Role of high-dose chemotherapy with hematopoietic stem cell rescue in the treatment of metastatic or recurrent rhabdomyosarcoma

Preclinical development of a chimeric antigen receptor T cell therapy targeting FGFR4 in rhabdomyosarcoma

Pediatric patients with relapsed or refractory rhabdomyosarcoma (RMS) have dismal cure rates, and effective therapy is urgently needed. The oncogenic receptor tyrosine kinase fibroblast growth factor receptor 4 (FGFR4) is highly expressed in RMS and lowly expressed in healthy tissues. Here, we describe a second-generation FGFR4-targeting chimeric antigen receptor (CAR), based on an anti-human FGFR4-specific murine monoclonal antibody 3A11, as an adoptive T cell treatment for RMS. The 3A11 CAR T cells induced robust cytokine production and cytotoxicity against RMS cell lines in vitro. In contrast, a panel of healthy human primary cells failed to activate 3A11 CAR T cells, confirming the selectivity of 3A11 CAR T cells against tumors with high FGFR4 expression. Finally, we demonstrate that 3A11 CAR T cells are persistent in vivo and can effectively eliminate RMS tumors in two metastatic and two orthotopic models. Therefore, our study credentials CAR T cell therapy targeting FGFR4 to treat patients with RMS.

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.

Approaches to identifying drug resistance mechanisms to clinically relevant treatments in childhood rhabdomyosarcoma

Aim

Despite aggressive multiagent protocols, patients with metastatic rhabdomyosarcoma (RMS) have poor prognosis. In a recent high-risk trial (ARST0431), 25% of patients failed within the first year, while on therapy and 80% had tumor progression within 24 months. However, the mechanisms for tumor resistance are essentially unknown. Here we explore the use of preclinical models to develop resistance to complex chemotherapy regimens used in ARST0431.

Methods

A Single Mouse Testing (SMT) protocol was used to evaluate the sensitivity of 34 RMS xenograft models to one cycle of vincristine, actinomycin D, cyclophosphamide (VAC) treatment. Tumor response was determined by caliper measurement, and tumor regression and event-free survival (EFS) were used as endpoints for evaluation. Treated tumors at regrowth were transplanted into recipient mice, and the treatment was repeated until tumors progressed during the treatment period (i.e., became resistant). At transplant, tumor tissue was stored for biochemical and omics analysis.

Results

The sensitivity to VAC of 34 RMS models was determined. EFS varied from 3 weeks to > 20 weeks. Tumor models were classified as having intrinsic resistance, intermediate sensitivity, or high sensitivity to VAC therapy. Resistance to VAC was developed in multiple models after 2-5 cycles of therapy; however, there were examples where sensitivity remained unchanged after 3 cycles of treatment.

Conclusion

The SMT approach allows for in vivo assessment of drug sensitivity and development of drug resistance in a large number of RMS models. As such, it provides a platform for assessing in vivo drug resistance mechanisms at a "population" level, simulating conditions in vivo that lead to clinical resistance. These VAC-resistant models represent "high-risk" tumors that mimic a preclinical phase 2 population and will be valuable for identifying novel agents active against VAC-resistant disease.

Recent Advances and Challenges in the Treatment of Rhabdomyosarcoma

Rhabdomyosarcoma, the most common soft tissue sarcoma noted in childhood, requires multimodality treatment, including chemotherapy, surgical resection, and/or radiation therapy. The majority of the patients with localized rhabdomyosarcoma can be cured; however, the long-term outcomes in patients with metastatic rhabdomyosarcoma remain poor. The standard chemotherapy regimen for patients with rhabdomyosarcoma is the combination of vincristine, actinomycin, and cyclophosphamide/ifosfamide. In recent clinical trials, modifications of the standard chemotherapy protocol have shown improvements in the outcomes in patients with rhabdomyosarcoma. In various type of malignancies, new treatments, such as molecular targeted drugs and immunotherapies, have shown superior clinical outcomes compared to those of standard treatments. Therefore, it is necessary to assess the benefits of these treatments in patients with rhabdomyosarcoma. Moreover, recent basic and clinical studies on rhabdomyosarcoma have reported promising therapeutic targets and novel therapeutic approaches. This article reviews the recent challenges and advances in the management of rhabdomyosarcoma.

Management of Refractory Pediatric Sarcoma: Current Challenges and Future Prospects

Paediatric sarcomas are a heterogeneous group of disorders constituting bone sarcoma and various soft tissue sarcomas. Almost one-third of these presents with metastasis at baseline and another one-third recur after initial curative treatment. There is a huge unmet need in this cohort in terms of curative options and/or prolongation of survival. In this review, we have discussed the current treatment options, challenges and future strategies of managing relapsed/refractory paediatric sarcomas. Upfront risk-adapted treatment with multidisciplinary management remains the main strategy to prevent future recurrence or relapse of the disease. In the case of limited local and/or systemic relapse or late relapse, initial multimodality management can be administered. In treatment-refractory cases or where cure is not feasible, the treatment options are limited to novel therapeutics, immunotherapeutic approach, targeted therapies, and metronomic therapies. A better understanding of disease biology, mechanism of treatment refractoriness, identifications of driver mutation, the discovery of novel targeted therapies, cellular vaccine and adapted therapies should be explored in relapsed/refractory cases. Close national and international collaboration for translation research is needed to fulfil the unmet need.

Current and Future Treatment Strategies for Rhabdomyosarcoma

Rhabdomyosarcoma (RMS) is the most common soft tissue sarcoma in children, and can be subcategorized histologically and/or based on PAX-FOXO1 fusion gene status. Over the last four decades, there have been no significant improvements in clinical outcomes for advanced and metastatic RMS patients, underscoring a need for new treatment options for these groups. Despite significant advancements in our understanding of the genomic landscape and underlying biological mechanisms governing RMS that have informed the identification of novel therapeutic targets, development of these therapies in clinical trials has lagged far behind. In this review, we summarize the current frontline multi-modality therapy for RMS according to pediatric protocols, highlight emerging targeted therapies and immunotherapies identified by preclinical studies, and discuss early clinical trial data and the implications they hold for future clinical development.

Fifty years of rhabdomyosarcoma studies on both sides of the pond and lessons learned

We review and summarize the highlights of almost five decades of cooperative group trials in rhabdomyosarcoma on both sides of the Atlantic, concentrating on chemotherapy regimens, what has been learned, and where remaining challenges are. The most important achievements have been to decrease or omit the dose of alkylator therapy for many patients, to clarify after much controversy that doxorubicin does not improve the outcome of patients even in the highest risk groups, and to show that high dose chemotherapy and stem cell rescue do not improve the outcome of the highest risk patients. In North America, vincristine/actinomycin/cyclophosphamide (VAC) remains an important part of therapy, whereas in Europe the alkylating agent of choice is ifosfamide. The highest risk patients, namely those with the poorest prognostic score, have had no improvement in outcome since the first cooperative group trial in 1972 and remain the greatest challenge. Philosophical differences between European and North American strategies still revolve somewhat around the total burden of therapy received, that is should certain groups of patients be spared aggressive local control in order to reduce late effects, recognizing that it is not possible to identify priori the children that can be cured with this approach exposing the whole population to a higher risk of relapse. Collaboration and joining resources may help answer some difficult questions.

Current standards of care in bladder and prostate rhabdomyosarcoma

Rhabdomyosarcoma (RMS) is the most common soft tissue tumor in children, and 15% to 20% arise from the genitourinary tract. Multicenter collaborative studies have improved survival substantially, and in addition to excellent oncologic control, current treatment focuses on organ preservation and minimization of late treatment effects. The multiple modalities needed to treat RMS dictate that treating physicians must be familiar with the disease as well as the goals and possible sequelae of treatment with chemotherapy, radiotherapy, and surgery. This article discusses the current standards of care for bladder and prostate RMS.

Relapse after localized rhabdomyosarcoma: Evaluation of the efficacy of second-line chemotherapy

PURPOSE

About one-third of patients with rhabdomyosarcoma relapse despite appropriate treatment and experience a poor outcome. Little meaningful improvement in the outcome of this disease has been observed over the last 30 years. There is no clear international recommendation concerning the use of salvage chemotherapy at relapse. A retrospective multicenter analysis was therefore conducted to analyze the efficacy of various second-line chemotherapy regimens in this setting.

METHODS

Forty-nine patients under the age of 18, with initially localized rhabdomyosarcoma, who relapsed after first complete remission, treated in three SFCE centers (Société Française des Cancers de l'Enfant) between 1995 and 2013, were analyzed.

RESULTS

First relapse occurred after a median interval of 22 months and remained localized in 71.4% of cases. All patients received second-line chemotherapy with an overall response to this salvage therapy of 39.1%. Best specific response rates were 73.3 and 42.9% for carboplatin/epirubicin/vincristine-ifosfamide/vincristine/etoposide (CEV/IVE) (15 patients) and vincristine/irinotecan ± temozolomide (VI[T]) (seven patients), respectively. Overall, 40 patients (81.6%) were then eligible for delayed local treatment (surgery and/or radiotherapy) and 30 of them (61.2%) achieved second complete remission. After a median follow-up of 5.4 years since the diagnosis of first relapse, 5-year overall survival is 49.4% (95% CI: 34.2-64.6).

CONCLUSION

Salvage chemotherapy plays a central role in the management of patients with relapsed rhabdomyosarcoma. CEV/IVE and VI(T) regimens can be recommended as neoadjuvant chemotherapy before local treatment for patients with relapsed rhabdomyosarcoma.

Intensive Multiagent Therapy, Including Dose-Compressed Cycles of Ifosfamide/Etoposide and Vincristine/Doxorubicin/Cyclophosphamide, Irinotecan, and Radiation, in Patients With High-Risk Rhabdomyosarcoma: A Report From the Children's Oncology Group

PURPOSE

Patients with metastatic rhabdomyosarcoma (RMS), except those younger than 10 years with embryonal RMS, have an estimated long-term event-free survival (EFS) of less than 20%. The main goal of this study was to improve outcome of patients with metastatic RMS by dose intensification with interval compression, use of the most active agents determined in phase II window studies, and use of irinotecan as a radiation sensitizer.

PATIENTS AND METHODS

Patients with metastatic RMS received 54 weeks of therapy: blocks of therapy with vincristine/irinotecan (weeks 1 to 6, 20 to 25, and 47 to 52), interval compression with vincristine/doxorubicin/cyclophosphamide alternating with etoposide/ifosfamide (weeks 7 to 19 and 26 to 34), and vincristine/dactinomycin/cyclophosphamide (weeks 38 to 46). Radiation therapy occurred at weeks 20 to 25 (primary) but was also permitted at weeks 1 to 6 (for intracranial or paraspinal extension) and weeks 47 to 52 (for extensive metastatic sites).

RESULTS

One hundred nine eligible patients were enrolled, with a median follow-up of surviving patients of 3.8 years (3-year EFS for all patients, 38% [95% CI, 29% to 48%]; survival, 56% [95% CI, 46% to 66%]). Patients with one or no Oberlin risk factor (age > 10 years or < 1 year, unfavorable primary site of disease, ≥ three metastatic sites, and bone or bone marrow involvement) had a 3-year EFS of 69% (95% CI, 52% to 82%); high-risk patients with two or more risk factors had a 3-year EFS of 20% (95% CI, 11% to 30%). Toxicity was similar to that on prior RMS studies.

CONCLUSION

Patients with metastatic RMS with one or no Oberlin risk factor had an improved 3-year EFS of 69% on ARST0431 compared with an historical cohort from pooled European and US studies; those with two or more risk factors have a dismal prognosis, and new approaches are needed for this very-high-risk group.

The role of high-dose therapy and autologous stem cell transplantation for pediatric bone and soft tissue sarcomas

The prognosis for children with bone and soft tissue sarcomas has significantly improved since the advent of effective multiagent chemotherapy, aggressive surgery for local disease and more precise delivery of radiotherapy doses. However, in a small proportion of patients that present with high-risk disease, long-term outcome has not substantially increased, with disease-free survival rates still in the order of 20-30%. It is therefore clear that novel therapies are needed for children with these tumors. Based on the highly chemosensitive nature of the majority of pediatric sarcomas, several small studies have been conducted to investigate the potential role of high-dose chemotherapy followed by hematopoietic stem cell reconstitution. This review will provide an overview of the current literature concerning the use of high-dose therapy with stem cell transplantation for the three main pediatric sarcomas--Ewing sarcoma, rhabdomyosarcoma and osteosarcoma.

Survival following disease recurrence of primary localized alveolar rhabdomyosarcoma

BACKGROUND

Recurrences in primary localized alveolar rhabdomyosarcoma (RMA) are common. Post-relapse survival is poor. We evaluated prognostic factors including relapse treatment in patients with recurrent RMA.

METHODS

Relapses occurred in 115/235 patients with nonmetastatic RMA treated in four consecutive CWS-trials after achievement of a complete remission. Sufficient information about post-relapse treatment and outcome could be obtained in 99 patients and was retrospectively analyzed.

RESULTS

Nine of 99 patients received no salvage therapy and died after a median of 2 months. The remaining 90 patients received multimodal relapse treatment including mandatory chemotherapy. Recurrences were grossly resected in 39 patients; 57 patients received radiation. At a median follow-up from relapse of 8 years, 20 patients were alive and disease-free (5-year post-relapse survival [PROS] 21.3 ± 8). All surviving patients apart from a single individual had an isolated, circumscribed recurrence. Sixteen of 20 survivors were treated with adequate local relapse therapy (ALRT, i.e., either complete resection or gross resection + radiation). Survival in the subgroup of 27 individuals with circumscribed recurrences and ALRT was significantly better (PROS 53.7 ± 19) compared with disseminated recurrences and/or tumors treated without ALRT. Absence of primary lymph node involvement, circumscribed relapses, ALRT, and achievement of a second CR were identified as independent favorable risk factors.

CONCLUSION

Post-relapse survival for primary localized RMA is generally poor. However, certain patient groups differed significantly in their likelihood of survival and 50% of patients with circumscribed relapses treated with ALRT survived. These findings may form the basis for an evidence-based risk-stratification for recurrent disease including relapse treatment.

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.

Common musculoskeletal tumors of childhood and adolescence

Osteosarcoma, Ewing sarcoma, and rhabdomyosarcoma are the most common malignant musculoskeletal tumors in children and adolescents. Today, most patients can be cured. Numerous factors have contributed to improved outcome for these patients over the past several decades. These include multidisciplinary care involving oncologists, radiation oncologists, surgeons, pathologists, and radiologists and enrollment of patients in clinical trials. Better understanding of molecular mechanisms of disease have resulted in studies using molecular targets in addition to standard chemotherapeutic agents, which hopefully will lead to better outcomes in the future. Moreover, new orthopedic techniques and devices as well as new technologies in radiation oncology hold promise for better local control of primary tumors and the potential for fewer late adverse effects. Despite this progress, patients must undergo lifelong follow-up for possible late effects of intense chemotherapy and radiation therapy. We review the diagnosis, prognosis, staging, multidisciplinary therapy, new directions in therapy, and long-term complications of treatment for these tumors. For this review, we searched MEDLINE using the terms rhabdomyosarcoma, osteosarcoma, Ewing sarcoma, biology, and humans and limited the search to articles from 2000 to September 2011. Additional references found in these articles were utilized as appropriate, as well as references from the background information in current therapeutic studies of the Children's Oncology Group. The same database and time frame were searched for articles written by leading authorities in the field.

Selecting multimodal therapy for rhabdomyosarcoma

Rhabdomyosarcoma is a typical tumor of childhood, characterized by a high grade of malignancy, local invasiveness and a marked propensity to metastasize, but also a generally good response to chemotherapy and radiotherapy. Multimodal therapy is essential to cure rhabdomyosarcoma patients, but different uses of surgery, radiotherapy and chemotherapy, and their intensity, need to be selected and modulated to different patient risk groups. This article attempts to give an account of the current treatment options, the open and debated issues and the potential novel strategies for the near future.

High-dose chemotherapy followed by autologous stem cell transplantation for metastatic rhabdomyosarcoma--a systematic review

INTRODUCTION

Patients with metastatic rhabdomyosarcoma (RMS) have a poor prognosis. The aim of this systematic review is to investigate whether high-dose chemotherapy (HDCT) followed by autologous hematopoietic stem cell transplantation (HSCT) in patients with metastatic RMS has additional benefit or harm compared to standard chemotherapy.

METHODS

Systematic literature searches were performed in MEDLINE, EMBASE, and The Cochrane Library. All databases were searched from inception to February 2010. PubMed was searched in June 2010 for a last update. In addition to randomized and non-randomized controlled trials, case series and case reports were included to complement results from scant data. The primary outcome was overall survival. A meta-analysis was performed using the hazard ratio as primary effect measure, which was estimated from Cox proportional hazard models or from summary statistics of Kaplan Meier product-limit estimations.

RESULTS

A total of 40 studies with 287 transplant patients with metastatic RMS (age range 0 to 32 years) were included in the assessment. We identified 3 non-randomized controlled trials. The 3-year overall survival ranged from 22% to 53% in the transplant groups vs. 18% to 55% in the control groups. Meta-analysis on overall survival in controlled trials showed no difference between treatments. Result of meta-analysis of pooled individual survival data of case series and case reports, and results from uncontrolled studies with aggregate data were in the range of those from controlled data. The risk of bias was high in all studies due to methodological flaws.

CONCLUSIONS

HDCT followed by autologous HSCT in patients with RMS remains an experimental treatment. At present, it does not appear justifiable to use this treatment except in appropriately designed controlled trials.

Autologous hematopoietic stem cell transplantation following high-dose chemotherapy for non-rhabdomyosarcoma soft tissue sarcomas

BACKGROUND

Soft tissue sarcomas (STS) are a highly heterogeneous group of rare malignant solid tumors. Non-rhabdomyosarcoma soft tissue sarcomas (NRSTS) comprise all STS except rhabdomyosarcoma. In patients with advanced local or metastatic disease, autologous hematopoietic stem cell transplantation (HSCT) applied after high-dose chemotherapy (HDCT) is a planned rescue therapy for HDCT-related severe hematologic toxicity.

OBJECTIVES

To assess the effectiveness and safety of HDCT followed by autologous HSCT for all stages of soft tissue sarcomas in children and adults.

SEARCH STRATEGY

We searched the electronic databases CENTRAL (The Cochrane Library 2010, Issue 2), MEDLINE and EMBASE (February 2010). Online trial registers, congress abstracts and reference lists of reviews were searched and expert panels and authors were contacted.

SELECTION CRITERIA

Terms representing STS and autologous HSCT were required in the title, abstract or keywords. In studies with aggregated data, participants with NRSTS and autologous HSCT had to constitute at least 80% of the data. Comparative non-randomized studies were included because randomized controlled trials (RCTs) were not expected. Case series and case reports were considered for an additional descriptive analysis.

DATA COLLECTION AND ANALYSIS

Study data were recorded by two review authors independently. For studies with no comparator group, we synthesised results for studies reporting aggregate data and conducted a pooled analysis of individual participant data using the Kaplan-Meyer method. The primary outcomes were overall survival (OS) and treatment-related mortality (TRM).

MAIN RESULTS

We included 54 studies, from 467 full texts articles screened (11.5%), reporting on 177 participants that received HSCT and 69 participants that received standard care. Only one study reported comparative data. In the one comparative study, OS at two years after HSCT was estimated as statistically significantly higher (62.3%) compared with participants that received standard care (23.2%). In a single-arm study, the OS two years after HSCT was reported as 20%. In a pooled analysis of the individual data of 54 participants, OS at two years was estimated as 49% (95% CI 34% to 64%). Data on TRM, secondary neoplasia and severe toxicity grade 3 to 4 after transplantation were sparse. All 54 studies had a high risk of bias.

AUTHORS' CONCLUSIONS

Due to a lack of comparative studies, it is unclear whether participants with NRSTS have improved survival from autologous HSCT following HDCT. Owing to this current gap in knowledge, at present HDCT and autologous HSCT for NRSTS should only be used within controlled trials.

High-dose chemotherapy for children and young adults with stage IV rhabdomyosarcoma

BACKGROUND

Rhabdomyosarcoma is the most common soft tissue sarcoma of childhood. Prognosis for patients with metastatic disease has not improved significantly in the past decades. High-dose chemotherapy (HDC) seems to be an attractive option to treat minimal residual disease in metastatic rhabdomyosarcoma patients.

OBJECTIVES

The objective of the review was to assess the effectiveness of HDC with stem cell rescue (SRC) versus standard-dose chemotherapy in improving event-free survival (EFS) and overall survival (OS) of children and young adults with metastatic rhabdomyosarcoma.

SEARCH STRATEGY

We searched the databases of MEDLINE (1966 to December 2009), EMBASE (1980 to December 2009) and CENTRAL (The Cochrane Library Issue 1, 2009). In addition, we handsearched the reference lists of selected papers and conference proceedings of the SIOP, ASPHO and ASCO meetings (all 2000 to 2009).

SELECTION CRITERIA

Randomised controlled trials (RCT), prospective or historical controlled clinical trials (CCT), in which HDC with SCR was compared to conventional chemotherapy and prospective case series (non-controlled clinical trials) including at least 20 naive metastatic rhabdomyosarcoma patients

DATA COLLECTION AND ANALYSIS

Two review authors independently performed the study selection, quality assessment and data extraction.

MAIN RESULTS

No RCTs could be identified. We identified one prospective CCT, one retrospective CCT and one non-controlled clinical trial. Another CCT has been published as an abstract. All studies have severe methodological limitations, in particular selection bias could not be excluded. One CCT reported a significantly worse OS compared to oral maintenance therapy, however in a subgroup of high-risk patients no difference could be found. The retrospective CCT reported a similar survival for HDC compared to conventional chemotherapy. The non-controlled clinical trial and the CCT reported as a conference proceeding reported survival outcomes comparable to previous studies. Data on toxicity showed more grade 3-4 toxicity in the HDC group. However, there was no difference in the number of toxic deaths.

AUTHORS' CONCLUSIONS

Overall, the results of this review do not justify the use of HDC with SCR as a standard therapy for children with metastatic rhabdomyosarcoma. However, all reported studies were possibly subject to significant bias, especially selection bias. This might have underestimated the measured effect of HDC. As a result, a clinically important excess of adverse risk patients in the HDC arms may explain the non-beneficial effect of HDC. Only a large prospective RCT will be able to answer the question of whether HDC with SCR adds to survival or not definitively.

Role of chemotherapy in the management of soft tissue sarcomas

Soft tissue sarcomas are a diverse group of rare tumors that comprise 1% of all cancers. Few randomized trials of chemotherapy have been performed but there is a clear role for agents such as doxorubicin and ifosfamide in the palliation of advanced disease. There is uncertainty as to whether sequential single-agent treatment is equivalent to combination chemotherapy. For the majority of histological subtypes adjuvant chemotherapy is not of proven value, although there may be situations where it is advantageous. However, there are other subtypes, such as the Ewing's sarcoma family tumors, for which chemotherapy is an essential part of primary management and has definitely improved survival. Apart from Ewing's sarcoma family tumor and rhabdomyosarcoma, there is increasing specialization of chemotherapy according to histological subtype, such as the use of taxanes for angiosarcoma, gemcitabine and docetaxel for leiomyosarcoma, and trabectedin for leiomyosarcoma and liposarcoma, especially the myxoid/round cell variant. Nevertheless, there are serious limitations to existing treatment and novel therapies need to be developed.

High-dose chemotherapy with blood or bone marrow transplants for rhabdomyosarcoma

Rhabdomyosarcoma (RMS), the most common soft-tissue sarcoma in children, is cured with conventional therapy in 70%. However, the 5-year survival for those who relapse is about 30%, and drops to about 15% for those with unfavorable histologies (alveolar/undifferentiated subtypes). We describe outcomes of 62 subjects receiving autologous blood/bone marrow (BM) transplants for RMS between 1989 and 2003, and reported to the Center for International Blood and Marrow Transplantation Research (CIBMTR). Histologic subtype was confirmed by reviewing pathology reports. Treatment-related mortality (TRM), progression-free survival (PFS), and overall survival (OS) were evaluated. Overall, 73% of subjects were <20 years; 39% had cancer bulk >5 cm, 63% had metastasis at diagnosis, 55% had unfavorable histologies, 92% had cancer responsive to chemotherapy pretransplant, and 67% were in first remission. The 1-year TRM was 5% (95% confidence interval [CI], 1%-12%) and the 5-year PFS and OS were 29% (95% CI, 18%-41%) and 32% (95% CI, 21%-44%), respectively. There was only a 4% relapse rate after the first year. There were no differences in 5-year PFS or survival based on histological subtype, transplant in first remission versus relapse (36% versus 29%; P = .5), or transplantation for poor-risk histologies in first remission versus relapse (34% versus 33%; P = .9). Our data indicate that autotransplants for RMS disease are typically done in patients with disease responsive to chemotherapy pretransplant, with approximately one-third long-term survivors. Despite high-risk factors, we also found a low TRM, perhaps reflecting the migration from marrow to blood stem cells as the graft source. Even when performed after relapse for alveolar/undifferentiated histologies, long-term survivals were seen seemingly better than results with conventional therapies.

Sequential high-dose chemotherapy for children with metastatic rhabdomyosarcoma

AIM

The RMS4.99 study was designed to explore the role of multiple sequential high-dose chemotherapy cycles administered early in the treatment of children with metastatic rhabdomyosarcoma.

PATIENTS AND METHODS

Seventy patients were enrolled and received three cycles of initial standard chemotherapy, followed by a course of cyclophosphamide and etoposide to obtain peripheral blood stem cells (PBSC), then three consecutive high-dose combinations followed by PBSC rescue. This was followed by surgery and/or radiotherapy, after which a final maintenance treatment with six courses of vincristine, actinomycin D and cyclophosphamide was administered.

RESULTS

Sixty-two patients underwent the high-dose chemotherapy phase. The 3-year overall survival (OS) and progression free survival (PFS) rates for the 70 patients were 42.3% (95% confidence interval [CI] 39.5-53.6) and 35.3% (95% CI, 24.3-46.5), respectively. By multivariate analysis survival correlated strongly with age > 10 years. In a subset of patients with only one or no unfavourable prognostic factors (age > 10 years, unfavourable site of primary tumour, bone or bone marrow involvement and number of metastatic sites >2) the PFS was significantly higher, i.e. 60.5% at 3 years.

CONCLUSION

Our study confirms that patients with favourable prognostic characteristics have a better survival. The use of sequential cycles of high-dose chemotherapy did not appear of benefit for patients with metastatic rhabdomyosarcoma.

Prognostic factors in metastatic rhabdomyosarcomas: results of a pooled analysis from United States and European cooperative groups

PURPOSE

To identify risk factors associated with outcome in children with metastatic rhabdomyosarcoma in a large cohort of patients

PATIENTS AND METHODS

Pooled data were obtained from 788 patients treated in nine studies performed by European and American cooperative groups. Clinical factors, including age, histology, site of primary, and site(s) and number of sites of metastatic disease, were correlated with event-free survival (EFS) and overall survival (OS).

RESULTS

Seven hundred eighty-eight patients were eligible for analysis. The 3-year OS and EFS were 34% (SE, 1.7) and 27% (SE, 1.6), respectively. By univariate analysis, 3-year EFS was significantly and adversely influenced by age, alveolar histology, location of primary tumor in unfavorable site (defined as extremity and "other" sites), presence of three or more sites of metastatic disease, and the presence of bone or bone marrow involvement. By multivariate analysis, EFS was strongly correlated to all factors except histology. Relative risks were 1.6 for age younger than 1 year or at least 10 years, 1.4 for unfavorable site of primary tumor, 1.4 for bone or bone marrow involvement, 1.4 for three or more metastatic sites. EFS was 50% for patients without any of these four adverse factors and was respectively 42%, 18%, 12%, and 5% in patients with one, two, three, or four factors (P < .0001).

CONCLUSION

This analysis identified subsets of patients with metastatic rhabdomyosarcoma with different outcomes to current therapy and offers a strategy to define patient candidates for experimental approaches to treatment.

Treatment of children with metastatic soft tissue sarcoma with oral maintenance compared to high dose chemotherapy: report of the HD CWS-96 trial

PURPOSE

We prospectively studied the efficacy of high dose therapy (HDT) versus an oral maintenance treatment (OMT) in patients with stage IV soft tissue sarcoma (STS).

PATIENTS AND METHODS

Both groups were pretreated with the CEVAIE combination consisting of carboplatin, etoposide, vincristine, actinomycin D, ifosfamide, and epirubicin. HDT consisted of a tandem cycle of thiotepa (600 mg/m(2)) plus cyclophosphamide (4,500 mg/m(2)) and melphalan (120 mg/m(2)) plus etoposide (1,800 mg/m(2)). This treatment was compared with OMT, consisting of four cycles trofosfamide (10 days 2 x 75 mg/m(2)/day) plus etoposide (10 days 2 x 25 mg/m(2)/day), and 4 cycles trofosfamide (10 days 2 x 75 mg/m(2)/day) plus idarubicin (10 days 4 x 5 mg/m(2)). Eligibility criteria were: diagnosis confirmed by reference pathology, primary stage IV, below 22 years of age, and having completed the study therapy.

RESULTS

From 96 patients 45 were treated with HDT and 51 with OMT. The main risk parameters were equally distributed in both arms. After a median follow-up of 57.4 months, 11/45 (24.4%) patients in the HDT-arm and 26/51 (57.8%) patients in OMT-arm were alive. Kaplan-Meier analysis demonstrated an overall survival for the whole group of 0.27 (OMT group: 0.52, HDT group 0.27, log rank P = 0.03). The proportional hazard analysis for patients with rhabdomyosarcoma (RMS) or "RMS-like" tumors (77.1% of all patients) demonstrated an independent benefit of OMT on outcome.

CONCLUSION

Oral maintenance therapy seems to be a promising option for patients with RMS-like stage IV tumors.

Clinical outcome of rhabdomyosarcoma in adolescent and adult patients: single center experience from Turkey

Rhabdomyosarcoma (RMS) is rare disease in adults (age >or= 16 years). The data from randomized prospective trials are scarce; the clinical outcome of these patients seems poor with the currently available treatment strategies. In this study, we report a single institution's experience in the treatment of adult RMS. We reviewed the medical records of patients with RMS who were >or= 16 years and have been treated in our institution between 1988 and 2003 retrospectively. We analyzed the survival outcome of these patients and the prognostic impact of clinical/pathological factors on their survival. In total, 23 patients with RMS were identified. Median age was 26 years (range, 16-72 years). Majority of patients were male (n: 17, 73.9%), and had large tumors (>or= 5 cm, n: 13, 56.5%), localized disease (N0, M0, n: 12, 52.2%), and embryonal histology (n: 10, 43.5%). Median overall survival was 31.3 months, and the 3-year progression-free survival and overall survival rates were 19.9% and 34.94%, respectively. Patients with smaller tumors (< 5 cm) (p < 0.04), local disease (p < 0.01), and normal lactic dehydrogenase (LDH) level (p < 0.01) at the time of diagnosis were found to have better survival outcome. The tumor size, serum LDH level, and metastatic disease at the time of diagnosis are potential predictors of outcome in patients with adult RMS. Adult RMS is an aggressive disease with poor survival despite treatment. The data from prospective, randomized multicenter trials are necessary in order to improve the clinical outcome of adult RMS patients.

Sarcoma

Sarcomas comprise a heterogeneous group of mesenchymal neoplasms. They can be grouped into 2 general categories, soft tissue sarcoma and primary bone sarcoma, which have different staging and treatment approaches. This review includes a discussion of both soft tissue sarcomas (malignant fibrous histiocytoma, liposarcoma, leiomyosarcoma, synovial sarcoma, dermatofibrosarcoma protuberans, angiosarcoma, Kaposi sarcoma, gastrointestinal stromal tumor, aggressive fibromatosis or desmoid tumor, rhabdomyosarcoma, and primary alveolar soft-part sarcoma) and primary bone sarcomas (osteosarcoma, Ewing sarcoma, giant cell tumor, and chondrosarcoma). The 3 most important prognostic variables are grade, size, and location of the primary tumor. The approach to a patient with a sarcoma begins with a biopsy that obtains adequate tissue for diagnosis without interfering with subsequent optimal definitive surgery. Subsequent treatment depends on the specific type of sarcoma. Because sarcomas are relatively uncommon yet comprise a wide variety of different entities, evaluation by oncology teams who have expertise in the field is recommended. Treatment and follow-up guidelines have been published by the National Comprehensive Cancer Network (www.nccn.org).

Efficacy of Consolidation High-Dose Chemotherapy with Ifosfamide, Carboplatin and Etoposide (HD-ICE) Followed by Autologous Peripheral Blood Stem Cell Rescue in Chemosensitive Patients with Metastatic Soft Tissue Sarcomas

BACKGROUND

Prognosis of patients with metastatic soft tissue sarcomas (MSTS) is poor even after response to doxorubicin-based chemotherapy. We report phase II data of high-dose chemotherapy and peripheral blood stem cell (PBSC) rescue in patients with MSTS responding to AI-G chemotherapy.

PATIENTS AND METHODS

From 1997 to 2002, 55 patients with MSTS were prospectively treated with 4 cycles of AI-G (doxorubicin 75 mg/m(2), ifosfamide 6 g/m(2) with G-CSF support). Responders received 2 further cycles of AI-G with collection of PBSCs. High-dose chemotherapy consisted of ifosfamide 12 g/m(2), carboplatin 1.2 g/m(2) and etoposide 1.2 g/m(2) (HD-ICE) followed by reinfusion of PBSCs.

RESULTS

Twenty-one of 55 patients (38%) were assessed as responders (3 complete response, 18 partial response). All but 2 patients refusing treatment received high-dose chemotherapy with PBSC rescue leading to grade IV hematologic toxicity without severe infections in all patients. No toxic death occurred. After a median follow-up time of 30 months, the median progression-free time was 12 months and survival time was 22 months for the entire group. By intent-to-treat analysis the probability of 5-year progression-free survival was significantly higher for patients allocated to HD-ICE compared to patients receiving second-line chemotherapy after failure of AI-G (14 vs. 3%; p = 0.003). The estimated 5-year overall survival between the 2 groups was different (27% vs. not reached) but did not reach significance (p = 0.08).

CONCLUSION

HD-ICE is feasible and promising in patients with chemosensitive MSTS. A randomized phase III trial is warranted to further define the role of HD-ICE as consolidation treatment in these patients.

Leukemia inhibitory factor: a newly identified metastatic factor in rhabdomyosarcomas

Rhabdomyosarcoma frequently infiltrates bone marrow and this process involves the stromal-derived factor-1 (SDF-1)-CXCR4 axis. Because leukemia inhibitory factor (LIF), like SDF-1, is secreted by bone marrow stroma and directs the regeneration of skeletal muscles, we examined whether the LIF-LIF receptor (LIF-R) axis affects the biology of rhabdomyosarcoma cells. We found that in rhabdomyosarcoma cells, LIF stimulates the following: (a) phosphorylation of mitogen-activated protein kinase p42/44, AKT, and signal transducers and activators of transcription 3, (b) adhesion and chemotaxis, and (c) increased resistance to cytostatics. To compare the biological effects of LIF versus SDF-1, we examined the RH30 cell line, which is highly responsive to both ligands, and found that the chemotaxis of these cells is significantly reduced when the inhibitors of both receptors (T140 for CXCR4 and gp190 blocking antibody for LIF-R) are added simultaneously. Subsequently, by using repetitive chemotaxis to LIF or SDF-1, we selected from the RH30 line subpopulations of cells that respond to LIF but not SDF-1 (RH30-L) or to SDF-1 but not LIF (RH30-S). We found that (a) RH30-L cells seed better to the bone marrow, liver, and lymph nodes of immunodeficient mice than RH30-S cells and (b) mice inoculated i.m. with the RH30-L cells had more rhabdomyosarcoma cells in the bone marrow and lung after 6 weeks. Thus, we present the first evidence that the LIF-LIF-R axis may direct rhabdomyosarcoma metastasis. Further, because we showed that the in vivo metastasis of RH30 cells is inhibited by small interfering RNA against LIF-R, molecular targeting of this axis could become a new strategy to control the metastasis of rhabdomyosarcoma.

Imatinib mesylate potentiates topotecan antitumor activity in rhabdomyosarcoma preclinical models

High levels of PDGFR expression in primary rhabdomyosarcoma (RMS) have been associated with disease progression. To date however, there are no reports on the activity of imatinib mesylate, a selective PDGFR inhibitor, in RMS preclinical models. A panel of 5 RMS cell lines was used to investigate the expression of PDGFRalpha and PDGFRbeta, c-Kit and the multidrug transporter ABCG2 (also inhibited by imatinib). In vitro and in vivo experiments were performed using RD (embryonal) and RH30 (alveolar) cell lines to determine the efficacy of imatinib as single agent and in combination with topotecan (TPT). PDGFRbeta was significantly expressed in all cell lines, with the highest levels in RD, while PDGFR alpha and ABCG2 were significantly expressed only in RH30 and RMZ-RC2. c-Kit was not detected. PDGFRbeta signaling was active in RD but not in RH30, whilst PDGFRalpha signaling was not active in either cell lines. Significant ABCG2-mediated extrusion of Hoechst 33342 was demonstrated in RH30 but not in RD, and was inhibited by imatinib and the specific ABCG2 inhibitor Ko143. In vitro, imatinib was not active as a single agent at therapeutic concentrations, but significantly potentiated TPT antitumor activity in both cell lines. In vivo experiments using tumor xenografts confirmed the synergistic interaction in both cell lines. These results suggest that at least 2 different mechanisms--inhibition of ABCG2 and/or PDGFRbeta--are involved in the synergistic interaction between imatinib and TPT, and support the use of this combination for the treatment of high-risk RMS patients.

New drugs for the treatment of metastatic or refractory soft tissue sarcomas in children

Children with relapsed, recurrent or metastatic sarcomas represent a therapeutic challenge for the pediatric oncologist. Strategies for the development of newer therapies for children with these sarcomas have, in the past, been histology-specific. For example, drug development in rhabdomyosarcoma has relied upon the preclinical xenograft model, whereas therapies for pediatric nonrhabdomyosarcomatous soft tissue sarcomas have mostly been derived from adult trials. The progress to date and the tools used in the treatment of advanced pediatric sarcomas will be summarized in this review.

Extracorporeal membrane oxygenation for support of children after hematopoietic stem cell transplantation: the Extracorporeal Life Support Organization experience

PURPOSE

Extracorporeal membrane oxygenation (ECMO) is a means of respiratory and hemodynamic support for patients failing conventional therapies. Children requiring hematopoietic stem cell transplantation who develop complications during therapy may require ECMO. Such patients pose medical and ethical challenges for clinicians considering initiation of ECMO. The authors review the outcomes of these patients and propose recommendations.

METHODS

The Extracorporeal Life Support Organization Registry was queried for all patients younger than 18 years with an International Classification of Diseases, Ninth Revision, or Current Procedural Terminology code related to bone or stem cell transplant.

RESULTS

Nineteen children in the registry met inclusion criteria. The median age was 9.6 years (7 months to 17.5 years). Initiation of ECMO was for pulmonary support (n = 17), cardiac support (n = 1), or cardiopulmonary resuscitation (n = 1). The median duration of ECMO support was 5.1 days (range, 30 hours to 42 days). Pulmonary infections included 3 parainfluenza, 2 Pneumocystis carinii, 1 influenza A, and 1 respiratory syncytial virus. Overall, 15 (79%) died during their ECMO run, whereas only 4 (21%) survived to come off ECMO. Furthermore, of those who survived their ECMO run, only one patient survived to discharge from the hospital. Risk factors for death on ECMO include development of renal complications and development of multiorgan dysfunction.

CONCLUSION

Patients who require ECMO for cardiopulmonary support after hematopoietic stem cell transplantation have a poor prognosis. Clinicians must be cautious in presenting this option to parents and present them with appropriate expectations in this high-risk population.

Radioimmunotargeting of human rhabdomyosarcoma using monoclonal antibody 8H9

Although metastatic rhabdomyosarcoma (RMS) is chemotherapy and radiotherapy responsive, few patients are cured. 8H9, a murine IgG(1) monoclonal antibody, recognizes a unique cell surface tumor antigen broadly distributed on neuroectodermal, epithelial, and mesenchymal tumors, including RMS. We now report on the in vitro characterization of radiolabeled 8H9 and its in vivo immunotargeting potential in mice with subcutaneous human RMS. Saturation-binding studies carried out to determine (125)I-8H9 affinity to the RMS cell line HTB82 demonstrated that (125)I-8H9 had a K(d) of 10.3nM with an estimated 115,000 binding sites on every HTB82 cell. (125)I-8H9 was retained on the cell surface without significant internalization. Biodistribution of (125)I-8H9 was studied in athymic mice bearing HTB82 xenografts. Following intravenous injection of 4.44MBq of (125)I-8H9, selective tumor uptake was evident 4 to 172 hours after injection. Average tumor uptake was 7.0 +/- 1.8, 11.5 +/- 3.9, 15.1 +/- 3.7, and 5.4 +/- 1.2% injected dose per gram at 4, 24, 48, and 172 hours, respectively. Mean tumor: tissue ratios were maximal at 172 hours (for lung, 4, kidney, 6, liver, 7, spleen, 11, femur, 14, muscle, 18, and brain, 48). Established RMS xenografts treated with a single injection of 18.5 MBq (131)I-8H9 were significantly suppressed compared to controls. Radiolabeled 8H9 effectively targeted RMS xenografts and may have a potential clinical role in radioimmunotherapy.

Current chemotherapeutic strategies for rhabdomyosarcoma

Rhabdomyosarcoma is a typical tumor of childhood and adolescence. Over the years there has been a gradual but important improvement in survival for patients with this tumor, despite its high grade of malignancy. These results are due to multidisciplinary treatment approaches including surgery, radiotherapy and especially chemotherapy. Rhabdomyosarcoma is a highly chemosensitive neoplasm, and the role of this therapeutic approach has also been clearly demonstrated in the adjuvant setting. This review covers current concepts on chemotherapy for rhabdomyosarcoma, with an overview of the results of the main clinical trials conducted over recent years and considerations of possible strategies for the near future. Recommendations for adult patients with rhabdomyosarcoma are also discussed, suggesting that these patients should be treated according to pediatric guidelines.

Rhabdomyosarcoma: new windows of opportunity

Rhabdomyosarcoma is a highly malignant, small blue cell tumor characterized by muscle differentiation. With modern treatment, more than 70% of children and adolescents with this disease are cured. Adequate biopsy to obtain sufficient tissue for accurate diagnosis and molecular characterization is critical. Patients must be assessed for tumor extent; the Intergroup Rhabdomyosarcoma Study (IRS) clinical group and Staging system is universally applied in North America. Multidisciplinary therapy is necessary to maximize cure rates. Local control relies on complete surgical excision when possible; those whose tumors are not completely excised and those with alveolar histology tumors require local irradiation to maximize local control. In North America, vincristine (Oncovin); Eli Lilly and Company, Indianapolis, http://www.lilly.com), dactinomycin (Cosmegen); Merck & Co., Inc., Whitehouse Station, NJ, http://www.merck.com), and cyclophosphamide are the standard chemotherapy agents. The IRS has used therapeutic window studies to confirm the predictive nature of preclinical xenograft models and to identify several new single agents and combinations of agents with activity in high-risk patient groups. Despite these efforts, the outcome for these high-risk patients remains poor. The next generation of Children's Oncology Group studies will evaluate the efficacy of topoisomerase-I inhibitors and dose-compression therapy approaches. New advances in molecular characterization of tumors, including gene-expression analysis, may identify new therapeutic targets that can be exploited by expanded preclinical drug discovery efforts, and hold the promise of revolutionizing risk-based therapies.

National estimates of the use of hematopoietic stem-cell transplantation in children with cancer in the United States

National utilization data for hematopoietic stem-cell transplantation (HSCT) for childhood cancers in the United States have not been reported. We identified cancer encounters for children aged 18 years and younger from 1997 to 2001 in US nonfederal, acute care hospitals. We compared patient, hospital, and resource use characteristics and in-patient mortality associated with HSCT and non-HSCT encounters, estimated the number of HSCT encounters by stem-cell source and cancer type, and examined resource use and mortality in each category. We identified 461,175 cancer encounters, of which 6380 (1.4%) were HSCT encounters. There was wide variation in resource use and mortality by stem-cell source and cancer type. Of note, 17% of HSCT encounters were for patients with acute lymphoblastic leukemia without remission or sarcoma, conditions for which there is little evidence of benefit from HSCT in children. These encounters were associated with high in-patient mortality and long lengths of stay. Also, we observed an increasing use of cord blood over the study period. Future research should examine potentially important sociodemographic differences in patients undergoing HSCT compared to those who do not. Additional analyses incorporating disease stage and severity are needed.

Effectiveness of chemotherapy in rhabdomyosarcoma: example of orbital primary

The survival of patients with rhabdomyosarcoma has been progressively improved with successive protocols due to the development of multidisciplinary management and the data accumulated by international groups. Orbital rhabdomyosarcoma represents 10% of all cases and affects young children (median age: 6.8 years). It is a chemosensitive and radiosensitive tumour. Chemotherapy is designed to decrease the indications for local therapy (mainly radiotherapy) responsible for a high rate of sequelae (cosmetic, functional or secondary cancer). According to the International Society of Paediatric Oncology guidelines, local therapy is not indicated as first-line treatment in case of complete remission after chemotherapy. The 10-year survival of children with non-parameningeal orbital rhabdomyosarcoma is currently 87% and identical survivals are reported by the various collaborative groups despite the use of different treatments. Despite clinical trials demonstrating the efficacy of many types of chemotherapy (cisplatin, etoposide, doxorubicin, dacarbazine), the value of adding these drugs to combination chemotherapy comprising of an alkylating agent (cyclophosphamide or ifosfamide), vincristine and dactinomycin has not been formally demonstrated in terms of survival benefit for children with rhabdomyosarcoma. The authors review these various results and compare the current guidelines for the management of orbital rhabdomyosarcoma recommended by North American and European groups.

Cyclophosphamide Dose Intensification during Induction Therapy for Intermediate-Risk Pediatric Rhabdomyosarcoma Is Feasible but Does Not Improve Outcome

PURPOSE

More than half of pediatric rhabdomyosarcoma cases have intermediate-risk features and suboptimal outcome (3-year failure-free survival estimates, 55 to 76%). Dose intensification of known active agents may improve outcome.

EXPERIMENTAL DESIGN

This pilot study evaluated the feasibility of dose intensification of cyclophosphamide in previously untreated patients ages < 21 years with intermediate-risk rhabdomyosarcoma. Induction therapy comprised four 3-week cycles of VAC: vincristine (V) 1.5 mg/m2 on days 0, 7, and 14; actinomycin D (A) 1.35 mg/m2 on day 0; and dose-intensified cyclophosphamide (C) on days 0, 1, and 2. The three cyclophosphamide dose levels tested were as follows: (a) 1.2 g/m2/dose; (b) 1.5 g/m2/dose; and (c) 1.8 g/m2/dose. Continuation therapy comprised nine additional cycles of VAC with 2.2 g/m2/cycle of C. Radiotherapy was administered at week 0 (parameningeal tumors with intracranial extension) or week 12 or 15 (all others).

RESULTS

Between October 1996 and August 1999, 115 eligible patients were enrolled. Three of 15 patients treated at dose level 2 experienced life-threatening dose-limiting toxicity (typhlitis +/- other severe toxicity). Dose level 1 was the maximum-tolerated dose, and 91 evaluable patients were treated at this level. The 3-year failure-free and overall survival estimates for patients treated at the maximum-tolerated dose were 52% (95% confidence interval, 41-64%) and 67% (95% confidence interval, 56-77%), respectively, at a median follow-up of 3 years.

CONCLUSIONS

A 64% increase in the standard cyclophosphamide dosage during induction (to 3.6 g/m2/cycle) was tolerated. However, outcomes were similar to those observed at lower dosages, suggesting that alkylator dose intensification does not benefit patients with intermediate-risk rhabdomyosarcoma.

Metastatic rhabdomyosarcoma: a retrospective review of patients treated at the hospital for sick children between 1989 and 1999

Children with metastatic rhabdomyosarcoma (RMS) continue to fare poorly (3-year survival 20-30%). Various therapies, including end-intensification with high-dose chemotherapy and stem cell support, have been used in an attempt to improve the outcome of these patients. The authors reviewed their clinical experience over a 10-year period to identify predictors of outcome in these patients. The authors reviewed the clinical characteristics, treatment, and outcome of all patients with metastatic RMS diagnosed and treated at the Hospital for Sick Children between 1989 and 1999. Kaplan-Meier curves were generated to compare survival and failure-free survival of different subgroups of patients. Differences between groups were analyzed using univariate analysis and the log-rank test. Seventeen patients with metastatic RMS were identified. Thirteen patients were treated with standard chemotherapy +/- radiotherapy and four received high-dose end-intensification therapy with stem cell support. The estimated 3-year overall survival (OS) and failure-free survival rates for all patients were 35% (95% CI 13-58) and 29% (95% CI 18-40), respectively. Patients with embryonal histology, metastases confined to the lung, and age younger than 10 years had a 3-year OS of 100%, compared with an OS of 0% for the remaining patients (P < 0.0006). The median follow-up for the five survivors was 5.5 years. The authors have identified a subset of children with metastatic RMS having embryonal histology, age less than 10 years, and only pulmonary metastases who have favorable survival outcomes when treated with chemotherapy with or without stem cell support.

Pediatric soft tissue sarcomas

Many of the soft tissue sarcomas that occur in children are of the same histology as those in adults; however, the relative prevalence of these sarcomas is different between children and adults. In some cases, the biologic behavior of pediatric sarcomas is more benign than that in adults. Treatment for sarcomas in children is also different. Pediatric sarcomas are more commonly responsive to chemotherapy. Furthermore, in children who are still growing, surgery and radiation are associated with higher morbidity than in adults. This article discusses the diagnosis and treatment of rhabdomyosarcoma and undifferentiated sarcomas, with an emphasis on surgical considerations, and the diagnosis and treatment of nonrhabdomyosarcomatous soft tissue sarcomas in children.

Prognostic factors and clinical outcomes in children and adolescents with metastatic rhabdomyosarcoma--a report from the Intergroup Rhabdomyosarcoma Study IV

PURPOSE

To identify risk factors associated with outcomes in children with metastatic rhabdomyosarcoma (RMS) treated on the fourth Intergroup Rhabdomyosarcoma Study (IRS-IV).

PATIENTS AND METHODS

Patients with metastatic RMS were treated with one of two regimens that incorporated a window of either ifosfamide and etoposide (IE) with vincristine, dactinomycin, and cyclophosphamide (VAC) or vincristine, melphalan (VM) and VAC. Study end points were failure-free survival (FFS) and overall survival (OS). Clinical factors including age, histology, sites of primary and metastatic disease, and number of sites of metastatic disease were correlated with those end points.

RESULTS

One hundred twenty-seven patients were eligible for analysis. The estimated 3-year OS and FFS for all patients were 39% and 25%, respectively. By univariate analysis, 3-year OS was significantly influenced by histology (47% for embryonal v 34% for all others, P =.026) and increasing number of metastatic sites (P =.028). By multivariate analysis, the presence of two or fewer metastatic sites was the only significant predictor (P =.007 and.006, respectively). The combination of embryonal histology with two or fewer metastatic sites identified a subgroup with 3-year FFS of 40% and OS of 47%.

CONCLUSION

Children with group IV RMS treated on the IRS-IV study had improved OS and FFS if they had two or fewer metastatic sites and embryonal histology. This favorable subset of patients has outcomes approaching those observed in selected patients with localized, nonmetastatic disease. Thus, these patients might not be appropriate candidates for regimens that include experimental agents with substantial toxicities or unproven antitumor activity.

CXCR4-SDF-1 signaling is active in rhabdomyosarcoma cells and regulates locomotion, chemotaxis, and adhesion

We hypothesized that the CXC chemokine receptor-4 (CXCR4)-stromal-derived factor-1 (SDF-1) axis may be involved in metastasis of CXCR4(+) tumor cells into the bone marrow and lymph nodes, which secrete the alpha-chemokine SDF-1. To explore this hypothesis, we phenotyped by fluorescence-activated cell sorter analysis various human tumor cell lines for expression of CXCR4 and found that it was highly expressed on several rhabdomyosarcoma (RMS) cell lines. We also observed that cell lines derived from alveolar RMS, which is characterized by recurrent PAX3- and PAX7-FKHR gene fusions and is associated with a poor prognosis, expressed higher levels of CXCR4 than lines derived from embryonal RMS. Furthermore, transfer of a PAX3-FKHR gene into embryonal RMS cell activates CXCR4 expression. Because alveolar RMS frequently metastasizes to the bone marrow and lymph nodes, it seems that the CXCR4-SDF-1 axis could play an important role in this process. These findings prompted us to determine whether SDF-1 regulates the metastatic behavior of RMS cells. Accordingly, we found that, although SDF-1 did not affect proliferation or survival of these cell lines, it induced in several of them (1) phosphorylation of mitogen-activated protein kinase p42/44; (2) locomotion; (3) directional chemotaxis across membranes covered by laminin, fibronectin, or Matrigel; (4) adhesion to laminin, fibronectin, and endothelial cells; and (5) increased MMP-2 and diminished tissue inhibitors of metalloproteinases secretion. The small-molecule CXCR4-specific inhibitor, T140, effectively blocked the in vitro responses of RMS cells to SDF-1. On the basis of these observations we suggest that the CXCR4-SDF-1 axis may play an important role in tumor spread and metastasis of RMS cells to bone marrow and that molecular strategies aimed at inhibiting this axis could thus prove to be useful therapeutic measures.

Differential susceptibility of pediatric sarcoma cells to oncolysis by conditionally replication-competent herpes simplex viruses

PURPOSE

Attenuated viruses derived from herpes simplex virus (HSV) type 1 that kill tumor cells (oncolysis) are currently in clinical trials for selected cancers, primarily carcinomas and gliomas. The authors sought to determine if pediatric sarcoma cells are also sensitive to HSV-mediated oncolysis.

MATERIALS AND METHODS

The authors tested a panel of ten cell lines derived from rhabdomyosarcoma, osteosarcoma, Ewing sarcoma, and a secondary malignant fibrous histiocytoma for survival after exposure to attenuated HSV vectors. The viruses used included NV1020, haploid for the neurovirulence gene, and G207, deleted for both and ribonucleotide reductase but expressing the beta-galactosidase reporter gene. G207 transduction was determined by measuring beta-galactosidase expression.

RESULTS

Sarcoma cells differed in their sensitivity to viral oncolysis but were relatively consistent by histologic type. Rhabdomyosarcoma and malignant fibrous histiocytoma cells were most sensitive while osteosarcoma cells were intermediately sensitive to oncolysis by both HSV recombinants. Although Ewing sarcoma cells showed efficient viral entry and gene transfer, these cells were the least susceptible to oncolysis by HSV.

CONCLUSIONS

Conditionally replication-competent HSV-derived vectors may be useful for the treatment of rhabdomyosarcoma and osteosarcoma, but may not be as efficacious for treating Ewing sarcoma until the mechanism of resistance is defined and circumvented.

Pediatric genitourinary tumors

Each year advances are made in the clinical evaluation and treatment of genitourinary tumors in children. Understanding of cellular, molecular, and genetic processes in tumorigenesis is evolving rapidly. In addition, information is accumulating about the long-term outcome and complications associated with treatment modalities. This article reviews the 2001 literature on pediatric Wilms tumor, other renal tumors, rhabdomyosarcoma of the pelvis, paratesticular rhabdomyosarcoma, and testicular tumors. The emphasis in molecular biology is to identify molecular or genetic markers that predict outcome. The National Wilms' Tumor Study Group reported on the complications of surgery and the decreased complication rate when these procedures are performed by pediatric surgical specialists. Long-term complications of treatment are also discussed, including short stature and leukemia. The Intergroup Rhabdomyosarcoma Study Group reported on the results of treatment for nonmetastatic disease and the goals of the upcoming Study V, reduction of chemotherapy and radiotherapy. They also presented data from Study IV and discussed the findings on improved prognosis.