Sarcomas in children with neurofibromatosis type 1-poor prognosis despite aggressive combined therapy in four patients treated in a single oncological institution

Rhabdomyosarcoma as the first presentation in Neurofibromatosis Type 1: case series and review of the literature

Neurofibromatosis Type 1 (NF1) is a neurocutaneous syndrome characterized by multiple café-au-lait macules, neurofibromas, and predisposition to malignancies, including rhabdomyosarcomas (RMS). Somatic NF1 mutations occur in RMS and other cancers, and ∼1% of patients with RMS have NF1. We describe three patients who presented prior to one year of age with RMS and were subsequently diagnosed with NF1. Compared to sporadic RMS, patients with this cancer predisposition syndrome are diagnosed younger, genitourinary sites are more common, and tumors are almost exclusively the embryonal subtype. Genomic sequencing of the tumor was initiated in one patient, and we identified a second sequence variant in NF1. The identification of molecular drivers in tumors is changing the nature of pediatric oncology by informing therapeutics targeted to specific molecular pathways and selecting patients who are likely to harbor germline variants in cancer predisposition genes who would benefit from a Medical Genetics assessment.

Retroperitoneal malignant triton tumor in an infant: a case report and literature review

Malignant triton tumor (MTT) is a rare subtype of malignant peripheral nerve sheath tumor (MPNST) with rhabdomyoblastic differentiation. MTTs are solid tumors commonly located in the head, neck, extremities, and trunk. The presence of this tumor in an infant's retroperitoneum is extremely rare, and prompted the authors to report this case with reference to existing literature.

The association of Neurofibromatosis Type 1 and lower urinary tract dysfunction in the paediatric population - A critical review of literature

INTRODUCTION

Neurofibromatosis Type 1 (NF1) is an autosomal dominant, multisystem, neurocutaneous disorder. This condition has been associated with lower urinary tract dysfunction due to either direct genitourinary organ involvement or spinal cord compression. Based on current literature, there are no reviews examining the relationship between NF1 and lower urinary tract dysfunction (LUTD) in the paediatric population.

METHODS

A critical review of the literature was conducted using a systematic search of MEDLINE, PubMed and Embase yielding a total of 1285 manuscripts published up to 2019. Two independent reviewers selected studies for screening, eligibility and inclusion into the review. Following title, abstract and full-text review, 46 articles were analyzed.

RESULTS

Within these 46 articles, 79 cases were presented. The mean patient age at the time of presentation was 6.97 ± 9.19 years. The most common urologic presentations were irritative lower urinary tract symptoms (30%) and a newly discovered abdominopelvic mass (21%). Diagnostic investigations commonly demonstrated a retrovesical mass with direct invasion of the bladder in 58 cases (73%) and other genitourinary organ involvement in 39 cases (39%). Throughout the total case volume, LUTD was present in 49%. Pathology of malignancy was most commonly malignant peripheral nerve sheath tumour and rhabdomyosarcoma (20% and 14%, respectively). When indicated, surgical management of the lower urinary tract included both radical and partial cystectomy. Conservative management of urinary retention included clean intermittent catheterization (56%), suprapubic catheterization (22%), vesicostomy creation (11%) and mitrofanoff creation (11%).

CONCLUSION

A complete urologic evaluation including clinical, radiologic, and possibly pathologic investigation is warranted and should be performed for both diagnosis and appropriate management of LUTD in patients with NF1.

A Comprehensive Review of Pediatric Tumors and Associated Cancer Predisposition Syndromes

An understanding of the role of inherited cancer predisposition syndromes in pediatric tumor diagnoses continues to develop as more information is learned through the application of genomic technology. Identifying patients and their relatives at an increased risk for developing cancer is an important step in the care of this patient population. The purpose of this review is to highlight various tumor types that arise in the pediatric population and the cancer predisposition syndromes associated with those tumors. The review serves as a guide for recognizing genes and conditions to consider when a pediatric cancer referral presents to the genetics clinic.

Rhabdomyosarcomas in children with neurofibromatosis type I: A national historical cohort

BACKGROUND

Rhabdomyosarcoma (RMS) occasionally occurs in a context of a predisposition syndrome. The most common predisposition syndromes include germline TP53 mutations and constitutive alterations in RAS pathway activation, such as Costello syndrome, Noonan syndrome and neurofibromatosis type 1. We report a national retrospective series of 16 RMS occurring in neurofibromatosis type 1 (NF1) patients during childhood, within a 20-year period.

RESULTS

The mean age at diagnosis of the cancer was 2.5 years. All were embryonal subtype. Most tumours developed in the pelvis. One was metastatic. Chemotherapy and radiotherapy were normally scheduled without any specific toxicity. The 5-year event-free survival and overall survival were 67% and 87%, respectively. Long-term sequel related to chemotherapy consisted in two chronic tubulopathies, hence not obviously different from non-NF1 patients. No second cancer was reported so far with a median follow-up of 9.7 years. The genomic analysis performed on six samples revealed the abnormalities commonly observed in sporadic RMS: gain of chromosome 2 (5/6), 8 (6/6) and chromosome 11p loss of heterozygosity (5/6). Interestingly, we identified small deletions in tumour suppressor genes that may synergize with NF1 inactivation.

CONCLUSIONS

Patients with neurofibromatosis are prone to develop embryonal-type RMS that require the same treatment as sporadic cases.

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. The rationale for this update is to determine whether any randomized controlled trials (RCTs) have been conducted and to clarify whether HDCT followed by autologous HSCT has a survival advantage.

OBJECTIVES

To assess the effectiveness and safety of HDCT followed by autologous HSCT for all stages of non-rhabdomyosarcoma soft tissue sarcomas (NRSTS) in children and adults.

SEARCH METHODS

For this update we modified the search strategy to improve the precision and reduce the number of irrelevant hits. All studies included in the original review were considered for re-evaluation in the update. We searched the electronic databases CENTRAL (2012, Issue 11) in The Cochrane Library , MEDLINE and EMBASE (05 December 2012) from their inception using the newly developed search strategy. Online trials registers and reference lists of systematic reviews were searched.

SELECTION CRITERIA

Terms representing STS and autologous HSCT were required in the title or abstract. In studies with aggregated data, participants with NRSTS and autologous HSCT had to constitute at least 80% of the data. Single-arm studies were included in addition to studies with a control arm because the number of comparative studies was expected to be very low.

DATA COLLECTION AND ANALYSIS

Two review authors independently extracted study data. Some studies identified in the original review were re-examined and found not to meet the inclusion criteria and were excluded in this update. For studies with no comparator group, we synthesized the 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

The selection process was carried out from the start of the search dates for the update. We included 57 studies, from 260 full text articles screened, reporting on 275 participants that were allocated to HDCT followed by autologous HSCT. All studies were not comparable due to various subtypes. We identified a single comparative study, an RCT comparing HDCT followed by autologous HSCT versus standard chemotherapy (SDCT). The overall survival (OS) at three years was 32.7% versus 49.4% with a hazard ratio (HR) of 1.26 (95% confidence interval (CI) 0.70 to 2.29, P value 0.44) and thus not significantly different between the treatment groups. In a subgroup of patients that had a complete response before treatment, OS was higher in both treatment groups and OS at three years was 42.8% versus 83.9% with a HR of 2.92 (95% CI 1.1 to 7.6, P value 0.028) and thus was statistically significantly better in the SDCT group. We did not identify any other comparative studies. We included six single-arm studies reporting aggregate data of cases; three reported the OS at two years as 20%, 48%, and 51.4%. One other study reported the OS at three years as 40% and one further study reported a median OS of 13 months (range 3 to 19 months). In two of the single-arm studies with aggregate data, subgroup analysis showed a better OS in patients with versus without a complete response before treatment. In a survival analysis of pooled individual data of 80 participants, OS at two years was estimated as 50.6% (95% CI 38.7 to 62.5) and at three years as 36.7% (95% CI 24.4 to 49.0). Data on TRM, secondary neoplasia and severe toxicity grade 3 to 4 after transplantation were sparse. The one included RCT had a low risk of bias and the remaining 56 studies had a high risk of bias.

AUTHORS' CONCLUSIONS

A single RCT with a low risk of bias shows that OS after HDCT followed by autologous HSCT is not statistically significantly different from standard-dose chemotherapy. Therefore, HDCT followed by autologous HSCT for patients with NRSTS may not improve the survival of patients and should only be used within controlled trials if ever considered.

Diffuse ganglioneuromatosis and plexiform neurofibroma of the urinary bladder: an uncommon cause of severe urological disease in an infant

Neurofibromatosis of the urinary tract occurs infrequently: fewer than 70 cases with bladder involvement have been reported to date and of these, only 25 cases occurred in the pediatric population. We describe an unusual case of plexiform neurofibroma and diffuse ganglioneuromatosis of the bladder in a small infant, diagnosed with neurofibromatosis 1 (NF1) at 3 months of age. At the moment, there are no established criteria for the treatment of this rare lesion. Due to the high morbidity, although not very common, bladder involvement should be considered in infants with NF1.

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.

Mechanisms in the pathogenesis of malignant tumours in neurofibromatosis type 1

Neurofibromatosis type 1 (NF1) is a familial tumour syndrome. Malignant tumours can arise in the nervous and non-nervous system in either childhood or adulthood, with malignant peripheral nerve sheath tumours being most common. Rhabdomyosarcoma and neuroblastoma are paediatric neoplasms that are more common in children with NF1 than in those without the syndrome. Gastrointestinal stromal tumours, somatostatinomas, breast cancer, and phaeochromocytomas are seen in adults with NF1. Several pathways are thought to be involved in the development of tumours associated with NF1: rat sarcoma viral oncogene homologue (RAS)-mitogen activated protein kinase (MAPK), mammalian target of rapamycin (mTOR), and P21 protein (Cdc42/Rac)-activated kinase 1 (PAK1). New insights into the pathogenesis of these tumours will lead to a better understanding of tumour origin and development and will hopefully allow the discovery of new and specific treatments.