from the National Cancer Database (2006-2019). Predictors of NCT were analyzed using univariate and multivariate logistic regression analyses. Differences in 5-year survival were examined using the Kaplan-Meier (KM) method and by Cox proportional hazard modeling.

RESULTS

A total of 2656 patients met inclusion criteria. Fifty-seven percent of patients had DDLS and 43.5% had LMS. Six percent of patients underwent NCT. Patients who received NCT were younger (median age 60 vs 64 years, p < 0.001) and more likely to have LMS (OR 1.4, p = 0.04). In comparing NCT with no-NCT patients, there was no difference in 5-year overall survival (OS) on KM analysis (57.3% vs 52.8%, p = 0.38), nor was any difference seen after propensity matching (54.9% vs 49.1%, p = 0.48, N = 144 per group). When stratified by histology, there was no difference in OS based on receipt of NCT (LMS: 59.8% for NCT group, 56.6% for no-NCT, p = 0.34; DDLS: 54.2% for NCT group, 50.1% for no-NCT, p = 0.99).

CONCLUSION

In patients undergoing surgical resection of RP LMS or DDLS, NCT does not appear to confer an OS advantage. Prospective randomized data from STRASS2 will confirm or refute these retrospective data.

IOeRT in retroperitoneal sarcoma: Towards more organ preservation with comparable oncological outcomes

BACKGROUND

Retroperitoneal sarcomas (RPS) present a surgical challenge with high rates of local recurrence (LR). We investigated the role of intraoperative electron radiotherapy (IOeRT) in reducing LR after surgical resection of RPS.

METHODS

A retrospective analysis of all patients who underwent surgical resection for RPS between 2014 and 2021 at a tertiary academic referral center (n = 172). Patients included underwent surgical resection of their RPS and received IOeRT (n = 36) and were compared by case control matching to patients with similar tumor characteristics (recurrence status and tumor grade) that did not receive IOeRT (n = 36).

RESULTS

The median length of hospitalization was 8 days (range, 4-34) in the IOeRT group and 10 days (range, 2-42) in the non-IOeRT group (p = 0.25). The mean operating room (OR) time was 4h (±1.3) and 4h (±1.9) in the IOeRT and non-IOeRT groups respectively, (p = 0.37). Complete resection with R0 margins was achieved in 30 patients (83.3%) and 24 patients (66.6%) in the IOeRT and non-IOeRT groups, respectively (p = 0.1). R1 resection was achieved in 6 patients (16.6%) and 12 patients (33.3%) respectively, (p = 0.1). The resected organ weighted score was significantly different between the groups; score 0 observed in 19 (52.7%) patients in the IOeRT group and 3 (8.3%) in the non-IOeRT group (p < 0.001), score 1 observed in 7 (19.4%) in the IOeRT group and 17 (47.2%) in the non-IOeRT group (p = 0.012). The rate of severe complications (CD score>3) did not differ between the groups, 5 (13.8%) patients in the IOeRT group and 9 (25%) patients in the non-IOeRT group (p = 0.23). No radiation associated complications were noted. The 2-year local recurrence free survival (LRFS) was 75.9% in the IOeRT group and 60.3% in the non-IOeRT group (p = 0.4). The 2-year IOeRT field recurrent free survival (IRFS) was 88.4% in the IOeRT group and 60.3% in the non-IOeRT group (p = 0.04).

CONCLUSIONS

The use of IOeRT did not increase the rate of surgical complications and was associated with superior local control in the radiation field, improved organ preservation without an impact on overall survival.

Radiation Therapy for Retroperitoneal Sarcomas: A Strass-Ful Situation

Locoregional recurrence (LRR) is the predominant pattern of relapse and often the cause of death in patients with retroperitoneal sarcomas (RPS). As a result, reducing LRR is a critical objective for RPS patients. However, unlike soft tissue sarcomas (STS) of the superficial trunk and extremity where the benefits of radiation therapy (RT) are well-established, the role of RT in the retroperitoneum remains controversial. Historically, preoperative or postoperative RT, either alone or in combination with intraoperative radiation (IORT), was commonly justified for RPS based on extrapolation from the superficial trunk and extremity STS literature. However, long-awaited results were recently published from the European Organization for Research and Treatment of Cancer (EORTC) STRASS study of preoperative radiotherapy plus surgery versus surgery alone for patients with RPS; there was no statistical difference in the primary endpoint of abdominal recurrence-free survival. However, several subset analyses and study limitations complicate the interpretation of the results. This review explores and contextualizes the body of evidence regarding RT's role in managing RPS.

Evidence for the Current Management of Soft-tissue Sarcoma and Gastrointestinal Stromal Tumors and Emerging Directions

Soft-tissue sarcoma (STS) is not a single entity but, rather, a family of diseases with differing biologic behaviors and anatomic site- and histotype-specific responses to treatment. Whereas surgery remains the mainstay of treatment of primary, localized disease, evolving evidence is establishing the role of multimodality treatment of these tumors. This article summarizes prospective evidence to date informing our treatment of STS. Key future directions will include advancing our understanding of fundamental tumor biology and mechanisms of response and recurrence, as well as defining the optimal provision of regional, systemic, and targeted therapies, including the role of immunotherapy. Ongoing global collaborations will be integral to progress in treating these rare tumors.

Relevant Trials Update in Sarcomas and Gastrointestinal Stromal Tumors: What Surgeons Should Know

In the past few years, the sarcoma community has successfully completed several trials in patients with soft tissue sarcoma (STS) or gastrointestinal stromal tumor (GIST). The current review summarizes recently reported relevant trials or trial updates investigating radiotherapy, chemotherapy, and targeted therapy in patients with localized extremity or superficial trunk STS, retroperitoneal sarcoma, and GIST.

First and further-line multidisciplinary treatment of retroperitoneal sarcomas

PURPOSE OF REVIEW

To review current knowledge and recent advances in retroperitoneal sarcoma management.

RECENT FINDINGS

Surgery, radiotherapy, and medical treatments of retroperitoneal sarcomas should take into account the peculiarities of each histotype and the unique anatomical site. Surgery remains the mainstay of treatment and the only chance of cure for these diseases. In low-grade retroperitoneal sarcomas, like well differentiated liposarcoma, where the leading cause of death is dominated by local rather than distant relapses, treatment of the primary tumor encompasses extended surgery with multiorgan resection and evaluation of preoperative radiotherapy. Conversely, surgery is usually more conservative and without radiotherapy in those retroperitoneal sarcomas, such as leiomyosarcoma, characterized by a high risk of metastatic spread that prompted also the evaluation of neoadjuvant, histotype-driven chemotherapy. Surgery might have a role also for relapsed disease, despite long-term disease control probability declines at each recurrence. In advanced stages, anthracyclines still retain a key role and all medical treatment strategies should follow the specific chemosensitivity of each histotype to improve patient's outcomes.

SUMMARY

The rarity and heterogeneity in biological behavior and clinical presentation of retroperitoneal sarcomas deserves a multidisciplinary and histotype-driven treatment at all stages of the disease to be performed in highly specialized centers.

Soft Tissue Sarcoma, Version 2.2022, NCCN Clinical Practice Guidelines in Oncology

Soft tissue sarcomas (STS) are rare malignancies of mesenchymal cell origin that display a heterogenous mix of clinical and pathologic characteristics. STS can develop from fat, muscle, nerves, blood vessels, and other connective tissues. The evaluation and treatment of patients with STS requires a multidisciplinary team with demonstrated expertise in the management of these tumors. The complete NCCN Clinical Practice Guidelines in Oncology (NCCN Guidelines) for Soft Tissue Sarcoma provide recommendations for the diagnosis, evaluation, and treatment of extremity/superficial trunk/head and neck STS, as well as retroperitoneal/intra-abdominal STS, desmoid tumors, and rhabdomyosarcoma. This portion of the NCCN Guidelines discusses general principles for the diagnosis and treatment of retroperitoneal/intra-abdominal STS, outlines treatment recommendations, and reviews the evidence to support the guidelines recommendations.

Comparison of 3D Conformal Proton Therapy, Intensity-Modulated Proton Therapy, and Intensity-Modulated Photon Therapy for Retroperitoneal Sarcoma

Background

External beam radiation therapy (RT) for retroperitoneal sarcoma often requires treatment of large target volumes close to critical normal tissues. Radiation may be limited by adjacent organs at risk (OAR). Intensity-modulated radiation therapy has been shown to improve target coverage and reduce doses to OAR.

Objectives

To compare target coverage and dose to OAR with 3D conformal proton therapy (3D CPT), intensity-modulated proton therapy (IMPT), and intensity-modulated photon therapy (IMXT).

Methods

We performed a comparative study of treatment plans with 3D CPT, IMPT, and IMXT for ten patients with retroperitoneal sarcomas. RT was delivered to 50.4 Gy to the clinical target volume (CTV), the structures considered at risk for microscopic disease.

Results

CTVs ranged from 74 to 357 cc (mean 188 cc). Dose conformity was improved with IMPT, while 3D CPT provided better dose homogeneity. Mean dose to the liver, small bowel, and stomach was reduced with IMPT compared with 3D CPT or IMXT.

Conclusions

IMPT, 3D CPT, and IMXT provide excellent target coverage for retroperitoneal sarcomas. OAR dose is lower with IMPT and 3D CPT, and IMPT achieves the closest conformity. These techniques offer the opportunity for further dose escalation to areas with positive margins.

The evolution of adjuvant/neoadjuvant trials for resectable localized sarcoma

Soft-tissue sarcomas are rare tumors arising from mesenchymal tissues. As a heterogeneous group comprising more than 50 types, the development of clinical trials remains challenging. Decision-making for neoadjuvant or adjuvant chemotherapy and radiation therapy is based on the available evidence of contemporary trials and multidisciplinary clinical judgment.

Comparison of preoperative chemoradiation with radiation or chemotherapy alone in patients with non-metastatic, resectable retroperitoneal sarcoma

Aim:

Optimal preoperative therapy regimen in the treatment of resectable retroperitoneal sarcoma (RPS) remains unclear. This study compares the impact of preoperative radiation, chemoradiation and chemotherapy on overall survival (OS) in RPS patients.

Materials and Methods:

The National Cancer Database (NCDB) was queried for patients with non-metastatic, resectable RPS (2006–15). The primary endpoint was OS, evaluated by Kaplan–Meier method, log-rank test, Cox multivariable analysis and propensity score matching.

Results:

A total of 1,253 patients met the inclusion criteria, with 210 patients (17%) receiving chemoradiation, 850 patients (68%) receiving radiation and 193 patients (15%) receiving chemotherapy. On Cox multivariable analysis, when compared to preoperative chemoradiation, preoperative radiation was not associated with improved OS (hazards ratio [HR] 0·98, 95% CI 0·76–1·25, p = 0·84), while preoperative chemotherapy was associated with worse OS (HR 1·64, 95% CI 1·24–2·18, p < 0·001). Similar findings were observed in 199 and 128 matched pairs for preoperative radiation and chemotherapy, respectively, when compared to preoperative chemoradiation.

Findings:

Our study suggested an OS benefit in using preoperative chemoradiation compared to chemotherapy alone, but OS outcomes were comparable between preoperative chemoradiation and radiation alone.

Evaluation of two modalities of perioperative treatment in the management of extremity and truncal soft tissue sarcomas: neoadjuvant concurrent chemoradiotherapy and sequential treatment

PURPOSE

Patients with locally advanced grade 2-3 extremity/truncal soft tissue sarcomas (STS) are at high risk of recurrence. The objective of this study was to assess the efficacy and feasibility of neoadjuvant concurrent chemoradiotherapy (cCRT) in selected grade 2-3 patients with limb or trunk wall STS, and to compare this schedule to a sequential approach combining neoadjuvant chemotherapy and adjuvant radiotherapy.

METHODS

We retrospectively included patients who underwent neoadjuvant cCRT at two comprehensive cancer centers from 1992-2016. We then compared these results to those of patients treated with preoperative chemotherapy and postoperative radiotherapy from a third comprehensive cancer center with a propensity score matched analysis.

RESULTS

A total of 53 patients were treated by neoadjuvant cCRT; 58 patients could be matched with 29 patients in each treatment group after propensity score matching. Disease-free survival and overall survival at 5 years were 54.9 and 63.5%, respectively with neoadjuvant cCRT, with no significant difference when compared to the sequential treatment group. R0 resection rate was higher (90.9 vs 44.8%, p < 0.01) in the cCRT group than in the sequential treatment group during a shorter therapeutic sequence (118 vs 210.5 days, p < 0.01), with no impact on the surgical procedure or postoperative complications.

CONCLUSION

cCRT is feasible with acceptable immediate and late toxicities. It could facilitate surgery by increasing the R0 resection rate and improve patient compliance by shortening the therapeutic sequence.

Role of Radiation Therapy for Newly Diagnosed Retroperitoneal Sarcoma

OPINION STATEMENT

Soft tissue sarcomas (STS) are rare, aggressive, and heterogenous tumors, comprising approximately 1% of adult cancers with over 50 different subtypes. The mainstay of treatment for retroperitoneal sarcomas (RPS) includes surgical resection. The addition of radiation therapy (RT), either preoperatively or postoperatively, has been used to potentially decrease the risk of local recurrence. The recently published results from STRASS (EORTC-STBSG 62092-22092), which randomized patients to receive or not receive preoperative radiation, indicate no abdominal recurrence-free survival benefit (primary endpoint) nor overall survival benefit to date from the addition of preoperative RT prior to surgical resection in patients with RPS. Keeping in mind caveats of subgroup analyses, the data show a significant reduction in local recurrence with radiation therapy in resected patients and non-significant trends toward improved abdominal recurrence-free survival in all patients and improved local control and abdominal recurrence-free survival in patients with liposarcoma and low-grade sarcoma. Given the high rate of local failure with surgery alone, it is possible that higher RT dose and/or selective RT dose painting may improve outcomes. Prior to treatment, the authors encourage multidisciplinary review and discussion of management options at a sarcoma center for patients with RPS. Selective use of RT may be considered for patients at high risk of local recurrence.

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.

Intraoperative radiation therapy (IORT) for soft tissue sarcoma - ESTRO IORT Task Force/ACROP recommendations

PURPOSE

To describe guidelines for the use of intraoperative radiation therapy (IORT) in the treatment of soft-tissue sarcomas (STS).

METHODS

A panel of experts in the field performed a systematic literature review, supplemented their clinical experience and developed recommendations for the use of IORT in the treatment of STS.

RESULTS

Based on the evidence from the systematic literature review and the clinical experience of the panel members, recommendations regarding patient selection, incorporation into multimodal treatment concepts and the IORT procedure itself are made. The rationale for IORT in extremity and retroperitoneal STS is summarized and results of the major series in terms of patient and treatment characteristics, oncological outcome and toxicity are presented. We define surgical factors, volumes for irradiation, technical requirements, dose prescription, recording and reporting, treatment delivery and care during the course of IORT covering the main IORT techniques used for the treatment of STS. In extremity STS, evidence originates from a few small prospective and mainly from retrospective single centre studies. Based on those reports, IORT containing-approaches result in very high local control rates with low rates of acute and late toxicity. In retroperitoneal sarcomas, evidence is derived from one prospective randomized trial, a few prospective and a large number of retrospective studies. The randomized trial compared IORT combined with moderate doses of postoperative external-beam radiation therapy (EBRT) to high-dose postoperative EBRT alone after gross total resection, clearly favouring the IORT-containing approach. These results have been confirmed by the prospective and retrospective studies, which similarly showed high local control rates with acceptable toxicity, mainly favouring combinations of preoperative EBRT and IORT.

CONCLUSIONS

IORT-containing approaches result in high rates of local control with low to acceptable toxicity rates. Based on the available evidence, we made recommendations for the use of IORT in STS. Clinicians and researchers are encouraged to use these guidelines in clinical routine as well as in the design of future trials.

Soft-tissue sarcoma in adults: An update on the current state of histiotype-specific management in an era of personalized medicine

Soft-tissue sarcomas (STS) are rare tumors that account for 1% of all adult malignancies, with over 100 different histologic subtypes occurring predominately in the trunk, extremity, and retroperitoneum. This low incidence is further complicated by their variable presentation, behavior, and long-term outcomes, which emphasize the importance of centralized care in specialized centers with a multidisciplinary team approach. In the last decade, there has been an effort to improve the quality of care for patients with STS based on anatomic site and histology, and multiple ongoing clinical trials are focusing on tailoring therapy to histologic subtype. This report summarizes the latest evidence guiding the histiotype-specific management of extremity/truncal and retroperitoneal STS with regard to surgery, radiation, and chemotherapy.

Management of primary retroperitoneal synovial sarcoma: A case report and review of literature

BACKGROUND

Synovial sarcoma (SS) is a rare type of soft tissue sarcoma that is usually developed from areas where synovial tissue exists, especially at the extremities. Nevertheless, several cases of retroperitoneal SS (RSS) have been described. We herein report a case of RSS presented in our institution.

CASE SUMMARY

A 69-year-old female patient was admitted with a large, palpable, firm mass in the right abdominal space SS. Computerized tomography scan depicted a concentric, sharply marinated retro-peritoneal lesion which was displacing the right kidney and the lower edge of the liver. Subsequently, the patient underwent surgical excision of the mass with additional right nephrectomy and resection of the right adrenal gland and a part of the diaphragm. The final histological diagnosis of the tumour was grade II monophasic RSS.

CONCLUSION

RSS is encountered in the biphasic type, the monophasic fibrous, and the monophasic epithelial category as well. Relevant clinical manifestations are not always documented at early stages. Therefore, the final diagnosis is posed after complete histological examination taking into consideration the results of immunochemistry and genetic analysis. Therapeutic approach happens often late when metastases at the lungs and the liver are apparent. Thus, 5-year survival rates remain low.

Neoadjuvant and adjuvant strategies in retroperitoneal sarcoma

Extended surgery remains the mainstay of treatment in retroperitoneal sarcoma, although conflicting data exist on the benefit of neoadjuvant and adjuvant therapies, particularly with regard to tumour grade and histological type. Experience of radiotherapy and chemotherapy in extremity soft tissue sarcoma can inform treatment strategies, however these data cannot be universally extrapolated to the retroperitoneum where disease biology and anatomical considerations are different. The present review sets a historical context before discussing recent evidence and on-going multi-centre trials in retroperitoneal sarcoma. Promising data on histologically- and molecularly-targeted chemotherapy are discussed and the need for centralisation of retroperitoneal sarcoma services in order to facilitate large international collaborative trials is emphasised.

Local Control of Soft Tissue and Bone Sarcomas

Sarcomas of soft tissue and bone are mesenchymal malignancies that can arise in any anatomic location, most commonly the extremity, retroperitoneum, and trunk. Even for lower grade histologic subtypes, local recurrence can cause significant morbidity and even disease-related death. Although surgery remains the cornerstone of local control, perioperative radiation and systemic therapy are often important adjuvants. This review will summarize the current therapeutic approaches for local control of soft tissue and bone sarcomas.

Treatment of retroperitoneal sarcoma: current standards and new developments

PURPOSE OF REVIEW

Retroperitoneal sarcomas are rare tumors and with complex treatment. In this manuscript we give an overview of current standards in treatment of this disease and discuss new developments.

RECENT FINDINGS

Surgery with complete resection of the primary tumor is still the only curative modality. The role of preoperative radiotherapy is not clear and is currently being investigated in a clinical trial. Neo-adjuvant chemotherapy is not the standard of care but can be considered occasionally when complete resection is uncertain. Local and distant recurrent disease carries a dismal prognosis, although long-term survival can be achieved. Liposarcomas tend to recur locally, whereas distant recurrences are more often seen in leiomyosarcoma and other subtypes. Outcome improves when patients are treated in high volume sarcoma centers. In the metastatic setting, newer systemic agents have recently been approved.

SUMMARY

Treatment of retroperitoneal sarcomas is complex and all patients should be treated in multidisciplinary sarcoma centers. Increasing international collaboration of expert centers in sharing expertise and performing clinical trials might lead to better treatment and improved survival.

Retroperitoneal Sarcomas

BACKGROUND

The evaluation and treatment of retroperitoneal sarcomas are challenging because the tumors are relatively rare and frequently present with advanced disease in an anatomically complex location.

METHODS

We reviewed the literature on experience in the management of retroperitoneal sarcomas, and we present our own experience in the treatment of these tumors.

RESULTS

The identification of prognostic factors other than the adequacy of resection has been inconsistent. Due to a lack of associated symptoms, retroperitoneal sarcomas smaller than 5 cm are rare. Computed tomography is the most useful tool in the evaluation of retroperitoneal tumors. Surgery, radiation therapy, and chemotherapy are treatment options, but the most important factor in the treatment of primary tumors is complete surgical resection. The role of neoadjuvant and adjuvant therapies is not defined and should be considered within the context of clinical trials.

CONCLUSIONS

Early referral of patients with retroperitoneal soft tissue tumors will help to ensure that they will receive the benefits of multidisciplinary evaluation and treatment of their disease and ready access to clinical trials.

Phase 1 trial of preoperative image guided intensity modulated proton radiation therapy with simultaneously integrated boost to the high risk margin for retroperitoneal sarcomas

PURPOSE

To conduct phase 1 and 2 trials with photon intensity modulated radiation therapy and intensity modulated proton therapy (IMPT) arms to selectively escalate the retroperitoneal sarcoma preoperative radiation dose to tumor volume (clinical target volume [CTV] 2) that is judged to be at a high risk for positive margins and aim to reduce local recurrence. We report on the IMPT study arm in phase 1.

METHODS AND MATERIALS

Patients aged ≥18 years with primary or locally recurrent retroperitoneal sarcoma were treated with preoperative IMPT, 50.4 GyRBE in 28 fractions, to CTV1 (gross tumor volume and adjacent tissues at risk of subclinical disease) with a simultaneous integrated boost to CTV2 to doses of 60.2, 61.6, and 63.0 GyRBE in 28 fractions of 2.15, 2.20, and 2.25 GyRBE, respectively. The primary objective of the phase 1 study was to determine the maximum tolerated dose to CTV2, which will be further tested in the phase 2 study.

RESULTS

Eleven patients showed increasing IMPT dose levels without acute dose limiting toxicities that prevented dose escalation to maximum tolerated dose. Acute toxicity was generally mild with no radiation interruptions. No unexpected perioperative morbidity was noted. Eight months postoperatively, one patient developed hydronephrosis that was treated by stent with ureter dissected off tumor and received 57.5 GyRBE. Retained ureter(s) was (were) subsequently constrained to 50.4 GyRBE without further problem. With an 18-month median follow-up, there were no local recurrences.

CONCLUSIONS

IMPT dose escalation to CTV2 to 63 GyRBE was achieved without acute dose limiting toxicities. The phase 2 study of IMPT will accrue patients to that dose. Parallel intensity modulated radiation therapy phase 1 arm is currently accruing at the initial dose level. Ureters that undergo a high dose radiation and/or surgery are at risk for late hydro-ureter. Future studies will constrain retained ureters to 50.4 GyRBE to avoid ureteral stricture.

(Neo)adjuvant treatment in localised soft tissue sarcoma: The unsolved affair

Soft tissue sarcomas (STS) are rare and heterogeneous tumours. A correct definition of STS is imperative from the very beginning of disease management, to guide the diagnostic and imaging work-up, and help to establish the prognosis on which the therapeutic strategy will be based. Over the last few years, many efforts have been made to identify characteristics that could predict disease behaviour and to enrich the therapeutic armamentarium against the advanced disease, that is still characterised by poor prognosis. Surgery remains the milestone of treatment for localised STS, whereas many uncertainties regarding the role of adjuvant and neoadjuvant treatment persist. Some controlled evidence is available, but often conflicting and insufficient to make chemotherapy (CT) a standard practice and, currently, a common and shared strategy does not exist. The biggest question concerns the prospective identification of the subgroup of patients who would benefit the most from (neo)adjuvant therapies. In light of the growing understanding of different biologies and sensitivities of the various sarcoma subtypes, the value of histology in the selection of peri-operative treatments is one of the most intriguing topics under discussion. In this perspective, a new generation of neoadjuvant trials have been planned and are currently ongoing. The aim of this review was to rekindle interest in the long-standing topic of (neo)adjuvant CT in localised STS, providing an update on its role in sarcomas' management and highlighting future directions and consequential factors needed to further improve outcomes in this disease.

Looking for answers: the current status of neoadjuvant treatment in localized soft tissue sarcomas

PURPOSE

Sarcomas are a rare and heterogeneous variant of cancer. The standard of care treatment involves surgical resection with radiation in high-risk patients. Despite appropriate treatment approximately 50 % of patients will suffer and die from recurrent disease. The purpose of this article is to review the current evidence concerning the use of neoadjuvant chemotherapy with or without radiation in soft tissue sarcomas.

METHODS

An in-depth literature search was conducted using Ovid Medline and PubMed.

RESULTS

The most active chemotherapeutic agents in sarcoma are anthracyclines and ifosfamide. Adjuvant chemotherapy trials show only minimal benefit. Neoadjuvant chemotherapy offers the potential advantage of reducing the extent of surgery, increasing the limb salvage rate, early exposure of micrometastatic disease to chemotherapy, and assessment of tumor response to chemotherapy. Some retrospective and phase II trials suggest a benefit to neoadjuvant chemotherapy. Unfortunately, no clearly positive phase III prospectively randomized trials exist for neoadjuvant therapy in soft tissue sarcomas.

CONCLUSIONS

The current neoadjuvant chemotherapy trials that do exist are heterogeneous resulting in conflicting results. However, neoadjuvant chemotherapy with or without radiation can be considered in patients with high-risk disease in an attempt to improve long-term outcomes.

[Radiotherapy for retroperitoneal sarcomas]

The management of retroperitoneal sarcoma can be very challenging, and the quality of initial treatment strategy appears to be a crucial prognostic factor. En bloc surgery is currently the standard of care for these rare tumours and perioperative treatments such as chemotherapy or radiotherapy have not been validated yet. However, local-regional relapse constitutes the most common disease course. While adjuvant radiotherapy is less and less common due to gastrointestinal toxicities, preoperative radiation therapy offers numerous advantages and is being evaluated as part of a national multicentre phase II study (TOMOREP trial) and is the subject of a European randomized phase III study (STRASS trial). The objective of this article is to present data on preoperative irradiation in terms of dose, volumes and optimal radiotherapy techniques for the treatment of this rare disease.

The importance of surgical margins in retroperitoneal sarcoma

Surgery is the "gold-standard" treatment for retroperitoneal sarcomas, but local recurrence is common, and can cause disease-related death. Complete gross resection is associated with improved survival, but debate exists as to whether resection of adjacent organs to improve margins or prescription of neoadjuvant radiation leads to better outcomes. This review summarizes data addressing prognostic value of margin, extent of surgery necessary to optimize treatment of retroperitoneal sarcomas, and role of histology in optimizing therapy.

Retroperitoneal liposarcoma: a comprehensive review

Retroperitoneal liposarcomas are rare mesenchymal tumors of the retroperitoneum that typically present with advanced disease and often carry a poor prognosis. Because of their rarity and anatomic location, these malignant tumors can cause a diagnostic dilemma and present several therapeutic challenges. They are usually associated with a high rate of recurrence despite grossly complete resection, thus requiring long-term and often indefinite follow-up. Relevant data on this topic was procured and synthesized with the aid of a comprehensive Medline search in addition to oncologic, pathologic, urologic, radiologic, and surgical literature review on retroperitoneal sarcomas. This article provides an in-depth review into the natural history, pathology, clinical manifestations, and prognostic features of retroperitoneal liposarcomas. It also discusses the reliability of diagnostic procedures and novel curative approaches that are currently being evaluated for the disease.

Successful salvage treatment of myxoid liposarcoma with multiple peritoneal seeding using helical tomotherapy-based intraperitoneal radiotherapy: a case report

Background

Myxoid liposarcoma is the most common soft-tissue sarcoma that metastasizes to the peritoneal cavity. Recently, an advanced intensity-modulated radiotherapy, known as helical tomotherapy, has been introduced to improve target coverage, while reducing normal tissue radiation. Here, we report a case of myxoid liposarcoma with multiple peritoneal seeding that was chemotherapy-refractory, but was successfully salvaged by helical tomotherapy-based intraperitoneal radiotherapy.

Case presentation

A 71-year-old East-Asian male was initially diagnosed with myxoid liposarcoma in his left thigh by excision. Six years later, the patient underwent a left pneumonectomy for metastatic myxoid liposarcoma in the left lung. Since then, the patient was treated with two segmental resections, and multiple lines of chemotherapy, for repeated recurrences in the peritoneal cavity. The patient underwent intraperitoneal radiotherapy followed by tumor boost radiotherapy, as salvage treatment for chemotherapy-resistant metastatic peritoneal myxoid liposarcoma. The prescribed dose was 24 Gy delivered in 15 fractions of 1.6 Gy over 3 weeks, followed by a 16 Gy boost dose administered in eight fractions of 2 Gy, to multifocal peritoneal lesions. A positron emission tomography scan obtained 8 weeks after completion of radiotherapy, showed a complete metabolic response of metastatic peritoneal lesions. Radiotherapy was well tolerated, without any side effects. In a computed tomography scan obtained 20 weeks after completion of radiotherapy, most of the peritoneal metastatic lesions had disappeared, except for two small residual nodules.

Conclusion

This case suggests that low fraction-sized intraperitoneal radiotherapy (1.6 Gy administered once daily), followed by a focal boost using helical tomotherapy, is a feasible treatment without side effects. It produced an excellent tumor response, and durable intraperitoneal control for metastatic peritoneal myxoid liposarcoma.

Management of patients with retroperitoneal tumors and a review of the literature

Background

Retroperitoneal tumors (RTs) develop insidiously and are generally seen as large masses, and 50% of RTs are larger than 20 cm at the time of diagnosis. In this article, we share our experience of 5 years of surgical management of RTs.

Methods

We evaluated 28 RT cases operated on in three education hospitals in Turkey from January 2008 onwards, with regard to patients’ demographic characteristics, complaints, weight loss figures, the location and size of the tumor, blood transfusion, intra-operational time, metastases (in malignant cases), additional organ resection, histological grade, local recurrences, average life expectancy, and post-operative treatment methods.

Results

The mean age of the patients was 49 years (range, 18 to 78 years). Twenty (71.43%) were female, and 8 (28.57%) were male. The primary complaint was abdominal pain in 18 patients (64.28%). CT scans were performed in 17 (61%) patients, 10 (35.4%) underwent abdominal MR imaging, and 1 (3.6%) underwent both abdominal CT and abdominal MR imaging. A mass was palpated in the pelvis (suprapubic region) in seven (25%) of the patients during physical examination. The largest tumors were detected in the left lumbar area. The mean tumor size was 12.78 cm (range, 2 to 30 cm). The mean intra-operational time was 192 min (range, 70 to 380 min). The mean hospitalization period was 11 days (range, 8 to 23 days). Seven (25%) patients were reported to have benign tumors, while 21 (75%) were reported to have malignant tumors. The most frequently seen malignant pathology was liposarcoma (eight cases; 38.09%) followed by leiomyosarcoma (five cases; 23.8%) and malignant fibrous histiocytoma (four cases; 19.04%). The earliest local recurrence was detected in the 12th month and the latest in the 28th month. A total of 11 (52.3%) of the total of 21 malignant cases experienced local recurrence within 3 years. The 3-year average life expectancy was 85.7% in the 18 malignant cases.

Conclusions

Due to the low response rate of all but two types of RT to chemotherapy, the best remaining treatment option is surgery with wide resection margins, whereby all macroscopic traces of tumor are removed.

Adjuvant radiation for soft tissue sarcomas

Over recent decades, limb-preservation surgery in combination with radiotherapy achieves local control rates exceeding 90% for extremity soft tissue sarcoma (STS). Local control is not as successful for retroperitoneal sarcoma (approximately 60%) despite aggressive surgical approaches including en bloc resection of uninvolved adjacent organs combined with intensity modulated radiotherapy (IMRT). This review will discuss the indications for adjuvant radiation therapy (RT) for primary presentation of soft tissue sarcoma: "What," referring to the type and manner of planning and delivery of RT; "When," referring to the timing and scheduling of RT; and "Why," referring to the rationale for the use of RT will be addressed. From a practical stand point, this Educational Chapter on "adjuvant RT" will focus on pre- and postoperative RT in the context of gross total resection for extremity and retroperitoneal soft tissue sarcoma, the two most frequent paradigms for the use of adjuvant RT.

Role of radiation therapy for non-extremity soft tissue sarcomas

BACKGROUND

Negative surgical margins are uncommon for non-extremity soft tissue sarcomas. Radiation therapy is usually recommended to improve local control; however, appropriate RT dosing is challenging due to nearby dose-limiting normal structures.

MATERIAL AND METHODS

Comprehensive literature search using PubMed (March 2014).

RESULTS

Data suggest radiation therapy is an important modality in maximizing local tumor control in non-extremity sarcomas.

CONCLUSION

The literature supports the use of RT to improve local control for non-extremity soft tissue sarcomas.

Surgical management of retroperitoneal and pelvic sarcomas

Management of retroperitoneal sarcomas presents technical and oncological challenges. Imaging is crucial for diagnosis and to define local tumor extent. Complete gross resection at initial presentation is the best chance for cure, but there is controversy as to how this can be best achieved. There is a long-term risk of local recurrence, which is best treated with repeat resection if feasible. The roles of radiation and chemotherapy remain undefined.

Clinical phase I/II trial to investigate preoperative dose-escalated intensity-modulated radiation therapy (IMRT) and intraoperative radiation therapy (IORT) in patients with retroperitoneal soft tissue sarcoma: interim analysis

Background

To report an unplanned interim analysis of a prospective, one-armed, single center phase I/II trial (NCT01566123).

Methods

Between 2007 and 2013, 27 patients (pts) with primary/recurrent retroperitoneal sarcomas (size > 5 cm, M0, at least marginally resectable) were enrolled. The protocol attempted neoadjuvant IMRT using an integrated boost with doses of 45–50 Gy to PTV and 50–56 Gy to GTV in 25 fractions, followed by surgery and IOERT (10–12 Gy). Primary endpoint was 5-year-LC, secondary endpoints included PFS, OS, resectability, and acute/late toxicity. The majority of patients showed high grade lesions (FNCLCC G1:18%, G2:52%, G3:30%), predominantly liposarcomas (70%). Median tumor size was 15 cm (6–31).

Results

Median follow-up was 33 months (5–75). Neoadjuvant IMRT was performed as planned (median dose 50 Gy, 26–55) in all except 2 pts (93%). Gross total resection was feasible in all except one patient. Final margin status was R0 in 6 (22%) and R1 in 20 pts (74%). Contiguous-organ resection was needed in all grossly resected patients. IOERT was performed in 23 pts (85%) with a median dose of 12 Gy (10–20 Gy).

We observed 7 local recurrences, transferring into estimated 3- and 5-year-LC rates of 72%. Two were located outside the EBRT area and two were observed after more than 5 years. Locally recurrent situation had a significantly negative impact on local control. Distant failure was found in 8 pts, resulting in 3- and 5-year-DC rates of 63%. Patients with leiomyosarcoma had a significantly increased risk of distant failure. Estimated 3- and 5-year-rates were 40% for PFS and 74% for OS. Severe acute toxicity (grade 3) was present in 4 pts (15%). Severe postoperative complications were found in 9 pts (33%), of whom 2 finally died after multiple re-interventions. Severe late toxicity (grade 3) was scored in 6% of surviving patients after 1 year and none after 2 years.

Conclusion

Combination of neoadjuvant IMRT, surgery and IOERT is feasible with acceptable toxicity and yields good results in terms of LC and OS in patients with high-risk retroperitoneal sarcomas. Long term follow-up seems mandatory given the observation of late recurrences. Accrual of patients will be continued with extended follow-up.

Trial registration

NCT01566123.

Current concepts in multimodality therapy for retroperitoneal sarcoma

Radical surgical resection currently represents the most effective therapy for patients with retroperitoneal sarcoma. Unfortunately, margin-negative resection often mandates extirpation of multiple retroperitoneal viscera, and such operations are nonetheless fraught with high rates of locoregional recurrence. In an attempt to improve local control and ultimately survival, adjuvant strategies of radiation and chemotherapy have been increasingly employed, with promising results. To date, however, the rarity of the disease has limited large, prospective studies investigating the efficacy of these adjuvant modalities. In this article, we review the current literature pertaining to the diagnosis, staging and treatment of retroperitoneal sarcoma and demonstrate the critical need for future large, multi-institutional studies to advance our knowledge of this uncommon disease.

Radiation therapy for retroperitoneal sarcoma

Retroperitoneal soft-tissue sarcoma is an uncommon cancer of mesodermal origin, which is difficult to treat owing to its location and proximity to vital structures. Complete gross resection, often involving en bloc resection, is the standard of care as it represents the only treatment that improves overall survival. Unlike extremity sarcoma, retroperitoneal soft-tissue sarcoma tumor mortality is from local recurrence. Radiation therapy is the only adjuvant treatment that has improved local control in several institutional series. However, there remains no definitive prospective, randomized trial that establishes the role of adjuvant radiation versus no radiation. Owing to significant radiation morbidity with adjacent organs, especially the small bowel, there exists no consensus on radiation timing, delivery method or dosing. Recent and current protocols use preoperative external-beam radiation with or without a method of focal boost dosing. Methods of boost dosing include brachytherapy, intraoperative radiation therapy and intensity-modulated radiation therapy. Further studies are needed to definitively include radiation therapy in the standard treatment of retroperitoneal soft-tissue sarcoma and to find the optimal balance between acceptable radiation toxicity and effective local control in treatment protocols.

Preoperative radiation for retroperitoneal sarcoma is not associated with increased early postoperative morbidity

BACKGROUND AND OBJECTIVES

Preoperative radiation (PR) in the management of retroperitoneal sarcoma (RPS) is controversial. Concern for increased perioperative morbidity may influence the decision to recommend PR. Here we compare 30-day morbidity and mortality (M + M) after resection of RPS with and without PR.

METHODS

Patients undergoing resection of RPS were identified using ACS NSQIP (2005-2011). Patients with known PR status within 90 days of operation were included. Univariate and multivariate logistic regression analyses were performed to identify factors associated with M + M.

RESULTS

Of 696 patients operated on for RPS, 70 (10%) underwent PR. PR patients were younger (mean 55 vs. 61 years), more frequently had hypoalbuminemia (<3 g/dl; 19% vs. 10%), concomitant kidney (29% vs. 18%), or pancreas resections (11% vs. 5%), longer operations (mean 327 vs. 253 min), and increased transfusion requirements (mean 4.1 vs. 2.1 units, each P < 0.05). Despite these differences, the M + M rate (31% with vs. 30% without PR, P = 0.75) was comparable between the two groups. After adjustment for confounders, no association was identified between PR and M + M.

CONCLUSIONS

In a national cohort of RPS patients, PR is infrequently utilized. Despite the increased prevalence of multiple risk factors, PR patients do not have an increased 30-day postoperative M + M.

Management of recurrent retroperitoneal sarcoma

Approximately 15% of soft tissue sarcomas are retroperitoneal. The occult location and anatomic complexity results in local recurrences in the majority of patients. Predictors of recurrence include histological subtype, completeness of resection, and the hospital case volume. The most significant predictor of outcome following local recurrence is the resectability of the recurrent disease. An understanding of the implication of tumor biology on outcomes is essential in determining optimal management for patients with recurrent retroperitoneal sarcoma.

Integration of radiation oncology with surgery as combined-modality treatment

Integration of surgery and radiation (external beam, EBRT; intraoperative, IORT) has become more routine for patients with locally advanced primary cancers and those with local-regional relapse. This article discusses patient selection and treatment from a more general perspective, followed by a discussion of patient selection and treatment factors in select disease sites (pancreas cancer, colorectal cancer, retroperitoneal soft-tissue sarcomas). Outcomes with combined modality treatment (surgery, EBRT alone or with concurrent chemotherapy, IORT) are discussed. The ultimate in contemporary integration of radiation and surgery is found in patients who are candidates for surgery plus both EBRT and IORT.

Should adjuvant radiotherapy be administered in addition to front-line aggressive surgery (FAS) in patients with primary retroperitoneal sarcoma?

BACKGROUND

As most patients with retroperitoneal sarcomas (RPS) die of local recurrence, front-line aggressive surgery (FAS) has been developed, and it seems to achieve better local control. The aim of this study was to evaluate conformal postoperative radiotherapy (PORT) in patients who had enlarged surgery.

PATIENTS AND METHODS

Between 1994 and 2008, 110 patients with primary RPS mainly operated by FAS were analysed. Sixty-two patients underwent surgery and no PORT (group S), and 48 received surgery and PORT (group S + R). The median age was 52. Most patients had 3D conformal PORT (81%) with a median dose of 50 Gy.

RESULTS

Comparing results at 5 years in the S and the S + R group, the cumulative rate of local failure was, respectively, 36% and 22% (NS); relapse-free survival was 47% and 60% (P = 0.02), and overall survival was, respectively, 77% and 71% (NS).

CONCLUSION

Even if patients with adjuvant PORT were at higher risk of recurrence, there was a trend for radiotherapy (RT) to decrease the local relapse rate and improve recurrence-free survival. This study confirms that adjuvant conformal RT should be evaluated in a randomized trial, the control arm being FAS. Adjuvant RT in the preoperative setting is being evaluated in an EORTC trial.