Current patterns of care and outcomes for dermatofibrosarcoma protuberans: An international multi-institutional collaborative.

BACKGROUND: Dermatofibrosarcoma protuberans (DFSP) is a cutaneous sarcoma with an infiltrative growth pattern that makes it challenging to clear margins. High quality data regarding DFSP natural history, management, and outcomes are limited. METHODS: Data were retrospectively collected for adult DFSP patients who underwent resection at 10 institutions in eight countries. Demographics, tumor characteristics, treatment strategies, and outcomes were analyzed. RESULTS: Analysis included 347 patients consisting of young (median, 42 years), White (76.2%), males (54.2%) with truncal lesions (57.3%). The majority (76.8%) were symptomatic at presentation. Preoperative imaging was used in 55.9% of cases. Diagnosis was established with excisional biopsy in 50.9% versus incisional biopsy in 25.0% of cases. Despite planned margins of >1.0 cm in 67.4% of cases, only 69.0% of patients achieved R0 resection. Twenty-two percent of patients underwent at least one re-excision. R0 resection was achieved at a second procedure in 80.2% and a third procedure in 86.2%. Ultimately, R0 resection was feasible in 89.5% of all patients. Fibrosarcomatous transformation (FST) was observed in 12.6%. In total, 6.6% (N = 23) recurred (17 local, six distant). Of the six distant recurrences, 50.0% had FST. With a median follow-up of 47.0 months, disease-specific survival rate was 98.8%. In multivariable analysis, R0 margins at index resection were associated with wider circumferential margins and non-FST histology. CONCLUSIONS: In this international, multicenter collaborative, DFSP practice patterns were heterogeneous but achieved favorable recurrence rates and survival. Multiple excisions to clear margins remain commonplace and can inform future efforts to optimize margin selection.

Retrospective Analysis of Retroperitoneal-Abdominal-Pelvic Ganglioneuromas: An International Study by the Transatlantic Australasian Retroperitoneal Sarcoma Working Group (TARPSWG).

OBJECTIVE: The Transatlantic Australasian Retroperitoneal Sarcoma Working Group conducted a retrospective study on the disease course and clinical management of ganglioneuromas. BACKGROUND: Ganglioneuromas are rare tumors derived from neural crest cells. Data on these tumors remain limited to case reports and single-institution case series. METHODS: Patients of all ages with pathologically confirmed primary retroperitoneal, intra-abdominal, and pelvic ganglioneuromas between January 1, 2000, and January 1, 2020, were included. We examined demographic, clinicopathologic, and radiologic characteristics, as well as clinical management. RESULTS: Overall, 328 patients from 29 institutions were included. The median age at diagnosis was 37 years with 59.1% of patients being female. Symptomatic presentation comprised 40.9% of cases, and tumors were often located in the extra-adrenal retroperitoneum (67.1%). At baseline, the median maximum tumor diameter was 7.2 cm. One hundred sixteen (35.4%) patients underwent active surveillance, whereas 212 (64.6%) patients underwent resection with 74.5% of operative cases achieving an R0/R1 resection. Serial tumor evaluations showed that malignant transformation to neuroblastoma was rare (0.9%, N=3). Tumors undergoing surveillance had a median follow-up of 1.9 years, with 92.2% of ganglioneuromas stable in size. With a median follow-up of 3.0 years for resected tumors, 84.4% of patients were disease free after resections, whereas recurrences were observed in 4 (1.9%) patients. CONCLUSIONS: Most ganglioneuromas have indolent disease courses and rarely transform to neuroblastoma. Thus, active surveillance may be appropriate for benign and asymptomatic tumors particularly when the risks of surgery outweigh the benefits. For symptomatic or growing tumors, resection may be curative.

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

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

Where Are We Now with Liver Transplantation in Neuroendocrine Neoplasms? The Place of Liver Transplantation for Grades 1 and 2 Well-Differentiated Unresectable Liver Metastatic Neuroendocrine Tumours.

PURPOSE OF REVIEW: This review outlines the role of liver transplantation in selected patients with unresectable neuroendocrine tumour liver metastases. It discusses the international consensus on eligibility criteria and outlines the efforts taking place in the UK and Ireland to develop effective national liver transplant programmes for neuroendocrine tumour patients. RECENT FINDINGS: In the early history of liver transplantation, indications included cancer metastases to the liver as well as primaries of liver origin. Often, liver transplantation was a salvage procedure. The early results were disappointing, including in patients with neuroendocrine tumours. These data discouraged the widespread adoption of liver transplantation for neuroendocrine tumour liver metastases (NET LM). A few centres persisted in performing liver transplantation for patients with NET LM and in determining parameters predictive of good outcomes. Their work has provided evidence for benefit of liver transplantation in a selected group of patients with NET LM. Liver transplantation for NET LM is now accepted as a valid indication by many professional bodies, including the European Neuroendocrine Tumour Society (ENETS) and the United Network for Organ Sharing (UNOS). It is nevertheless rarely utilised. The UK and the Republic of Ireland are commencing a pilot programme of liver transplantation in selected patients. This programme will help develop the expertise and infrastructure to make liver transplantation for NET LM a routine procedure.

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

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

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

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

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

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

Defining the role of neoadjuvant systemic therapy in high-risk retroperitoneal sarcoma: A multi-institutional study from the Transatlantic Australasian Retroperitoneal Sarcoma Working Group.

BACKGROUND: In patients with retroperitoneal sarcoma (RPS), the incidence of recurrence after surgery remains high. Novel treatment approaches are needed. This retrospective study evaluated patients with primary, high-risk RPS who received neoadjuvant systemic therapy followed by surgery to 1) determine the frequency and potential predictors of radiologic tumor responses and 2) assess clinical outcomes. METHODS: Clinicopathologic data were collected for eligible patients treated at 13 sarcoma referral centers from 2008 to 2018. Univariable and multivariable logistic models were performed to assess the association between clinical predictors and response. Overall survival (OS) and crude cumulative incidences of local recurrence and distant metastasis were compared. RESULTS: Data on 158 patients were analyzed. A median of 3 cycles of neoadjuvant systemic therapy (interquartile range, 2-4 cycles) were given. The regimens were mostly anthracycline based; however, there was significant heterogeneity. No patients demonstrated a complete response, 37 (23%) demonstrated a partial response (PR), 88 (56%) demonstrated stable disease, and 33 (21%) demonstrated progressive disease (PD) according to the Response Evaluation Criteria in Solid Tumors, version 1.1. Only a higher number of cycles given was positively associated with PR (P = .005). All patients underwent complete resection, regardless of the tumor response. Overall, patients whose tumors demonstrated PD before surgery showed markedly worse OS (P = .005). An indication of a better clinical outcome was seen in specific regimens given for grade 3 dedifferentiated liposarcoma and leiomyosarcoma. CONCLUSIONS: In patients with high-risk RPS, the response to neoadjuvant systemic therapy is fair overall. Disease progression on therapy may be used to predict survival after surgery. Subtype-specific regimens should be further validated.

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

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

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

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

Morbidity and Outcomes After Distal Pancreatectomy for Primary Retroperitoneal Sarcoma: An Analysis by the Trans-Atlantic Australasian Retroperitoneal Sarcoma Working Group.

BACKGROUND: Multi-visceral resection often is used in the treatment of retroperitoneal sarcoma (RPS). The morbidity after distal pancreatectomy for primary pancreatic cancer is well-documented, but the outcomes after distal pancreatectomy for primary RPS are not. This study aimed to evaluate morbidity and oncologic outcomes after distal pancreatectomy for primary RPS. METHODS: In this study, 26 sarcoma centers that are members of the Trans-Atlantic Australasian Retroperitoneal Sarcoma Working Group (TARPSWG) retrospectively identified consecutive patients who underwent distal pancreatectomy for primary RPS from 2008 to 2017. The outcomes measured were 90-day severe complications (Clavien-Dindo ≥ 3), postoperative pancreatic fistula (POPF) rate, and oncologic outcomes. RESULTS: Between 2008 and 2017, 280 patients underwent distal pancreatectomy for primary RPS. The median tumor size was 25 cm, and the median number of organs resected, including the pancreas, was three. In 96% of the operations, R0/R1 resection was achieved. The 90-day severe complication rate was 40 %. The grades B and C POPF complication rates were respectively 19% and 5% and not associated with worse overall survival. Administration of preoperative radiation and factors to mitigate POPF did not have an impact on the risk for the development of a POPF. The RPS invaded the pancreas in 38% of the patients, and local recurrence was doubled for the patients who had a microscopic, positive pancreas margin (hazard ratio, 2.0; p = 0.042). CONCLUSION: Distal pancreatectomy for primary RPS has acceptable morbidity and oncologic outcomes and is a reasonable approach to facilitate complete tumor resection.

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

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

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

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

Improved Biopsy Accuracy in Retroperitoneal Dedifferentiated Liposarcoma.

BACKGROUND: Biopsy sensitivity in retroperitoneal dedifferentiated liposarcoma (DDLPS) is variable. Patients with grade 3 DDLPS face a significant risk of metastatic disease and may potentially benefit from neoadjuvant therapy, making highly accurate pretherapy diagnosis essential. Our study aimed to establish whether diagnostic sensitivity could be improved by targeting solid areas of tumor on percutaneous biopsy. METHODS: Between 2016 and 2019, data on patients with suspected primary retroperitoneal sarcoma who underwent a biopsy were collected, and diagnostic accuracy was calculated. These data were compared with our previously reported series from 2005 to 2016. For DDLPS tumors, comparisons were then made between biopsies that targeted the solid component and those that did not. RESULTS: Data were available for 121 patients in the current series and 238 from the previous study. The proportion of biopsies returning a histological subtype concordant with postoperative pathology was 83% in the current series, marking a significant improvement over our previous study (67%, p = 0.001). For diagnosis of DDLPS, biopsy sensitivity improved from 40 to 74% (p < 0.001), with an increase from 13 to 50% (p = 0.006) where grade 3 DDLPS was treated as a separate disease. Within the current series, targeted biopsy yielded a sensitivity of 100% for identifying DDLPS, compared with 10% in nontargeted biopsy (p < 0.001). CONCLUSION: Systematic targeting of solid areas of tumor within suspected retroperitoneal liposarcoma has improved sensitivity for detection of both DDLPS and grade 3 DDLPS on biopsy. This approach minimizes the risk of underdiagnosis of patients with DDLPS who could benefit from neoadjuvant chemotherapy.

Biphasic malignant tumours of the abdominal cavity.

Carcinosarcomas (CS) are uncommon, highly aggressive, biphasic tumours consisting of both sarcomatous and carcinomatous elements. They appear to originate from a common cell of origin, either via transformation from a single premature precursor or conversion of a mature epithelial cell through an epithelial-mesenchymal transition. CS should be considered a unique cancer subtype with cells typically displaying diffuse mitotic activity and widespread atypical mitoses predisposing to early metastasis and a tendency to local recurrence following resection. This review addresses the pathophysiology of CS and discusses its presentation, natural history and management at a variety of sites within the abdominal cavity and retroperitoneum.