Therapeutic benefit of larotrectinib over the historical standard of care in patients with locally advanced or metastatic infantile fibrosarcoma (EPI VITRAKVI study)

BACKGROUND

Patients with infantile fibrosarcoma (IFS) have shown strong and long-lasting responses to larotrectinib, a tropomyosin receptor kinase inhibitor (TRKi), in single-arm clinical trials. Conventional chemotherapy has also shown important efficacy. But, until now, no comparative data exist. This study aims to assess the therapeutic benefit of larotrectinib over the current standard of care (SOC) of chemotherapy in paediatric patients with locally advanced or metastatic IFS.

PATIENTS AND METHODS

EPI VITRAKVI is a retrospective, observational, externally controlled study (NCT05236257). Data of patients aged ≤21 years with locally advanced or metastatic IFS treated with larotrectinib in the phase I/II SCOUT trial (NCT02637687) were compared with those of an external historical control group (data of Institut Curie and Cooperative Weichteilsarkom Studiengruppe) treated with a chemotherapy-based regimen. Between-group differences were assessed after balancing groups using inverse probability of treatment weighting (IPTW).

RESULTS

In total, 93 patients were compared, 51 in the larotrectinib arm and 42 in the external control arm. After therapy, 4 patients (7.8%) in the larotrectinib group had a medical treatment failure event [start of new systemic treatment (2 cases), mutilating surgery (2 cases)] versus 15 (35.7%) in the external control group [start of new systemic treatment (6 cases), mutilating surgery (5 cases), radiation therapy (2 cases), and death (2 cases)]. Larotrectinib was associated with an 80% reduced likelihood of encountering a medical treatment failure event, when compared to the external control group (weighted and stratified hazard ratio 0.20, 95% confidence interval 0.06-0.63, P = 0.0060). These results were confirmed by sensitivity analyses, including exact matching, and subgroup analyses for number of lines of treatment.

CONCLUSIONS

Treatment with larotrectinib reduced the need of subsequent therapies compared to SOC with chemotherapy in children with locally advanced or metastatic IFS, regardless of the line of treatment.

Significance of fusion status, Oberlin risk factors, local and maintenance treatment in pediatric and adolescent patients with metastatic rhabdomyosarcoma: Data of the European Soft Tissue Sarcoma Registry SoTiSaR

BACKGROUND

Outcome of primary metastatic rhabdomyosarcoma (RMS) is poor. Certain risk factors as fusion status, Oberlin score, and local treatment of primary tumor are known to influence prognosis.

PROCEDURE

Patients with metastatic RMS were treated according to Cooperative Weichteilsarkom Studiengruppe (CWS) guidance with chemotherapy (CHT), radiotherapy (RT) excluding total lung irradiation (TLI), complete resection of the primary tumor, and metastasectomy if possible. Kaplan-Meier estimators and Cox proportional hazard models were used to examine event-free survival (EFS) and overall survival (OS) involving also landmark analyses.

RESULTS

In the European Soft Tissue Sarcoma Registry SoTiSaR (2009-2018), 211 patients were analyzed. Many patients had fusion-positive alveolar RMS (n = 83; 39%). Median age was 9.4 years [0.1-19.7 years]. Treatment primarily consisted of CHT with CEVAIE (carboplatin, epirubicine, vincristine, actinomycin-D, ifosfamide, etoposide: 86%, other regimens: 14%), RT (71%), resection of primary tumor (37%), metastasectomy (19%), and lymph node sampling/dissection (21%). Maintenance treatment (MT) (oral trofosfamide, idarubicin, etoposide) was added in 74% of patients. Oberlin factors, fusion status, and MT were predictive for EFS and OS. MT with O-TIE was not improving outcome when adjusting for the immortal time bias. Local treatment of the primary tumor and radical irradiation (except TLI) improved EFS, not OS, when adjusting for the Oberlin score. Patients with fusion-negative alveolar RMS (n = 9) had an excellent outcome with a 5-year EFS and OS of 100%, compared to patients with embryonal RMS (49%/62%), PAX7- (22%/47%) and PAX3/FOXO1-positive ARMS (10/13%), respectively (p < .001).

CONCLUSIONS

Prognosis of metastatic RMS primarily depends on fusion status and Oberlin score. Fusion status needs to be considered in future trials to optimize treatment outcome. The role of radical irradiation needs further investigation.

Radiotherapy and long-term sequelae in pediatric patients with parameningeal rhabdomyosarcoma: Results of two Cooperative Weichteilsarkom Studiengruppe (CWS) trials and one registry

BACKGROUND

Parameningeal location of rhabdomyosarcoma (PM RMS) is known to be an unfavorable prognostic factor. Scarce data are available on radiotherapy (RT) concepts with regard to outcome.

METHODS

Treatment and outcome of 395 children with PM RMS registered within two Cooperative Weichteilsarkom Studiengruppe (CWS) trials and one registry (1995-2021) were evaluated.

RESULTS

Patients were IRS group II (n = 15) and III (n = 380) and received systemic treatment according to the enrolled protocols: I2VA (n = 172), VAIA/CEVAIE (n = 223). Delayed resection was performed in 88/395 (22%) patients, and RT was additionally given in 79/88 (90%) resected patients. RT was the predominant local treatment in 355/395 (90%) patients: hyperfractionated accelerated photon (HART; n = 77), conventionally fractionated photon (n = 91) or proton beam (n = 126), brachytherapy (n = 4), heavy ions (n = 1), not available (n = 56). In the subgroup of RT as only local treatment (n = 278), no intracranial tumor extension and complete remission at end of treatment were significant positive prognostic factors. No significant difference on tumor outcome was seen between different radiotherapy concepts. Long-term toxicity with mostly endocrinological and visual deficiencies was reported in 161/279 (58%) surviving patients with a lower trend after proton beam RT (48%) when compared to HART or conventionally fractionated photon RT (71% and 72%, respectively). Ten-year event-free and overall survival in the overall group were 62% (±5, 95% confidence interval [CI]) and 67% (±5, 95% CI); in the RT-only group 67% (±6, 95% CI) and 71% (±6, 95% CI), respectively.

CONCLUSION

CWS data confirm the recent RT concept in PM RMS. Long-term sequelae as endocrinological and visual deficiencies need to be addressed.

Which Patients With Rhabdomyosarcoma Need Radiotherapy? Analysis of the Radiotherapy Strategies of the CWS-96 and CWS-2002P Studies and SoTiSaR Registry

PURPOSE

To analyze and compare the indications, doses, and application methods of radiotherapy (RT) and their influence on prognosis of patients with localized rhabdomyosarcoma (RMS).

METHODS

One thousand four hundred seventy patients with localized RMS 21 years and younger entered on CWS-96, CWS-2002P, and SoTiSaR were eligible for the analysis. The median follow-up was 6.5 years (IQR, 3.3-9.5).

RESULTS

The 5-year event-free survival (EFS) and local control survival (LCS) for 910 (62%) irradiated versus nonirradiated patients were 71% versus 69% and 78% versus 73% (P = .03), respectively. Ninety-five percent of patients in IRS I (90% embryonal RMS [eRMS]) were nonirradiated (EFS, 87%). Irradiated patients with IRS II had improved LCS (91% v 80%; P = .01) and EFS (not significant). In IRS III, EFS and LCS were significantly better for RT patients: 71% versus 56% (P = 3.1e-06) and 76% versus 61% (P = 4.1e-07). Patients with tumors in the head and neck region (orbita, parameningeal, and nonparameningeal) and in other sites had significantly better EFS and LCS and in parameningeal also overall survival (OS). The efficacy of low RT doses of 32 Gy (hyperfractionated, accelerated RT [HART]) and 36 and 41.4 Gy (conventional fractionated RT [CFRT]) in the favorable groups and higher doses of 44.8 Gy (HART) and 50.4 and 55.4 Gy (CFRT) in the unfavorable groups was comparable. Proton RT was used predominantly in head/neck-parameningeal (HN-PM) tumors, with similar EFS and LCS to photon RT.

CONCLUSION

RT can be omitted in patients with IRS I eRMS. RT improves LCS and EFS in IRS II and III. RT improves OS in patients with HN-PM, with proton RT comparable with photon RT. Doses of 32 Gy (HART) or 36 and 41.4 Gy (CFRT) had comparable efficacy in patients with favorable risk profiles and 44.8 Gy (HART) or 50.4 and 55.8 Gy (CFRT) in the unfavorable groups.

Local treatment of rhabdomyosarcoma of the female genital tract: Expert consensus from the Children's Oncology Group, the European Soft-Tissue Sarcoma Group, and the Cooperative Weichteilsarkom Studiengruppe

The International Soft-Tissue Sarcoma Consortium (INSTRuCT) was founded as an international collaboration between different pediatric soft-tissue sarcoma cooperative groups (Children's Oncology Group, European Pediatric Soft-Tissue Sarcoma Group, and Cooperative Weichteilsarkom Studiengruppe). Besides other tasks, a major goal of INSTRuCT is to develop consensus expert opinions for best clinical treatment. This consensus paper for patients with rhabdomyosarcoma of the female genital tract (FGU-RMS) provides treatment recommendations for local treatment, long-term follow-up, and fertility preservation. Therefore, a review of the current literature was combined with recommendations of the treatment protocols of the appropriate clinical trials. Additionally, opinions of international FGU-RMS experts were incorporated into recommendations. Results were that the prognosis of FGU-RMS is favorable with an excellent response to chemotherapy. Initial complete surgical resection is not indicated, but diagnosis should be established properly. In patients with tumors localized at the vagina or cervix demonstrating incomplete response after induction chemotherapy, local radiotherapy (brachytherapy) should be carried out. In patients with persistent tumors at the corpus uteri, hysterectomy should be performed. Fertility preservation should be considered in all patients. In conclusion, for the first time, an international consensus for the treatment of FGU-RMS patients could be achieved, which will help to harmonize the treatment of these patients in different study groups.

Second-line treatment of pediatric patients with relapsed rhabdomyosarcoma adapted to initial risk stratification: Data of the European Soft Tissue Sarcoma Registry (SoTiSaR)

BACKGROUND

Outcome of relapsed disease of localized rhabdomyosarcoma remains poor. An individual treatment approach considering the initial systemic treatment and risk group was included in the Cooperative Weichteilsarkom Studiengruppe (CWS) Guidance.

METHODS

Second-line chemotherapy (sCHT) ACCTTIVE based on anthracyclines (adriamycin, carboplatin, cyclophosphamide, topotecan, vincristine, etoposide) was recommended for patients with initial low- (LR), standard- (SR), and high-risk (HR) group after initial treatment without anthracyclines. TECC (topotecan, etoposide, carboplatin, cyclophosphamide) was recommended after initial anthracycline-based regimen in the very high-risk (VHR) group. Data of patients with relapse (n = 68) registered in the European Soft Tissue Sarcoma Registry SoTiSaR (2009-2018) were retrospectively analyzed.

RESULTS

Patients of initial LR (n = 2), SR (n = 16), HR (n = 41), and VHR (n = 9) group relapsed. sCHT consisted of ACCTTIVE (n = 36), TECC (n = 12), or other (n = 15). Resection was performed in 40/68 (59%) patients and/or radiotherapy in 47/68 (69%). Initial risk stratification, pattern/time to relapse, and achievement of second complete remission were significant prognostic factors. Microscopically incomplete resection with additional radiotherapy was not inferior to microscopically complete resection (p = .17). The 5-year event-free survival (EFS) and overall survival (OS) were 26% (±12%) and 31% (±14%). The 5-year OS of patients with relapse of SR, HR, and VHR groups was 80% (±21%), 20% (±16%), and 13% (±23%, p = .008), respectively.

CONCLUSION

Adapted systemic treatment of relapsed disease considering the initial risk group and initial treatment is reasonable. New treatment options are needed for patients of initial HR and VHR groups.

Pediatric Patients with Stage IV Rhabdomyosarcoma Significantly Benefit from Long-Term Maintenance Therapy: Results of the CWS-IV 2002 and the CWS DOK IV 2004-Trials

Rhabdomyosarcoma (RMS) is the most common soft tissue sarcoma (STS) in childhood. Whereas more than 90% of patients with localized low-risk RMS can be cured, metastatic RMS have a dismal outcome, with survival rates of less than 30%. The HD CWS-96 trial showed an improved outcome for patients receiving maintenance therapy after completing intensive chemotherapy. Consequently, the international clinical trials CWS-IV 2002 and CWS DOK IV 2004 on metastatic disease of STS of the Cooperative Weichteilsarkom Studiengruppe (CWS) were designed in addition to the CWS-2002P trial for localized RMS disease. All patients received a multimodal intensive treatment regimen. To maintain remission, three options were compared: long-term maintenance therapy (LTMT) versus allogeneic hematopoietic stem cell transplantation (alloHSCT) versus high-dose chemotherapy (HDCT). A total of 176 pediatric patients with a histologically confirmed diagnosis of metastatic RMS or RMS-like tumor were included. A total of 89 patients receiving LTML showed a significantly better outcome, with an event-free survival (EFS) of 41% and an overall survival (OS) of 53%, than alloHSCT (n = 21, EFS 19%, p = 0.02, OS 24%, p = 0.002). The outcome of LTML was slightly improved compared to HDCT (n = 13, EFS 35%, OS 34%). In conclusion, our data suggest that in patients suffering from metastatic RMS, long-term maintenance therapy is a superior strategy in terms of EFS and OS compared to alloHSCT. EFS and OS of HDCT are similar in these strategies; however, the therapeutic burden of LTMT is much lower.

Surgical management of extremity rhabdomyosarcoma: A consensus opinion from the Children's Oncology Group, the European Pediatric Soft-Tissue Sarcoma Study Group, and the Cooperative Weichteilsarkom Studiengruppe

The treatment of extremity rhabdomyosarcoma remains a challenge due to several adverse prognostic factors frequently associated with this tumor site. The International Soft-Tissue Sarcoma Database Consortium (INSTRuCT) is a collaboration of the Children's Oncology Group Soft-Tissue Sarcoma Committee, the European Pediatric Soft-Tissue Sarcoma Study Group, and the Cooperative Weichteilsarkom Studiengruppe. The INSTRuCT surgical committee developed an internationally applicable consensus opinion document for the surgical treatment of extremity rhabdomyosarcoma. This document addresses surgical management, including biopsy, nodal staging, timing of therapy, resection and reexcision, reconstruction, and surgical approach at relapse.

Haploidentical hematopoietic stem cell transplantation as individual treatment option in pediatric patients with very high-risk sarcomas

Background

Prognosis of children with primary disseminated or metastatic relapsed sarcomas remains dismal despite intensification of conventional therapies including high-dose chemotherapy. Since haploidentical hematopoietic stem cell transplantation (haplo-HSCT) is effective in the treatment of hematological malignancies by mediating a graft versus leukemia effect, we evaluated this approach in pediatric sarcomas as well.

Methods

Patients with bone Ewing sarcoma or soft tissue sarcoma who received haplo-HSCT as part of clinical trials using CD3+ or TCRα/β+ and CD19+ depletion respectively were evaluated regarding feasibility of treatment and survival.

Results

We identified 15 patients with primary disseminated disease and 14 with metastatic relapse who were transplanted from a haploidentical donor to improve prognosis. Three-year event-free survival (EFS) was 18,1% and predominantly determined by disease relapse. Survival depended on response to pre-transplant therapy (3y-EFS of patients in complete or very good partial response: 36,4%). However, no patient with metastatic relapse could be rescued.

Conclusion

Haplo-HSCT for consolidation after conventional therapy seems to be of interest for some, but not for the majority of patients with high-risk pediatric sarcomas. Evaluation of its future use as basis for subsequent humoral or cellular immunotherapies is necessary.

Amplification of the PLAG-family genes-PLAGL1 and PLAGL2-is a key feature of the novel tumor type CNS embryonal tumor with PLAGL amplification

Pediatric central nervous system (CNS) tumors represent the most common cause of cancer-related death in children aged 0-14 years. They differ from their adult counterparts, showing extensive clinical and molecular heterogeneity as well as a challenging histopathological spectrum that often impairs accurate diagnosis. Here, we use DNA methylation-based CNS tumor classification in combination with copy number, RNA-seq, and ChIP-seq analysis to characterize a newly identified CNS tumor type. In addition, we report histology, patient characteristics, and survival data in this tumor type. We describe a biologically distinct pediatric CNS tumor type (n = 31 cases) that is characterized by focal high-level amplification and resultant overexpression of either PLAGL1 or PLAGL2, and an absence of recurrent genetic alterations characteristic of other pediatric CNS tumor types. Both genes act as transcription factors for a regulatory subset of imprinted genes (IGs), components of the Wnt/β-Catenin pathway, and the potential drug targets RET and CYP2W1, which are also specifically overexpressed in this tumor type. A derived PLAGL-specific gene expression signature indicates dysregulation of imprinting control and differentiation/development. These tumors occurred throughout the neuroaxis including the cerebral hemispheres, cerebellum, and brainstem, and were predominantly composed of primitive embryonal-like cells lacking robust expression of markers of glial or neuronal differentiation (e.g., GFAP, OLIG2, and synaptophysin). Tumors with PLAGL1 amplification were typically diagnosed during adolescence (median age 10.5 years), whereas those with PLAGL2 amplification were diagnosed during early childhood (median age 2 years). The 10-year overall survival was 66% for PLAGL1-amplified tumors, 25% for PLAGL2-amplified tumors, 18% for male patients, and 82% for female patients. In summary, we describe a new type of biologically distinct CNS tumor characterized by PLAGL1/2 amplification that occurs predominantly in infants and toddlers (PLAGL2) or adolescents (PLAGL1) which we consider best classified as a CNS embryonal tumor and which is associated with intermediate survival. The cell of origin and optimal treatment strategies remain to be defined.

Creating a data commons: The INternational Soft Tissue SaRcoma ConsorTium (INSTRuCT)

In this article, we will discuss the genesis, evolution, and progress of the INternational Soft Tissue SaRcoma ConsorTium (INSTRuCT), which aims to foster international research and collaboration focused on pediatric soft tissue sarcoma. We will begin by highlighting the current state of clinical research for pediatric soft tissue sarcomas, including rhabdomyosarcoma and non-rhabdomyosarcoma soft tissue sarcoma. We will then explore challenges and research priorities, describe the development of INSTRuCT, and discuss how the consortium aims to address key research priorities.

Fusion transcripts as liquid biopsy markers in alveolar rhabdomyosarcoma and synovial sarcoma: A report of the Cooperative Weichteilsarkom Studiengruppe (CWS)

BACKGROUND

The possible application of gene fusion transcripts as tumor-specific noninvasive liquid biopsy biomarkers was investigated in blood plasma from patients with alveolar rhabdomyosarcoma (ARMS) and synovial sarcoma (SS).

METHODS

Patients entered in the CWS Soft-Tissue Sarcoma Registry (SoTiSaR) with tumors positive for fusion genes and available blood/plasma samples were included in our analysis. Cell-free exosomal RNA was extracted and used to detect PAX-FOXO1 or SYT-SSX fusion transcripts by reverse transcription quantitative PCR (RT-qPCR).

RESULTS

The analysis included 112 ethylene diamine tetraacetic acid blood samples from 80 patients (65 with ARMS, 15 with SS; 34 with localized, 46 with metastatic disease). For patients with metastatic ARMS, 62% (n = 18) of initial liquid biopsies were positive, and 16 (89%) of them showed initial bone marrow (BM) metastases. For all patients with primary localized ARMS, liquid biopsy was negative at diagnosis. Of the 48 plasma samples collected during therapy and follow-up, five were positive. None of the liquid biopsies from patients with SS were positive.

CONCLUSIONS

This liquid biopsy assay based on the detection of fusion transcripts in cell-free RNA from blood exosomes is suitable for analysis of patients with ARMS. Results showed good correlation with the initial tumor status; liquid biopsy was positive in 94% of patients with metastatic ARMS and initial BM involvement, whereas biopsies from all patients with localized tumors were negative. Prospective validation and optimization of the assay, as well as its application for other markers in diagnostics and monitoring of soft-tissue sarcoma, are ongoing.

Long-term results from the multicentric European randomized phase 3 trial CWS/RMS-96 for localized high-risk soft tissue sarcoma in children, adolescents, and young adults

BACKGROUND

CWS/RMS-96 was an international multicenter trial with randomization between two therapy arms of the standard four-drug therapy (vincristine, ifosfamide, adriamycin, dactinomycin [VAIA]) versus an intensified six-drug regimen (carboplatin, epirubicin, vincristine, dactinomycin, ifosfamide, and etoposide [CEVAIE]) for high-risk rhabdomyosarcoma (RMS), extraskeletal Ewing sarcoma (EES), and undifferentiated sarcoma (UDS) in children, adolescents, and young adults aiming to improve their survival. Intensified chemotherapy with CEVAIE did not improve outcome.

METHODS

Patients younger than 21 years with a previously untreated localized HR-RMS, EES, and UDS were enrolled from Cooperative Weichteilsarkom Studiengruppe (CWS) centers in Germany, Austria, Poland, Switzerland, and from Italian Soft Tissue Sarcoma Committee (STSC) centers. Randomization (1:1) to receive either 9 × 21 days cycles of VAIA or CEVAIE was performed separately in CWS and STSC. Hyperfractionated accelerated radiotherapy (32-44.8 Gy) was added at week 9-12 according to histology and response to chemotherapy. A secondary microscopically complete nonmutilating resection was performed if possible. Primary endpoints were response to chemotherapy, event-free (EFS) and overall survival (OS).

RESULTS

Five hundred fifty-seven patients (HR-RMS: n = 416, EES and UDS: n = 141) underwent randomization: VAIA (n = 273) or CEVAIE (n = 284). Radiotherapy was given to 70% of patients in both groups. A secondary resection was performed in 47% and 48% patients, respectively. The 5-year EFS and OS for the VAIA and CEVAIE treatment arms were 59.8% and 60.8% (p = .89), and 74.2% and 68.3% (p = .16), respectively. No differences in response, toxicity, or second malignancies emerged in the two groups.

CONCLUSION

The use of an intensified regimen failed to show a significant improvement in tumor response and outcome of patients with localized HR-RMS, EES, and UDS.

Molecular testing of rhabdomyosarcoma in clinical trials to improve risk stratification and outcome: A consensus view from European paediatric Soft tissue sarcoma Study Group, Children's Oncology Group and Cooperative Weichteilsarkom-Studiengruppe

Rhabdomyosarcomas (RMSs) are the most common soft tissue sarcomas in children/adolescents less than 18 years of age with an annual incidence of 1-2/million. Inter/intra-tumour heterogeneity raise challenges in clinical, pathological and biological research studies. Risk stratification in European and North American clinical trials previously relied on clinico-pathological features, but now, incorporates PAX3/7-FOXO1-fusion gene status in the place of alveolar histology. International working groups propose a coordinated approach through the INternational Soft Tissue SaRcoma ConsorTium to evaluate the specific genetic abnormalities and generate and integrate molecular and clinical data related to patients with RMS across different trial settings. We review relevant data and present a consensus view on what molecular features should be assessed. In particular, we recommend the assessment of the MYOD1-LR122R mutation for risk escalation, as it has been associated with poor outcomes in spindle/sclerosing RMS and rare RMS with classic embryonal histopathology. The prospective analyses of rare fusion genes beyond PAX3/7-FOXO1 will generate new data linked to outcomes and assessment of TP53 mutations and CDK4 amplification may confirm their prognostic value. Pathogenic/likely pathogenic germline variants in TP53 and other cancer predisposition genes should also be assessed. DNA/RNA profiling of tumours at diagnosis/relapse and serial analyses of plasma samples is recommended where possible to validate potential molecular biomarkers, identify new biomarkers and assess how liquid biopsy analyses can have the greatest benefit. Together with the development of new molecularly-derived therapeutic strategies that we review, a synchronised international approach is expected to enhance progress towards improved treatment assignment, management and outcomes for patients with RMS.

Pre-operative radiotherapy is associated with superior local relapse-free survival in advanced synovial sarcoma

PURPOSE

Optimization of local therapies in synovial sarcoma (SS) considered unresectable at diagnosis is needed. We evaluated the effects of neoadjuvant versus adjuvant radiation versus surgery only on long-term outcomes.

METHODS

Patients with macroscopic SS tumors before chemotherapy (IRS-group-III) in the trials CWS-81, CWS-86, CWS-91, CWS-96, CWS-2002-P and SoTiSaR-registry were analyzed. Local therapies were scheduled after 3 neoadjuvant chemotherapy cycles.

RESULTS

Median age of 145 patients was 14.5 years. 106 survivors had median follow-up of 7.0 years. Tumor site was 96 extremities, 19 head-neck, 16 shoulder/hip, 14 trunk. Tumors were < 3 cm in 16, 3-5 cm in 28, 5-10 cm in 55, > 10 cm in 34 patients. In a secondary resection during chemotherapy, R0-status was accomplished in 82, R1 in 30, R2 in 21 (12 missing). Radiotherapy was administered to 115 (R0 61, R1 29, R2 20, missing 5), thereof 57 before and 52 after tumor resection. 23 were treated with surgery only. For all patients, 5 year event-free (EFS) and overall survival (OS) was 68.9% ± 7.6 (95%CI) and 79.1% ± 6.9. To establish independent significance, tumor site, size, surgical results and sequencing of local therapies were analyzed in a Cox regression analysis. Variables associated with EFS and OS are site, size and sequencing of local therapies. Variables associated with local recurrence are site, surgical results and sequencing of local therapies. The only variable associated with suffering metastatic recurrence is tumor size.

CONCLUSION

Differences in sequencing of local therapy procedures are independently associated with outcomes. Best local control is achieved when tumors are irradiated pre-operatively and undergo R0 or R1 resection thereafter.

Metronomic oral maintenance chemotherapy in patients with localized high-risk rhabdomyosarcoma (RMS) and RMS-like tumors: A report from a randomized, multicenter, phase III trial CWS-2007HR

10033

Background: Low dose maintenance therapy as consolidation after multimodal standard therapy has been shown to improve survival in patients with sarcoma. It is however unclear which drugs and how long would be optimal. We investigated whether adding oral maintenance chemotherapy after standard multimodal therapy (ST) in patients with localized RMS and RMS-like sarcoma defined as high and very-high risk (HR and VHR), according to CWS stratification, would improve survival. Methods: Patients (pts) age > 6 months < 21 years, with 1. embryonal RMS N0, incompletely resected, (Group II or III), tumor size > 5cm and/or ≥10 years, in unfavorable primary sites and all N1 (HR RMS Group), 2. alveolar RMS N0/N1 (VHR RMS Group) 3.Unidfferentiated sarcoma (UDS), extraskeletal Ewing sarcoma (EES) and primary non resectable (Group III) synovial sarcoma (SS) (HR RMS-like Group) in complete remission after ST including 9 cycles of ifosfamide, vincristine and actinomycin D +/- doxorubicin, surgery and/or radiotherapy were eligible for randomization to stop treatment (S-arm) or receive maintenance chemotherapy (M-arm) with eight 10-days courses consisting of trofosfamide (2x 75mg/m²/day) and idarubicine (1 x 5mg/m²/day 1,4,7,10) alternating with trofosfamide and etoposide (2x 25mg/m²/day). The study was designed with 80% power and a two-sided alpha level of 5% to detect an increase in 3 yr EFS from 60 to 75%. Randomisation was stratified according to risk groups. To reduce possible imbalances in the number of treatment assignments, a permuted block design was used. The initial calculated sample size was 145 pts in each group (recruitment period six years). Due to the lower than planned recruitement rate, the accrual was extended to 10 years and sample size recalculated to 98 pts in each group. Results: Between 1.7.2009 and 30.6.2019, 441 pts were eligible at diagnosis and 337 at the end of ST. 195 pts were randomized: 99 were assigned to the S-arm and 96 to M-arm. The distribution of the following clinical features:age, gender, tumor size, IRS-Group, T-Status, N-Status, histology and localisation showed no significant difference between the treatment groups. In the intent to treat population, with a median follow up of 4.9 years (IQR 3.0-5.7) in surviving pts, 3yr EFS and OS in M-arm vs S-arm were respectively: EFS 66.2% (95% IC 57.1-76.79) vs 75.0% (95% IC 66.8-84.3) (p 0.07) and OS 81.9% (95% IC 74.2-90.4) vs 84.6 (95% IC 77.5-92.4) (p 0.15). Toxicity grade 3 (no grade 4) in the M-arm was: hematological in 51 %, febrile infection 5%, sensory neuropathy in 1% pts. Conclusions: The addition of maintenance therapy with trofosfamide, etoposide and idarubicine after ST does not improve EFS and OS in patients with high risk RMS and RMS-like sarcomas. Clinical trial information: 2007-0001478-10.

No Improvement of Survival for Alveolar Rhabdomyosarcoma Patients After HLA-Matched Versus -Mismatched Allogeneic Hematopoietic Stem Cell Transplantation Compared to Standard-of-Care Therapy

Background

Patients with stage IV alveolar rhabdomyosarcoma (RMA) have a 5-year-survival rate not exceeding 30%. Here, we assess the role of allogeneic hematopoietic stem cell transplantation (allo-HSCT) for these patients in comparison to standard-of-care regimens. We also compare the use of HLA-mismatched vs. HLA-matched grafts after reduced vs. myeloablative conditioning regimens, respectively.

Patients and Methods

In this retrospective analysis, we compare event-free survival (EFS), overall survival (OS), and toxicity of HLA-mismatched vs. -matched transplanted patients in uni- and multivariate analyses (total: n = 50, HLA-matched: n = 15, HLA-mismatched: n = 35). Here, the factors age at diagnosis, age at allo-HSCT, sex, Oberlin score, disease status at allo-HSCT, and HLA graft type are assessed. For 29 primarily transplanted patients, three matched non-transplanted patients per one transplanted patient were identified from the CWS registry. Outcomes were respectively compared for OS and EFS. Matching criteria included sex, age at diagnosis, favorable/unfavorable primary tumor site, and metastatic sites.

Results

Median EFS and OS did not differ significantly between HLA-mismatched and -matched patients. In the mismatched group, incidence of acute GvHD was 0.87 (grade III-IV: 0.14) vs. 0.80 in HLA-matched patients (grade III-IV: 0.20). Transplant-related mortality (TRM) of all patients was 0.20 and did not differ significantly between HLA-mismatched and -matched groups. A proportion of 0.58 relapsed or progressed and died of disease (HLA-mismatched: 0.66, HLA-matched: 0.53) whereas 0.18 were alive in complete remission (CR) at data collection. Multivariate and competing risk analyses confirmed CR and very good partial response (VGPR) status prior to allo-HSCT as the only decisive predictor for OS (p < 0.001). Matched-pair survival analyses of primarily transplanted patients vs. matched non-transplanted patients also identified disease status prior to allo-HSCT (CR, VGPR) as the only significant predictor for EFS. Here, OS was not affected, however.

Conclusion

In this retrospective analysis, only a subgroup of patients with good response at allo-HSCT survived. There was no survival benefit of allo-transplanted patients compared to matched controls, suggesting the absence of a clinically relevant graft-versus-RMA effect in the current setting. The results of this analysis do not support further implementation of allo-HSCT in RMA stage IV patients.

Congenital spindle cell rhabdomyosarcoma: An international cooperative analysis

BACKGROUND

Spindle cell rhabdomyosarcoma (RMS) is a rare variant of RMS accounting for up to 10% of cases in infants. In older children and adults, spindle cell RMS is associated with MYOD1 mutations and a poor prognosis. In infants, it is associated with recurring fusions involving NCOA2 and VGLL2. Reports in the literature suggest a favorable prognosis for this subset, however, little is known about treatment and outcome data of infants with spindle cell RMS.

METHODS

Characteristics, treatment, and outcome of an international cohort of 40 patients aged ≤ 12 months with spindle cell RMS treated from 1997 to 2018 were evaluated.

RESULTS

Localized disease (LD) was diagnosed in 39 patients. The median age at diagnosis was 2.5 months (range 0-12 months). Expert pathologic review confirmed the diagnosis of spindle cell RMS in all patients. Among 26 tumors that had molecular evaluation, 13 had rearrangements of NCOA and/or VGLL. Multimodal treatment of infants with LD included conventional (age adjusted) chemotherapy (n = 37), resection (n = 31) and radiotherapy (RT) (n = 5, brachytherapy in 3). Complete remission was achieved in 37/39 patients. Progressive disease occurred in two infants, relapsed disease in three. Microscopically complete surgical resection was associated with five-year event-free survival (EFS) and overall survival (OS) of 100%. Two patients with tumors ≤ 5 cm were treated with microscopically complete resection only and were alive 1 and 4.2 years after diagnosis. The 5-year EFS and OS for infants with LD were 86% (±11; CI 95%) and 91% (±9; CI 95%), respectively. One patient had metastatic disease (NCOA fusion positive) with primary tumor in head and neck and brain metastases. This patient died despite chemotherapy and delayed resection of the primary tumor due to respiratory failure secondary to cytomegalovirus infection 1.2 years after diagnosis.

CONCLUSION

Infants with spindle cell RMS have an excellent prognosis. Multimodal treatment including microscopically complete resection of the tumor is strongly recommended.

Infantile myofibromatosis: Excellent prognosis but also rare fatal progressive disease. Treatment results of five Cooperative Weichteilsarkom Studiengruppe (CWS) trials and one registry

BACKGROUND

Infantile myofibromatosis (IM) is a rare benign soft tissue tumor and often a self-limiting disease but rarely includes life-threatening complications. Little is known about optimal treatment of primary localized (LD) and multifocal disease (MFD).

METHODS

Treatment and outcome of 95 children with IM registered within five Cooperative Weichteilsarkom Studiengruppe (CWS) trials and one registry (1981-2016) were evaluated.

RESULTS

LD was diagnosed in 71 patients at a median age of 0.4 years (range 0.0-17.7). MFD was present in 24 patients. The mainstay of treatment was watch-and-wait strategy (w&w) after initial biopsy or resection. Low-dose chemotherapy (CHT) was administered to 16/71 (23%) patients with LD and eight of 24 (33%) patients with MFD, imatinib was added in two. A delayed resection was possible in eight of 71 (11%) and five of 24 (21%) patients with LD and MFD, respectively. Overall, patients were alive in complete remission (n = 77) and partial remission (n = 10) at a median follow-up time of 3.4 years after diagnosis (range 0.01-19.4); no data available (n = 5). Three patients died of progressive disease (PD) despite CHT. Gender, tumor size, and location correlated with a favorable event-free survival (EFS) in patients with LD. The 5-year EFS and overall survival of patients with LD were 73% (±12, confidence interval [CI] 95%) and 95% (±6, CI 95%), respectively; for MFD 51% (±22, CI 95%) and 95% (±10, CI 95%).

CONCLUSION

Prognosis is excellent in patients with LD and MFD. Targeted treatment needs to be evaluated for rare fatal PD.

Secondary malignant neoplasms after bone and soft tissue sarcomas in children, adolescents, and young adults

BACKGROUND

Increased survival in young sarcoma patients comes along with a higher incidence of second malignant neoplasms (SMNs). The incidence, latency, histiotype, and outcome of these patients were analyzed because this information is essential to design evidence-based long-term follow-up care programs for young sarcoma survivors.

METHODS

Patients entered on clinical trials or registered in registries with a primary sarcoma in 1 of the cooperative sarcoma study groups in the framework of the Society for Pediatric Oncology and Hematology (GPOH) were screened for SMNs. Descriptive analysis, the Kaplan-Meier method, the Gray model, the Fine-Gray model, and the Cox regression model were used for the statistical analyses.

RESULTS

A total of 159 out of 7079 (2.2%) patients were registered with a SMN. Among them, 104 solid SMNs (65%) and 56 hematologic SMNs (35%) occurred. Median latency from first diagnosis of sarcoma to the diagnosis of SMN was 6.8 years (range, 0-26.7 years). Cumulative incidence of SMN was 8.8% after 30 years. Five-year-survival was 67.1% (95% confidence interval [CI], 66.0-68.2) for the 7079 patients and it was 45.1% (95% CI, 36.2-53.6) after the diagnosis of a SMN (subcohort of n = 159 patients).

CONCLUSIONS

There is a remarkable high cumulative incidence of SMNs after bone and soft tissue sarcomas in children, adolescents, and young adults. Therefore, effective transition as well as risk adapted long-term follow-up care programs should be developed and offered to young sarcoma survivors.

LAY SUMMARY

Bone sarcomas and soft tissue tumors are rare tumors in children, adolescents, and young adults. The treatment varies, but may comprise chemotherapy, surgery, and/or radiotherapy. Developing a subsequent malignant tumor is a long-term risk for the patients. To better characterize this risk, we analyzed the data of 7079 patients (up to 21 years old) with bone sarcomas or soft tissue tumors. Our findings provide a basis to counsel young sarcoma survivors on their individual risk of subsequent malignant tumors. Moreover, these data can help to establish recommendations for aftercare in young sarcoma survivors.

Children with progressive and relapsed pleuropulmonary blastoma: A European collaborative analysis

BACKGROUND

Children with progressive (PD) or relapsed disease (RD) of pleuropulmonary blastoma (PPB) type II/III are known to have a very poor outcome.

METHODS

A retrospective review of children registered in national and European databases and trials (2000-2018) with diagnosis of PPB type II/III and PD or RD was performed.

RESULTS

A total of 35 patients with PPB were analysed: patients with PD (n = 9) and RD (n = 26). Patients experienced PD at the median age of 3.9 years [range, 0.5-17.8] despite surgery, chemotherapy (CHT, n = 9) and radiotherapy (RT, n = 1) with a median time to progression of 0.58 years [range, 0.02-1.27] from diagnosis. All of them died. Patients suffered from RD at the median age of 4.3 years [1.7-15.1], median delay to relapse 1.03 years [range, 0.03-2.95]. RD occurred locally (n = 12), combined (n = 1) and in metastatic sites (n = 13): central nervous system (n = 11) and unspecified site (n = 2). Patients were treated with salvage CHT (n = 20), surgery (n = 10) ± RT (n = 10). After a median follow-up of 4.2 years [range, 2.1-14.6], a second complete remission (CR) was achieved in nine out of 26 patients. Patients were alive in the second CR (n = 6), in the third CR (n = 1), in partial remission (n = 2) and lost of follow-up (n = 1). Five-year event-free survival (EFS) and overall survival (OS) for patients with RD were both 37% (±19, CI 95%). Local therapy (surgery, RT) had a favourable impact on OS (p = 0.03 and 0.02, respectively).

CONCLUSIONS

Cure of patients with RD of PPB type II/III with multimodal treatment is possible but rare. Progressive PPB is fatal and patients need new treatment options.

The Pediatric Precision Oncology INFORM Registry: Clinical Outcome and Benefit for Patients with Very High-Evidence Targets

INFORM is a prospective, multinational registry gathering clinical and molecular data of relapsed, progressive, or high-risk pediatric patients with cancer. This report describes long-term follow-up of 519 patients in whom molecular alterations were evaluated according to a predefined seven-scale target prioritization algorithm. Mean turnaround time from sample receipt to report was 25.4 days. The highest target priority level was observed in 42 patients (8.1%). Of these, 20 patients received matched targeted treatment with a median progression-free survival of 204 days [95% confidence interval (CI), 99-not applicable], compared with 117 days (95% CI, 106-143; P = 0.011) in all other patients. The respective molecular targets were shown to be predictive for matched treatment response and not prognostic surrogates for improved outcome. Hereditary cancer predisposition syndromes were identified in 7.5% of patients, half of which were newly identified through the study. Integrated molecular analyses resulted in a change or refinement of diagnoses in 8.2% of cases. SIGNIFICANCE: The pediatric precision oncology INFORM registry prospectively tested a target prioritization algorithm in a real-world, multinational setting and identified subgroups of patients benefiting from matched targeted treatment with improved progression-free survival, refinement of diagnosis, and identification of hereditary cancer predisposition syndromes.See related commentary by Eggermont et al., p. 2677.This article is highlighted in the In This Issue feature, p. 2659.

Pediatric Cancer Data Commons: Federating and Democratizing Data for Childhood Cancer Research

The international pediatric oncology community has a long history of research collaboration. In the United States, the 2019 launch of the Children's Cancer Data Initiative puts the focus on developing a rich and robust data ecosystem for pediatric oncology. In this spirit, we present here our experience in constructing the Pediatric Cancer Data Commons (PCDC) to highlight the significance of this effort in fighting pediatric cancer and improving outcomes and to provide essential information to those creating resources in other disease areas. The University of Chicago's PCDC team has worked with the international research community since 2015 to build data commons for children's cancers. We identified six critical features of successful data commons design and implementation: (1) establish the need for a data commons, (2) develop and deploy the technical infrastructure, (3) establish and implement governance, (4) make the data commons platform easy and intuitive for researchers, (5) socialize the data commons and create working knowledge and expertise in the research community, and (6) plan for longevity and sustainability. Data commons are critical to conducting research on large patient cohorts that will ultimately lead to improved outcomes for children with cancer. There is value in connecting high-quality clinical and phenotype data to external sources of data such as genomic, proteomics, and imaging data. Next steps for the PCDC include creating an informed and invested data-sharing culture, developing sustainable methods of data collection and sharing, standardizing genetic biomarker reporting, incorporating radiologic and molecular analysis data, and building models for electronic patient consent. The methods and processes described here can be extended to any clinical area and provide a blueprint for others wishing to develop similar resources.

Extraskeletal Ewing sarcoma in children, adolescents, and young adults. An analysis of three prospective studies of the Cooperative Weichteilsarkomstudiengruppe (CWS)

BACKGROUND

We have analyzed the outcome of patients with localized extraskeletal Ewing sarcoma (EES) treated in three consecutive Cooperative Weichteilsarkomstudiengruppe (CWS) soft tissue sarcoma (STS) studies: CWS-91, CWS-96, and CWS-2002P.

METHODS

Patients were treated in CWS-91 with four- (vincristine, dactinomycin, doxorubicin, and ifosfamide [VAIA] or cyclophosphamide [VACA II]) or five-drug (+etoposide [EVAIA]) cycles, in CWS-96 they were randomly assigned to receive VAIA or CEVAIE (+carboplatin and etoposide), and in CWS-2002P with VAIA III plus optional maintenance therapy (MT) with cyclophosphamide and vinblastine. Local therapy consisted of resection and/or radiotherapy (RT).

RESULTS

Two hundred forty-three patients fulfilled the eligibility criteria. The 5-year event-free survival (EFS) and overall survival (OS) were 63% (95% confidence interval [CI] 57-69) and 73% (95% CI 67-79), respectively. The 5-year EFS by study was 64% (95% CI 54-74) in CWS-91, 57% (95% CI 48-66) in CWS-96, and 79% (95% CI 67-91) in CWS-2002P (n.s.). The 5-year OS was 72% (95% CI 62-82) in CWS-91, 70% (95% CI 61-79) in CWS-96, and 86% (95% CI 76-96) in CWS-2002P (n.s.). In CWS-96, 5-year EFS and OS in the VAIA arm versus the CEVAIE were 65% (95% CI 52-81) versus 55% (95% CI 39-76) log-rank p = .13, and 85% (95% CI 75-96) versus 61% (95% CI 45-82), log-rank p = .09.

CONCLUSION

Our analysis provides interesting information on the treatment and specificities of EES, which can be useful for a better understanding of this rare entity and should be considered in the development of future clinical trials for Ewing sarcoma defined as FET-ETS fusion positive tumors.

Pleuropulmonary blastoma in children and adolescents: The EXPeRT/PARTNER diagnostic and therapeutic recommendations

Pleuropulmonary blastoma (PPB) is a rare cancer occurring mainly during early childhood and often associated with germline DICER1 mutations. It is classified by the macroscopic appearance into three interrelated clinico-pathologic entities on a developmental continuum. Complete tumor resection is a main prognostic factor and can be performed at diagnosis or after neoadjuvant treatment that includes chemotherapy and in some cases radiotherapy. Optimal modalities of neo- or adjuvant treatments can be challenging taking into account potential long-term toxicities in this young population. This paper presents the recommendations for diagnosis and treatment of children and adolescents with PPB elaborated by the European Cooperative Study Group for Pediatric Rare Tumors (EXPeRT) within the European Union-funded project PARTNER (Paediatric Rare Tumours Network - European Registry).

Surgical management of paratesticular rhabdomyosarcoma: A consensus opinion from the Children's Oncology Group, European paediatric Soft tissue sarcoma Study Group, and the Cooperative Weichteilsarkom Studiengruppe

The treatment of paratesticular rhabdomyosarcoma (PT-RMS) has varied over time and by cooperative group. The International Soft Tissue Sarcoma Database 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 Cooperative Weichteilsarkom Studiengruppe (CWS). The INSTRuCT surgical committee has been given charge of the development of internationally applicable consensus guidelines for the surgical treatment of rhabdomyosarcoma. This clinical consensus opinion document addresses accepted principles and areas of controversy, such as scrotal violation and retroperitoneal nodal evaluation, providing an evidence-based guideline for the surgical treatment for PT-RMS.

Rhabdomyosarcoma of the female genitourinary tract: Primary and relapsed disease in infants and older children. Treatment results of five Cooperative Weichteilsarkom Studiengruppe (CWS) trials and one registry

BACKGROUND

Rhabdomyosarcoma (RMS) of the female genitourinary tract (FGU-RMS) located at the vagina or uterus is one of the most favorable RMS sites. Little is known about treatment and outcome in infants and relapsed disease (RD).

METHODS

Characteristics, treatment, and outcome of 71 children with FGU-RMS registered within five Cooperative Weichteilsarkom Studiengruppe (CWS) trials and one registry (1981-2019) were evaluated.

RESULTS

FGU-RMS was diagnosed in 67 patients with localized disease (LD) at a median age of 2.89 years (0.09-18.08). Multimodal treatment consisted of chemotherapy (CHT) (n = 66), secondary surgery (n = 32), and radiotherapy (n = 11). Age at diagnosis ≤12 months was the only significant negative prognostic factor influencing the event-free survival (EFS). Ten-year EFS and overall survival (OS) for infants ≤12 months were 50% and 81%, respectively. In contrast, children with LD >1 year and ≤10 years had a 10-year EFS and OS of 78% and 94% (P = .038), and >10 years of 82% and 88%, respectively (P = .53). Metastatic disease was observed in four patients of which three are alive. RD occurred in five of 12 infants ≤1 year and 10/55 children at a median of 1.38 years (0.53-2.97) after initial diagnosis. Treatment of patients with RD consisted of multimodal treatment (n = 13) or resection only (n = 2). Nine patients (60%) were alive in clinical remission at a median of 7.02 years (1.23-16.72) after diagnosis of RD.

CONCLUSION

Infants with FGU-RMS have a higher relapse rate than older children with FGU-RMS, but prognosis is fair.

Pathology of childhood rhabdomyosarcoma: A consensus opinion document from the Children's Oncology Group, European Paediatric Soft Tissue Sarcoma Study Group, and the Cooperative Weichteilsarkom Studiengruppe

The diagnosis and classification of rhabdomyosarcoma (RMS) has undergone several shifts over the last 30 years. While the main diagnostic categories remained the same, changes in the histologic criteria necessary for diagnosis, as well as varied reliance on immunohistochemical and molecular data over time, have created confusion, particularly regarding how these shifts impacted risk stratification and enrollment onto clinical trials. The goal of this report is to review the evolution and current status of RMS diagnosis, focusing on diagnostic criteria in the Children's Oncology Group (COG), the European Paediatric Soft Tissue Sarcoma Group (EpSSG), and the Cooperative Weichteilsarkom Studiengruppe (CWS). In addition, we emphasize research tools used to classify RMS and address biological questions within current clinical trials run by each group. The INternational Soft Tissue SaRcoma ConsorTium (INSTRuCT) initiative will maximize potential to optimize risk stratification by recognizing and accounting for differences in historical data and current practices.

Undifferentiated sarcoma of the liver: Multicenter international experience of the Cooperative Soft-Tissue Sarcoma Group and Polish Paediatric Solid Tumor Group

BACKGROUND

Undifferentiated embryonal sarcomas of the liver (UESL) are extremely rare and continue to pose a diagnostic and therapeutic challenge. The aim of the study was to present a multicenter experience of the German CWS and Polish PPSTG groups in the treatment of UESL in children.

PROCEDURE

Twenty-five patients were treated according to the CWS-96, CWS-2002, and CYVADIC protocols. Distant metastases were observed in four cases (16%). In four cases, an initial disease presentation mimicked other entities. A pure cystic appearance of liver mass led to misdiagnosis of hydatid cyst in three cases. In one case, laparotomy was performed due to the signs of appendicitis, and bleeding from ruptured liver tumor was found. All these patients were finally diagnosed as UESL.

RESULTS

Thirteen patients received preoperative chemotherapy. Partial response was observed in 10 cases. Tumor resection was performed in 20 patients (primary resections, 12; delayed resections-, 8). In five patients, the primary tumor never became operable. The macroscopically complete resection rate was 95% (19/20). Postoperative chemotherapy was given to 20 children. Local radiotherapy was used in three children. After a median follow-up time of 136 months, 17 patients (68%) were alive with no evidence of disease. All children with unresectable tumor and three out of four patients with distant metastases died. The five-year overall survival (OS) rate was 72%.

CONCLUSIONS

In summary, a complete tumor excision plays the central role in the treatment of UESL. A cystic presentation of the liver lesion on imaging does not exclude the diagnosis of malignant tumor.

The impact of local control in the treatment of children with advanced infantile and adult-type fibrosarcoma: Experience of the cooperative weichteilsarkom studiengruppe (CWS)

BACKGROUND AND OBJECTIVES

This study aims at examining the potential survival benefits of primary versus secondary surgery of children diagnosed with advanced infantile (iFS) and adult-type fibrosarcoma (aFS).

METHODS

Treatment and outcome of 89 children with FS treated within prospective Cooperative Studiengruppe (CWS) trials (1981-2016) were analyzed retrospectively.

RESULTS

Localized disease (LD) was diagnosed in 87 patients: 64/66 patients with iFS (≤2 years) and 23 with aFS (>2 ≤ 18 years). Two patients (iFS) had metastatic disease. Resection was the mainstay of therapy of patients with LD resulting in microscopically complete (R0, IRS group I) (n = 29/87, 33%), microscopically incomplete (R1, IRS group II) (n = 17/87, 20%) and macroscopically incomplete (R2, IRS group III) (n = 41/87, 47%). Advanced LD (IRS group III) was present in 32/64 (50%) patients with iFS and in 9/23 (39%) with aFS. Chemotherapy was added predominantly in patients with advanced disease and an assessable objective response to CHT was seen in 71% iFS and 75% aFS. The 5-year event-free survival (EFS) of patients with iFS and aFS was 81% (±10, 95% CI) and 70% (±19, 95% CI) (p = 0.24); the 5-year overall survival (OS) was 98% (±3, 95% CI) and 82% (±16, 95% CI) (p = 0.02). Primary resection was no prognostic factor. Secondary R0/ R1 resection in patients with advanced disease improved 5-year EFS and OS in aFS (p = 0.002 and p = 0.000) but not in infants.

CONCLUSIONS

Secondary resection improves outcome in advanced aFS but not in infants. Mutilating surgery in infants should be avoided.

TYPE OF STUDY AND LEVEL OF EVIDENCE

Treatment study: patients were enrolled in five prospective studies and one registry, prognosis study: retrospective study.

LEVEL OF EVIDENCE

II/ III.

MINI-ABSTRACT

Fibrosarcoma is a very rare malignant tumor. Little is known about differences of local treatment of advanced infantile and adult-type. Data of 89 patients registered in five prospective trials and one registry of the Cooperative Weichteilsarkom Studiengruppe (CWS) (1981-2016) were analyzed.

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.

Dermatofibrosarcoma protuberans in children and adolescents: Primary and Relapsed disease-Experience of the Cooperative Weichteilsarkomstudiengruppe (CWS)

BACKGROUND

Dermatofibrosarcoma protuberans (DFSP) is a rare low-grade tumor. Little is known about best treatment of primary and relapsed disease (RD).

METHODS

Treatment and outcome of 40 patients with DFSP prospectively registered within the CWS-96 and -2002P trials and the registry SoTiSaR (1996-2016) were analysed.

RESULTS

Median age was 8 years (range, 0.64-17.77). Fluorescence in situ hybridization analysis to detect COL1A1-PDGFB fusion genes was positive in 86% (12/14) of evaluated patients. Primary resection was performed in all patients. Patients had IRS group I (n = 28), II (n = 9), and III (n = 2); not available (n = 1). To achieve complete remission (CR), a secondary resection was performed in 18 patients resulting in microscopically complete (R0, n = 34/40) and microscopically incomplete (R1, n = 5/40) resection. All patients achieved CR. The 5-year event-free survival (EFS) and overall survival was 86% (±12; CI, 95%) and 100% (±0; CI, 95%), respectively. R0 resection/IRS I was significantly favorable for the 5-year EFS. Local relapse occurred after a median time of 1.1 years (range, 0.04-5.1) in 15% (6/40) after CR. All patients with RD underwent resection and achieved CR. Three patients had fibrosarcomatous DFSP, two were alive after R0 resection.

CONCLUSION

Complete surgical resection is mandatory to prevent relapse of DFSP.

Endothelial cell malignancies in infants, children and adolescents: Treatment results of three Cooperative Weichteilsarkom Studiengruppe (CWS) trials and one registry

BACKGROUND

Endothelial cell malignancies are extremely rare in childhood. New identification of genetic abnormalities (WWTR1:CAMTA1 translocation) helps to recognize potential therapeutic targets. Little is known about treatment and outcome of these patients.

METHODS

Clinical course, treatment, and outcome in patients with endothelial cell malignancies treated within the Cooperative Weichteilsarkom Studiengruppe (CWS) trials CWS-91, -96, -2002P, and the Soft-Tissue Sarcoma Registry (SoTiSaR) were analyzed (1991-2019).

RESULTS

Patients had angiosarcoma (AS) (n = 12), malignant epithelioid hemangioendothelioma (EHE) (n = 16), and kaposiform hemangioendothelioma (KHE) (n = 13). The median age was 5.39 years (range, 0.8-17.34); 33 patients had localized disease (LD), and 8 patients had metastatic disease. Therapy consisted of chemotherapy (CHT) (AS n = 8, EHE n = 9, KHE n = 5), interferon or new agent therapy (EHE n = 5, 2 KHE n = 2), microscopically or macroscopically complete resection (AS n = 3, EHE n = 6, KHE n = 3), and radiotherapy (AS n = 6, EHE n = 2, KHE n = 1). Two patients (KHE) had watch-and-wait strategy resulting in stable disease. Complete remission (CR) was achieved in AS (10/12; 83%), EHE (10/16; 63%), and KHE (5/13; 38%). The five-year EFS and OS for patients with AS was 64% (± 29 CI 95%) and 80% (± 25, CI 95%), with EHE 62% (± 24, CI 95%) and 78% (± 23, CI 95%), with KHE 33% (± 34, CI 95%) and 92% (± 15, CI 95%), respectively. Complete resection was a significant prognostic factor for AS, LD for EHE.

CONCLUSIONS

Endothelial cell malignancies in childhood have a fair outcome with multimodal treatment. New treatment options are needed for metastic disease.

Low-grade fibromyxoid sarcoma: A report of the Cooperative Weichteilsarkom Studiengruppe (CWS)

BACKGROUND

Low-grade fibromyxoid sarcoma (LGFMS) is a rare soft-tissue tumor with benign histologic appearance, though fully malignant behavior is possible.

METHODS

Patients with LGFMS <21 years registered in Cooperative Weichteilsarkom Studiengruppe trials until 2017 were analyzed. Firstline treatment consisted of complete surgical resection whenever possible.

RESULTS

Median age of 31 patients was 10.9 years (first month to 17.1 years). Twenty-six tumors were confirmed to the tissue of origin (T1), four invaded contiguous structures (T2), one was TX. Eight were >5 cm. The best surgical result was resection with free margins (R0) in 24 and microscopic residuals (R1) in seven. Five-year event-free (EFS), 5-year local-relapse-free (LRFS), and 5-year overall-survival were 71 ± 18.6% confidence interval (CI) 95%, 76 ± 17.6% CI 95%, and 100%, respectively. Six patients suffered local relapse in a median of 1 year, one combined within 1.3 year and one metastatic relapse with lesions in the lung, back muscles, and thigh discovered in whole-body imaging 6 years after the first diagnosis. In univariate analysis, T status correlated with EFS (T1 79.6 ± 18.6%, T2 50.0 ± 49.0%, P = .038). Resection with free margins tends to be associated with better LRFS (R0 82.4 ± 18.6%, R1 53.6 ± 39.4%, P = .053). Among 24 patients with R0 resection, five (21%) suffered relapse, thereof three local, one metastatic, and one combined. Among seven patients with R1-resection, three (43%) suffered local relapse.

CONCLUSION

Special caution is advisable in T2 tumors. The metastatic potential with lesions in unusual sites indicates that affected patients need to be informed. If long-term follow-up with whole-body imaging is beneficial, it may be addressed in larger intergroup analyses. Further research in disease biology is essential for optimal treatment and follow-up care.

Synovial sarcoma disease characteristics and primary tumor sites differ between patient age groups: a report of the Cooperative Weichteilsarkom Studiengruppe (CWS)

BACKGROUND

Older age is associated with worse outcome in synovial sarcoma (SS) patients. Differences in disease presentation among distinct age groups, however, are currently unknown.

METHODS

SS patients < 21 years registered in consecutive CWS trials over the period of 1981-2018 were evaluated. Characteristics were analyzed according to age groups using the Fisher's exact test.

RESULTS

The study population included 432 SS patients. Disease characteristics differed according to age groups of children (0-12 years, n = 176), adolescents (13-16 years, n = 178), and young adults (17-21 years, n = 78). The proportion of invasive tumors (T2) was significantly higher in older patients: children 33%, adolescents 39% and young adults 54%, p = 0.009805. Similarly, the proportion of tumors > 10 cm was higher (13%, 21%, 31%; p = 0.005657) whereas conversely, the proportion of small tumors < 3 cm was lower in older patients (29%, 24%, 6%; p = 0.000104). The presence of metastases at first diagnosis was also highest in older patients (6%, 10%, 21%, p = 0.000963). Notably, the proportion of thigh tumors was higher in older patients (p = 0.04173), whereas the proportion of head-neck tumors was lower in older patients (p = 0.08896).

CONCLUSIONS

The rates of large, invasive tumors and the presence of metastases are significantly associated with older patient age. Localization to the thigh is more frequent in older patients.

DISCUSSION

The causes for these variations require further exploration.

Epithelioid sarcoma in children, adolescents, and young adults: Localized, primary metastatic and relapsed disease. Treatment results of five Cooperative Weichteilsarkom Studiengruppe (CWS) trials and one registry

BACKGROUND

Epithelioid sarcoma (ES) is a rare malignant soft-tissue tumor. Little is known about the optimal treatment of primary localized (LD), metastatic (MD), and relapsed disease (RD).

METHODS

Characteristics, treatment, and outcome of 67 patients registered within the Cooperative Weichteilsarkom Studiengruppe CWS-81, -86, -91, -96, -2002P trials and the registry SoTiSaR were analyzed (1981-2016).

RESULTS

The median age was 14 years (range, 0.7-26.9); 53 patients had localized disease (LD) and 14 metastatic disease (MD). A total of 58 of 67 patients were treated with primary resection. Resection was microscopically complete (R0) in 35, microscopically incomplete (R1) in 12, macroscopically incomplete (R2) in 20 patients. Radiotherapy (RT) was administered to 33 of 67 patients and 49 of 67 patients received chemotherapy (CHT). Complete remission (CR) was achieved in 45 of 53 (85%) patients with LD. Twenty-seven of 53 patients relapsed after a median time of 0.9 years (range, 0.1-2.3). Relapse therapy consisted of resection (n = 19/27), RT (n = 10/27), CHT (n = 12/27), and limb perfusion (n = 3/27). The five-year event-free survival and overall survival of patients with LD, MD, and RD was 35% (± 12, CI 95%) and 58% (± 14, CI 95%), 7% (± 14, CI 95%), and 9% (± 16, CI 95%), 24% (± 17, CI 95%), and 40% (± 20, CI 95%), respectively. Tumor size, IRS group, tumor invasiveness, nodal status, and best resection correlated with a favorable prognosis in patients with LD while best resection was the only significant factor in patients with RD.

CONCLUSIONS

Complete tumor resection correlates with long-term survival in patients with ES.

Treatment and outcome of patients with thoracic tumors of the Ewing sarcoma family: A report from the Cooperative Weichteilsarkom Studiengruppe CWS-81, -86, -91, -96, and -2002P trials

BACKGROUND

Ewing tumors are the most frequent malignant tumors of the chest wall in children and young adults. Surgical management of these tumors can be challenging. Optimal local control remains controversial. The aim of this study was to analyze treatment, outcome, and surgical procedures in patients with thoracic tumors of the Ewing sarcoma family (TES) treated within four Cooperative Soft-Tissue Sarcoma (CWS) trials and one registry.

PATIENTS AND METHODS

Sixty-two patients from 0 to 21 years treated between 1981 and 2014 were selected for this analysis. A retrospective chart analysis was carried out. Institutional review board approval was obtained for all trials.

RESULTS

The median age of the patients was 7 years. The 5-year overall (OS) and event-free survival (EFS) rates were 58.7% (52.7-64.7) and 52.8% (46.8-58.8). Patients with intrathoracic tumor localization (n = 24) had a worse outcome (EFS: 37.5%; 27.5-37.5) compared with those with chest wall tumors (n = 38; EFS: 62.3%; 54.3-70.3, P = 0.008). Patients ≤10 years (n = 38) had a better survival compared with those > 10 years (EFS: 65.7%; 57.7-73.7 vs 31.3%; 21.3-41.3, P = 0.01). Tumor size ≤5 cm (n = 15) was associated with significantly better survival compared with a size > 5 cm (n = 47, EFS: 93.3%; 87.3-99.3 vs 40%; 33-47, P = 0.002). Primary resections were carried out in 36 patients, of which 75% were incomplete resulting in inferior EFS (P = 0.006). Complete secondary resections were performed in 22 of 40.

CONCLUSIONS

Positive predictive factors for outcome are age ≤10 years, size ≤5 cm, and localization at the chest wall. Diverse IRS groups require individual treatment.

Rhabdomyosarcoma diagnosed in the first year of life: Localized, metastatic, and relapsed disease. Outcome data from five trials and one registry of the Cooperative Weichteilsarkom Studiengruppe (CWS)

BACKGROUND

Rhabdomyosarcoma (RMS) diagnosed during the first year of life is reported to have poor outcome. Little is known about treatment and outcome data of relapsed disease (RD).

METHODS

Characteristics, treatment, and outcome of 155 patients ≤ 12 months registered within the Cooperative Weichteilsarkom Studiengruppe (CWS) between 1981 and 2016 were evaluated.

RESULTS

Localized disease (LD) was diagnosed in 144 patients and metastatic disease (MD) in 11. The histological diagnosis was alveolar (RMA) (n = 38, 23/25 examined patients PAX7/3:FOXO1-positive), embryonal (RME) (n = 100), botryoid (n = 10), anaplastic (n = 1), and spindle-cell RMS (n = 6). Multimodal treatment including conventional (age-adjusted) chemotherapy (CHT) (n = 150), resection (n = 137), and radiotherapy (RT) (n = 37) was administered. Complete remission was achieved in 129 of 144 patients with LD. RD occurred in 51 infants at a median age of 1.7 years (range, 0.3-8.8). Sixty-three percent of patients with RMA suffered RD, in contrast to 28% of patients with RME. Relapse treatment consisted of conventional CHT (n = 48), resection (n = 28), and RT (n = 21). The pattern of relapse and best resection were significant prognostic factors for patients with RD (P = 0.000 and P = 0.002). Late effects occurred as secondary malignancies in 6%, long-term toxicity in 21%, and resection-related impairment in 33% of the 105 surviving patients. The 5-year event-free survival and overall survival for infants with initial LD were 51% and 69%, 14% and 14% for patients with initial MD and 39% and 41% for relapsed patients, respectively.

CONCLUSION

Multimodal treatment including microscopically complete resection is strongly recommended to achieve a good prognosis in LD and RD of infants with RMS.

What is the best therapy for grossly resected synovial sarcoma? Experience of the CWS Study Group

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Background: Adjuvant therapy in patients with localized grossly resected synovial sarcoma (SS) still is a matter of debate. This analysis was performed to contribute to the clarification. Methods: SS patients of all ages with initially gross tumor resection registered in the prospective international CWS-trials 1981–2013 were evaluated. CWS-protocols currently recommend chemotherapy for all SS patients. Results: 185 patients with median age of 13.9 years (range 0.1–56.9) and median follow-up of 7.2 years (0.2-31.1) had 5-year event-free (EFS) and overall survival (OS) of 82.9%±5.7 (95%CI) and 92.5%±3.9, respectively. All but six patients received adjuvant chemotherapy. Best surgical treatment consisted of R0-resection in 107 and R1-resection in 70; no information in 7. 135 (73%) were irradiated. In the univariate analysis factors associated with EFS are tumor size and the application of chemotherapy; factors associated with OS are tumor site, size and invasiveness. In the multivariate analysis independent factors for adverse EFS are large tumor size and the application of chemotherapy, for OS tumor site and size. In the group of 58 patients with tumors < 3cm one patient suffered metastatic recurrence (2%), in those 59 patients with tumors 3-5cm 3 suffered metastatic recurrence (5%). In 42 patients with tumors 5-10cm, 4 metastatic and 2 combined recurrences were reported (14%), and in those 13 patients with tumors > 10cm 4 suffered metastatic and 1 combined relapse (38%). Conclusions: Patients with grossly resected SS treated according to the CWS recommendations have an excellent prognosis. A subgroup with very low metastatic potential probably does not need chemotherapy. Whether tumor size and surgery are sufficient criteria has still to be proven by long term results. Biological studies are needed.

Treatment and outcome of patients with thoracic tumors of the Ewing sarcoma family: A report from the Cooperative Weichteilsarkom Studiengruppe CWS-81, -86, -91, -96, and -2002P trials

BACKGROUND

Ewing tumors are the most frequent malignant tumors of the chest wall in children and young adults. Surgical management of these tumors can be challenging. Optimal local control remains controversial. The aim of this study was to analyze treatment, outcome, and surgical procedures in patients with thoracic tumors of the Ewing sarcoma family (TES) treated within four Cooperative Soft-Tissue Sarcoma (CWS) trials and one registry.

PATIENTS AND METHODS

Sixty-two patients from 0 to 21 years treated between 1981 and 2014 were selected for this analysis. A retrospective chart analysis was carried out. Institutional review board approval was obtained for all trials.

RESULTS

The median age of the patients was 7 years. The 5-year overall (OS) and event-free survival (EFS) rates were 58.7% (52.7-64.7) and 52.8% (46.8-58.8). Patients with intrathoracic tumor localization (n = 24) had a worse outcome (EFS: 37.5%; 27.5-37.5) compared with those with chest wall tumors (n = 38; EFS: 62.3%; 54.3-70.3, P = 0.008). Patients ≤10 years (n = 38) had a better survival compared with those > 10 years (EFS: 65.7%; 57.7-73.7 vs 31.3%; 21.3-41.3, P = 0.01). Tumor size ≤5 cm (n = 15) was associated with significantly better survival compared with a size > 5 cm (n = 47, EFS: 93.3%; 87.3-99.3 vs 40%; 33-47, P = 0.002). Primary resections were carried out in 36 patients, of which 75% were incomplete resulting in inferior EFS (P = 0.006). Complete secondary resections were performed in 22 of 40.

CONCLUSIONS

Positive predictive factors for outcome are age ≤10 years, size ≤5 cm, and localization at the chest wall. Diverse IRS groups require individual treatment.

Desmoplastic small round cell tumors: Multimodality treatment and new risk factors

Background

To evaluate optimal therapy and potential risk factors.

Methods

Data of DSRCT patients <40 years treated in prospective CWS trials 1997‐2015 were analyzed.

Results

Median age of 60 patients was 14.5 years. Male:female ratio was 4:1. Tumors were abdominal/retroperitoneal in 56/60 (93%). 6/60 (10%) presented with a localized mass, 16/60 (27%) regionally disseminated nodes, and 38/60 (63%) with extraperitoneal metastases. At diagnosis, 23/60 (38%) patients had effusions, 4/60 (7%) a thrombosis, and 37/54 (69%) elevated CRP. 40/60 (67%) patients underwent tumor resection, 21/60 (35%) macroscopically complete. 37/60 (62%) received chemotherapy according to CEVAIE (ifosfamide, vincristine, actinomycin D, carboplatin, epirubicin, etoposide), 15/60 (25%) VAIA (ifosfamide, vincristine, adriamycin, actinomycin D) and, 5/60 (8%) P6 (cyclophosphamide, doxorubicin, vincristine, ifosfamide, etoposide). Nine received high‐dose chemotherapy, 6 received regional hyperthermia, and 20 received radiotherapy. Among 25 patients achieving complete remission, 18 (72%) received metronomic therapies. Three‐year event‐free (EFS) and overall survival (OS) were 11% (±8 confidence interval [CI] 95%) and 30% (±12 CI 95%), respectively, for all patients and 26.7% (±18.0 CI 95%) and 56.9% (±20.4 CI 95%) for 25 patients achieving remission. Extra‐abdominal site, localized disease, no effusion or ascites only, absence of thrombosis, normal CRP, complete tumor resection, and chemotherapy with VAIA correlated with EFS in univariate analysis. In multivariate analysis, significant factors were no thrombosis and chemotherapy with VAIA. In patients achieving complete remission, metronomic therapy with cyclophosphamide/vinblastine correlated with prolonged time to relapse.

Conclusion

Pleural effusions, venous thrombosis, and CRP elevation were identified as potential risk factors. The VAIA scheme showed best outcome. Maintenance therapy should be investigated further.

Alveolar soft-part sarcoma: Primary metastatic disease and metastatic relapse occurring during long-term follow-up: Treatment results of four Cooperative Weichteilsarkom Studiengruppe (CWS) trials and one registry

BACKGROUND

Patients with metastatic alveolar soft-part sarcoma (ASPS) are known to have a very poor prognosis. Little is known about best treatment of primary metastatic disease (MD) or relapsed metastatic disease (rMD).

PATIENTS AND METHODS

Patients with localized disease (LD), primary MD, and metastatic recurrence after complete remission (CR) treated within the CWS-86, -91, -96, -2002P trials and the recent registry SoTiSaR (1985-2016) were analyzed.

RESULTS

Fifteen of 61 patients had primary metastases at initial diagnosis at the age of 14.6 years (range, 7.8-19.7). Nine of 46 patients with initial LD suffered of rMD at a median age of 9.9 years (range, 3.5-30), 3.75 years (0.75-21) after CR of primary disease. Complete resection (microscopically or macroscopically) was possible in 2 of 15 patients with MD and in 5 of 9 with rMD. RT was administered in 4 of 15 MD and 1 of 9 rMD. Chemotherapy was administered to 11 of 15 MD and 3 of 9 rMD, targeted therapy to 3 of 15 MD and 1 of 9 rMD. Median time to progression of patients treated with targeted therapy (n = 4), CHT (n = 14), and resection only (n = 6) was 56, 17, and 23 months, respectively. The 5-year event-free survival and overall survival (OS) rates were 19.8% and 61%, respectively, for patients with MD compared with 79% and 98% for patients with LD. The 5-year progression-free survival and OS were 67% and 100% for patients with rMD.

CONCLUSIONS

Complete tumor resection correlates with long-term survival in patients with primary and relapsed MD.

Demographic and Treatment Variables Influencing Outcome for Localized Paratesticular Rhabdomyosarcoma: Results From a Pooled Analysis of North American and European Cooperative Groups

PURPOSE

Treatment recommendations for localized paratesticular rhabdomyosarcoma (PT RMS) differ in North America and Europe. We conducted a pooled analysis to identify demographic features and treatment choices that affect outcome.

PATIENTS AND METHODS

We retrospectively analyzed the effect of nine demographic variables and four treatment choices on event-free survival (EFS) and overall survival (OS) from 12 studies conducted by five cooperative groups.

RESULTS

Eight hundred forty-two patients with localized PT RMS who enrolled from 1988 to 2013 were included. Patients age ≥ 10 years were more likely than younger patients to have tumors that were > 5 cm, enlarged nodes (N1), or pathologically involved nodes ( P ≤ .05 each). With a median follow-up of 7.5 years, Kaplan-Meier estimates for 5-year EFS and OS were 87.7% and 94.8%, respectively. Of demographic variables, cooperative group, era of enrollment, age category, tumor size, Intergroup Rhabdomyosarcoma Study group, and T stage affected EFS ( P ≤ .05 each). Surgical assessment of regional nodes, which was performed in 23.5% of patients-usually in those age ≥ 10 years or with suspicious or N1 nodes-was the only treatment variable associated with EFS by univariable and multivariable analyses ( P ≤ .05 each) in patients age ≥ 1 year. A variable selection procedure on a proportional hazards regression model selected era of enrollment, age, tumor size, and surgical assessment of regional nodes as significant ( P ≤ .05 each) in the EFS model, and era of enrollment, age, tumor size, and histology ( P ≤ .05 each) in the OS model.

CONCLUSION

Localized PT RMS has a favorable prognosis. Age ≥ 10 years at diagnosis and tumor size larger than 5 cm are unfavorable prognostic features. Surgical assessment of regional nodes is important in patients age ≥ 10 years and in those with N1 nodes as it affects EFS.

Inflammatory myofibroblastic tumors-A retrospective analysis of the Cooperative Weichteilsarkom Studiengruppe

BACKGROUND

Inflammatory myofibroblastic tumors (IMTs) are a rare subgroup of soft tissue tumors. The outcome of patients with IMT has been reported as favorable when the tumor is completely resected. If surgical resection is not possible, systemic therapy has to be considered. However, the best systemic treatment and response rates are currently unclear.

METHODS

Thirty-eight patients under the age of 21, who were registered between 2000 and 2014 with a primary diagnosis of IMT, were analyzed.

RESULTS

IMT was typically localized intra-abdominally or in the pelvis. In 20 patients, the tumor was resected without further therapy; 17 patients were in complete remission at last evaluation and two patients were in partial remission. Eighteen patients received systemic therapy, 15 of whom had macroscopically incomplete resection. Systemic therapy most commonly consisted of regimens with dactinomycin, ifosfamide or cyclophosphamide, and vincristine, with or without doxorubicin, and it seemed to reduce tumor extension in individual cases. Five-year event-free survival was 74 ± 14% and 5-year overall survival was 91 ± 10% for all patients. The patients who died due to the disease were those with incomplete resection (n = 3).

CONCLUSIONS

Surgery without further systemic therapy was a feasible and acceptable therapeutic option for every second patient with IMT. Standard chemotherapy for pediatric soft tissue sarcoma produced favorable results in individual cases and was able to shrink the tumor enough to enable resection. Superior efficacy of new targeted therapies such as anaplastic lymphoma kinase-inhibitors compared to standard chemotherapy has to be proven in the future.