Shorter-duration therapy using vincristine, dactinomycin, and lower-dose cyclophosphamide with or without radiotherapy for patients with newly diagnosed low-risk rhabdomyosarcoma: a report from the Soft Tissue Sarcoma Committee of the Children's Oncology Group

Roadmap for the next generation of Children's Oncology Group rhabdomyosarcoma trials

Clinical trials conducted by the Intergroup Rhabdomyosarcoma (RMS) Study Group and the Children's Oncology Group have been pivotal to establishing current standards for diagnosis and therapy for RMS. Recent advancements in understanding the biology and clinical behavior of RMS have led to more nuanced approaches to diagnosis, risk stratification, and treatment. The complexities introduced by these advancements, coupled with the rarity of RMS, pose challenges to conducting large-scale phase 3 clinical trials to evaluate new treatment strategies for RMS. Given these challenges, systematic planning of future clinical trials in RMS is paramount to address pertinent questions regarding the therapeutic efficacy of drugs, biomarkers of response, treatment-related toxicity, and patient quality of life. Herein, the authors outline the proposed strategic approach of the Children's Oncology Group Soft Tissue Sarcoma Committee to the next generation of RMS clinical trials, focusing on five themes: improved novel agent identification and preclinical to clinical translation, more efficient trial development and implementation, expanded opportunities for knowledge generation during trials, therapeutic toxicity reduction and quality of life, and patient engagement.

Results of the JRS-I LRA0401 and LRB0402 Japan Rhabdomyosarcoma Study Group trials for low-risk embryonal rhabdomyosarcoma

BACKGROUND

Failure-free survival (FFS) rates of low-risk patients with rhabdomyosarcoma improved in Intergroup Rhabdomyosarcoma Study IV after the escalation of cyclophosphamide total dose to 26.4 g/m2. However, this dose may increase the risk of adverse events, including infertility, in some patients. The JRS-I LRA0401 and LRB0402 protocols aimed to reduce the cyclophosphamide dose to 9.6 g/m2 and 17.6 g/m2, respectively, without decreasing the FFS rates.

METHODS

Subgroup-A patients received eight cycles (24 weeks) of vincristine, actinomycin D, and 1.2 g/m2/cycle cyclophosphamide. Subgroup-B patients received eight cycles (24 weeks) of vincristine, actinomycin D, and 2.2 g/m2/cycle cyclophosphamide, followed by six cycles (24 weeks) of vincristine and actinomycin D. Group II/III patients in both subgroups received radiotherapy.

RESULTS

In subgroup A (n = 12), the 3-year FFS rate was 83% (95% confidence interval [CI], 48-96), and the 3-year overall survival (OS) rate was 100%. Only one isolated local recurrence was observed (8.3%). There were no unexpected grade-4 toxicities and no deaths. In subgroup B (n = 16), the 3-year FFS and OS rates were 88% (95% CI, 59-97) and 94% (95% CI, 63-99), respectively. There were no unexpected grade 4 toxicities and no deaths.

CONCLUSIONS

Shorter duration therapy using vincristine, actinomycin D, and lower dose cyclophosphamide with or without radiotherapy for patients with low-risk subgroup A rhabdomyosarcoma (JRS-I LRA0401 protocol) and moderate reduction of cyclophosphamide dose for patients with low-risk subgroup B rhabdomyosarcoma (JRS-I LRB0402 protocol) did not compromise FFS.

Outcomes for patients with perineal and perianal rhabdomyosarcoma: A report from the Children's Oncology Group Soft Tissue Sarcoma Committee

PURPOSE

To describe clinical features, risk factors, and outcomes of patients with perineal and perianal rhabdomyosarcoma.

METHODS

The records of 51 patients (38 perineal and 13 perianal) enrolled on Children's Oncology Group clinical trials between 1997 and 2012 were reviewed.

RESULTS

At presentation, 53% were female, 65% were older than 10 years of age, 76% were alveolar histology, 76% were more than 5 cm, 84% were invasive, 65% were regional node positive by imaging, 49% were metastatic, only 16% were grossly resected upfront, and 25% of patients had a delayed excision. At a median follow-up of 6.13 years, estimated 5-year event-free survival (EFS) was 38% [22.17%-53.38%], and overall survival (OS) was 42% [26.66%-58.21%]. The rates of local, regional, and distant failure were 15.6%, 13.7%, 43.1%, respectively; all failures ultimately died. By univariate analysis, only age more than 10 years negatively impacted 5-year EFS (p = .023) and OS (p = .09), and IRS Group also impacted OS (p = .043). In Cox proportional hazards model, neither of these variables were significant after adjusting for other factors.

CONCLUSION

Patients with perineal and perianal rhabdomyosarcoma have a poor overall prognosis, probably related to poor patient and disease characteristics at presentation.

Identifying Novel Genetic Markers in Pediatric Rhabdomyosarcoma

BACKGROUND/PURPOSE

Rhabdomyosarcoma risk stratification is traditionally determined by tumor histology and staging. Recent studies revealed the importance of molecular features in predicting prognosis. We investigated prognosis by age of onset and mutation incidence in rhabdomyosarcoma tumors.

METHODS

We retrospectively extracted clinical and genomic data from the Clinomics dataset (n = 641). Inclusion criteria was tumors with at least one gene mutation with >5% mutation incidence. Exclusion criteria were unknown risk stratification and age of onset. Statistical analysis was performed using ANOVA (p < 0.05) and Tukey's HSD to compare mutation incidence, EFS, and OS among age groups.

RESULTS

Among 641 patients with rhabdomyosarcoma, 8 of 39 screened genes had >5% mutation incidence: NRAS, BCOR, NF1, TP53, FGFR4, KRAS, HRAS, and CTNNB1. The final cohort consisted of 370 patients: 51 (Age: 0-2 Years), 140 (Age: 2-5 Years), 112 (Age: 5-12 Years) and 67 (Age: 12+). Later age of onset is associated with higher incidence of BCOR and HRAS mutations (p < 0.005, p < 0.001) and poorer EFS and OS (p < 0.05, p < 0.001). In patients with BCOR mutations, later age of onset is associated with poorer EFS and OS (p < 0.005, p < 0.001). NF1 mutations are equally distributed among age groups (p = 0.82), but later age of onset is associated with poorer EFS and OS (p < 0.005, p < 0.001).

CONCLUSION

In patients with at least one mutation in BCOR, NF1, TP53, KRAS, HRAS, or CTNNB1, later age of onset is associated with poorer prognosis. In patients with mutations only in tumor suppressor genes BCOR or NF1, later age of onset is associated with poorer prognosis.

TYPE OF STUDY

Retrospective Cohort Study.

LEVEL OF EVIDENCE

II.

Adolescents and young adults with rhabdomyosarcoma: A report from the Soft Tissue Sarcoma Committee of the Children's Oncology Group

INTRODUCTION

The impact of established prognostic factors on survival outcomes for childhood rhabdomyosarcoma (RMS) have not been well described in the adolescent and young adult (AYA) RMS patient population.

METHODS

This is a retrospective analysis of patients with newly diagnosed RMS enrolled between 1997 and 2016 on seven previously reported Children's Oncology Group (COG) clinical trials. Demographics, clinical features, treatment details, and outcome data were collected. Five-year event-free survival (EFS) and overall survival (OS) were estimated for patients diagnosed at age 15-39 years and those diagnosed under age 15 years using the Kaplan-Meier method. Log-rank test was used to compare prognostic factors for EFS and OS. Factors significant in the univariable analysis were included in a Cox proportional hazards regression model. Nonsignificant covariates were removed from the multiple regression model.

RESULTS

Total 2151 patients including 402 AYAs were analyzed. AYAs were more likely to present with primary tumors ≥5 cm in size, metastatic disease, alveolar histology, and have FOXO1 fusions compared to children. Five-year EFS for the AYA cohort was 44.2% versus 67% for children (p < .001), and 5-year OS was 52% for the AYA cohort versus 78% for children (p < .001). Multivariable analysis revealed tumor site, size and invasiveness, clinical group, and histology were prognostic in AYAs.

CONCLUSION

AYAs with RMS have a poorer prognosis compared to younger children due to multiple factors. Further research focused on AYAs to better understand RMS biology and improve treatments is critical to improve survival.

Soft Tissue Sarcomas in Adolescents and Young Adults

Soft tissue sarcomas (STS) represent a heterogeneous group of extraskeletal mesenchymal tumors that affect individuals throughout the entire age continuum. Despite this pervasive influence, key differences exist in the presentation of these sarcomas across varying age groups that have prevented a more uniform approach to management. Notably, rhabdomyosarcoma (RMS) is more common in children, while most nonrhabdomyosarcoma soft tissue sarcoma (NRSTS) subtypes are more prevalent in adults. Older patients with NRSTS appear to have more molecularly complex biology and often present with more advanced disease compared with children. Poorer outcome disparities are observed in older patients with RMS despite receiving similar treatment as younger patients. In this review, we highlight differences in epidemiology, biology, and management paradigms for pediatric and adult patients with STS and explore opportunities for a unified approach to enhance the care and outcomes within the AYA population.

A Practical Approach to Small Round Cell Tumors Involving the Gastrointestinal Tract and Abdomen

Small round cell neoplasms are diagnostically challenging owing to their clinical and pathologic overlap, necessitating use of large immunopanels and molecular analysis. Ewing sarcomas (ES) are the most common, but EWSR1 is translocated in several diverse neoplasms, some with round cell morphology. Molecular advances enable classification of many tumors previously termed 'atypical ES'. The current WHO Classification includes two new undifferentiated round cell sarcomas (with CIC or BCOR alterations), and a group of sarcomas in which EWSR1 partners with non-Ewing family transcription factor genes. This article reviews the spectrum of small round cell sarcomas within the gastrointestinal tract and abdomen.

Children's Oncology Group's 2023 blueprint for research: Soft tissue sarcomas

In the United States, approximately 850-900 children and adolescents each year are diagnosed with soft tissue sarcomas (STS). STS are divided into rhabdomyosarcoma (RMS) and non-rhabdomyosarcoma STS (NRSTS). RMS and NRSTS are risk stratified into low-, intermediate-, and high-risk categories, with 5-year survival rates of approximately 90%, 50%-70%, and 20%, respectively. Recent key achievements from the Children's Oncology Group (COG) STS Committee include the identification of new molecular prognostic factors for RMS, development and validation of a novel risk stratification system for NRSTS, successful completion of a collaborative NRSTS clinical trial with adult oncology consortia, and collaborative development of the INternational Soft Tissue SaRcoma ConsorTium (INSTRuCT). Current COG trials for RMS are prospectively evaluating a new risk stratification system that incorporates molecular findings, de-intensification of therapy for a very low-risk subgroup, and augmented therapy approaches for intermediate- and high-risk RMS. Trials for NRSTS exploring novel targets and local control modalities are in development.

Chemotherapeutic drugs for soft tissue sarcomas: a review

Despite the low incidence of soft tissue sarcomas (STSs), hundreds of thousands of new STS cases are diagnosed annually worldwide, and approximately half of them eventually progress to advanced stages. Currently, chemotherapy is the first-line treatment for advanced STSs. There are difficulties in selecting appropriate drugs for multiline chemotherapy, or for combination treatment of different STS histological subtypes. In this study, we first comprehensively reviewed the efficacy of various chemotherapeutic drugs in the treatment of STSs, and then described the current status of sensitive drugs for different STS subtypes. anthracyclines are the most important systemic treatment for advanced STSs. Ifosfamide, trabectedin, gemcitabine, taxanes, dacarbazine, and eribulin exhibit certain activities in STSs. Vinca alkaloid agents (vindesine, vinblastine, vinorelbine, vincristine) have important therapeutic effects in specific STS subtypes, such as rhabdomyosarcoma and Ewing sarcoma family tumors, whereas their activity in other subtypes is weak. Other chemotherapeutic drugs (methotrexate, cisplatin, etoposide, pemetrexed) have weak efficacy in STSs and are rarely used. It is necessary to select specific second- or above-line chemotherapeutic drugs depending on the histological subtype. This review aims to provide a reference for the selection of chemotherapeutic drugs for multi-line therapy for patients with advanced STSs who have an increasingly long survival.

Management and outcomes of chest wall rhabdomyosarcoma: A report from the Children's Oncology Group Soft Tissue Sarcoma Committee

INTRODUCTION

Rhabdomyosarcoma (RMS) of the chest wall presents unique management challenges and local control considerations. The benefit of complete excision is uncertain and must be weighed against potential surgical morbidity. Our aim was to assess factors, including local control modality, associated with clinical outcomes in children with chest wall RMS.

METHODS

Forty-four children with RMS of the chest wall from low-, intermediate-, and high-risk Children's Oncology Group studies were reviewed. Predictors of local failure-free survival (FFS), event-free survival (EFS), and overall survival (OS) were assessed, including clinical characteristics and staging, primary tumor anatomic locations, and local control modalities. Survival was assessed by Kaplan-Meier analysis and the log-rank test.

RESULTS

Tumors were localized in 25 (57%) and metastatic in 19 (43%), and they involved the intercostal region (52%) or superficial muscle alone (36%). Clinical group was I (18%), II (14%), III (25%), and IV (43%), and ultimately 19 (43%) patients had surgical resection (upfront or delayed), including 10 R0 resections. Five-year local FFS, EFS, and OS were 72.1%, 49.3%, and 58.5%, respectively. Univariate factors associated with local FFS included age, International Rhabdomyosarcoma Study (IRS) group, extent of surgical excision, tumor size, superficial tumor location, and presence of regional or metastatic disease. Other than tumor size, the same factors were associated with EFS and OS.

CONCLUSIONS

Chest wall RMS has variable presentation and outcome. Local control is a significant contributor to EFS and OS. Complete surgical excision, whether upfront or after induction chemotherapy, is usually only possible for smaller tumors confined to the superficial musculature but is associated with improved outcomes. While overall outcomes remain poor for patients with initially metastatic tumors, regardless of local control modality, complete excision may be beneficial for patients with localized tumors if it can be achieved without excess morbidity.

Extremity Rhabdomyosarcoma-An Integrated Clinicopathologic and Genomic Study to Improve Risk Stratification

PURPOSE

Extremity rhabdomyosarcoma (RMS) is associated with a very poor outcome compared with other sites, mainly because of its high incidence of alveolar histology and regional lymph node involvement. To better define prognostic markers in this clinical subset, we investigated our experience of 61 patients with extremity RMS treated at our tertiary cancer center for the past 2 decades.

PATIENTS AND METHODS

The patients had a median age of 8 years at diagnosis, equal gender distribution, and two-thirds occurred in the lower extremity. Most (85%) patients had FOXO1 fusion-positive alveolar RMS (ARMS), with 70% having a PAX3::FOXO1 transcript. Remaining were seven patients with fusion-negative embryonal RMS (ERMS) and two with MYOD1-mutant spindle cell/sclerosing RMS (SRMS). In 40% of the patients, material was available for DNA-based targeted sequencing using MSK-IMPACT cancer gene panel.

RESULTS

One-third of patients presented with localized disease at diagnosis while the remaining had regional nodal (18%) or distant metastases (51%). Metastatic disease, high-risk group, and age 10 years or older significantly affected the overall survival (OS; hazard ratio [HR], 2.68 [P = .004], 2.78 [P = .010] and 2.26 [P = .034], respectively). Although the presence of metastatic disease had a dismal impact on 5-year EFS and OS (19% and 29%, respectively), nodal involvement had a comparatively lower impact on 5-year EFS and 5-year OS (43% and 66%, respectively). PAX3::FOXO1 ARMS had worse prognosis and afflicted older children compared with PAX7::FOXO1 (HR = 3.45, P = .016). The most common events in the ARMS group included MED12 alterations, CDK4 amplifications, and CDKN2A deletions (8%-17%). The latter two abnormalities were mutually exclusive, enriched for acral and high-risk lesions, and correlated with poor outcome on OS (P = .02).

CONCLUSION

Our data provide rationale for considering the integration of molecular abnormalities to refine risk stratification in extremity RMS.

Rhabdomyosarcoma with isolated lung metastases: A report from the Soft Tissue Sarcoma Committee of the Children's Oncology Group

BACKGROUND

To determine outcomes of children with rhabdomyosarcoma (RMS) with isolated lung metastases.

METHODS

Data were analyzed for 428 patients with metastatic RMS treated on COG protocols. Categorical variables were compared using Chi-square or Fisher's exact tests. Event-free survival (EFS) and overall survival (OS) were estimated using Kaplan-Meier method and compared using the log-rank test.

RESULTS

Compared with patients with other metastatic sites (n = 373), patients with lung-only metastases (n = 55) were more likely to be <10 years of age, have embryonal histology (embryonal rhabdomyosarcoma), have N0 disease, and less likely to have primary extremity tumors. Lung-only patients had significantly better survival outcomes than patients with all other sites of metastatic disease (p < .0001) with 5-year EFS of 48.1 versus 18.8% and 5-year OS of 64.1 versus 26.9%. Patients with lung-only metastases, and those with a single extrapulmonary site of metastasis, had better survival compared with patients with two or more sites of metastatic disease (p < .0001). In patients with ERMS and lung-only metastases, there was no significant difference in survival between patients ≥10 years and 1-9 years (5-year EFS: 58.3 vs. 68.2%, 5-year OS: 66.7 vs. 67.7%).

CONCLUSIONS

With aggressive treatment, patients with ERMS and lung-only metastatic disease have superior EFS and OS compared with patients with other sites of metastatic disease, even when older than 10 years of age. Consideration should be given to including patients ≥10 years with ERMS and lung-only metastases in the same group as those <10 years in future risk stratification algorithms.

Impact of race and ethnicity on presentation and outcomes of patients treated on rhabdomyosarcoma clinical trials: A report from the Children's Oncology Group

BACKGROUND

Racial and ethnic disparities have been demonstrated in pediatric and adult cancers. However, there is no consensus on whether such disparities exist in the presentation, treatment, and outcome of patients with rhabdomyosarcoma (RMS).

METHODS

Patient information from the seven most recent RMS clinical trials was obtained from the Children's Oncology Group (COG). Chi-squared analyses were used to compare patient, tumor, and treatment characteristics across racial and ethnic groups. Pairwise analyses comparing Non-Hispanic Black (NHB) versus Non-Hispanic White (NHW) racial groups and Hispanic versus NHW ethnic groups were conducted for significant characteristics. Kaplan-Meier method and Wilcoxon signed-rank tests were performed to analyze outcomes.

RESULTS

In the overall cohort (n = 2157), patients' self-identified race/ethnicity was: 0.4% American Indian/Alaska Native, 2.6% Asian, 12.6% Hispanic, 0.2% Native American/other Pacific Islander, 12.8% NHB, 61.9% NHW, and 9.6% unknown. Six characteristics differed by race/ethnicity: age, histology, IRS group, invasiveness, metastatic disease, and FOXO1 fusion partner. Five were significant in pairwise comparisons: NHB patients were more likely to present at age ≥ 10 years and with invasive tumors than NHW patients; Hispanic patients were more likely to present with alveolar histology, metastatic disease, and IRS group IV disease than NHW patients. No differences were found in event free or overall survival of the entire cohort, in risk group-based subset analyses, or among patients with high-risk characteristics significant on pairwise analysis.

CONCLUSIONS

While NHB and Hispanic patients enrolled in COG trials presented with higher risk features than NHW patients, there were no outcome differences by racial or ethnic group.

Survival of patients with orbital and eyelid rhabdomyosarcoma treated on Children's Oncology Group studies from 1997 to 2013: A report from the Children's Oncology Group

BACKGROUND

Orbital rhabdomyosarcoma (ORMS) commonly presents as low-risk disease (stage 1, group I-III, embryonal RMS) with excellent outcome. Long-term follow-up of patients with low-risk ORMS and outcomes of less common subgroups of ORMS treated on recent Children's Oncology Group (COG) trials have not been reported.

METHODS

Patients with ORMS enrolled on COG trials from 1997 to 2013 were identified. Demographic information and disease characteristics were collected. Outcomes were determined for the following subgroups: 1) low-risk ORMS, 2) resected (group I/II) low-risk ORMS, 3) non-low-risk ORMS, and 4) recurrent ORMS. Event-free survival (EFS) and overall survival (OS) were estimated using the Kaplan-Meier method. ResultsThe authors identified 218 patients with ORMS. Most tumors were embryonal/botryoid (n = 169; 77.5%), <5 cm (n = 213; 97.7%), group III (n = 170; 78.0%), and without lymph node involvement (N0; n = 215; 98.6%). For 192 patients with low-risk ORMS, the 10-year EFS and OS rates were 85.5% (95% confidence interval [CI], 77.0%-94.0%) and 95.6% (95% CI, 90.8%-100.0%), respectively. Those with group I/II low-risk ORMS (n = 5 in group I; n = 39 in group IIA) had 10-year EFS and OS rates of 88.0% (95% CI, 72.6%-100.0%) and 97.6% (95% CI, 90.0%-100.0%), respectively. Twenty-six patients with non-low-risk ORMS had 5-year EFS and OS rates of 88.5% (95% CI, 75.6%-100.0%) and 95.8% (95% CI, 87.7%-100.0%), respectively. For patients with recurrent ORMS, the 10-year OS rate from the time of recurrence was 69.4% (95% CI, 50.0%-88.8%).

CONCLUSIONS

Patients with ORMS had favorable long-term survival outcomes on COG studies from 1997 to 2013, including those who had both low-risk and non-low-risk disease. A significant proportion of patients with recurrent ORMS may achieve long-term survival.

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.

Alveolar rhabdomyosarcoma has superior response rates to vinorelbine compared to embryonal rhabdomyosarcoma in patients with relapsed/refractory disease: A meta-analysis

BACKGROUND

Patients with alveolar rhabdomyosarcoma (ARMS) have inferior outcomes compared to patients with embryonal rhabdomyosarcoma (ERMS) and more effective chemotherapy options are needed for these patients. Vinorelbine is a semisynthetic vinca alkaloid that has clinical activity in relapsed rhabdomyosarcoma (RMS) when used alone or in combination with cyclophosphamide.

AIMS

The goal of our study was to evaluate whether RMS histology subtype influences response rate to vinorelbine alone or in combination.

MATERIALS & METHODS

Five Phase 2 trials that enrolled RMS patients were included in the meta-analysis. Two studies evaluated vinorelbine alone, two studies evaluated vinorelbine in combination with low dose oral cyclophosphamide, and one study evaluated vinorelbine and intravenous cyclophosphamide in combination with temsirolimus or bevacizumab. All RMS patients had relapsed or refractory disease and had received at least one prior therapy. Response was reported according to RECIST1.1 and was defined as a complete or partial response. Response data was obtained from published results or from trial principal investigator. RMS NOS patients were grouped with ERMS patients for this analysis. Summary estimates comparing differences between ARMS and ERMS response rates were generated using a random-effects model to account for heterogeneity among the studies.

RESULTS

One hundred fifty-six enrolled patients evaluable for response were included in the meta-analysis, 85 ARMS, 64 ERMS and 7 RMS-NOS. The combined effect generated from the random-effects model demonstrated a 41% increase (p = 0.001, 95% CI; 0.21-0.60) in response to vinorelbine as a single agent or in combination in patients with ARMS compared to patients with ERMS. There was no significant difference in the rate of progressive disease between patients with ARMS compared to ERMS (p = 0.1, 95%CI; -0.26-0.02).

DISCUSSION

Vinorelbine is an active agent for the treatment of relapsed or refractory RMS and a meta-analysis of Phase 2 studies shows that radiographic responses in patients with ARMS were significantly higher than ERMS or RMS-NOS.

CONCLUSION

These data support further investigation of vinorelbine in newly diagnosed patients with RMS particularly those with alveolar histology.

Outcome and prognostic variables in childhood rhabdomyosarcoma (RMS) with emphasis on impact of FOXO1 fusions in non-metastatic RMS: experience from a tertiary cancer centre in India

While factors influencing outcomes of rhabdomyosarcoma (RMS) in developed countries have evolved from clinical characteristics to molecular profiles, similar data from developing countries are scarce. This is a single-centre analysis of outcomes in treated cases of RMS, with emphasis on prevalence, risk-migration and prognostic impact of Forkhead Box O1 (FOXO1) in non-metastatic RMS. All children with histopathologically proven RMS, treated between January 2013 and December 2018 were included. Intergroup Rhabdomyosarcoma Study-4 risk stratification was used, with treatment based on a multimodality-regimen with chemotherapy (Vincristine/Ifosfamide/Etoposide and Vincristine/Actinomycin-D/Cyclophosphamide) and appropriate local therapy. Formalin-fixed paraffin-embedded tissues were tested using Reverse Transcriptase-Polymerase Chain Reaction for FOXO1-fusions (PAX3(P3F); PAX7(P7F)). A total of 221 children (Cohort-1) were included, of which 182 patients had non-metastatic disease (Cohort-2). Thirty-six (16%), 146 (66%), 39 (18%) patients were low-risk (LR), intermediate-risk (IR) and high-risk, respectively. FOXO1-fusion status was available in 140 patients with localised RMS (Cohort 3). P3F and P7F were detected in 25/49 (51%) and 14/85 (16.5%) of alveolar and embryonal variants, respectively. The 5-year-event-free survival (EFS)/overall survival (OS) of Cohorts 1, 2 and 3 was 48.5%/55.5%, 54.6%/62.6% and 55.1%/63.7%, respectively. Amongst the localised RMS, presence of nodal metastases and primary tumour size > 10 cms were adverse prognostic factorvs (p < 0.05). On incorporating fusion-status in risk-stratification, 6/29 (21%) patients migrated from LR (A/B) to IR. All patients who re-categorised as LR (FOXO1 negative) had a 5-year EFS/OS of 80.81%/90.91%. FOXO1-negative tumours had a better 5-year relapse-free survival (58.92% versus 44.63%; p = 0.296) with a near-significant correlation in favourable-site tumours (75.10% versus 45.83%; p = 0.063). While FOXO1-fusions have superior prognostic utility compared to histology alone in localised, favourable-site RMS, traditional prognostic factors (tumour size and nodal metastases) impacted outcome the most in this subset. Strengthening of early referral systems in community and timely local intervention can help in improving outcome in resource-constrained countries.

Spindle Cell/Sclerosing Rhabdomyosarcoma of the Orbit

A 3-year-old boy developed proptosis over 3 weeks. CT and MRI disclosed a 3.2 × 1.9 cm soft-tissue mass of the right extraconal and intraconal orbit with sphenoid bone erosion. After debulking through an upper eyelid crease incision, the tumor was diagnosed as a spindle cell/sclerosing rhabdomyosarcoma. DNA sequencing was negative for an L122R mutation in MyoD1 . Spindle cell/sclerosing rhabdomyosarcoma is an uncommon variant of this neoplasm, and only 2 patients with orbital tumors have been reported in 2 case series. Spindle cell/sclerosing rhabdomyosarcomas confined to the orbit are considered to have an excellent prognosis when treated with chemotherapy and radiation therapy. Diagnosis and treatment planning rely on histology, immunohistochemistry, and molecular analysis.

Oral vinorelbine and continuous low doses of cyclophosphamide in pediatric rhabdomyosarcoma: a real-world study

Introduction: Metronomic maintenance therapy (MMT) has significantly improved the survival of patients with high-risk rhabdomyosarcoma in clinical trials. However, there remains a lack of relevant data on its effectiveness in real-world situations. Methods: We retrospectively retrieved data of 459 patients < 18 years of age diagnosed with rhabdomyosarcoma at Sun Yat-sen University Cancer Center from January 2011 to July 2020 from our database. The MMT regimen was oral vinorelbine 25-40 mg/m² for twelve 4-week cycles on days 1, 8, and 15, and oral cyclophosphamide 25-50 mg/m² daily for 48 consecutive weeks. Results: A total of 57 patients who underwent MMT were included in the analysis. The median follow-up time was 27.8 (range: 2.9-117.5) months. From MMT to the end of follow-up, the 3-year PFS and OS rates were 40.6% ± 6.8% and 58.3% ± 7.2%, respectively. The 3-year PFS was 43.6% ± 11.3% in patients who were initially diagnosed as low- and intermediate-risk but relapsed after comprehensive treatment (20/57), compared with 27.8% ± 10.4% in high-risk patients (20/57) and 52.8% ± 13.3% in intermediate-risk patients who did not relapse (17/57). The corresponding 3-year OS for these three groups was 65.8% ± 11.4%, 50.1% ± 12.9%, and 55.6% ± 13.6%, respectively. Conclusion: We present a novel study of MMT with oral vinorelbine and continuous low doses of cyclophosphamide in real-world pediatric patients with RMS. Our findings showed that the MMT strategy significantly improved patient outcomes and may be an effective treatment for high-risk and relapsed patients.

Patients with completely resected nongenitourinary low-risk embryonal rhabdomyosarcoma are candidates for reduced duration low-intensity chemotherapy

BACKGROUND

The survival of patients with localized embryonal rhabdomyosarcoma (RMS) completely resected at diagnosis is greater than 90%. Most patients have paratesticular, uterine, or vaginal RMS, limiting specific analyses of RMS localized in other anatomic regions. This international study was conducted to define the outcome for completely resected embryonal RMS at sites other than paratesticular, uterine, or vaginal primary sites.

METHODS

A total of 113 patients aged 0-18 years were identified who were enrolled from January 1995 to December 2016 in Children's Oncology Group (COG) (64 patients) and European protocols (49). Genitourinary nonbladder and prostate RMS were excluded. The recommended chemotherapy was vincristine and actinomycin-D (VA) for 24 weeks or ifosfamide plus VA in the European protocols and VA for 48 weeks or VA plus cyclophosphamide in the COG protocols.

RESULTS

The most common primary sites were nonparameningeal head and neck (40.7%), other (23.9%), and extremities (20.4%). In the COG studies, 42% of patients received VA and 58% VA plus cyclophosphamide. In Europe, 53% received VA and 47% ifosfamide plus VA. With a median follow-up of 97.5 months, the 5-year progression-free and overall survival was 80.0% (71.2%-86.4%) and 92.5% (85.6%-96.2%), respectively, without significant differences between chemotherapy regimens. Tumor size (< or >5 cm) significantly influenced overall survival: 96.2% (88.6%-98.8%) vs. 80.6% (59.5%-91.4%), respectively (p = .01).

CONCLUSIONS

Survival of patients with nonalveolar RMS completely resected at diagnosis is excellent among tumors arising from nonparatesticular, uterine, and vaginal sites, and patients may be treated successfully with low-intensity chemotherapy. To reduce the burden of treatment, VA for 24 weeks may be considered in children with tumors <5 cm.

Translational Implications for Radiosensitizing Strategies in Rhabdomyosarcoma

Rhabdomyosarcoma (RMS) is the most common soft tissue sarcoma of childhood and adolescence that includes FP-RMS, harboring the fusion oncoprotein PAX3/7-FOXO1 and FN-RMS, often mutant in the RAS pathway. Risk stratifications of RMS patients determine different prognostic groups and related therapeutic treatment. Current multimodal therapeutic strategies involve surgery, chemotherapy (CHT) and radiotherapy (RT), but despite the deeper knowledge of response mechanisms underpinning CHT treatment and the technological improvements that characterize RT, local failures and recurrence frequently occur. This review sums up the RMS classification and the management of RMS patients, with special attention to RT treatment and possible radiosensitizing strategies for RMS tumors. Indeed, RMS radioresistance is a clinical problem and further studies aimed at dissecting radioresistant molecular mechanisms are needed to identify specific targets to hit, thus improving RT-induced cytotoxicity.

Vincristine-induced neurotoxicity in pediatric patients with rhabdomyosarcoma: A retrospective analysis of clinical features and outcome

Vincristine is an essential component of rhabdomyosarcoma treatment. However, it can cause motor neurotoxicity, necessitating dose reductions. We retrospectively reviewed the rates and patterns of vincristine-induced motor neuropathy in children treated for rhabdomyosarcoma, and investigated effects on outcome. Fifteen of 43 patients (35%) developed motor neuropathies necessitating dose reductions, which ranged from 1.7% to 58% of planned cumulative dose. Older age was the only significant clinical risk factor. Almost half (47%) recovered during treatment with subsequent dose escalation. Most patients had complete resolution of symptoms upon follow-up. There was no discernible effect of treatment reduction on survival or relapse rates.

Clinical group and modified TNM stage for rhabdomyosarcoma: A review from the Children's Oncology Group

The Children's Oncology Group (COG) uses Clinical Group (CG) and modified Tumor Node Metastasis (TNM) stage to classify rhabdomyosarcoma (RMS). CG is based on surgicopathologic findings and is determined after the completion of initial surgical procedure(s) but prior to chemotherapy and/or radiation therapy. The modified TNM stage is based on clinical and radiographic findings and is assigned prior to any treatment. These systems have evolved over several decades. We review the history, evolution, and rationale behind the current CG and modified TNM classification systems used by COG for RMS. Data from the seven most recently completed and reported frontline COG trials (D9602, D9802, D9803, ARST0331, ARST0431, ARST0531, ARST08P1) were analyzed, and confirm that CG and modified TNM stage remain relevant and useful for predicting prognosis in RMS. We propose updates based on recent data and discuss factors warranting future study to further optimize these classification systems.

Pediatric Sarcomas: The Next Generation of Molecular Studies

Pediatric sarcomas constitute one of the largest groups of childhood cancers, following hematopoietic, neural, and renal lesions. Partly because of their diversity, they continue to offer challenges in diagnosis and treatment. In spite of the diagnostic, nosologic, and therapeutic gains made with genetic technology, newer means for investigation are needed. This article reviews emerging technology being used to study human neoplasia and how these methods might be applicable to pediatric sarcomas. Methods reviewed include single cell RNA sequencing (scRNAseq), spatial multi-omics, high-throughput functional genomics, and clustered regularly interspersed short palindromic sequence-Cas9 (CRISPR-Cas9) technology. In spite of these advances, the field continues to be challenged by a dearth of properly annotated materials, particularly from recurrences and metastases and pre- and post-treatment samples.

An update on rhabdomyosarcoma risk stratification and the rationale for current and future Children's Oncology Group clinical trials

Children and adolescents with rhabdomyosarcoma (RMS) comprise a heterogeneous population with variable overall survival rates ranging between approximately 6% and 100% depending on defined risk factors. Although the risk stratification of patients has been refined across five decades of collaborative group studies, molecular prognostic biomarkers beyond FOXO1 fusion status have yet to be incorporated prospectively in upfront risk-based therapy assignments. This review describes the evolution of risk-based therapy and the current risk stratification, defines a new risk stratification incorporating novel biomarkers, and provides the rationale for the current and upcoming Children's Oncology Group RMS studies.

Epidemiological profile and clinico-pathological features of pediatric gynecological cancers at Moi Teaching & Referral Hospital, Kenya

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Fertility-sparing surgery for pediatric gynecological cancers should be the primary management.

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Dysgerminomas are the commonest ovarian germ cell tumors.

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Neo-adjuvant chemotherapy is feasible in advanced germ cell tumors.

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Pediatric gynecological cancers can have excellent prognosis.

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Early diagnosis and treatment can improve prognosis for germ cell tumors in LMICs.

Background

The main pediatric (0–18 years) gynecologic cancers include stromal carcinomas (juvenile granulosa cell tumors and Sertoli-Leydig cell tumors), genital rhabdomyosarcomas and ovarian germ cell. Outcomes depend on time of diagnosis, stage, tumor type and treatment which can have long-term effects on the reproductive career of these patients. This study seeks to analyze the trends in clinical-pathologic presentation, treatment and outcomes in the cases seen at our facility. This is the first paper identifying these cancers published from sub-Saharan Africa.

Method

Retrospective review of clinico-pathologic profiles and treatment outcomes of pediatric gynecologic oncology patients managed at MTRH between 2010 and 2020. Data was abstracted from gynecologic oncology database and medical charts.

Results

Records of 40 patients were analyzed. Most, (92.5%, 37/40) of the patients were between 10 and 18 years. Ovarian germ cell tumors were the leading histological diagnosis in 72.5% (29/40) of the patients; with dysgerminomas being the commonest subtype seen in 12 of the 37 patients (32.4%). The patients received platinum-based chemotherapy in 70% of cases (28/40). There were 14 deaths among the 40 patients (35%)

Conclusion

Surgery remains the main stay of treatment and fertility-sparing surgery with or without adjuvant platinum-based chemotherapy are the standard of care with excellent prognosis following early detection and treatment initiation. LMICs face several challenges in access to quality care and that affects survival of these patients. Due to its commonality, ovarian germ cell cancers warrant a high index of suspicion amongst primary care providers attending to adnexal masses in this age group.

Brachytherapy in children, adolescents, and young adults: An underutilized modality in the United States?

BACKGROUND

Brachytherapy (BT) delivers highly conformal radiation and spares surrounding tissues, which may limit late effects in pediatric, adolescent, and young adult (AYA) patients. We aimed to characterize trends in BT use for this population in the United States, focusing on patients with rhabdomyosarcoma (RMS).

METHODS

The National Cancer Database was queried to identify patients ≤ 21 who were treated for solid tumor malignancies in the United States from 2004 to 2016. We obtained disease, treatment, and outcome data for patients treated with BT, in particular for RMS.

RESULTS

99 506 pediatric and AYA patients met study inclusion. Of these, 22 586 (23%) received radiation therapy (external beam radiation therapy [EBRT] and/or BT) and 240 (0.2%) received BT. Among patients treated with BT, 139 (58%) underwent surgery and 58 (24%) received EBRT. A total of 3836 patients were treated for RMS during this period. Of these, 2531 (66%) received any radiation and 37 (1%) received BT (EBRT + BT in 3, BT in 34). Of patients treated with BT for RMS, 28 (76%) underwent surgery + BT. Survival data were available for 31 patients treated with BT for RMS. With a median follow-up of 63 months, overall survival was 100% for patients with RMS of a favorable site treated with BT.

CONCLUSIONS

BT is rarely used to treat pediatric and AYA patients in the United States. Patients treated with BT for RMS experienced favorable survival, suggesting that this approach may not compromise oncologic outcomes and warrants further study as a therapeutic option in pediatric and AYA patients, specifically in RMS.

Long-Term Clinical Outcome and Prognostic Factors of Children and Adolescents with Localized Rhabdomyosarcoma Treated on the CWS-2002P Protocol

We report here the results of the prospective, non-randomized, historically controlled CWS-2002P study in patients ≤ 21 years with localized RMS developed with the aim to improve the long-term outcome by adapting the burden of therapy to risk profile and to investigate the feasibility and relation to the outcome of maintenance therapy (MT) in the high-risk groups. Patients were allocated into low-risk (LR), standard-risk (SR), high-risk (HR), and very high-risk (VHR) groups. Chemotherapy consisted of vincristine (VCR) and dactinomycin (ACTO-D) for all patients with the addition of ifosfamide (IFO) in the SR, HR, and VHR and doxorubicin (DOX) in the HR and VHR groups. Low-dose cyclophosphamide and vinblastine maintenance therapy (MT) over 6 months was recommended in the HR and VHR groups. A total of 444 patients have been included in this analysis. With a median follow-up of 9·6 years (IQR 7·6–10·9) for patients alive, the 5-year EFS and OS for the whole group was 73% (95% CI 69–77) and 80% (95% CI 76–84), respectively. The 5-year EFS by risk group was 100% in the LR, 79% (95% CI 72–84) in the SR, 69% (95% CI 63–75) in the HR, and 42% (95% CI 23–61) in the VHR (log-rank p = 0.000). The 5-year EFS was 77% (95% CI 70–84%) for 155 patients in the HR group who received MT as compared to 63% (95% CI 50–76) for 49 patients who did not (log-rank p = 0.015). Neither the reduction in the IFO dose in the SR nor the increased dose intensity of DOX in HR groups influenced the outcome when compared to the previous CWS and other European studies. MT was feasible, seemed to have an impact on prognosis, and should be studied in a well-controlled prospective trial in this patient population. The weighting of risk factors used for therapy stratification needs to be reevaluated.

Genetic Characterization, Current Model Systems and Prognostic Stratification in PAX Fusion-Negative vs. PAX Fusion-Positive Rhabdomyosarcoma

Rhabdomyosarcoma (RMS) is the most common soft tissue sarcoma in children and adolescents and accounts for approximately 2% of soft tissue sarcomas in adults. It is subcategorized into distinct subtypes based on histological features and fusion status (PAX-FOXO1/VGLL2/NCOA2). Despite advances in our understanding of the pathobiological and molecular landscape of RMS, the prognosis of these tumors has not significantly improved in recent years. Developing a better understanding of genetic abnormalities and risk stratification beyond the fusion status are crucial to developing better therapeutic strategies. Herein, we aim to highlight the genetic pathways/abnormalities involved, specifically in fusion-negative RMS, assess the currently available model systems to study RMS pathogenesis, and discuss available prognostic factors as well as their importance for risk stratification to achieve optimal therapeutic management.

Proton beam therapy with concurrent chemotherapy is feasible in children with newly diagnosed rhabdomyosarcoma

Background

The optimal treatment for rhabdomyosarcoma (RMS) requires multidisciplinary treatment with chemotherapy, surgery, and radiotherapy. Surgery and radiotherapy are integral to the local control (LC) of RMS. However, postsurgical and radiotherapy-related complications could develop according to the local therapy and tumor location. In this study, we conducted a single-center analysis of the outcomes and toxicity of multidisciplinary treatment using proton beam therapy (PBT) for pediatric RMS.

Materials and methods

RMS patients aged younger than 20 years whose RMS was newly diagnosed and who underwent PBT at University of Tsukuba Hospital (UTH) during the period from 2009 to 2019 were enrolled in this study. The patients' clinical information was collected by retrospective medical record review.

Results

Forty-eight patients were included. The 3-year progression-free survival (PFS) and overall survival (OS) rates of all the patients were 68.8% and 94.2%, respectively. The 3-year PFS rates achieved with radical resection, conservative resection, and biopsy only were 65.3%, 83.3%, and 67.6%, respectively (p = 0.721). The 3-year LC rates achieved with radical resection, conservative resection, and biopsy only were 90.9%, 83.3%, and 72.9%, respectively (p = 0.548). Grade 3 or higher mucositis/dermatitis occurred in 14 patients. Although the days of opioid use due to mucositis/dermatitis during the chemotherapy with PBT were longer than those during the chemotherapy without PBT [6.1 and 1.6 (mean), respectively, p = 0.001], the frequencies of fever and elevation of C-reactive protein were equivalent.

Conclusions

Multidisciplinary therapy containing PBT was feasible and provided a relatively fair 3-year PFS, even in children with newly diagnosed RMS without severe toxicity.

More Than Meets the Eye? A Cautionary Tale of Malignant Ectomesenchymoma Treated as Low-risk Orbital Rhabdomyosarcoma

Malignant ectomesenchymoma (MEM) is a rare multiphenotypic tumor comprised of mesenchymal and neuroectodermal components. MEM is typically diagnosed in infants and younger children and outcomes are variable. The current approach for treating MEM includes targeting the more aggressive mesenchymal component of the tumor, which is often rhabdomyosarcoma. Here, we describe a case of an orbital tumor initially diagnosed and treated as low-risk rhabdomyosarcoma. Local failure prompting a second biopsy revealed neuronal differentiation consistent with a diagnosis of MEM. Intensifying therapy and local radiotherapy led to a long-term cure. This case offers a cautionary tale that while outcomes for MEM were similar to matched rhabdomyosarcoma cohorts when treated on conventional Intergroup Rhabdomyosarcoma Study Group (IRSG) III/IV protocols, treating MEM using a decreased intensity low-risk rhabdomyosarcoma regimen may not be sufficient.

Radiation Therapy in the Treatment of Head and Neck Rhabdomyosarcoma

The use of radiation therapy is an important part of multimodality treatment for rhabdomyosarcoma. The specific doses, treatment volumes, and techniques used in radiation therapy can vary dramatically based upon a number of factors including location, tumor size, and molecular characteristics, resulting in complex decisions in treatment planning. This article reviews the principles of evaluation and management for head and neck rhabdomyosarcoma including a summary of the historical studies upon which current management is based.

Recent progress in the treatment of cancer in children

Although significant improvements have been made in the outcomes of children with cancer, the pace of improvement has slowed in recent years as the limits of therapy intensification may have been reached for many pediatric cancers. Furthermore, with increasing numbers of pediatric cancer survivors, the long-term side effects of treatment have become increasingly apparent. Therefore, attention has shifted to the use of molecularly targeted agents and immunotherapies to improve the outcomes of children who are not cured by traditional cytotoxic chemotherapies and to decrease exposure to cytotoxic chemotherapy and reduce late effects. This review describes the recent progress in the treatment of children with cancer, focusing in particular on diseases in which targeted and immunotherapeutic agents have made an impact.

Clinical Characteristics and Treatment Outcome of Paediatric Rhabdomyosarcoma; A Retrospective Review

Introduction

Rhabdomyosarcoma (RMS) is the most common soft tissue sarcoma in children. This paper aimed to assess the stage, site and treatment outcome among RMS patients.

Materials and Methods

A retrospective chart review was completed from January 2011 to December 2017 of patients that presented to the Department of Paediatric Oncology, Shaukat Khanum Memorial Cancer Hospital, Lahore, Pakistan, for the management of RMS. Data collection included clinical characteristics, staging, grouping, risk stratification, treatment plan, radiotherapy doses and treatment outcome.

Results

Among 24 subjects, there were a total of 13 (54.2%) males and 11 (45.8%) females. The median age at the time of diagnosis was 2.5 years (range: 0.75-17 years). The majority of the subjects (91.7%) were <10 years of age. The median follow-up time was 0.6 years. According to the Children's Oncology Group Classification, 4 (16.7%) subjects were classified as low risk, 14 (58.3%) subjects were rated as intermediate risk and 6 (0.25%) subjects were stratified as high risk. The most common primary tumour site was genitourinary (62.5%) and abdomen/retroperitoneal (20.8%) regions. At the time of analysis, nine (37.5%) subjects had died because of the disease, 12 (50%) were alive with no evidence of disease and one subject had a recurrence of disease and was alive. One subject had abandoned the therapy and another was lost to follow-up.

Conclusion

Patients with RMS presented at the late stages of the disease and it most frequently affected genitourinary and abdomen or retroperitoneal areas. Overall, RMS was found to have a poor outcome to therapy.

Childhood Cancer: Occurrence, Treatment and Risk of Second Primary Malignancies

Cancer represents the leading cause of disease-related death and treatment-associated morbidity in children with an increasing trend in recent decades worldwide. Nevertheless, the 5-year survival of childhood cancer patients has been raised impressively to more than 80% during the past decades, primarily attributed to improved diagnostic technologies and multiagent cytotoxic regimens. This strong benefit of more efficient tumor control and prolonged survival is compromised by an increased risk of adverse and fatal late sequelae. Long-term survivors of pediatric tumors are at the utmost risk for non-carcinogenic late effects such as cardiomyopathies, neurotoxicity, or pneumopathies, as well as the development of secondary primary malignancies as the most detrimental consequence of genotoxic chemo- and radiotherapy. Promising approaches to reducing the risk of adverse late effects in childhood cancer survivors include high precision irradiation techniques like proton radiotherapy or non-genotoxic targeted therapies and immune-based treatments. However, to date, these therapies are rarely used to treat pediatric cancer patients and survival rates, as well as incidences of late effects, have changed little over the past two decades in this population. Here we provide an overview of the epidemiology and etiology of childhood cancers, current developments for their treatment, and therapy-related adverse late health consequences with a special focus on second primary malignancies.

Rhabdomyosarcoma

Rhabdomyosarcoma is a heterogeneous disease both in presentation and histology. Improvements in a multimodality therapy resulted in the improved overall survival for patients with a low-risk and intermediate-risk disease but not for patients with a metastatic disease. We reviewed and contrasted the North American and European practice patterns, though ultimately the principles of staging, surgery, radiation therapy, and chemotherapy are similar in both Children's Oncology Group and International Society of Paediatric Oncology treatment approaches. Efforts are underway to investigate improved local control rates in higher risk patients using radiation dose escalation strategies, and delayed primary excision in select cases. The prognostic significance of imaging-based chemotherapy response, proton therapy, novel biomarkers, and targeted drugs will be determined in upcoming clinical trials.

PET with 18F-Fluorodeoxyglucose/Computed Tomography in the Management of Pediatric Sarcoma

The role for PET with fludeoxyglucose F 18 (¹⁸F-FDG PET)/computed tomography (CT) in the management of pediatric sarcomas continues to be controversial. The literature supports a role for PET/CT in the staging and surveillance of certain specific pediatric sarcoma subtypes; however, the data are less clear regarding whether PET/CT can be used as a biomarker for prognostication. Despite the interest in using this imaging modality in the management of pediatric sarcomas, most studies are limited by retrospective design and small sample size. Additional data are necessary to fully understand how best to use ¹⁸F-FDG PET/CT in pediatric sarcoma management.

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.

Suboptimal outcome for patients with biliary rhabdomyosarcoma treated on low-risk clinical trials: A report from the Children's Oncology Group

BACKGROUND

Biliary rhabdomyosarcoma (RMS) is the most common biliary tumor in children. The biliary tract is classified as a favorable primary site. Therefore, patients with localized biliary RMS were included in two consecutive low-risk studies, D9602 and ARST0331, by the Children's Oncology Group (COG). The outcome for these patients treated with low-risk therapy has not been reported.

PROCEDURE

Patients with biliary RMS enrolled on COG low-risk trials D9602 or ARST0331 were analyzed. All patients received systemic chemotherapy and those with Group II (microscopic residual) or Group III (macroscopic residual) disease received 36-50.4 Gy adjuvant radiotherapy (RT). Delayed primary excision (DPE) was allowed on both studies.

RESULTS

Seventeen patients with biliary RMS were treated on D9602 (n = 7) or ARST0331 (n = 10). Median age was 3.5 years (range 1.7-10.3). Ten (59%) patients had tumors >5 cm and 14 (82%) had Group III disease. Fifteen (88%) patients received RT. The 5-year event-free survival (EFS) and overall survival (OS) were 70.6% (95% confidence interval [CI]: 46.9-94.3%) and 76.5% (95% CI: 54.6-98.4%), respectively. The majority of patients (80%) who received RT did not have disease recurrence while both patients who did not receive RT had local relapse. Five (36%) of 14 patients with Group III disease underwent DPE; two experienced a local relapse. In the nine patients without DPE, two developed local relapse.

CONCLUSIONS

Patients with localized biliary RMS treated on low-risk studies had suboptimal outcomes. These patients may benefit from therapy on intermediate-risk studies.

Advances in the Diagnosis and Management of Neonatal Sarcomas

Neonatal sarcomas comprise a heterogeneous group of rare soft tissue neoplasms that present unique diagnostic and therapeutic challenges. Recent advances in molecular profiling have improved diagnostic capabilities and reveal novel therapeutic targets. Clinical trials demonstrate differences in behavior between sarcoma subtypes that allow for better clinical management. Surgical resection has been replaced with a multimodal approach that includes chemotherapy and radiotherapy. Despite these advances, neonates with sarcoma continue to fare worse than histologically similar sarcomas in older children, likely reflecting differences in tumor biology and the complexities of neonatal medicine. This review focuses on recent advances in managing neonatal sarcomas.

Embryonal rhabdomyosarcoma completely resected at diagnosis: The European paediatric Soft tissue sarcoma Study Group RMS2005 experience

BACKGROUND

Rhabdomyosarcoma (RMS) is the most common form of soft tissue sarcoma in children. We report the results of the European paediatric Soft tissue sarcoma Study Group (EpSSG) RMS 2005 study, which prospectively evaluated the reduction of chemotherapy in patients with embryonal RMS (ERMS) after initial surgery.

METHODS

Between October 2005 and December 2016, all patients with localised ERMS with an initial microscopically complete resection (IRS group I) with lymph node-negative (N0) were prospectively enrolled in the low-risk (n = 70, subgroup A; age < 10 years and tumour size ≤ 5 cm) or standard-risk group (n = 108, subgroup B; age ≥ 10 years or tumour size > 5 cm. Subgroup A received 8 courses of vincristine and dactinomycin (VA) for 22 weeks; subgroup B received 4 courses of VA with ifosfamide (IVA) and 5 courses of VA for 25 weeks.

RESULTS

The 5-year event-free survival (EFS) and overall survival (OS) were 90.8% (95% confidence interval [CI]: 85.0-94.4) and 95.7% (95% CI: 90.5-98.1), respectively (n = 178). The EFS and OS were 95.5% (95% CI: 86.8-98.5) and 100% (subgroupA), and 87.8% (95% CI: 79.3-93.0) and 93.0% (95% CI: 84.8-96.8)(subgroup B), respectively. Bearman stage 2 veno-occlusive disease (VOD) occurred in 4 very young patients.

CONCLUSION

VA treatment for 8 courses was effective and well tolerated by the subgroup of patients with low-risk ERMS (group A). Four courses of IVA and 5 courses of VA instead of 9 courses of IVA also has very good results. Careful monitoring for liver toxicity is important in very young patients. European union drug regulating authorities clinical trials EUDRACT No. 2005-000217-35.

Metabolic response as assessed by 18 F-fluorodeoxyglucose positron emission tomography-computed tomography does not predict outcome in patients with intermediate- or high-risk rhabdomyosarcoma: A report from the Children's Oncology Group Soft Tissue Sarcoma Committee

BACKGROUND

Strategies to optimize management in rhabdomyosarcoma (RMS) include risk stratification to assign therapy aiming to minimize treatment morbidity yet improve outcomes. This analysis evaluated the relationship between complete metabolic response (CMR) as assessed by ¹⁸ F-fluorodeoxyglucose positron emission tomography-computed tomography (FDG-PET) imaging and event-free survival (EFS) in intermediate-risk (IR) and high-risk (HR) RMS patients.

METHODS

FDG-PET imaging characteristics, including assessment of CMR and maximum standard uptake values (SUVmax) of the primary tumor, were evaluated by central review. Institutional reports of SUVmax were used when SUVmax values could not be determined by central review. One hundred and thirty IR and 105 HR patients had FDG-PET scans submitted for central review or had SUVmax data available from institutional report at any time point. A Cox proportional hazards regression model was used to evaluate the relationship between these parameters and EFS.

RESULTS

SUVmax at study entry did not correlate with EFS for IR (p = 0.32) or HR (p = 0.86) patients. Compared to patients who did not achieve a CMR, EFS was not superior for IR patients who achieved a CMR at weeks 4 (p = 0.66) or 15 (p = 0.46), nor for HR patients who achieved CMR at week 6 (p = 0.75) or 19 (p = 0.28). Change in SUVmax at week 4 (p = 0.21) or 15 (p = 0.91) for IR patients or at week 6 (p = 0.75) or 19 (p = 0.61) for HR patients did not correlate with EFS.

CONCLUSION

Based on these data, FDG-PET does not appear to predict EFS in IR or HR-RMS. It remains to be determined whether FDG-PET has a role in predicting survival outcomes in other RMS subpopulations.

The prognostic significance of anaplasia in childhood rhabdomyosarcoma: A report from the Children's Oncology Group

BACKGROUND

Established prognostic indicators in rhabdomyosarcoma (RMS), the most common childhood soft tissue sarcoma, include several clinicopathologic features. Among pathologic features, anaplasia has been suggested as a potential prognostic indicator, but the clinical significance of anaplasia remains unclear.

METHODS

Patients enrolled on one of five recent Children's Oncology Group clinical trials for RMS (D9602, n = 357; D9802, n = 80; D9803, n = 462; ARST0331, n = 335; and ARST0531, n = 414) with prospective central pathology review were included in this study. Clinicopathologic variables including demographic information, risk group, histologic subtype, and anaplasia were recorded along with overall survival (OS) and failure-free survival (FFS) with failure defined by recurrence, progression, or death. The log-rank test was used to compare OS and FFS.

RESULTS

Anaplasia was more common in embryonal RMS (27% of all embryonal RMS) than other subtypes of RMS (11% for alveolar RMS, 7% for botryoid RMS, 11% for spindle cell RMS). On multivariate analyses, anaplasia was not an independent prognostic factor in RMS (OS:hazard ratio (HR) = 1.12, p = 0.43; FFS:HR = 1.07, p = 0.56) across all subtypes or within embryonal RMS only (OS:HR = 1.41, p = 0.078; FFS:HR = 1.25, p = 0.16). Among tumors with TP53 mutations, 69% had anaplasia, while only 24% of tumors with anaplasia had a tumoral TP53 mutation.

CONCLUSIONS

Anaplasia is not an independent indicator of adverse outcomes in RMS. Emerging information on the prognostic significance of TP53 mutations raises the possibility that anaplasia may be a surrogate marker of TP53 mutations in some cases. Tumoral TP53 mutation status may be investigated as a prognostic indicator in future studies.

Epidemiology and survival outcome of adult kidney, bladder, and prostate rhabdomyosarcoma: A SEER database analysis

Rhabdomyosarcoma (RMS) is rare in adulthood, accounting for 2%-5% of adult soft tissue tumors, and less than 20% occur in genitourinary organs. Given its rarity, survival data on adult kidney, bladder, and prostate RMSs is limited. In this population-based analysis, we performed an analysis of all adult RMS cases reported in Surveillance, Epidemiology, and End Results (SEER) database to understand prognostic factors among kidney, bladder, and prostate RMS. A query of the SEER database was performed from 1973 to 2016 for patients >18 of age with RMS. The final cohort consisted of 14 kidney, 35 bladder, and 21 prostate RMS cases in the adult population. Demographic, treatment, and survival data were obtained. Analysis was performed using Fisher's exact test, survival analysis, and model. The median (range) age of diagnosis for adult bladder RMS was 65 years old (19-84) compared to 52.5 (28-68) and 42 (19-87) for kidney and prostate (p = 0.007). About 78.6% of patients underwent surgical intervention. Five-year overall survival (OS) for adult kidney, bladder, and prostate RMS are 17.1% (2.9-41.6%), 22.2% (9.4-38.4%), and 33.0 (12.8-55.0%), respectively. OS was not statistically associated with primary site (p = 0.209). On multivariable analysis, compared to adult bladder RMS, kidney RMS had a higher incidence of mortality (HR: 2.16, 95% CI 1.03-4.53, p = 0.041). Incidence of mortality from prostate RMS was not significantly different from bladder RMS (HR: 0.70, 95% CI 0.30-1.65, p = 0.411). Extent of disease (HR: 5.17, 95% CI 2.09-12.79, p < 0.001) and older age (HR 1.03, 95% CI 1.01-1.04, p = 0.002) were adverse prognostic factors for OS. Overall survival at 5 years for adult kidney, bladder, and prostate RMS is poor. Localized disease and younger age are prognostic factors for improved outcomes in adult RMS. Hence, early diagnosis and intervention appear paramount to improved survival for this rare malignancy in adulthood.

Advances in the management of pediatric genitourinary rhabdomyosarcoma

Recent clinical trials have revealed several unanticipated complexities in the optimal management of genitourinary rhabdomyosarcoma (RMS). Improvement in outcomes for low- and intermediate-risk RMS over the past several decades led to the design of clinical trials aimed at reducing acute and late toxicity from extirpative surgeries, conventional radiotherapy, and cytotoxic chemotherapy. Results from these studies are mixed and have illuminated areas where historical risk stratification strategies need refining. Although radiotherapy has now become the standard for local control for most patients with genitourinary RMS, recent studies are demonstrating that there may be opportunities to minimize radiation toxicity while maintaining acceptable failure-free survival. A reduction in cyclophosphamide exposure may benefit select low-risk RMS patients but recent results illustrate that decreasing therapy intensity for most genitourinary RMS patients will require careful consideration in future prospective trials. Finally, recent studies highlight differences in perspective between European and North American investigators regarding the optimal balance of increased local failure rates but less toxicity versus improved event-free survival at a cost of higher toxicity. This review focuses on the results from the most recent RMS clinical trials and discusses their implications for the management of pediatric genitourinary RMS.

Deep learning enabled prediction of 5-year survival in pediatric genitourinary rhabdomyosarcoma

BACKGROUND

Genitourinary rhabdomyosarcoma (GU-RMS) is a rare, pediatric malignancy originating from embryonic mesenchyme. Current approaches to prognostication rely upon conventional statistical methods such as Cox proportional hazards (CPH) models and have suboptimal predictive ability. Given the success of deep learning approaches in other specialties, we sought to develop and compare deep learning models with CPH models for the prediction of 5-year survival in pediatric GU-RMS patients.

METHODS

Patients less than 20 years of age with GU-RMS were identified within the Surveillance, Epidemiology, and End Results (SEER) database (1998-2011). Deep neural networks (DNN) were trained and tested on an 80/20 split of the dataset in a 5-fold cross-validated fashion. Multivariable CPH models were developed in parallel. The primary outcomes were 5-year overall survival (OS) and disease-specific survival (DSS). Variables used for prediction were age, sex, race, primary site, histology, degree of tumor extension, tumor size, receipt of surgery, and receipt of radiation. Receiver operating characteristic curve analysis was conducted, and DNN models were tested for calibration.

RESULTS

277 patients were included. The area under the curve (AUC) for the DNN models was 0.93 for OS and 0.91 for DSS. AUC for the CPH models was 0.82 for OS and 0.84 for DSS. The DNN models were well-calibrated: OS model (slope = 1.02, intercept = -0.06) and DSS model (slope = 0.79, intercept = 0.21).

CONCLUSIONS

A deep learning-based model demonstrated excellent performance, superior to that of CPH models, in the prediction of pediatric GU-RMS survival. Deep learning approaches may enable improved prognostication for patients with rare cancers.

Rigosertib Induces Mitotic Arrest and Apoptosis in RAS-Mutated Rhabdomyosarcoma and Neuroblastoma

Relapsed pediatric rhabdomyosarcomas (RMS) and neuroblastomas (NBs) have a poor prognosis despite multimodality therapy. In addition, the current standard of care for these cancers includes vinca alkaloids that have severe toxicity profiles, further underscoring the need for novel therapies for these malignancies. Here, we show that the small-molecule rigosertib inhibits the growth of RMS and NB cell lines by arresting cells in mitosis, which leads to cell death. Our data indicate that rigosertib, like the vinca alkaloids, exerts its effects mainly by interfering with mitotic spindle assembly. Although rigosertib has the ability to inhibit oncogenic RAS signaling, we provide evidence that rigosertib does not induce cell death through inhibition of the RAS pathway in RAS-mutated RMS and NB cells. However, the combination of rigosertib and the MEK inhibitor trametinib, which has efficacy in RAS-mutated tumors, synergistically inhibits the growth of an RMS cell line, suggesting a new avenue for combination therapy. Importantly, rigosertib treatment delays tumor growth and prolongs survival in a xenograft model of RMS. In conclusion, rigosertib, through its impact on the mitotic spindle, represents a potential therapeutic for RMS.