Clinical features and outcome of initially unresected nonmetastatic pediatric nonrhabdomyosarcoma soft tissue sarcoma

Clinical features and outcomes of young patients with low-grade non-rhabdomyosarcoma soft tissue sarcomas treated with a risk-based strategy: A report from Children's Oncology Group study ARST0332

BACKGROUND

In retrospective analyses, the Pediatric Oncology Group [POG) and the Federation National des Centres de Lutte Contre le Cancer (FNCLCC) histologic grade predict outcome in pediatric non-rhabdomyosarcoma soft tissue sarcoma (NRSTS), but prospective data on grading, clinical features, and outcomes of low-grade NRSTS are limited.

METHODS

We analyzed patients less than 30 years of age enrolled on Children's Oncology Group (COG) study ARST0332 (NCT00346164) with POG grade 1 or 2 NRSTS. Low-risk patients were treated with surgery alone. Intermediate-/high-risk patients received ifosfamide/doxorubicin and radiotherapy, with definitive resection either before or after 12 weeks of chemoradiotherapy.

RESULTS

Estimated 5-year event-free and overall survival were 90% and 100% low risk (n = 80), 55% and 78% intermediate risk (n = 15), and 25% and 25% high risk (n = 4). In low-risk patients, only local recurrence was seen in 10%; none with margins greater than 1 mm recurred locally. Sixteen of 17 intermediate-/high-risk patients who completed neoadjuvant chemoradiotherapy underwent gross total tumor resection, 80% with negative margins. Intermediate-/high-risk group events included one local and seven metastatic recurrences. Had the FNCLCC grading system been used to direct treatment, 29% of low-risk (surgery alone) patients would have received radiotherapy ± chemotherapy.

CONCLUSIONS

Most low-risk patients with completely resected POG low-grade NRSTS are successfully treated with surgery alone, and surgical margins greater than 1 mm may be sufficient to prevent local recurrence. Patients with intermediate- and high-risk low-grade NRSTS have outcomes similar to patients with high-grade histology, and require more effective therapies. Use of the current FNCLCC grading system may result in overtreatment of low-risk NRSTS curable with surgery alone.

Proton Therapy in Non-Rhabdomyosarcoma Soft Tissue Sarcomas of Children and Adolescents

This paper provides insights into the use of Proton Beam Therapy (PBT) in pediatric patients with non-rhabdomyosarcoma soft tissue sarcomas (NRSTS). NRSTS are a heterogeneous group of rare and aggressive mesenchymal extraskeletal tumors, presenting complex and challenging clinical management scenarios. The overall survival rate for patients with NRSTS is around 70%, but the outcome is strictly related to the presence of various variables, such as the histological subtype, grade of malignancy and tumor stage at diagnosis. Multimodal therapy is typically considered the preferred treatment for high-grade NRSTS. Radiotherapy plays a key role in the treatment of children and adolescents with NRSTS. However, the potential for radiation-induced side effects partially limits its use. Therefore, PBT represents a very suitable therapeutic option for these patients. The unique depth-dose characteristics of protons can be leveraged to minimize doses to healthy tissue significantly, potentially allowing for increased tumor doses and enhanced preservation of surrounding tissues. These benefits suggest that PBT may improve local control while reducing toxicity and improving quality of life. While clear evidence of therapeutic superiority of PBT over other modern photon techniques in NRSTS is still lacking-partly due to the limited data available-PBT can be an excellent treatment option for young patients with these tumors. A dedicated international comprehensive collaborative approach is essential to better define its role within the multidisciplinary management of NRSTS. Shared guidelines for PBT indications-based on the patient's age, estimated outcome, and tumor location-and centralization in high-level referral centers are needed to optimize the use of resources, since access to PBT remains a challenge due to the limited number of available proton therapy facilities.

Local treatment in initially unresected non-rhabdomyosarcoma soft-tissue sarcomas of children and adolescents: A retrospective single-center experience

BACKGROUND

Pediatric non-rhabdomyosarcoma soft-tissue sarcomas (NRSTS) are a heterogeneous group of aggressive tumors. Patients with locally advanced/initially unresected disease represent a subset of patients with unsatisfactory outcome: limited data are available on the best treatment approach, in particular regarding local therapy.

METHODS

This retrospective analysis concerned 71 patients < 21 years old with nonmetastatic, initially unresected adult-type NRSTS, treated at a referral center for pediatric sarcomas from 1990 to 2021. Patients were treated using a multimodal approach, based on the protocols adopted at the time of their diagnosis.

RESULTS

The series included a selected group of patients with unfavorable clinical characteristics, i.e., most cases had high-grade and large tumors, arising from axial sites in 61% of cases. All patients received neoadjuvant chemotherapy, 58 (82%) had delayed surgery (R0 in 45 cases), and 50 (70%) had radiotherapy. Partial response to chemotherapy was observed in 46% of cases. With a median follow-up of 152 months (range, 18-233), 5-year event-free survival (EFS) and overall survival (OS) were 39.9% and 56.5%, respectively. Survival was significantly better for patients who responded to chemotherapy, and those who had a delayed R0 resection. Local relapse at 5 years was 7.7% for patients who did not undergo delayed surgery.

CONCLUSIONS

Our series underscores the unsatisfactory outcome of initially unresected NRSTS patients. Improving the outcome of this patient category requires therapeutic strategies able to combine novel effective systemic therapies with a better-defined local treatment approach to offer patients the best chances to have R0 surgery.

PAX3-FOXO1 dictates myogenic reprogramming and rhabdomyosarcoma identity in endothelial progenitors

Fusion-positive rhabdomyosarcoma (FP-RMS) driven by the expression of the PAX3-FOXO1 (P3F) fusion oncoprotein is an aggressive subtype of pediatric rhabdomyosarcoma. FP-RMS histologically resembles developing muscle yet occurs throughout the body in areas devoid of skeletal muscle highlighting that FP-RMS is not derived from an exclusively myogenic cell of origin. Here we demonstrate that P3F reprograms mouse and human endothelial progenitors to FP-RMS. We show that P3F expression in aP2-Cre expressing cells reprograms endothelial progenitors to functional myogenic stem cells capable of regenerating injured muscle fibers. Further, we describe a FP-RMS mouse model driven by P3F expression and Cdkn2a loss in endothelial cells. Additionally, we show that P3F expression in TP53-null human iPSCs blocks endothelial-directed differentiation and guides cells to become myogenic cells that form FP-RMS tumors in immunocompromised mice. Together these findings demonstrate that FP-RMS can originate from aberrant development of non-myogenic cells driven by P3F.

Metastatic adult-type non-rhabdomyosarcoma soft tissue sarcomas in children and adolescents: A cohort study from the European paediatric Soft tissue sarcoma Study Group

BACKGROUND

Limited data exist on the clinical behavior of pediatric non-rhabdomyosarcoma soft tissue sarcomas (NRSTS) with distant metastases at onset, and a clear standard of care has not yet been defined.

METHODS

This cohort study reports on pediatric adult-type metastatic NRSTS enrolled in two concurrent prospective European studies, i.e., the randomized BERNIE study and the single-arm MTS 2008 study developed by the European paediatric Soft tissue sarcoma Study Group. Treatment programs were originally designed for patients with metastatic rhabdomyosarcoma, i.e., nine courses of multidrug chemotherapy (with or without bevacizumab in the BERNIE study), followed by 12 cycles of maintenance therapy, whereas radiotherapy and/or surgery (on primary tumor and/or metastases) were delayed until after seven courses of chemotherapy had been administered.

RESULTS

The study included 61 patients <21 years old treated from July 2008 to December 2016. The lung was the site of metastases in 75% of the cases. All patients received multi-agent chemotherapy, 44% had local therapy to primary tumor, and 18% had treatment of metastases. Median time to progression/relapse was 6 months. A high rate of tumor progression was observed during the initial part of the chemotherapy program. With a median follow-up of 41.5 months (range, 2-111 months), 3-year event-free survival and overall survival were 15.4% (95% confidence interval [CI], 7.6-25.7) and 34.9% (95% CI, 22.7-47.5), respectively. There were no statistically significant differences in outcome depending on the type of treatment administered.

CONCLUSIONS

The study confirmed the overall poor outcome for patients with metastatic NRSTS, whose treatment remains a challenge.

PLAIN LANGUAGE SUMMARY

Pediatric non-rhabdomyosarcoma soft tissue sarcomas form a heterogeneous group of rare tumors. Although recent international studies have defined the standard of care for patients with localized disease, limited data are available on the clinical behavior of patients with distant metastases. This study on 61 metastatic cases treated on two prospective European protocols confirms that the chances of survival of such patients are often dismal and a standard treatment is still lacking.

The significance of margins in pediatric Non-Rhabdomyosarcoma soft tissue sarcomas: Consensus on surgical margin definition harmonization from the INternational Soft Tissue SaRcoma ConsorTium (INSTRuCT)

BACKGROUND

Margin status following surgery in children, adolescents, and young adults with soft tissue sarcomas is controversial and has been defined differently by various specialties, with definitions changing over time and by cooperative group. The International Soft Tissue Sarcoma Consortium (INSTRuCT) is a collaboration of the Children's Oncology Group (COG) Soft Tissue Sarcoma Committee, European pediatric Soft Tissue sarcoma Study Group (EpSSG), and the European Cooperative Weichteilsarkom Studiengruppe (CWS) devoted to improving patient outcomes by pooling and mining cooperative group clinical trial data.

METHODS

The INSTRuCT non-rhabdomyosarcoma soft tissue sarcoma (NRSTS) working group aimed to develop international harmonized recommendations regarding surgical margin assessment and definitions in children and adolescents with soft tissue tumors.

RESULTS AND CONCLUSION

This review addresses accepted principles and areas of controversy, including the perspectives of surgeons, pathologists, radiation oncologists, and pediatric oncologists, to develop a framework for building common guidelines for future research.

Lymph node metastases in paediatric and young adult patients with non-rhabdomyosarcoma soft tissue sarcoma (NRSTS): Findings from Children's Oncology Group (COG) study ARST0332

PURPOSE

The aim of this paper is to better define the clinical features and outcomes of young patients with non-rhabdomyosarcoma soft tissue sarcoma (NRSTS) with regional and distant lymph node (LN) metastases treated in a standardised fashion, we analysed LN involvement in COG study ARST0332, which evaluated a risk-based treatment strategy for young patients with all stages of NRSTS.

PATIENTS AND METHODS

Patients <30 years old with newly diagnosed NRSTS and LN metastases enrolled on ARST0332 were studied. Regional LN sampling was required for those with epithelioid sarcoma, clear cell sarcoma or clinically/radiographically enlarged LNs. Tumour features and extent of pre-enrolment resection determined treatment, including chemotherapy, radiotherapy, and delayed surgery. Recommendations for LN metastases included LN dissection at the time of primary tumour resection and dose-adapted radiotherapy based on extent of LN resection.

RESULTS

Twenty of 529 eligible and evaluable ARST0332 patients with NRSTS had LN metastases; epithelioid sarcoma had the highest incidence (18%, 5 of 28). Pre-treatment imaging identified LN enlargement in 19 of 20 patients; 1 had no pre-treatment LN imaging. At 6.9 years median follow-up for surviving patients, 5-year overall survival was 85.7% (95% CI: 33.4%, 97.9%) for seven patients with isolated LN metastases and 15.4% (95% CI: 2.5%, 38.8%) for 13 patients with additional extranodal metastases. LN recurrence occurred in only one patient without LNs sampled at initial diagnosis.

CONCLUSION

LN metastases occur in about 4% of paediatric/young adult NRSTS, are limited to a few histologic subtypes, and are rare in patients who did not have clinical or imaging evidence of lymphadenopathy, suggesting that biopsies of non-enlarged LNs are not necessary to identify occult involvement. Patients with isolated LN metastases have high 5-year overall survival (∼85%) and should be treated with curative intent.

CLINICALTRIALS

GOV REGISTRY NO

NCT00346164.

Relapsing pediatric non-rhabdomyosarcoma soft tissue sarcomas: The impact of routine imaging surveillance on early detection and post-relapse survival

PURPOSE

The chances of patients with relapsing pediatric non-rhabdomyosarcoma soft tissue sarcomas (NRSTS) being cured are limited. This retrospective single-institutional study examines the potential role of routine surveillance imaging for detecting recurrent tumor, and its impact on post-relapse survival.

METHODS

The analysis concerned 86 patients < 21 years old with relapsing NRSTS treated from 1985 to 2020. Clinical findings, treatment modalities and survival were analyzed, comparing patients whose relapse was first suspected from symptoms (symptomatic group) with those whose relapse was detected by radiological surveillance (imaging group).

RESULTS

Tumor relapses were identified from clinical symptoms in 49 cases and on routine imaging in 37. Time to relapse was similar in the two groups. Routine imaging detected 6/32 local relapses and 31/48 distant relapses (and 79% of the cases of lung metastases). Overall survival (OS) at 5 years was 34.3% for the symptomatic group, and 24.0% for the imaging group (p-value 0.270). In patients with lung metastases at relapse, the 5-year OS was statistically better for the imaging group, that is, 25.8% versus 0% for the symptomatic group (p-value 0.044).

CONCLUSION

This is the first study to explore the role of surveillance imaging in pediatric NRSTS. Judging from our findings, the value of routine scanning of primary sites seems limited, while radiological surveillance may help to detect lung metastases, improving survival for this patient category. The potentially negative effects of periodic radiological exams should be considered in deciding the optimal follow-up for patients off therapy.

Pediatric Non-Rhabdomyosarcoma Soft Tissue Sarcomas: Standard of Care and Treatment Recommendations from the European Paediatric Soft Tissue Sarcoma Study Group (EpSSG)

This paper describes the standard of care for patients with non-rhabdomyosarcoma soft tissue sarcomas (NRSTS) and the therapeutic recommendations developed by the European paediatric Soft tissue sarcoma Study Group (EpSSG). NRSTS form a very mixed group of mesenchymal extraskeletal malignancies. Their rarity, heterogeneity, and aggressiveness make the management of children and adolescents with these tumors complex and challenging. The overall cure rate for patients with NRSTS is around 70%, but survival depends on several prognostic variables, such as histotype and tumor grade, extent of disease and stage, tumor size, and tumor site. While surgery remains the mainstay of treatment for most of these tumors, a multimodal therapeutic approach including radiotherapy and chemotherapy is required in many cases. The EpSSG NRSTS 2005 study was the first prospective protocol tailored specifically to NRSTS. Together with the ARST0332 study developed by the North-American Soft Tissue Sarcoma Committee of the Children's Oncology Group (COG), the EpSSG NRSTS 2005 study currently represents the benchmark for these tumors, establishing risk-adapted standards of care. The EpSSG has developed common treatment recommendations for the large group of adult-type NRSTS (including synovial sarcoma), and specific treatment recommendations for other particular adult-type histologies (ie, alveolar soft-part sarcoma, clear cell sarcoma and dermatofibrosarcoma protuberans); other highly malignant tumors with a biology and clinical behavior differing from those of adult-type NRSTS (ie, rhabdoid tumors and desmoplastic small round cell tumor); and soft tissue tumors of intermediate malignancy (ie desmoid-type fibromatosis, inflammatory myofibroblastic tumors, and infantile fibrosarcoma). New effective drugs are needed for patients whose NRSTS carries the worst prognosis, ie, those with unresectable tumors, metastases at diagnosis, or relapsing disease. Progress in this area relies on our ability to develop international integrated prospective collaborations, both within existing pediatric oncology networks and, importantly, between the communities of specialists treating pediatric and adult sarcoma.

Radical Resection of Pediatric Fibrosarcoma Is Not Associated With Survival Benefit: A Nationwide Database Analysis

INTRODUCTION

Fibrosarcoma is one of the most common nonrhabdomyosarcoma soft tissue sarcomas in the pediatric population. Surgical resection is the cornerstone of treatment; however, optimal factors regarding the extent of fibrosarcoma resection in localized versus regional disease is poorly understood.

METHODS

The Surveillance, Epidemiology, and End Results database was queried for patients who are 19 y old or younger with a diagnosis of fibrosarcoma from 1975 to 2016. Kaplan-Meier analyses were performed for disease-specific survival on clinical and pathologic variables. Multivariate analysis was performed based on significant predictors of disease-specific survival.

RESULTS

There were 1290 patients (median age 13 [7-17] y) identified with fibrosarcoma. The overall survival rate at 20 y was 93%. Radical resection was performed on 22%, 40%, and 52% of patients with localized, regional, and distant Surveillance, Epidemiology, and End Results disease stage, respectively. Chemotherapy (P < 0.001), radiation (P < 0.001), histology (P < 0.001), and stage (P = 0.004) were significant predictors of increased mortality using univariate Kaplan-Meier analysis. Most patients (86%) with localized or regional stage who underwent radiation had fibrosarcomas of nondermatofibrosarcoma histology (P < 0.001). Dermatofibrosarcoma subtype comprised most radical resections (41%). Excluding distant stage, nondermatofibroma histology (hazard ratio 16.94, 95% confidence interval 3.77-76.01) and regional stage (hazard ratio 8.15, 95% confidence interval 2.93-22.69) were independent prognostic factors of mortality (both P < 0.001). Radical resection was not a significant independent prognostic indicator of survival.

CONCLUSIONS

Nondermatofibrosarcoma subtype is independently associated with increased mortality. Although surgery remains the mainstay of treatment, the extent of resection is not a predictor of survival for patients with the localized and regional stage of disease.

Trends of lymph node sampling and metastasis in pediatric and young adult patients with clear cell, epithelioid, and synovial sarcomas

BACKGROUND

Clear cell sarcoma of soft tissue (CCS), epithelioid sarcoma, and synovial sarcoma are rare tumors historically identified as high risk for lymph node metastasis. This study investigates incident nodal metastasis and associated survival in children and young adults with these subtypes.

PROCEDURE

Using the National Cancer Database (2004-2015), we created a retrospective cohort of 1303 patients (aged ≤25 years) who underwent local control therapy for CCS, epithelioid sarcoma, and synovial sarcoma. Kaplan-Meier curves estimated overall survival (OS) by subtype. Stratifying on subtype, Cox regressions assessed OS by lymph node sampling status and nodal metastasis.

RESULTS

There were 103 (7.9%) patients with CCS, 221 (17.0%) with epithelioid sarcoma, and 979 (75.1%) with synovial sarcoma. Lymph node sampling was more frequent in patients with CCS (56.3%) and epithelioid sarcoma (52.5%) versus synovial sarcoma (20.5%, p < .001). Synovial sarcoma metastasized to lymph nodes less frequently than CCS or epithelioid sarcoma (2.1% vs. 14.6% and 14.9%, p < .001). Across all subtypes, lymph node metastasis was associated with inferior OS (HR 2.02, CI 1.38-2.95, p < .001). Lymph node sampling was associated with improved OS in CCS (HR 0.35, CI: 0.15-0.78, p = .010), inferior OS in synovial sarcoma (HR 1.60, CI: 1.13-2.25, p = .007), and no statistical association with OS in epithelioid sarcoma.

CONCLUSIONS

Lymph node metastasis is rare in children and young adults with synovial sarcoma. Lymph node sampling procedures were not consistently performed for patients with CCS or epithelioid sarcoma, but improved OS supports routine lymph node sampling in children and young adults with CCS.

Treatment at Specialized Cancer Centers Is Associated with Improved Survival in Adolescent and Young Adults with Soft Tissue Sarcoma

Background: Soft tissue sarcomas (STS) are a heterogeneous group of tumors whose management benefits from a multidisciplinary therapeutic approach. Published data suggest that cancer treatment at a specialized cancer center (SCC) can improve survival in other cancers. Therefore, we examined the impact of the location of treatment on survival in children and adolescents and young adults (AYAs) with STS. Methods: We performed a population-based analysis of children and AYAs hospitalized within 1 year of diagnosis with first primary STS (2000-2014) using the California Cancer Registry linked with hospitalization data. Patients were categorized based on receiving all inpatient treatments at a SCC versus part/none. Multivariable Cox proportional hazards regression identified factors associated with overall and STS-specific survival by age group. Results are presented as adjusted hazard ratios (HRs) and 95% confidence intervals (CIs). Results: Of the 1,674 patients with STS, 142 were children (0-14) and 1,532 were AYAs (15-39) and 89.4% and 40.4% received all inpatient treatments at a SCC, respectively. Overall, the 5-year survival was improved for patients who received all inpatient care at a SCC (59.8% vs. those who received part/none, 50.7%). Multivariable regression analysis found that having all treatments at a SCC was associated with better overall survival (HR, 0.79, CI: 0.65-0.95) in AYAs, but not in children. Conclusions: Our findings demonstrate that treatment for STS at a SCC is associated with better survival in AYAs. Eliminating barriers to treatment of AYAs with STS at SCCs could improve survival in this population.

Local Control For High-Grade Nonrhabdomyosarcoma Soft Tissue Sarcoma Assigned to Radiation Therapy on ARST0332: A Report From the Childrens Oncology Group

PURPOSE

The ARST0332 trial for pediatric and young adults with nonrhabdomyosarcoma soft tissue sarcoma (NRSTS) used risk-based treatment including primary resection with lower-than-standard radiation doses to optimize local control (LC) while minimizing long-term toxicity in those requiring radiation therapy (RT). RT for high-grade NRSTS was based on extent of resection (R0: negative margins, R1: microscopic margins, R2/U: gross disease/unresectable); those with >5 cm tumors received chemotherapy (CT; ifosfamide/doxorubicin). This analysis evaluates LC for patients assigned to RT and prognostic factors associated with local recurrence (LR).

METHODS AND MATERIALS

Patients aged <30 years with high-grade NRSTS received RT (55.8 Gy) for R1 ≤5 cm tumor (arm B); RT (55.8 Gy)/CT for R0/R1 >5 cm tumor (arm C); or neoadjuvant RT (45 Gy)/CT plus delayed surgery, CT, and postoperative boost to 10.8 Gy R0 <5 mm margins/R1 or 19.8 Gy for R2/unresected tumors (arm D).

RESULTS

One hundred ninety-three eligible patients had 24 LRs (arm B 1/15 [6.7%], arm C 7/65 [10.8%], arm D 16/113 [14.2%]) at median time to LR of 1.1 years (range, 0.11-5.27). Of 95 eligible for delayed surgery after neoadjuvant therapy, 89 (93.7%) achieved R0/R1 margins. Overall LC after RT were as follows: R0, 106 of 109 (97%); R1, 51 of 60 (85%); and R2/unresectable, 2 of 6 (33%). LR predictors include extent of delayed resection (P <.001), imaging response before delayed surgery (P < .001), histologic subtype (P <.001), and no RT (P = .046). The 5-year event-free survival was significantly lower (P = .0003) for patients unable to undergo R0/R1 resection.

CONCLUSIONS

Risk-based treatment for young patients with high-grade NRSTS treated on ARST0332 produced very high LC, particularly after R0 resection (97%), despite lower-than-standard RT doses. Neoadjuvant CT/RT enabled delayed R0/R1 resection in most patients and is preferred over adjuvant therapy due to the lower RT dose delivered.

Paediatric non-rhabdomyosarcoma soft tissue sarcomas: the prospective NRSTS 2005 study by the European Pediatric Soft Tissue Sarcoma Study Group (EpSSG)

BACKGROUND

A standardised approach to treatment of paediatric non-rhabdomyosarcoma soft tissue sarcomas (NRSTS), which account for about 4% of childhood cancers, is still lacking. We report the results of the NRSTS 2005 protocol developed specifically by the European Pediatric Soft Tissue Sarcoma Study Group (EpSSG) to determine a risk-adapted multimodal standard of care for this group of tumours.

METHODS

The EpSSG NRSTS 2005 study included two prospective, non-randomised, historically controlled trials (one on localised adult-type NRSTS and the other on localised synovial sarcoma) done at 100 academic centres and hospitals in 14 countries. Patients younger than 21 years with a pathologically proven diagnosis of synovial sarcoma or an adult-type NRSTS, no evidence of metastatic disease, no previous treatment other than primary surgery, and diagnostic specimens available for pathological review were included. Patients were stratified by surgical stage, tumour size, nodal involvement, tumour grade (for adult-type NRSTS), and tumour site (for synovial sarcoma). Patients were then divided into four treatment groups: surgery alone, adjuvant radiotherapy, adjuvant chemotherapy (with or without radiotherapy), or neoadjuvant chemotherapy (with or without radiotherapy). The main chemotherapy regimen was ifosfamide (3·0 g/m² intravenously per day for 3 days) plus doxorubicin (37·5 mg/m² intravenously per day for 2 days); only ifosfamide (3·0 g/m² intravenously per day for 2 days) was given concomitantly with radiotherapy (delivered with three-dimensional conformal external beam technique, using conventional fractionation [1·8 daily fractions, 5 days per week] at a dose of 50·4 Gy or 54·0 Gy, to a maximum of 59·4 Gy). The number of chemotherapy cycles ranged from three to seven depending on the stage of the disease. The primary outcomes were event-free survival and overall survival. This study has been completed, and is registered under EudraCT, 2005-001139-31.

FINDINGS

Between May 31, 2005, and Dec 31, 2016, 1321 patients were enrolled, of whom 569 (206 with synovial sarcoma and 363 with adult-type NRSTS), with a median age of 12·6 years (IQR 8·2-14·9), were included in this analysis. With a median follow-up of 80·0 months (IQR 54·3-111·3) for the 467 patients alive, 5-year event-free survival was 73·7% (95% CI 69·7-77·2) and 5-year overall survival was 83·8% (95% CI 80·3-86·7). 5-year event-free survival was 91·4% (95% CI 87·0-94·4) and 5-year overall survival was 98·1% (95% CI 95·0-99·3) in the surgery alone group (n=250); 75·5% (46·9-90·1) and 88·2% (60·6-96·9) in the adjuvant radiotherapy group (n=17); 65·6% (54·8-74·5) and 75·8% (65·3-83·5) in the adjuvant chemotherapy group (n=93); and 56·4% (49·3-63·0) and 70·4% (63·3-76·4) in the neoadjuvant chemotherapy group (n=209). Reported severe adverse events included one case of generalised seizures (probably related to ifosfamide) and six cases of secondary tumours.

INTERPRETATION

Findings from the EpSSG NRSTS 2005 study help to define the risk-adapted standard of care for this patient population. Adjuvant treatment can be safely omitted in the low-risk population (classified here as the surgery alone group). Improving the outcome for patients with high-risk, initially resected adult-type NRSTS and those with initially unresectable disease remains a major clinical challenge.

FUNDING

Fondazione Città della Speranza.

Non-rhabdomyosarcoma soft-tissue sarcoma

Non-rhabdomyosarcoma soft-tissue sarcomas (NRSTS) comprise 4% of childhood cancers and consist of numerous histologic subtypes. Prognostic factors associated with poor outcome include high histologic grade, large tumor size, presence of metastases, and unresectability. Complete surgical resection is critical for the best oncologic outcomes and is prioritized in treatment algorithms. The use of radiation therapy (RT) and chemotherapy is based upon factors such as resectability, histologic grade, tumor size, and stage. North American and European trials are defining a risk-based approach to NRSTS to limit treatment-related toxicity and to maximize therapeutic efficacy. In this paper, we summarize the current roles of surgery, RT, and chemotherapy in NRSTS and describe ongoing research that is advancing the care of NRSTS patients.

Malignant peripheral nerve sheath tumors in children, adolescents, and young adults: Treatment results of five Cooperative Weichteilsarkom Studiengruppe (CWS) trials and one registry

BACKGROUND AND OBJECTIVES

Malignant peripheral nerve sheath tumors (MPNST) are aggressive soft tissue sarcomas that present as large, invasive tumors. Our aim was to assess outcomes, identify prognostic factors, and analyze treatment strategies in a prospectively collected pediatric cohort.

METHODS

Patients less than 21 years with MPNST treated in the consecutive prospective European Cooperative Weichteilsarkom Studiengruppe (CWS)-trials (1981-2009) and the CWS-SoTiSaR registry (2009-2015) were analyzed.

RESULTS

A total of 159 patients were analyzed. Neurofibromatosis type I (NF1) was reported in thirty-eight patients (24%). Most were adolescents (67%) with large (>10 cm, 65%) tumors located at extremities (42%). Nodal involvement was documented in 15 (9%) and distant metastases in 15 (9%) upon diagnosis. Overall, event-free survival (EFS) was 40.5% at 5 and 36.3% at 10 years, and overall survival (OS) was 54.6% at 5 and 47.1% at 10 years. Age, NF1 status, tumor site, tumor size, Intergroup Rhabdomyosarcoma Study (IRS) group, metastatic disease, and achieving first complete remission (CR1) were identified as prognostic factors for EFS and/or OS in the univariate analysis.

CONCLUSIONS

Prognostic factors were identified and research questions for future clinical trials were addressed.

Neurofibromatosis-associated malignant peripheral nerve sheath tumors in children have a worse prognosis: A nationwide cohort study

BACKGROUND

Malignant peripheral nerve sheath tumors (MPNST) are rare and aggressive non-rhabdomyoblastic soft-tissue sarcomas (NRSTS) in children. This study set out to investigate clinical presentation, treatment modalities, and factors associated with survival in pediatric MPNST using Dutch nationwide databases.

METHODS

Data were obtained from the Netherlands Cancer Registry (NCR) and the Dutch Pathology Database (PALGA) from 1989 to 2017. All primary MPNSTs were collected. Demographic differences were analyzed between adult and pediatric (age ≤18 years) MPNST. In children, demographic and treatment differences between neurofibromatosis type 1 (NF1) and non-NF1 were analyzed. A Cox proportional hazard model was constructed for localized pediatric MPNSTs.

RESULTS

A total of 70/784 MPNST patients were children (37.1% NF1). Children did not present differently from adults. In NF1 children, tumor size was more commonly large (> 5 cm, 92.3% vs 59.1%). Localized disease was primarily resected in 90.6%, and radiotherapy was administered in 37.5%. Non-NF1 children tended to receive chemotherapy more commonly (39.5% vs 26.9%). Overall, estimated five-year survival rates of localized NF1-MPNST was 52.4% (SE: 10.1%) compared with 75.8% (SE: 7.1%) in non-NF1 patients. The multivariate model showed worse survival in NF1 patients (HR: 2.98; 95% CI, 1.17-7.60, P = 0.02) and increased survival in patients diagnosed after 2005 (HR: 0.20; 95% CI, 0.06-0.69, P = 0.01). No treatment factors were independently associated with survival.

CONCLUSION

Pediatric MPNSTs have presentations similar to adult MPNSTs. In children, NF1 patients present with larger tumors, but are treated similarly to non-NF1 MPNSTs. In localized pediatric MPNST, NF1 is associated with worse survival. Promisingly, survival has increased for pediatric MPNSTs after 2005.

Treatment of malignant peripheral nerve sheath tumors in pediatric NF1 disease

BACKGROUND

Malignant peripheral nerve sheath tumors (MPNSTs) are rare yet highly aggressive soft tissue sarcomas. Children with neurofibromatosis type 1 (NF1) have a 10% lifetime risk for development of MPNST. Prognosis remains poor and survival seems worse for NF1 patients.

METHODS

This narrative review highlights current practices and pitfalls in the management of MPNST in pediatric NF1 patients.

RESULTS

Preoperative diagnostics can be challenging, but PET scans have shown to be useful tools. More recently, functional MRI holds promise as well. Surgery remains the mainstay treatment for these patients, but careful planning is needed to minimize postoperative morbidity. Functional reconstructions can play a role in improving functional status. Radiotherapy can be administered to enhance local control in selected cases, but care should be taken to minimize radiation effects as well as reduce the risk of secondary malignancies. The exact role of chemotherapy has yet to be determined. Reports on the efficacy of chemotherapy vary as some report lower effects in NF1 populations. Promisingly, survival seems to ameliorate in the last few decades and response rates of chemotherapy may increase in NF1 populations when administering it as part of standard of care. However, in metastasized disease, response rates remain poor. New systemic therapies are therefore desperately warranted and multiple trials are currently investigating the role of drugs. Targeted drugs are nevertheless not yet included in first line treatment.

CONCLUSION

Both research and clinical efforts benefit from multidisciplinary approaches with international collaborations in this rare malignancy.

A risk-based treatment strategy for non-rhabdomyosarcoma soft-tissue sarcomas in patients younger than 30 years (ARST0332): a Children's Oncology Group prospective study

BACKGROUND

Tumour grade, tumour size, resection potential, and extent of disease affect outcome in paediatric non-rhabdomyosarcoma soft-tissue sarcoma (NRSTS), but no risk stratification systems exist and the standard of care is poorly defined. We developed a risk stratification system from known prognostic factors and assessed it in the context of risk-adapted therapy for young patients with NRSTS.

METHODS

In this prospective study, eligible patients enrolled in 159 hospitals in three countries were younger than 30 years, had a Lansky (patients ≤16 years) or Karnofsky (patients >16 years) performance status score of at least 50, and a new diagnosis of a WHO (2002 criteria) intermediate (rarely metastasising) or malignant soft-tissue tumour (apart from tumour types eligible for other Children's Oncology Group studies and tumours for which the therapy in this trial was deemed inappropriate), malignant peripheral nerve sheath tumour, non-metastatic and grossly resected dermatofibrosarcoma protuberans, undifferentiated embryonal sarcoma of the liver, or unclassified malignant soft-tissue sarcoma. Each patient was assigned to one of three risk groups and one of four treatment groups. Risk groups were: low (non-metastatic R0 or R1 low-grade, or ≤5 cm R1 high-grade tumour); intermediate (non-metastatic R0 or R1 >5 cm high-grade, or unresected tumour of any size or grade); or high (metastatic tumour). The treatment groups were surgery alone, radiotherapy (55·8 Gy), chemoradiotherapy (chemotherapy and 55·8 Gy radiotherapy), and neoadjuvant chemoradiotherapy (chemotherapy and 45 Gy radiotherapy, then surgery and radiotherapy boost based on margins with continued chemotherapy). Chemotherapy included six cycles of ifosfamide 3 g/m² per dose intravenously on days 1-3 and five cycles of doxorubicin 37·5 mg/m² per dose intravenously on days 1-2 every 3 weeks with sequence adjusted on the basis of timing of surgery or radiotherapy. The primary outcomes were event-free survival, overall survival, and the pattern of treatment failure. Analysis was done per protocol. This study has been completed and is registered with ClinicalTrials.gov, NCT00346164.

FINDINGS

Between Feb 5, 2007, and Feb 10, 2012, 550 eligible patients were enrolled, of whom 21 were treated in the incorrect group and excluded from this analysis. 529 evaluable patients were included in the analysis: low-risk (n=222), intermediate-risk (n=227), high-risk (n=80); surgery alone (n=205), radiotherapy (n=17), chemoradiotherapy (n=111), and neoadjuvant chemoradiotherapy (n=196). At a median follow-up of 6·5 years (IQR 4·9-7·9), 5-year event-free survival and overall survival were: 88·9% (95% CI 84·0-93·8) and 96·2% (93·2-99·2) in the low-risk group; 65·0% (58·2-71·8) and 79·2% (73·4-85·0) in the intermediate-risk group; and 21·2% (11·4-31·1) and 35·5% (23·6-47·4) in the high-risk group, respectively. Risk group predicted event-free survival and overall survival (p<0·0001). No deaths from toxic events during treatment were reported. Nine patients had unexpected grade 4 adverse events (chemoradiotherapy group, n=2; neoadjuvant chemoradiotherapy group, n=7), including three wound complications that required surgery (all in the neoadjuvant chemoradiotherapy group).

INTERPRETATION

Pre-treatment clinical features can be used to effectively define treatment failure risk and to stratify young patients with NRSTS for risk-adapted therapy. Most low-risk patients can be cured without adjuvant therapy, thereby avoiding known long-term treatment complications. Survival remains suboptimal for intermediate-risk and high-risk patients and novel therapies are needed.

FUNDING

National Institutes of Health, St Baldrick's Foundation, Seattle Children's Foundation, American Lebanese Syrian Associated Charities.

Outcome and prognostic factors in pediatric malignant peripheral nerve sheath tumors: An analysis of the European Pediatric Soft Tissue Sarcoma Group (EpSSG) NRSTS-2005 prospective study

BACKGROUND

Malignant peripheral nerve sheath tumors (MPNST) are rare tumors of childhood. The role of standard chemotherapy in unresectable MPNST is still unclear. We report the outcome and prognostic factors in the EpSSG risk-adapted prospective study for localized pediatric MPNST.

METHODS

Patients were stratified into four treatment groups defined by surgical resection, tumor size, and tumor grade (G): (a) surgery-only group-resected tumors G1; (b) adjuvant radiotherapy group-R0/R1, G2 tumors; (c) adjuvant chemotherapy group-R0/R1, G3 tumors; and (d) neoadjuvant chemotherapy group-R2 resected tumors and/or nodal involvement. Chemotherapy consisted of four courses of ifosfamide-doxorubicin and two courses of ifosfamide concomitant with radiotherapy (50.4-54 Gy).

RESULTS

Overall, the study included 51 patients. The 5-year event-free survival (EFS) and overall survival (OS) were 52.9% (95% confidence interval, 38.1-65.8) and 62.1% (46.7-74.3), respectively. The 5-year EFS was 92% (56.6-98.9) for treatment group 1 (N = 13), 33% (0.9-77.4) for treatment group 2 (N = 4), 29% (4.1-61.2) for treatment group 3 (N = 7), and 42% (23.1-60.1) for treatment group 4 (N = 27). Response rate to chemotherapy (partial response + complete response) in patients with measurable disease was 46%. The presence of neurofibromatosis type 1 (NF1; 51% of patients) was an independent poor prognostic factor for OS and EFS.

CONCLUSION

The outcome for patients with resectable MPNST was excellent. Standard ifosfamide-doxorubicin for unresectable MPNST rendered the best reported outcome. Children with NF1 disease seem to have worse prognosis.

An update in the management of pediatric sarcoma

PURPOSE OF REVIEW

Nonrhabdomyosarcoma soft tissue sarcoma (NRSTS) is a rare subgroup of malignancy in childhood that is composed of a variety of soft tissue and bony tumors. Prognosis for resectable localized disease is usually good and improved with systemic treatment. However, survival from locally advanced and metastatic disease remains poor. There have been numerous preclinical and clinical studies to define histopathology, biology, and genetic alteration of sarcomas. The purpose of this review is to clarify the progress in the management of NRSTS.

RECENT FINDINGS

Genomic analysis, including the use of next-generation sequencing, has revealed fusion transcripts or specific genetic alterations which provide diagnostic biomarkers and potential targets for novel therapies.

SUMMARY

Most cases are sporadic, but some are associated with genetic predispositions. Most present as a painless mass and diagnosis is frequently delayed because of a low index of suspicion. There is a wide array of histopathological subtypes. Investigations usually involve core, incisional or excisional biopsy for tissue diagnosis, and cross-sectional and nuclear imaging for staging. Management of pediatric sarcoma is largely dependent on the patient's histopathological diagnosis, age, disease stage, and co-morbidities but usually involves a combination of systemic and local therapies. Preclinical studies and phase I/II trials of newer targeted therapies are ongoing.

Clinical features and outcomes of young patients with epithelioid sarcoma: an analysis from the Children's Oncology Group and the European paediatric soft tissue Sarcoma Study Group prospective clinical trials

BACKGROUND

Data on the clinical features, optimal treatment and outcomes of paediatric patients with epithelioid sarcoma (ES) are limited and mostly retrospective.

METHODS

A subset analysis of ES patients < 30 years of age enrolled on two international prospective clinical trials conducted between 7/2005 and 11/2015 was performed. Risk-adapted therapy was based on tumour diameter, histologic grade, extent of surgery and presence/absence of metastases and included surgery ± radiotherapy for all patients with the addition of ifosfamide/doxorubicin chemotherapy for intermediate-/high-risk patients. Response to therapy, event-free and overall survival and pattern and predictors of treatment failure were evaluated.

RESULTS

Sixty-three ES patients (median age 13.1 years, 52% male) were eligible. Clinical features included the following: 68% extremity, median tumour diameter 3.5 cm, 56% high histologic grade, 14% nodal metastases, 14% distant metastases. Thirty-four low-risk patients underwent surgery (n = 30) or surgery/radiotherapy (n = 4); 16 intermediate-risk and 13 high-risk patients received chemotherapy ± surgery ± radiotherapy. Partial response was observed in 11/22 (50%) patients receiving neoadjuvant therapy. Events were local recurrence (n = 10) and distant recurrence (n = 15); estimated 5-year survival was 86.4%, 63.5% and 0%, respectively, for low-, intermediate- and high-risk patients. Locoregional nodal involvement, invasive tumour, high grade and lesser extent of resection predicted event-free survival in patients without metastases.

CONCLUSIONS

Most low-risk ES patients who have undergone an adequate resection fare well without adjuvant therapy. Large tumour size, high histologic grade, tumour invasiveness, inadequate tumour resection and metastatic disease predict poorer outcomes in higher risk ES patients, for whom more effective therapies are needed.

CLINICAL TRIAL REGISTRATION

COG ARST0332: ClinicalTrials.gov Identifier NCT00346164, EpSSG NRSTS 2005: European Union Drug Regulating Authorities Clinical Trials No. 2005-001139-31.

Pediatric nonrhabdomyosarcoma soft tissue sarcomas arising at visceral sites

BACKGROUND

Pediatric nonrhabdomyosarcoma soft tissue sarcomas (NRSTS) may rarely occur in visceral tissues, and little is known about their clinical history. The present study retrospectively analyzed a group of patients prospectively registered in Italian pediatric protocols conducted between 1979 and 2004.

METHODS

Inclusion criteria for the study were as follows: a pathological diagnosis of "adult-type NRSTS," arising at visceral sites (lung-pleurae, liver, kidney, and mesentery-bowel); age under 18 years; no previous treatment except for primary surgery; available clinical data; and written consent.

RESULTS

Thirty cases with visceral NRSTS were collected and analyzed. Sites of origin were as follows: mesentery-bowel in 12 cases, lung-pleurae in 11, liver in 5, and kidney in 2. According to the Intergroup Rhabdomyosarcoma Study (IRS) surgical grouping system, patients were classified as follows: nine IRS group I, three group II, 12 group III, and six group IV. Patients were treated with a multimodal approach including surgery, radiotherapy, and/or chemotherapy, according to their characteristics. For the series as a whole, the 5-year event-free and overall survival rates were 33.3% and 40.0%, respectively. The IRS group (reflecting the feasibility of initial complete resection) emerged as the main prognostic factor. Survival rates also correlated with tumor size and local invasiveness, histological subtype, and tumor sites (the worst outcome was seen for tumors arising in the lung and pleurae).

CONCLUSIONS

This study confirmed that visceral NRSTS are aggressive tumors carrying a worse prognosis than pediatric NRSTS arising in soft tissues of the extremities. Local treatment remains the main challenge for these tumors.

Nonrhabdomyosarcoma soft tissue sarcoma (NRSTS) in pediatric and young adult patients: Results from a prospective study using limited-margin radiotherapy

BACKGROUND

Indications for and delivery of adjuvant therapies for pediatric nonrhabdomyosarcoma soft tissue sarcoma (NRSTS) have been derived largely from adult studies; therefore, significant concern remains regarding radiation exposure to normal tissue. The authors report long-term treatment outcomes and toxicities for pediatric and young adult patients with high-grade NRSTS who were treated on a prospective trial using limited-margin radiotherapy.

METHODS

Sixty-two patients (ages 3-22 years) with predominantly high-grade NRSTS requiring radiation were treated on a phase 2 institutional study of conformal external-beam radiotherapy and/or brachytherapy using a 1.5-cm to 2-cm anatomically constrained margin. The estimated cumulative incidence of local failure, Gray's method estimated cumulative incidence of local failure, Kaplan-Meier method estimated survival, competing-risk regression model determined predictors of disease outcome, and toxicity was reported according to CTCAE v2.0.

RESULTS

At a median follow-up of 5.1 years (range, 0.2-10.9 years), 9 patients had experienced local failure. The 5-year overall cumulative incidence of local failure was 14.8% (95% confidence interval [CI], 7.2%-25%), and all but 1 local failure occurred outside the highest-dose irradiation volume. The 5-year Kaplan-Meier estimates for event-free and overall survival were 49.3% (95% CI, 36.3%-61.1%) and 67.9% (95% CI, 54.2%-78.3%), respectively. Multivariable analysis indicated that younger age was the only independent predictor of local recurrence (P = .004). The 5-year cumulative incidence of grade 3 or 4 late toxicity was 15% (95% CI, 7.2%-25.3%).

CONCLUSIONS

The delivery of limited-margin radiotherapy using conformal external-beam radiotherapy or brachytherapy provides a high rate of local tumor control without an increase in marginal failures and with acceptable treatment-related morbidity. Cancer 2017;123:4419-29. © 2017 American Cancer Society.

Surgery alone is sufficient therapy for children and adolescents with low-risk synovial sarcoma: A joint analysis from the European paediatric soft tissue sarcoma Study Group and the Children's Oncology Group

BACKGROUND

Multimodal risk-adapted treatment is used in paediatric protocols for synovial sarcoma (SS). Retrospective analyses suggest that low-risk SS patients can be safely treated with surgery alone, but no prospective studies have confirmed the safety of this approach. This analysis pooled data from the two prospective clinical trials to assess outcomes in SS patients treated with a surgery-only approach and to identify predictors of treatment failure.

METHODS

Patients with localised SS enrolled on the European paediatric Soft tissue sarcoma Study Group (EpSSG) NRSTS2005 and on the Children Oncology Group (COG) ARST0332 trials, treated with surgery alone were eligible for this analysis. Patients must have undergone initial complete resection with histologically free margins, with a grade 2 tumour of any size or a grade 3 tumour ≤5 cm.

RESULTS

Sixty patients under 21 years of age were eligible for the analysis; 36 enrolled in the COG (from 2007 to 2012) and 24 in the EpSSG study (from 2005 to 2012). The 3-year event-free survival was 90% (median follow-up 5.2 years, range 1.9-9.1). All eight events were local tumour recurrence, whereas no metastatic recurrences were seen. All patients with recurrence were effectively salvaged, resulting in 100% overall survival.

CONCLUSION

This joint prospective analysis showed that patients with adequately resected ≤5 cm SS, regardless of grade, can be safely treated with a surgery-only approach. Avoiding the use of adjuvant chemotherapy and radiotherapy in this low-risk patient population may decrease both short- and long-term morbidity and mortality.

Targeted therapy for soft tissue sarcomas in adolescents and young adults

Soft tissue sarcomas (STSs) are a heterogeneous group of tumors originating from the mesenchyme. Even though they affect individuals in all age groups, the prevalence of subtypes of STSs changes significantly from childhood through adolescence into adulthood. The mainstay of therapy is surgery, with or without the addition of chemotherapy and/or radiation therapy. These treatment modalities are associated, in many cases, with significant morbidity and, given the heterogeneity of tumor histologies encompassed by the term "STS", have not uniformly improved outcomes. Moreover, some subgroups of STSs appear to be more, and others less, responsive to conventional chemotherapy agents. Over the last two decades, our understanding of the biology of STSs is slowly increasing, allowing for the development of more targeted therapies. We review the new treatment modalities that have been tested on patients with STSs, with a special focus on adolescents and young adults, a group of patients that is often underrepresented in clinical trials and has not received the dedicated attention it deserves, given the significant differences in biology and treatment response in comparison to children and adults.

Pediatric Sarcomas

Pediatric sarcomas are a heterogeneous group of tumors accounting for approximately 10% of childhood solid tumors. Treatment is focused on multimodality therapy, which has improved the prognosis over the past two decades. Current regimens focus on decreasing treatment for low-risk patients to decrease the long-term side effects while maximizing therapy for patients with metastatic disease to improve survival. Pediatric sarcomas can be divided into soft tissue sarcomas and osseous tumors. Soft tissue sarcomas are further delineated into rhabdomyosarcomas, which affect young children and nonrhabdomyosarcomas, which are most common in adolescents. The most common bone sarcomas are osteosarcomas and Ewing's sarcoma.

Low-grade Nonrhabdomyosarcoma Soft Tissue Sarcoma: What is Peculiar for Childhood

BACKGROUND

Nearly half of soft tissue sarcomas are nonrhabdomyosarcomas (NRSTSs). The low-grade (LG) form comprises a heterogenous group of diseases that rarely metastasize but are known for local recurrence.

AIM OF THE STUDY

The aim of the study was to retrospectively evaluate pediatric LG-NRSTS with regard to demography, survival, and factors affecting outcome in Egyptian patients.

PATIENTS AND METHODS

The study reviewed 66 NRSTS patients who presented to the Pediatric Oncology Department, National Cancer Institute, Cairo University, between January 2008 and December 2013.

RESULTS

Out of the reviewed cases 32 patients had LG tumors and were eligible for analysis. The male to female ratio was 1:1 and the median age was 7.5 years (range, 1 mo to 18 y). Desmoid fibromatosis (N=18) showed frequent local recurrence and nearly half of this group was alive without disease. No recurrence of the disease occurred in the nonfibromatosis group (n=14) and all patients were alive and free of disease. The 5-year overall survival was 88% for the entire group of study patients versus 45% for event-free survival. Tumors >5 cm in diameter and fibromatosis histology subtype were associated with lower EFS.

CONCLUSIONS

LG-NRSTS generally has good prognosis, with overall survival reaching 90%. However, aggressive fibromatosis usually runs a poorer course in the form of high incidence of local recurrence and lower survival rates. This needs to be further assessed in larger prospective studies including novel therapies in addition to the current conventional modalities.

Non-rhabdomyosarcoma

Pediatric non-rhabdomyosarcoma soft tissue sarcomas (NRSTS) are a heterogeneous group encompassing more than 50 different histological diagnoses arising from primitive mesenchymal tissue. Together, they comprise about half the soft tissue sarcomas diagnosed in children and young adults. Despite each histologies relative rarity, their management schema is similar among the different NRSTS histologies. Surgical management is an important component of the multimodal treatment strategy of all these tumors. Resection with negative margins, while maintaining function, plays an important role as a primary treatment of these patients as well as diminishing the risks of local and distant recurrence.

Role, timing and technique of radiotherapy in pediatric pleuropulmonary synovial sarcoma

The management of pediatric thoracic synovial sarcoma remains a matter of debate in clinical oncology, especially as regard to the local control of the disease. Surgery remains the gold standard, while the role and timing of radiotherapy is still controversial. We report a 14-year-old male, who has not received proper treatment at the time of diagnosis and initial management. Intensity-modulated irradiation was performed only at relapse, as a salvage treatment and, at 10-month follow-up, the young patient was free from relapse, without significant acute and subacute toxicity. We discuss the role and timing of radiotherapy in thoracic synovial sarcoma, a disease in which the need to increase local control should be placed in the foreground.

Opportunities for Improvement in Pathology Reporting of Childhood Nonrhabdomyosarcoma Soft Tissue Sarcomas: A Report From Children's Oncology Group (COG) Study ARST0332

OBJECTIVES

Treatment of soft tissue tumors in young patients relies on the diagnostic information conveyed in the pathology report. We examined pathology reports from Children's Oncology Group ARST0332 for inclusion of data elements required in published guidelines.

METHODS

Pathology reports for 551 eligible patients were examined for required data elements defined by the College of American Pathologists, including tissue type, procedure, tumor site, tumor maximum diameter, macroscopic extent of tumor, histologic type, mitotic rate, extent of necrosis, tumor grade, margin status, use of ancillary studies, and pathologic stage.

RESULTS

Only 65 (12%) of 551 reports included all required data elements. Of reports containing synoptic templates, 57% were complete.

CONCLUSIONS

This study reveals significant opportunity to improve the quality of pathology reports in young patients with soft tissue tumors. Use of templates or checklists improves completeness of reports.

[Synovial sarcoma in children and adolescents]

Synovial sarcoma (SS) is a rare high-grade malignant mesenchymal tumor affecting children, adolescents, and young adults. Cytogenetically, more than 90% of SS is characterized by the t(X;18)(p11.2;q11.2), translocation resulting in two chimeric fusion genes SYT-SSX1 and SYT-SSX2, confirming histological diagnosis. Pediatric SS arises most often in soft tissues of the extremities (66% of cases), and is a localized tumor without spreading to regional lymph nodes (96% of cases) nor to metastatic sites (94% of cases). Although clinical and radiologic presentation, histologic analysis and tumor biology appear similar in pediatric and adolescent SS, outcome seems better in children than in adolescents, respectively 84% vs 60% of 5years overall survival (OS). If complete resection is the gold standard in SS, other therapeutic modalities differ between pediatric and adult populations, considering SS as an intermediate chemosensitive tumor more frequently by pediatric oncologists. Prognostic factors evaluation (tumor size, site of primary and IRS group) is necessary to establish optimal treatment strategies, with multimodal therapeutic approach in children and adolescents. Thus, recent results about the European prospective EpSSG NRSTS 05 study for children and adolescent patients with localized SS showed a 5years OS >90%. Moreover, recent somatic genetic data about SS open the debate on an appropriate strategy based and stratified on tumor genomic. Multinational prospective pediatric, adolescent and young adult study is necessary to improve optimal and appropriate approach in this rare tumor.

Non-rhabdomyosarcoma soft-tissue sarcomas in children: Contemporary appraisal and experience from a single centre

Nonrhabdmyosarcoma soft tissue sarcomas (NRSTS) include a cluster of different types of soft tissue sarcomas clubbed together due to the rarity of individual subtypes. The diagnostic accuracy is lately reinforced due to the availability of immunohistochemical and molecular markers. Surgery is the central modality of treatment since many of them are insensitive to chemotherapy. With the availability of rational risk stratification system, efforts are in progress to evaluate the role of neoadjuvant chemotherapy and radiotherapy to improve outcomes especially for the locally advanced disease. The survival remains dismal for metastatic disease. This review highlights the current status of NRSTS and also describes the experience from a single centre in treatment of NRSTS.

Non-Rhabdomyosarcoma Soft Tissue Sarcomas in Children: A Surveillance, Epidemiology, and End Results Analysis Validating COG Risk Stratifications

PURPOSE

Non-rhabdomyosarcoma soft tissue sarcomas (NRSTS) are a heterogeneous group of sarcomas that encompass over 35 histologies. With an incidence of ∼500 cases per year in the United States in those <20 years of age, NRSTS are rare and therefore difficult to study in pediatric populations. We used the large Surveillance, Epidemiology, and End Results (SEER) database to validate the prognostic ability of the Children's Oncology Group (COG) risk classification system and to define patient, tumor, and treatment characteristics.

METHODS AND MATERIALS

From SEER data from 1988 to 2007, we identified patients ≤18 years of age with NRSTS. Data for age, sex, year of diagnosis, race, registry, histology, grade, primary size, primary site, stage, radiation therapy, and survival outcomes were analyzed. Patients with nonmetastatic grossly resected low-grade tumors of any size or high-grade tumors ≤5 cm were considered low risk. Cases of nonmetastatic tumors that were high grade, >5 cm, or unresectable were considered intermediate risk. Patients with nodal or distant metastases were considered high risk.

RESULTS

A total of 941 patients met the review criteria. On univariate analysis, black race, malignant peripheral nerve sheath (MPNST) histology, tumors >5 cm, nonextremity primary, lymph node involvement, radiation therapy, and higher risk group were associated with significantly worse overall survival (OS) and cancer-specific survival (CSS). On multivariate analysis, MPNST histology, chemotherapy-resistant histology, and higher risk group were significantly poor prognostic factors for OS and CSS. Compared to low-risk patients, intermediate patients showed poorer OS (hazard ratio [HR]: 6.08, 95% confidence interval [CI]: 3.53-10.47, P<.001) and CSS (HR: 6.27; 95% CI: 3.44-11.43, P<.001), and high-risk patients had the worst OS (HR: 13.35, 95% CI: 8.18-21.76, P<.001) and CSS (HR: 14.65, 95% CI: 8.49-25.28, P<.001).

CONCLUSIONS

The current COG risk group stratification for children with NRSTS has been validated with a large number of children in the SEER database.

Mesenchymal Chondrosarcoma in Children and Young Adults: A Single Institution Retrospective Review

Background. Mesenchymal chondrosarcoma is an aggressive, uncommon histologic entity arising in bone and soft tissues. We reviewed our institutional experience with this rare diagnosis. Methods. We conducted a retrospective chart review on patients with mesenchymal chondrosarcoma over a 24-year period. Clinicopathologic and radiographic features were reviewed. Results. Twelve patients were identified. Nine were females; median age was 14.5 years (1.2–19.7 years). The most common site was the head/neck (7/12). Disease was localized in 11/12 patients (one with lung nodules). Six with available tissue demonstrated NCOA2 rearrangement by FISH. Six underwent upfront surgical resection, and six received neoadjuvant therapy (2 chemotherapy alone and 4 chemotherapy and radiation). All patients received adjuvant chemotherapy (most commonly ifosfamide/doxorubicin) and/or radiation (median dose 59.4 Gy). At a median follow-up of 4.8 years, 5-year disease-free survival and overall survival were 68.2% (95% CI 39.8%, 96.6%) and 88.9% (95% CI 66.9%, 100%). Two patients had distant recurrences at 15 and 42 months, respectively. Conclusion. Aggressive surgical resection of mesenchymal chondrosarcoma with chemoradiotherapy yields excellent local control and may reduce likelihood of late recurrence. Characterization of downstream targets of the HEY1-NCOA2 fusion protein, xenograft models, and drug screening are needed to identify novel therapeutic strategies.

Sarcomas

Malignant bone tumors (osteosarcoma, Ewing sarcoma) and soft-tissue sarcomas (rhabdomyosarcoma, nonrhabdomyosarcoma) account for approximately 14% of childhood malignancies. Successful treatment of patients with sarcoma depends on a multidisciplinary approach to therapy, including oncology, surgery, radiation oncology, radiology, pathology, and physiatry. By combining systemic treatment with chemotherapy and primary tumor control using surgery and/or radiation, survival rates for localized disease range from 70% to 75%. However, children with metastatic or recurrent disease continue to have dismal outcomes. A better understanding of the biology underlying both bone and soft-tissue sarcomas is required to further improve outcomes for children with these tumors.

Proton radiotherapy for pediatric sarcoma

Pediatric sarcomas represent a distinct group of pathologies, with approximately 900 new cases per year in the United States alone. Radiotherapy plays an integral role in the local control of these tumors, which often arise adjacent to critical structures and growing organs. The physical properties of proton beam radiotherapy provide a distinct advantage over standard photon radiation by eliminating excess dose deposited beyond the target volume, thereby reducing both the dose of radiation delivered to non-target structures as well as the total radiation dose delivered to a patient. Dosimetric studies comparing proton plans to IMRT and 3D conformal radiation have demonstrated the superiority of protons in numerous pediatric malignancies and data on long-term clinical outcomes and toxicity is emerging. In this article, we review the existing clinical and dosimetric data regarding the use of proton beam radiation in malignant bone and soft tissue sarcomas.

New concepts for the treatment of pediatric nonrhabdomyosarcoma soft tissue sarcomas

Nonrhabdomyosarcoma soft tissue sarcomas form a group of rare tumors with a different biology and clinical behavior. The recently established European Pediatric Soft Tissue Sarcoma Study Group is organizing a new study devoted specifically to these tumors that were formerly treated according to the principles derived from experience with rhabdomyosarcoma, which is a clearly distinct entity. The new study includes two prospective trials, one for synovial sarcoma and the other for adult-type nonrhabdomyosarcoma soft tissue sarcomas. While surgery remains the mainstay of treatment, the role of adjuvant therapy is not yet clear and our understanding of the biology and natural history of nonrhabdomyosarcoma soft tissue sarcomas is still incomplete. This review presents the latest data on nonrhabdomyosarcoma soft tissue sarcoma treatment and outcome, and the rationale behind a risk-adapted treatment program that investigates the role of full-dose ifosfamide-doxorubicin chemotherapy in improving the response rate of patients with unresectable disease, the chances of avoiding adjuvant chemotherapy in low-risk synovial sarcomas, and the possible role of chemotherapy in high-risk adult-type soft tissue sarcomas.

Treatment options for children with nonrhabdomyosarcoma soft tissue sarcoma

Nonrhabdomyosarcoma soft tissue sarcomas account for approximately 40% of all soft tissue sarcomas in children. Although these tumors are typically grouped together, individual tumor types with different biological characteristics have been found that may impact on the optimal therapy for each type of sarcoma in the future. Most of the current information regarding this tumor comes from the adult literature. Wide local excision appears to provide the best chance of cure. Future studies are needed to determine which adjuvant therapies are most useful in improving local control and overall survival in the different subsets of patients.

Children's Oncology Group's 2013 blueprint for research: Soft tissue sarcomas

In the US, approximately 850-900 children are diagnosed each year with soft tissue sarcomas (STS). Key findings from recent Children's Oncology Group (COG) clinical trials include safe reduction in therapy for low risk rhabdomyosarcoma (RMS), validation of FOXO1 fusion as a prognostic factor, a modest improvement in outcome for high-risk RMS, and a biologically designed non-cytotoxic therapy for pediatric desmoid tumor. Planned Phase 2 trials include targeted agents for VEGF/PDGF, mTOR, and IGF-1R for children with RMS and VEGF for children with non-RMS STS (NRSTS). For RMS, COG Phase 3 trials potentially will explore VEGF/mTOR inhibition or chemotherapy interval compression. For NRSTS, a COG Phase 3 trial will explore VEGF inhibition.

Epidemiology and therapies for metastatic sarcoma

Sarcomas are cancers arising from the mesenchymal layer that affect children, adolescents, young adults, and adults. Although most sarcomas are localized, many display a remarkable predilection for metastasis to the lungs, liver, bones, subcutaneous tissue, and lymph nodes. Additionally, many sarcoma patients presenting initially with localized disease may relapse at metastatic sites. While localized sarcomas can often be cured through surgery and often radiation, controversies exist over optimal management of patients with metastatic sarcoma. Combinations of chemotherapy are the most effective in many settings, and many promising new agents are under active investigation or are being explored in preclinical models. Metastatic sarcomas are excellent candidates for novel approaches with additional agents as they have demonstrated chemosensitivity and affect a portion of the population that is motivated toward curative therapy. In this paper, we provide an overview on the common sarcomas of childhood (rhabdomyosarcoma), adolescence, and young adults (osteosarcoma, Ewing sarcoma, synovial sarcoma, and malignant peripheral nerve sheath tumor) and older adults (leiomyosarcoma, liposarcoma, and undifferentiated high grade sarcoma) in terms of the epidemiology, current therapy, promising therapeutic directions and outcome with a focus on metastatic disease. Potential advances in terms of promising therapy and biologic insights may lead to more effective and safer therapies; however, more clinical trials and research are needed for patients with metastatic sarcoma.

Some general considerations about the clinicopathologic aspects of soft tissue tumors in children and adolescents

Soft tissue tumors in children and adolescents are an important group of neoplasms, pseudoneoplasms, and tumefactive malformations with some distinctive clinicopathologic, genetic, syndromic, and therapeutic implications. In addition to the basic pathologic examination, there is the availability of diagnostic adjuncts in various settings based upon the histopathologic features that facilitate and/or corroborate a diagnosis. Immunohistochemistry, cytogenetics, molecular genetics, and an ever-increasing array of new technologies are available to address specific diagnostic questions and even potential therapeutic strategies. This review focuses upon some of the unique aspects of soft tissue tumors in children, including the classification, approach to the diagnosis, grading, clinical and pathologic staging, therapy-related changes, pathogenesis, and risk factors.

Metastatic soft tissue sarcoma chemotherapy: an opportunity for personalized medicine

BACKGROUND

Soft tissue sarcoma (STS) includes biologically and histologically diverse mesenchymal tumors that are relatively chemotherapy-resistant compared with other sarcoma subtypes.

METHODS

The authors discuss the clinical challenges frequently encountered by medical oncologists and review the literature for predictive strategies to systematically approach chemotherapy decision making.

RESULTS

There are no clinically validated predictive tests for chemotherapeutic response or resistance in STS. Clinical features including histology, stage, and patient age are currently used to guide therapy decisions in STS.

CONCLUSIONS

A method to predict response or resistance to chemotherapy, utilizing both targeted and conventional agents, would be beneficial in reducing toxicity and improving response rates for patients with STS and also in designing clinical trials for this disease.

Definitive radiotherapy for unresectable pediatric and young adult nonrhabdomyosarcoma soft tissue sarcoma

BACKGROUND

Few published articles describe outcomes following definitive radiation for unresectable pediatric and young adult nonrhabdomyosarcoma soft tissue sarcoma (NRSTS). The purpose of this study is to evaluate the prognostic factors, outcomes, and complications in patients age 30 years or younger with NRSTS treated at the University of Florida from 1973 to 2002.

PROCEDURE

Nineteen pediatric and young adult patients with NRSTS were treated with radiotherapy after biopsy. Thirteen patients had high-grade tumors. The median age at radiotherapy was 19.6 years; the median dose was 55.2 Gy. Twelve patients received chemotherapy. Prognostic factors for local recurrence, distant metastases, and survival were analyzed.

RESULTS

Median follow-up was 2.6 years. The 5-year local-control rate was 40%. Nine out of 13 local failures occurred in the absence of metastatic disease. All patients with local failures died of their cancer, and 8 patients died without evidence of distant metastases. There was a trend toward improved local control with low/intermediate-grade tumors. Freedom from distant metastases at 5 years was 68%. Fourteen patients died of their disease. The 5-year overall survival was 37%. There was one grade 4 complication based on NCI Common Terminology Criteria for Adverse Events version 3.

CONCLUSION

Young patients with unresectable NRSTS have a poor outcome thereby justifying current study efforts focused on treatment intensification. By demonstrating that all patients with local recurrence died of disease and more than half of these deaths occurred in the absence of distant spread, these results suggests that improved means of local control may translate into improvement in survival.