Retroperitoneal sarcomas: grade and survival

Explainable machine learning predicts survival of retroperitoneal liposarcoma: A study based on the SEER database and external validation in China

OBJECTIVE

We have developed explainable machine learning models to predict the overall survival (OS) of retroperitoneal liposarcoma (RLPS) patients. This approach aims to enhance the explainability and transparency of our modeling results.

METHODS

We collected clinicopathological information of RLPS patients from The Surveillance, Epidemiology, and End Results (SEER) database and allocated them into training and validation sets with a 7:3 ratio. Simultaneously, we obtained an external validation cohort from The First Affiliated Hospital of Naval Medical University (Shanghai, China). We performed LASSO regression and multivariate Cox proportional hazards analysis to identify relevant risk factors, which were then combined to develop six machine learning (ML) models: Cox proportional hazards model (Coxph), random survival forest (RSF), ranger, gradient boosting with component-wise linear models (GBM), decision trees, and boosting trees. The predictive performance of these ML models was evaluated using the concordance index (C-index), the integrated cumulative/dynamic area under the curve (AUC), and the integrated Brier score, as well as the Cox-Snell residual plot. We also used time-dependent variable importance, analysis of partial dependence survival plots, and the generation of aggregated survival SHapley Additive exPlanations (SurvSHAP) plots to provide a global explanation of the optimal model. Additionally, SurvSHAP (t) and survival local interpretable model-agnostic explanations (SurvLIME) plots were used to provide a local explanation of the optimal model.

RESULTS

The final ML models are consisted of six factors: patient's age, gender, marital status, surgical history, as well as tumor's histopathological classification, histological grade, and SEER stage. Our prognostic model exhibits significant discriminative ability, particularly with the ranger model performing optimally. In the training set, validation set, and external validation set, the AUC for 1, 3, and 5 year OS are all above 0.83, and the integrated Brier scores are consistently below 0.15. The explainability analysis of the ranger model also indicates that histological grade, histopathological classification, and age are the most influential factors in predicting OS.

CONCLUSIONS

The ranger ML prognostic model exhibits optimal performance and can be utilized to predict the OS of RLPS patients, offering valuable and crucial references for clinical physicians to make informed decisions in advance.

Clinical Impact of External Beam Radiotherapy for Surgically Resected Primary Retroperitoneal Liposarcoma

INTRODUCTION

EORTC-62092 (STRASS) was a phase 3, randomized study that compared surgery alone versus surgery plus neoadjuvant radiotherapy (RT) for retroperitoneal sarcomas. RT was not associated with improved abdominal recurrence-free survival, the primary outcome measure, although on subanalysis, there may have been benefit for well-differentiated (WD) liposarcoma. This study investigated the real-world use and outcomes of RT (neoadjuvant and adjuvant) for the management of retroperitoneal liposarcoma.

METHODS

We queried the National Cancer Database (NCDB) (2004-2017) for patients with nonmetastatic, primary retroperitoneal liposarcoma treated with resection with or without RT (n = 3911). Patients were stratified by treatment type and histology [WD (n = 2252), dedifferentiated (DD) (n = 1659)]. Propensity score (PS) matching was used before comparison of treatment groups. Overall survival (OS) was the primary outcome measure.

RESULTS

Median follow-up time was 4.1 years, and median OS was 10.7 years. There was no association between RT and OS for either WDLPS or DDLPS cohorts. We performed a subgroup analysis of neoadjuvant RT only, similar to STRASS. For WDLPS after PS matching (n = 208), neoadjuvant RT was not associated with OS (hazard ratio [HR] 1.01, p = 0.0523) but was associated with longer postoperative hospital stay (p = 0.012). For DDLPS after PS matching (n = 290), neoadjuvant RT was not associated with OS (HR 1.02, p = 0.889). For both WD-LPS and DD-LPS, utilization of neoadjuvant RT was associated with treatment at high-volume (≥ 10 cases/year) and academic/network facilities.

CONCLUSIONS

For primary retroperitoneal liposarcoma treated with surgical resection, radiotherapy was not associated with an overall survival benefit in this propensity-matched, adjusted analysis of the NCDB.

Impact of time to first relapse on long-term outcome in adult retroperitoneal sarcoma patients after radical resection

BACKGROUND

Local recurrence of primary retroperitoneal sarcoma (RPS) is one of the major causes of treatment failure and death. We attempted to assess the effects of time to local recurrence (TLR) on the survival after recurrence (SAR) and overall survival (OS) of RPS.

METHODS

Included in this study were 224 patients who underwent R0 resection for primary RPS at our institution between January 2000 and December 2020, 118 of whom had local recurrence. Based on the median TLR (19.8 months), patients were divided into two groups: early local recurrence (ELR < 20 months) and late local recurrence (LLR > 20 months). The Kaplan-Meier method was employed to calculate the local recurrence-free survival (LRFS), SAR and OS. Univariate and multivariate analyses were conducted to explore the prognostic value of TLR.

RESULTS

The median follow-up time was 60.5 months for the entire cohort and 58.5 months for the recurrence cohort. There were 60 (50.8%) patients in the ELR group and 58 (49.2%) in the LLR group. The ELR group exhibited a worse SAR (29.2 months vs. 73.4 months, P < 0.001), OS (41.8 months vs. 120.9 months, P < 0.001), and a lower 5-year OS rate (35.9% vs. 73.2%, P = 0.004) than the LLR group. Furthermore, multivariate analysis indicated that TLR was an independent prognostic indicator for SAR (P = 0.014) and OS (P < 0.001).

CONCLUSIONS

In patients with RPS, ELR after R0 resection presents adverse effects on OS and SAR than those with LLR, and TLR could serve as a promising predictor for OS and SAR.

Characteristics and Outcomes of Locally Recurrent Retroperitoneal Sarcoma After First Relapse in a Single Tertiary Asian Centre and Applicability of the Sarculator

Objective

Retroperitoneal sarcomas (RPS) comprise of 15% of soft tissue sarcomas where five-year overall survival rate is about 50%. Locoregional recurrences are observed in up to 50% of patients within the first five years following resection. Various factors have been shown to influence survival outcomes, such as histological subtype and tumour size. A nomogram for first relapse locally recurrent RPS was developed using 602 patients from 22 centres. The recurrent RPS Sarculator is available in an electronic interface and includes variables of age, size, margins of re-resection, radiotherapy, chemotherapy and histology to predict for 6-year disease-free survival (DFS) and overall survival (OS). It has not been validated externally. This study aims to validate the Sarculator recurrence nomogram in predicting the survival outcomes of recurrent RPS in an Asian population as well as examine relapse patterns.

Methods

Patients diagnosed with first recurrent RPS from 1 January 2000 to 31 December 2017 with first local relapse and eligible for curative re-resection were retrospectively analysed. The type of surgery was unique for individual patients and suggestions of adjuvant therapy were based on globally recognised standards. Patients were followed up every 3 to 4 months post-operatively for the first 2 to 3 years and 6-monthly to a year thereafter. A R0 or R1 margin is deemed as complete resection, including a microscopically negative margin (R0) and microscopically positive but macroscopically clear margin (R1). R2 is classified as an incomplete resection with tumour rupture or remaining disease. Harrell’s C concordance index was used to determine the nomogram’s discriminative ability and calibration plots were used to assess accuracy. For the calibration, the patients were divided into 3 groups. Death data was retrieved from the National Birth and Death registry for accuracy.

Results

There were 53 patients included in this study. Patient and tumour characteristics have been summarised in Table 1. All patients had their second resection at a single centre. 66.0% had their first resection at the same centre. The median age was 53 (range 21- 79) at diagnosis, median tumour size was 17cm (12cm to 28cm) and median follow-up duration was 44.1 months. The most commonly encountered subtypes were de-differentiated liposarcoma (DDLPS) (56.6%), well-differentiated liposarcoma (WDLPS) (20.8%) and leiomyosarcoma (LMS) (11.3%) with a majority being high-grade (75.5%). The median disease-free interval was 2.9 years (2- 5.3 years) from the first surgery. The median age at second surgery was 56 (21- 79) and all patients had a complete resection (R0/R1). Recurrence patterns differed with subtypes where 90.9% and 9.1% of WDLS, 76.7% and 16.7% of DDLPS and 83.3% and 16.7% of LMS had local and distant relapses respectively from the second surgery. 62.5% of distant relapses was in the lung followed by nodes (18.8%) and liver (12.5%). The 5-year OS from the second surgery was 66.2% (95% CI: 54.3%- 80.8%). The 1-year, 3 years and 6 years DFS were 50.2% (95% CI: 38.2% - 65.9%), 10.4% (4.26% - 25.5%) and 3.91% (0.684% - 22.4%) respectively. Overall, 32 patients (60.4%) had passed away from sarcoma. The concordance indices for 6-year OS and DFS were 0.7 and 0.65 (Figure 1) respectively which represents a fairly accurate prediction by Sarculator.

Conclusion

Our study has shown the Sarculator nomogram for primary recurrent was applicable in our cohort and its potential application in an Asian setting. The Sarculator nomogram will be a useful tool in clinical practice to improve risk stratification and facilitate prognosis-based decision-making. Moving forward, novel therapeutic strategies are required to enhance the prognosis of patients with recurrent RPS.

[Active surgical approach for retroperitoneal liposarcoma]

OBJECTIVE

To assess the influence of active surgical approach on the long-term postoperative outcomes in patients with retroperitoneal liposarcoma.

MATERIAL AND METHODS

A retrospective study included 190 patients with retroperitoneal liposarcoma. The effect of malignancy grade, adjuvant chemotherapy, number of separate tumor nodes in primary neoplasm and the first relapse, as well as the number of previous total resections on survival rate was analyzed.

RESULTS

Overall and relapse-free survival is significantly worse in patients with high-grade retroperitoneal liposarcoma (G2-3) compared to low-grade (G1) tumor (p_log-rank=0.000). Multifocal growth of primary tumor (p=0.869; p_log-rank=0.607) and multiple (>1) separately located nodes in abdominal cavity and retroperitoneal space at the first relapse (p_log-rank=0.158 to 0.985) did not significantly impair prognosis after total resection of all types of retroperitoneal liposarcoma regardless malignancy grade. Adjuvant chemotherapy does not significantly improve relapse-free survival. Overall survival was significantly higher in patients who underwent ≥4 previous total resections compared to 1 surgical treatment for all types of retroperitoneal liposarcoma regardless malignancy grade (p=0.000; p_log-rank=0.001).

CONCLUSION

The only potentially radical treatment for patients with retroperitoneal liposarcoma is surgery. We reported the advantages of active surgical approach for improvement of long-term outcomes in patients with retroperitoneal liposarcoma.

Cytoreductive surgery (CRS) with hyperthermic intraperitoneal chemotherapy (HIPEC) in peritoneal sarcomatosis-A systematic review and meta-analysis

Cytoreductive surgery (CRS) with hyperthermic intraperitoneal chemotherapy (HIPEC) play an important role in the treatment of various peritoneal surface malignancies, but its efficacy in peritoneal sarcomatosis (PS) remains unknown. Hence, we performed a systematic review and meta-analysis to investigate outcomes of CRS-HIPEC in PS, in accordance with PRISMA guidelines. 16 studies with a total of 320 patients were included in the meta-analysis. Pooled mean length of hospital stay after CRS-HIPEC was 16.0 days (95% CI: 12.2-19.8) and rate of serious complications was 17.4% (95% CI: 9.8-26.3). The median DFS was 12.0 months (95% CI: 8.0-16.0) and the 5-year DFS was 21.8% (95% CI: 13.2-31.7). Overall pooled median OS was 29.3 months (95% CI: 23.8-34.8), with a 5-year OS of 35.3% (95% CI: 26.3-44.8). Subgroup analysis showed that patients with CC-0 cytoreduction had a higher median OS of 34.6 months (95% CI: 23.2-45.9). Median OS for patients with a primary tumour histology of leiomyosarcoma and liposarcoma was 33.5 months (95% CI: 15.9-51.1) and 39.1 months (95% CI: 20.8-57.5) respectively. The site of recurrence was locoregional in 57.3% (95% CI: 38.9-74.8), distant in 17.3% (95% CI: 3.9-35.6), and both in 17.4% (95% CI: 5.8-32.2). In conclusion, our results suggest that CRS-HIPEC may improve outcomes in a select group of PS patients.

Surgical Diagnosis and Treatment of Primary Retroperitoneal Liposarcoma

Background: Primary retroperitoneal liposarcoma (PRPLS) is the most common soft tissue sarcoma of the retroperitoneum with high recurrence rate and short overall survival (OS).

Methods: A retrospective review of 51 patients with PRPLS, treated between September 1, 2009 and November 30, 2020, was conducted to evaluate clinical outcomes of PRPLS resection. Patient demographics, histopathologic subtypes, overall survival (OS), progression-free survival (PFS), disease recurrence rate, and tumor stage were reviewed and analyzed. Univariate analysis was done to identify factors potentially affecting OS and PFS of PRPLS patients. Multivariate Cox proportional hazards analysis was used to evaluate the impact of various clinicopathological factors on OS and PFS of PRPLS patients.

Results: Fifty-one PRPLS patients (28 Males, 23 Females; mean age 56.25 years) were evaluated. There was no significant effect of age, gender, contiguous organ resection, degree of differentiation and tumor size on the OS and PFS of the patients. Univariate analysis showed that negative surgical margin and early tumor stage significantly correlated with OS and PFS (all P < 0.001). Multivariate analysis showed that tumor stage [hazard ratio (HR) = 1.177, P = 0.001] was an independent predictors of poor progression-free survival, and surgical margins [HR = 4.0674 P = 0.038] and tumor stage [HR = 1.167 P = 0.001] were identified as independent predictors of poor overall survival.

Conclusion: Negative surgical margin is a prognostic factor of OS, and can prolong the postoperative survival time of PRPLS patients. Tumor stage is a prognostic factor for OS and PFS, and can influence the survival of PRPLS patients. Earlier tumor stages of PRPLS are associated with significantly better outcomes.

Primary localized retroperitoneal sarcomas: report from Slovenian sarcoma referral center

BACKGROUND

Sarcoma patients should be treated in high volume referral sarcoma centers. Compartmental resection is proposed as the best treatment option in retroperitoneal sarcoma patients.

METHODS

Institute of Oncology Ljubljana is the only referral sarcoma center in Slovenia. Having a population of 2.1 million poses a unique situation. We manage all sarcoma patients in the country and operate on patients with soft tissue tumors of extremities, trunk, and abdomen. Data for all consecutive patients surgically treated from January 1999 to December 2018 for primary localized retroperitoneal sarcoma was extracted from a prospective surgical database. Data about the incidence of sarcoma patients in Slovenia was extracted from the Cancer Registry of Republic of Slovenia. Clinicopathologic variables and the outcome were analyzed.

RESULTS

In total, 89 patients were included in the study. Median age was 62 years. Dedifferentiated liposarcoma was the most common histology (38.2%). Median tumor size was 21 cm. Compartmental resection was performed in 47.2% (42/89). Postoperative complication grade 3a or higher according to Clavien-Dindo classification had 30.3% (27/89) of patients. The 30-day and 90-day mortality rate was 2.2% and 5.6%. Median follow-up was 62.1 months. Corresponding 5-year overall survival was 67.2%, 5-year disease-specific survival was 72.6%, and 5-year local recurrence-free survival was 81.5%, respectively.

CONCLUSION

Results from our institution show that referral sarcoma centers may achieve very good results in management of retroperitoneal sarcoma patients, despite not meeting the criteria for high volume hospitals, as long as they have multidisciplinary team, appropriate facilities, and expertise.

Has the Outcome for Patients Who Undergo Resection of Primary Retroperitoneal Sarcoma Changed Over Time? A Study of Time Trends During the Past 15 years

BACKGROUND

This study aimed to investigate changes in treatment strategy and outcome for patients with primary retroperitoneal sarcoma (RPS) undergoing resection at referral centers during a recent period.

METHODS

The study enrolled consecutive adult patients with primary non-metastatic RPS who underwent resection with curative intent between 2002 and 2017 at 10 referral centers. The patients were grouped into three periods according to date of surgery: t1 (2002-2006), t2 (2007-2011), and t3 (2012-2017). Five-year overall survival (OS), disease-specific survival (DSS), and crude cumulative incidence (CCI) of local recurrence (LR) and distant metastasis (DM) were calculated. Multivariable analyses for OS and DSS were performed.

RESULTS

The study included 1942 patients. The median follow-up period after resection varied from 130 months (interquartile range [IQR], 124-141 months) in t1 to 37 months (IQR, 35-39 months) in t3. The 5-year OS was 61.2% (95% confidence interval [CI], 56.4-66.3%) in t1, 67.0% (95 CI, 63.2-71.0%) in t2, and 71.9% (95% CI, 67.7-76.1%) in t3. The rate of macroscopically incomplete resection (R2) was 7.1% in t1 versus 4.7% in t3 (p = 0.066). The median number of resected organs increased over time (p < 0.001). In the multivariable analysis resection during t3 was associated with better OS and DSS. The 90-day postoperative mortality improved over time (4.3% in t1 to 2.3% in t3; p = 0.031). The 5-year CCI of LR and DM did not change significantly over time.

CONCLUSIONS

The long-term survival of patients who underwent resection for primary RPS has increased during the past 15 years. This increased survival is attributable to better patient selection for resection, quality of surgery, and perioperative patient management.

En Bloc Resection of a Giant Retroperitoneal Liposarcoma: A Surgical Challenge

Liposarcomas are exceedingly rare entities that evoke malignant transformation of connective tissue and fat cells. These tumours occur throughout the soft tissues of the body, afflicting a myriad of regions. In the adult population, liposarcomas represent the most prevalent subtype of sarcomas, and often arise de novo. Retroperitoneal liposarcomas (RLS) are a ubiquitous subset of sarcomas that, due to their deep location in the hollow abdomen, can grow to astronomical proportions before manifesting any noticeable symptoms; a prompt diagnosis of RLS is therefore often rendered dilatory. We hereby delineate the case of a 43-year-old woman who presented with vague left hemiabdominal distention and discomfort. A subsequent computed tomography scan divulged a giant retroperitoneal growth impaling on and thus displacing the pancreas. A compartmental, en bloc resection was performed, with subsequent histopathology of the excised specimen revealing a well-differentiated liposarcoma. The surgical intervention was curative and led to an uneventful recovery. This paper highlights the pertinence of surgical management as an appropriate treatment modality for a complete resection of RLS. 

Retroperitoneal soft-tissue sarcomas: Radiotherapy experience from a tertiary cancer center and review of current evidence

Background

Surgery remains to be the main therapeutic approach for retroperitoneal sarcomas (RPS) although evidence supports that complementary radiotherapy increases local-control and survival. We present a multidisciplinary management and experience of a tertiary cancer center in the treatment of RPS and analyze current evidence of radiotherapy efficacy.

Patients and methods

We retrospectively reviewed 19 patients with primary or relapsed RPS treated between November 2009 and October 2018. Multidisciplinary approach comprised complete resection in 15 patients (79%) achieving resection R0 in 11 patients (58%), R1 in 4 patients (21%) and R2 in 2 patients (10%). Seven patients (37%) underwent a preoperative radiation (PRORT), 10 patients (53%), post-operative radiation (PORT) and 2 patients (10%), received radiotherapy exclusively. Ten patients (53%) received adjuvant chemotherapy.

Results

With a median follow-up of 24 months (2-114 months), actuarial rates of loco-regional relapse free survival (LRFS) at 1, 2 and 3 years were 77%, 77% and 67%, respectively. Actuarial rates of distant-metastases-free survival (DMFS), disease-free survival (DFS) and overall survival (OS) at 1, 2 and 3 years were 100%, 100% and 80% for DMFS; 94%, 77% and 67% for DFS and 100%, 91% and 91% for OS, respectively. Only surgical margins (negative vs. positive) showed significance for 3y-LRFS: 100% vs. 34.3%, p = 0.018. Treatment tolerance was acceptable with no acute or late toxicity higher than grade 2.

Conclusions

Complementary radiotherapy appears to be useful and well tolerated for the multidisciplinary management of RPS. Presence of positive surgical margins seems to be the most relevant prognostic factor through the follow-up.

Liver resection as a component of en-bloc multivisceral resection for upper abdominal tumors is associated with increased morbidity

BACKGROUND AND METHODS

Complex en-bloc multivisceral and oncovascular resections for upper abdominal tumors remain rare, but there is increasing interest in their role. We analyze complications and survival for these operations. We performed a retrospective cohort study of patients who underwent en-bloc upper abdominal resections for tumors involving multiple organs. Primary outcomes were complications as per the Clavien-Dindo Classification and Comprehensive Complication Index (CCI). Secondary outcome was overall survival (OS).

RESULTS

We identified 60 consecutive patients who underwent resection from 2011 to 2018. Histopathology was heterogeneous, the most common being renal cell carcinoma. Eighteen patients had major complications. Mean (interquartile range) CCI was 29.6 (9.6-43.9). Liver resection was significantly associated with an increased CCI and increased the odds of a major complication (odds ratio: 4.67, 95% confidence interval [CI]: 1.31-16.59; P = .017). Charlson Comorbidity Score was significantly associated with the presence of at least one major complication. Mean OS was 47.1 months (95% CI: 37.6-56.6).

CONCLUSION

In appropriately selected patients, and when undertaken in centers with appropriate subspecialist surgical teams and intensive care services, en-bloc multivisceral resection of upper abdominal tumors is safe, but liver resection is associated with an increase in major complications.

Incisions and reconstruction approaches for large sarcomas

Large intraabdominal, retroperitoneal, and abdominal wall sarcomas provide unique challenges in treatment due to their variable histology, potential considerable size at the time of diagnosis, and the ability to invade into critical structures. Historically, some of these tumors were considered inoperable if surgical access was limited or the consequential defect was unable to be closed primarily as reconstructive options were limited. Over time, there has been a greater understanding of the abdominal wall anatomy and mechanics, which has resulted in the development of new techniques to allow for sound oncologic resections and viable, durable options for abdominal wall reconstruction. Currently, intra-operative positioning and employment of a variety of abdominal and posterior trunk incisions have made more intraabdominal and retroperitoneal tumors accessible. Primary involvement or direct invasion of tumor into the abdominal wall is no longer prohibitive as utilization of advanced hernia repair techniques along with the application of vascularized tissue transfer have been shown to have the ability to repair large area defects involving multiple quadrants of the abdominal wall. Both local and distant free tissue transfer may be incorporated, depending on the size and location of the area needing reconstruction and what residual structures are remaining surrounding the resection bed. There is an emphasis on selecting the techniques that will be associated with the least amount of morbidity yet will restore and provide the appropriate structure and function necessary for the trunk. This review article summarizes both initial surgical incisional planning for the oncologic resection and a variety of repair options for the abdominal wall spanning the reconstructive ladder.

Did outcomes improve in retroperitoneal sarcoma surgery?

In the last decades, the deeper understanding of the biological basis of the disease, along with the advances of surgical techniques and oncologic multimodal treatments, have led to an overall increase of survival of cancer patients. However, significant amelioration of the prognosis of rare and under-investigated tumors such as soft tissue sarcoma is less evident. In this review, main changes in the surgical management of retroperitoneal sarcoma (RPS) are discussed in order to figure out whether actual improvement in RPS outcome has been occurred in the last years.

Resection of the Inferior Vena Cava for Retroperitoneal Sarcoma: Six Cases and a Review of Literature

Resection of the inferior vena cava (IVC) for malignancy is a technically demanding procedure. We present a series of six cases of resection of the IVC for retroperitoneal sarcomas, four of which were primary caval tumors. We outline the technical difficulties faced in these complex procedures and discuss the oncological outcomes of these rare tumors. We performed a retrospective review of six patients operated for retroperitoneal masses involving the inferior vena cava between April 2015 and July 2016 at our tertiary care institute. Six patients underwent resection of the IVC, three of which required a multivisceral resection. An artificial prosthesis was used to reconstruct the IVC in three patients, whereas two patients underwent primary repair of the vein wall. One patient did not require any reconstruction. Margins were microscopically positive in two out of six patients. All patients received radiotherapy, either in the neo-adjuvant or adjuvant setting. Two patients developed local recurrences with a median follow-up of 24.5 months. Resection of the IVC for extirpation of retroperitoneal sarcomas is a technically complex and difficult procedure. The availability of a multidisciplinary team of surgeons and state-of-the-art intensive care support is essential for good outcomes.

Cytoreductive Surgery in Combination with HIPEC in the Treatment of Peritoneal Sarcomatosis

Cytoreductive surgery (CRS) with hyperthermic intraperitoneal chemotherapy (HIPEC) is an effective treatment for peritoneal carcinomatosis, but it has been debated for peritoneal sarcomatosis. The purpose of the study is the presentation of perioperative and long-term results of CRS and hyperthermic intraoperative intraperitoneal chemotherapy in patients with peritoneal sarcomatosis. Retrospective study in a prospectively maintained database of 20 patients that underwent 29 CRS + HIPEC for peritoneal sarcomatosis. Clinical and histopathologic variables were correlated to survival. Complete cytoreduction was possible in 86.2% of the cases. The hospital mortality and morbidity rate were 0 and 20.7%, respectively. The median follow-up was 26 months, and recurrence was recorded in 20 cases (69%). The median and 5-year survival was 55 ± 13 (34-58) months and 43%, respectively. Prior surgical score (PSS) was the single variable related to survival (p = 0.018). The histologic subtype of the tumor was related to recurrence (p < 0.001). CRS and HIPEC in peritoneal sarcomatosis may offer a survival benefit in selected patients with low hospital mortality. The variety of histologic types of sarcomatosis has not made possible the identification of subgroups of patients that may be offered significant benefit by CRS and HIPEC. Further studies are required.

Current principles of surgery for retroperitoneal sarcomas

Surgery for primary retroperitoneal sarcomas (RPS) often requires a technically challenging, en bloc multivisceral resection to optimize outcomes. Surgery may also be appropriate for patients with localized recurrent RPS. Anatomic considerations and tumor biology driven by histologic subtype may guide the extent of resection in patients with RPS. This review provides an overview of the current surgical principles for primary and recurrent RPS.

Renal Function Preservation in Surgical Resection of Primary Inferior Vena Cava Leiomyosarcoma Involving the Renal Veins

OBJECTIVE

This retrospective study aimed to show the practice of preserving renal function during curative resection of inferior vena cava leiomyosarcoma (IVCL) involving the renal veins at a single institution over a 7 year period.

MATERIALS AND METHODS

From February 2009 to February 2017, 10 patients (6 women; median age 49 years) with IVCL involving the renal veins were treated surgically at Peking Union Medical College Hospital. En bloc resections were performed in all patients, and the renal outflows were preserved in eight patients using a new method: venoplasty of the renal ostia (VRO). Data regarding patient details, pre-operative preparation, surgical procedures, post-operative recovery, and follow-up results were obtained and reviewed retrospectively.

RESULTS

Computed tomography and intra-operative examinations revealed that renal vein confluences were involved but not invaded in all cases except Patient 4. All patients underwent curative en bloc tumour excision; a right nephrectomy was performed in only one patient (Patient 4) whose tumour invaded the right renal vein. The mean operation time was 358 min and the mean blood loss 1935 mL. At a median follow-up of 54.5 months, the 5 year local recurrence, distant metastasis, overall survival, and disease-free survival rates were 20%, 10%, 68.6%, and 38.1%, respectively.

CONCLUSIONS

Venoplasty of the renal ostia is an effective method of preserving the renal veins and reconstructing renal outflow.

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.

The modified frailty index to predict morbidity and mortality for retroperitoneal sarcoma resections

BACKGROUND

The modified frailty index (mFI) is an important method to risk-stratify surgical patients and has been validated for general surgery and selected surgical subspecialties. However, there are currently no data assessing the efficacy of the mFI to predict acute morbidity and mortality in patients undergoing surgery for retroperitoneal sarcoma.

METHODS

Using the American College of Surgeons' National Surgical Quality Improvement Program from 2007 to 2012, we performed a retrospective analysis of patients with a diagnosis of primary malignant retroperitoneal neoplasm who underwent surgical resection. The mFI was calculated according to standard published methods. Univariate and multivariate statistical analyses including χ² and logistic regression were used to identify predictors of 30-d overall morbidity, 30-d severe morbidity (Clavien III/IV), and 30-d mortality.

RESULTS

We identified 846 patients with the diagnosis of primary malignant retroperitoneal neoplasm who underwent surgical resection. The distribution mFI scores was 0 (48.5%) or 1 (36.3%), with only 4.5% of patients presenting with a score ≥3. Rates of 30-d overall morbidity, serious morbidity, and mortality were 22.6%, 12.9%, and 1.2%, respectively. Only selected mFI scores were associated with serious morbidity and overall morbidity on multivariate analysis (P < 0.05), and mFI did not predict 30-d mortality (P > 0.05).

CONCLUSIONS

Our data demonstrate that the majority of patients undergoing retroperitoneal sarcoma resections have few, if any, comorbidities. The mFI was a limited predictor of overall and serious complications and was not a significant predictor of mortality. Better discriminators of preoperative risk stratification may be needed for this patient population.

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.

Challenges in the Surgical Treatment of Retroperitoneal Sarcomas

The objective of this study is to assess long-term prognosis and patterns of failure in patients with retroperitoneal sarcoma who underwent surgery with curative intent at a single institution. We also provide a thorough review of the literature including several series and widely variable data regarding local and distant failure. During a 25-year period (1988-2013), 45 consecutive patients who underwent surgery for retroperitoneal sarcoma at a single referral center were reviewed retrospectively. We recorded and analyzed the presenting symptoms, type of surgical excision, and the 5-year survival rate as well as the local recurrence rate of patients with complete tumor resection. Overall survival is significantly diminished in patients in whom resection margins are not adequate. In our series, 5-year recurrence rate for patients with complete and incomplete resection of the tumor was 30.76 and 68.42 %, respectively. The 5-year survival rate was 51.12 %, and the 5-year survival rate according to type of resection was 76.93 % for complete and 15.79 % for incomplete resections. Local recurrence after first surgery and high-grade malignancy are associated with poor survival. The role of radiation therapy and chemotherapy in the treatment of retroperitoneal sarcoma (RPS) should be investigated further. Complete en bloc resection of the tumor mass and adjacent structures is the single most important factor that improves survival.

Retroperitoneal Sarcoma. Outcome Analysis in a Teaching Hospital in Eastern India- a Perspective

Primary Retroperitoneal Sarcomas are relatively uncommon tumors with varied manifestations, ill-defined prognostic factors and uncertain management modalities. We undertook this study to review patients who presented with primary or recurrent RPS at our institute during the study period. Between 2008 and 2010, 23 patients were evaluated. Statistical analysis was done using the chi square test or Fisher's exact test. Recurrence was calculated using Kaplan Meier curves. The log-rank test was used to compare differences in survival or relapse. Among the 23 patients, 13 were males. Majority (52.2 %) presented with abdominal lump located in umbilical and right hypochondrial region. Surgery was done in 20 (87 %) patients for primary RPS and three (13 %) for recurrent RPS at initial presentation. 14 (61 %) received complete tumor resection, six (27 %) incomplete microscopic resection, and three (13 %) incomplete macroscopic resection. In univariate Cox's proportional hazard model on time ('timer') to event ('relapse') analysis, all the variables like older age (p = 0.027), male sex (p = 0.012), incomplete resection (p = 0.008), large size (0.047) and high grade (p = 0.047) became significant predictor of early recurrence. However, multivariate analysis showed that only extent of resection, grade and sex were statistically significant predictors. Complete tumor resection of retroperitoneal sarcoma (n = 14) was associated with a significantly lesser recurrence compared with unclear resection (n = 9, p = 0.002). The median time between surgery and first recurrence was 15 months. High-grade sarcomas had a significantly higher recurrence (n = 10; median: 24, 95 % CI) than low-grade sarcomas (n = 13, median: 15; 95 %CI P < 0.01). Furthermore, the survival of male patients were worse than that of females (p = 0.036). Completeness of resection, tumor grade and sex are prognostic factors of retroperitoneal soft tissue sarcomas.

Combined Modality Management of Retroperitoneal Sarcomas: A Single-Institution Series of 121 Patients

PURPOSE

The purpose of this study was to investigate local control, survival outcomes, and complication rates of patients treated with aggressive surgery and radiation therapy (RT) for retroperitoneal sarcomas (RPS).

METHODS AND MATERIALS

We reviewed the medical records of 121 consecutive patients treated for RPS with surgery and RT between 1965 and 2012. The most common histology was liposarcoma (n = 42; 35%). The median follow-up was 100 months (range: 20-467 months). Eighty-six patients (71%) were treated for initial presentation of RPS, and 35 patients (29%) presented with and were treated for RPS recurrence. RT was preoperative in 88 patients (73%; median dose: 50.4 Gy) and postoperative in 33 patients (27%; median dose: 55 Gy).

RESULTS

Five-year local control and overall survival rates were 56% and 57%, respectively. Two factors were associated with higher risk of any intra-abdominal recurrence at 5 years: positive or uncertain margins (58% vs 30% for negative margins, P < .001; hazard ratio [HR]: 2.7; 95% confidence interval [CI]: 1.6-4.8) and disease recurrence after previous resection (76% vs 31% for de novo RPS, P < .001; HR: 4.4; 95% CI: 2.5-7.5). The 10-year complication rate was 5%, and RT-related complications were associated with postoperative RT (P < .001) and RT dose of ≥ 60 Gy (P < .001).

CONCLUSIONS

Intra-abdominal RPS recurrence continues to be a significant challenge despite the use of aggressive surgery and radiation therapy. Given the complications associated with postoperative radiation therapy, we recommend that preoperative radiation therapy is the preferred strategy when combined modality therapy is recommended.

Inferior vena cava leiomyosarcoma: preoperative diagnosis and surgical management

Inferior vena cava (IVC) leiomyosarcoma is a rare malignant neoplasm more commonly seen in women in the fifth to sixth decade of life. Complete resection of the tumor with negative margins is the only therapeutical option that has demonstrated a survival benefit. This report presents a case of a 67-year-old woman affected by a lower segment IVC leiomyosarcoma incidentally detected during a chronic abdominal pain study. The patient was treated with tumorectomy, resection and ligation of the infrarenal IVC without signs or recurrence on a 12-month follow-up.

Retroperitoneal liposarcoma: current insights in diagnosis and treatment

Retroperitoneal liposarcoma (RLS) is a rare, biologically heterogeneous tumor that present considerable challenges due to its size and deep location. As a consequence, the majority of patients with high-grade RLS will develop locally recurrent disease following surgery, and this constitutes the cause of death in most patients. Here, we review current insights and controversies regarding histology, molecular biology, extent of surgery, (neo)adjuvant treatment, and systemic treatment including novel targeted agents in RLS.

Adjuvant radiotherapy in retroperitoneal sarcomas. A Scandinavian Sarcoma Group study of 97 patients

BACKGROUND

Currently there is no consensus on the use of adjuvant radiotherapy (RT) in retroperitoneal sarcoma (RPS). We have analysed clinical outcomes in patients with localised RPS treated at two Scandinavian Sarcoma Group (SSG) centres: Haukeland University Hospital (HUH), Bergen, Norway and Skåne University Hospital (SUH), Lund, Sweden to clarify the effects of adjuvant RT on local control and overall survival (OS).

MATERIAL AND METHODS

Local databases and registers at HUH and SUH as well as the SSG central register were used to identify RPS patients. Patients with localised RPS who underwent surgery in Bergen between 1988 and 2009 and in Lund from 1998 to 2009 were included. Medical records were examined for clinical data, tumour characteristics, treatment factors and follow-up status. Archived tumour sections and tumour tissue were reviewed, and when necessary, restained and reclassified. Cox regression was used to analyse the association of potential prognostic factors with local recurrence-free survival (LRFS), metastasis-free survival (MFS) and OS.

RESULTS

The study included 97 patients: 52 from Norway and 45 from Sweden. The proportion of high-grade tumours was 73%. The five-year LRFS, MFS and OS were 55%, 59% and 60%, respectively. RT was significantly associated with improved local control resulting in a five-year LRFS of 77% compared with 39% without (p < 0.001). Furthermore, five-year OS was 71% in the RT group in contrast to 52% with surgery alone (p = 0.019). In the adjusted analysis RT proved to be a significant factor also for MFS (HR = 0.42, 95% CI 0.20-0.88, p = 0.021). In addition, high-grade malignancy, large tumour and positive surgical margin were risk factors for local recurrence. High malignancy grade was the only significant adverse prognostic factor for metastasis. High age and high-grade malignancy were negative prognostic factors for OS.

CONCLUSION

Adjuvant RT was significantly associated with an improved five-year LRFS and OS.

Outcomes in the management of adult soft tissue sarcomas

Adult soft tissue sarcomas (STSs) are heterogeneous neoplasms that account for 11,410 new diagnoses and 4,390 deaths per year. This article summarizes recent NCCN guidelines for diagnosis and management of STSs of the extremities and retroperitoneum, as well as gastrointestinal stromal tumors (GIST). AJCC staging and recently reported NCDB data regarding outcomes are reviewed. Currently accepted STS prognostic variables are presented, as are future directions regarding the utility of molecular prognosticators and nomograms.

Primary leiomyosarcoma of the adrenal gland: a case report with immunohistochemical study and literature review

Primary adrenal leiomyosarcoma is extremely rare tumor. We report a case with adrenal leiomyosarcoma. Our case was a 48-year-old man who presented with lower urinary tract symptoms. Ultrasonography and magnetic resonance imaging revealed approximately 9 cm solid mass originating from right adrenal gland. He underwent right adrenalectomy. Pathology of the specimen showed histologic and immunohistochemical features of adrenal leiomyosarcoma.

Retroperitoneal liposarcoma with colonic involvement: a case report

A 72-year-old male visited a local hospital on presentation of melena. Colonoscopy revealed a protruded lesion in the ascending colon, and computed tomography revealed a 20 cm retroperitoneal tumor. Biopsy failed to provide a definitive diagnosis of the colonic lesion. He was diagnosed as having a retroperitoneal liposarcoma and an ascending colon tumor using computed tomography, and referred to our hospital. Biopsy of the ascending colon lesion showed spindle cells with fibrosis. On immunohistochemical staining, tumor cells were positive for cyclin-dependent kinase 4 and murine double minute 2, and the lesion was diagnosed as a well-differentiated or dedifferentiated liposarcoma. The retroperitoneal liposarcoma, which had infiltrated the ascending colon, was resected along with the right colon and the right kidney. Macroscopically, the tumor had infiltrated the ascending colon, forming a multinodular solid mass in the lumen and the right kidney. Microscopic finding of the main tumor revealed a well-differentiated liposarcoma, and that of the colonic lesion revealed a dedifferentiated liposarcoma with nuclei of different sizes and shapes and increased spindle cell morphology. The right kidney and ureter were surrounded by tumor cells but were not infiltrated, and there was no lymph node involvement. The diagnosis of retroperitoneal liposarcoma is often difficult because symptoms appear only after the tumor becomes very large. Some retroperitoneal liposarcomas are found on computed tomography by chance. The clinical course of this case was very rare because of the presentation of melena as the first symptom and the detection of an invasive mass in the ascending colon using colonoscopy.

A retrospective study comparing contrast-enhanced computed tomography with 18F-FDG-PET/CT in the early follow-up of patients with retroperitoneal sarcomas

OBJECTIVE

To compare 18-fluorine-labeled 2-deoxy-2-fluoro-D-glucose PET/computed tomography ((18)F-FDG-PET/CT) with contrast enhancement computed tomography (CECT) in the early follow-up of patients who had undergone treatment for primitive retroperitoneal sarcomas (RS).

METHODS

This is a retrospective study on 24 patients who underwent (18)F-FDG-PET/CT and CECT within 2 years after therapy for RS. (18)F-FDG-PET/CT and CECT results were compared with results of histological examination and clinical-instrumental follow-up. We calculated the sensitivity and specificity of CECT and (18)F-FDG-PET/CT for retroperitoneal recurrences and compared them with results of the McNemar test. Negative predictive values (NPVs) and positive predictive values (PPVs) were calculated and the positive percentage agreement and negative percentage agreement were evaluated.

RESULTS

The sensitivity and specificity of (18)F-FDG-PET/CT were 66.7 and 100% and those for CECT were 58.3 and 50%, respectively. For (18)F-FDG-PET/CT, PPV was 100% [95% confidence interval (CI): 67-100%] and NPV was 75% (95% CI: 58-75%); for CECT, PPV was 54% (95% CI: 33-73%) and NPV was 55% (95% CI: 30-78%). Positive percentage agreement and negative percentage agreement were, respectively, 38 and 72% for retroperitoneal lesions, 42.8 and 100% for liposarcomas, 40 and 50% for leiomyosarcomas, 14.2 and 94% for abdominal lymph nodes, and 16.6 and 100% for lung metastasis. Neither technique gave reliable results for liver metastasis.

CONCLUSION

Our data show that (18)F-FDG-PET/CT has a higher overall specificity compared with CECT in identifying areas of recurrence, demonstrating its validity for early whole-body detection of lesions. In our hands (18)F-FDG-PET/CT seems to be a good tool in the early follow-up of patients experiencing recurrence of RS.

Multifocal retroperitoneal sarcoma

Introduction. Retroperitoneal sarcomas comprise a small proportion of all soft tissue sarcomas, and multiple factors influence their clinical behavior. Histopathological type and grade as well as complete surgical resection especially on the first operative attempt are well recognized as the main prognostic factors. Multifocality is another prognostic factor, which compromises therapy and finally makes prognosis worse due to multiple adverse implications. Case Presentation. A rare case of a 65-year-old male patient suffering from a multifocal retroperitoneal liposarcoma successfully treated in our hospital is presented herein. Discussion. Also, general considerations for these tumors are discussed, and especially multifocality is underlined as an ominous sign of retroperitoneal sarcomas behavior. Despite multifocality, once again complete surgical excision remains the mainstay of treatment of these patients, as long as further systemic and local therapies do not provide durable results.

Outcome prediction in primary resected retroperitoneal soft tissue sarcoma: histology-specific overall survival and disease-free survival nomograms built on major sarcoma center data sets

PURPOSE

Integration of numerous prognostic variables not included in the conventional staging of retroperitoneal soft tissue sarcomas (RPS) is essential in providing effective treatment. The purpose of this study was to build a specific nomogram for predicting postoperative overall survival (OS) and disease-free survival (DFS) in patients with primary RPS.

PATIENTS AND METHODS

Data registered in three institutional prospective sarcoma databases were used. We included patients with primary localized RPS resected between 1999 and 2009. Univariate (Kaplan and Meier plots) and multivariate (Cox model) analyses were carried out. The a priori chosen prognostic covariates were age, tumor size, grade, histologic subtype, multifocality, quality of surgery, and radiation therapy. External validation was performed by applying the nomograms to the patients of an external cohort. The model's discriminative ability was estimated by means of the bootstrap-corrected Harrell C statistic.

RESULTS

In all, 523 patients were identified at the three institutions (developing set). At a median follow-up of 45 months (interquartile range, 22 to 72 months), 171 deaths were recorded. Five- and 7-year OS rates were 56.8% (95% CI, 51.4% to 62.6%) and 46.7% (95% CI, 39.9% to 54.6%. Two hundred twenty-one patients had disease recurrence. Five- and 7-year DFS rates were 39.4% (95% CI, 34.5% to 45.0%) and 35.7% (95% CI, 30.3% to 42.1%). The validation set consisted of 135 patients who were identified at the fourth institution for external validation. The bootstrap-corrected Harrell C statistics for OS and DFS were 0.74 and 0.71 in the developing set and 0.68 and 0.69 in the validating set.

CONCLUSION

These nomograms accurately predict OS and DFS. They should be used for patient counseling in clinical practice and stratification in clinical trials.

Retroperitoneal sarcomas- a challenging problem

Retroperitoneal sarcomas are relatively rare tumours and usually present in a locally advanced stage. Liposarcoma is the most common histopathology. If operable, surgery is the treatment of choice. The role of adjuvant chemotherapy or radiotherapy is not yet defined. Advanced cases are treated by chemotherapy. The prognosis is poor in patients with positive resection margins, high-grade tumours and recurrent tumours.

Luteinizing hormone, sex steroids and extracorporeal circulation - a promising link to treat retroperitoneal sarcomas. A reconsideration of cancer treatment

Retroperitoneal sarcomas are rare and aggressive tumors with a negative prognosis as there is currently no satisfactory treatment for them. The only proven factor that can significantly increase the otherwise poor survival of sarcoma patients is the radically of resection. However, the completeness of resection is hindered by the hypervascularized nature of sarcomas and the frequent involvement of major blood vessels. In this context, we propose to operate on retroperitoneal sarcomas only with the use of extracorporeal circulation, applying vascular clamps above and below the tumor, even with short periods of hypothermic circulatory arrest in complex cases. This technique would allow the surgeon to achieve complete tumor resections, approach large blood vessels easier and perform sofisticated vascular reconstructions with no fear of hemorrhage which is fundamental to achieve a bloodless surgical field. Also, we speculate on the etiology of retroperitoneal sarcomas that appear mostly during the period of menopause/andropause. Although both estrogens and androgens have been incriminated in inducing various cancer types, including sarcomas, an endogenous estradiol cathabolyte has been shown to have anti-tumor effects. Considering that during menopause/andropause sex steroid levels actually decrease, our second working hypothesis is that the increasing follicle-stimulating hormone (FSH) and especially luteinizing hormone (LH) levels, together with the relative estrogen/androgen imbalance, may be the triggering cause. Also, a certain level of estrogens (Methoxyestradiol) may be essential in limiting tumor development and dedifferentiation. Given that extragonadal sarcomas appear to behave as endocrine tumors, a targeted hormonal therapy, together with controlled radical resections in complex cases of tumor vascular involvement, would certainly provide a strong link to both prevention and treatment of retroperitoneal sarcomas and even of cancer in general.