Rhabdomyosarcoma and undifferentiated sarcoma in the first two decades of life: a selective review of intergroup rhabdomyosarcoma study group experience and rationale for Intergroup Rhabdomyosarcoma Study V

Opportunity in Complexity: Harnessing Molecular Biomarkers and Liquid Biopsies for Personalized Sarcoma Care

Due to their rarity and complexity, sarcomas represent a substantial therapeutic challenge. However, the incredible diversity within and across sarcoma subtypes presents an opportunity for personalized care to maximize efficacy and limit toxicity. A deeper understanding of the molecular alterations that drive sarcoma development and treatment response has paved the way for molecular biomarkers to shape sarcoma treatment. Genetic, transcriptomic, and protein biomarkers have become critical tools for diagnosis, prognostication, and treatment selection in patients with sarcomas. In the future, emerging biomarkers like circulating tumor DNA analysis offer the potential to improve early detection, monitoring response to treatment, and identifying mechanisms of resistance to personalize sarcoma treatment. Here, we review the current state of molecular biomarkers for sarcomas and highlight opportunities and challenges for the implementation of new technologies in the future.

Adult head and neck rhabdomyosarcoma: radiotherapy- based treatment, outcomes, and predictors of survival

BACKGROUND

Adult head and neck rhabdomyosarcoma (HNRMS) is an exceptionally rare malignancy, and there is a paucity of data and research dedicated to understanding its characteristics and management in adult populations. This study aimed to assess the outcomes and identify survival predictors in adult HNRMS.

METHODS

We retrospectively evaluated 42 adult patients (> 16 years) with HNRMS who received radiotherapy (RT)-based treatment at our institute between 2008 and 2022. We analysed the clinical characteristics and prognosis of these patients, including the locoregional recurrence-free survival (LRFS), progression-free survival (PFS), and overall survival (OS), using the Kaplan-Meier method. The chi-square and Fisher's exact tests were used to analyse differences between groups for dichotomous and categorical variables, respectively. Survival rates were calculated using the Kaplan-Meier method. Prognostic variables were assessed through univariate Cox analyses.

RESULTS

The median patient age was 28 years (range, 16-82 years). Alveolar RMS was the most common histological type, observed in 21 patients (50.0%), followed by embryonal in 16 patients (38.1%). The anatomic sites of origin were orbital in one (2.4%), parameningeal in 26 (61.9%), and non-orbital/non-parameningeal in 15 (35.7%) patients. Nineteen patients (45.2%) had regional lymph node metastasis, and five patients (11.9%) presented with distant metastatic disease. Distant metastasis (n = 17) was the primary cause of treatment failure. At a median follow-up of 47.0 months, the 5-year LRFS, PFS, and OS rates were 69.0%, 39.7%, and 41.0%, respectively. Univariate analysis revealed that tumour size, lymph node involvement, and the local treatment pattern (surgery and RT vs. RT alone) were significant predictors of survival.

CONCLUSIONS

The main failure pattern in patients with HNRMS receiving RT-based treatment was distant metastasis. Tumour size > 5 cm and lymph node involvement were predictors of worse LRFS. Multimodality local treatment, combining surgery and RT, is effective and provides survival benefits.

Management of a pure uterine corpus rhabdomyosarcoma in a postmenopausal patient: A rare case report and review of the literature

Key Clinical Message

Rhabdomyosarcoma of the female genital tract often involves the vagina and cervix. It usually occurs in infants and children. Such tumors are uncommon in the uterus, especially in adults. Treatment options are based on studies of younger individuals.

Abstract

Rhabdomyosarcoma (RMS) is a malignant mesenchymal neoplasm with a tendency to differentiate into skeletal muscle cells. RMS is an aggressive tumor that tends to develop in children and younger patients. A vast majority of genital tract RMSs occur in the vagina and cervix. Such tumors rarely occur in adults. Usually, these tumors either occur as a component of a biphasic uterine tumor (carcinosarcoma or adenosarcoma) or can be a pure heterologous tumor. Pure uterine RMSs are extremely rare in adult patients and difficult to diagnose. Accurate diagnosis of these tumors depends on precise histopathological evaluation. The present report describes a rare case of embryonal RMS of the uterus in a postmenopausal female and explores the most recent literature. The aim is to strengthen the existing literature and aid clinicians in the management of similar cases. A 64-year-old postmenopausal female presented with a history of abdominal pain associated with abdominal distension, per vaginal bleeding, and foul-smelling discharge for 6 months. A transabdominal ultrasound revealed a bulky uterus with a well-circumscribed heterogeneous lesion. Histopathology confirmed the diagnosis of high-grade embryonal RMS within the corpus region of the uterus. A total abdominal hysterectomy with bilateral salpingo-oophorectomy was performed, followed by adjuvant chemotherapy to prevent relapse of the disease. Six months after oncological care has passed, the patient remains symptoms-free without evidence of recurrence or metastasis.

Generation of Orthotopic and Subcutaneous Patient-Derived Xenograft Models from Diverse Clinical Tissue Samples of Pediatric Extracranial Solid Tumors

Realistic and renewable laboratory models that accurately reflect the distinct clinical features of childhood cancers have enormous potential to speed research progress. These models help us to understand disease biology, develop new research methods, advance new therapies to clinical trial, and implement personalized medicine. This chapter describes methods to generate patient-derived xenograft models of neuroblastoma and rhabdomyosarcoma, two tumor types for which children with high-risk disease have abysmal survival outcomes and survivors have lifelong-debilitating effects from treatment. Further, this protocol addresses model development from diverse clinical tumor tissue samples, subcutaneous and orthotopic engraftment, and approaches to avoid model loss.

Induction Chemotherapy Prior to Endoscopic Resection of Alveolar Rhabdomyosarcoma

Head and neck rhabdomyosarcoma (HNRMS) is a rare type of soft tissue tumor that affects both adults and children with an overall incidence of 0.041 per 100,000 people. Adults make up approximately 31.2% of all HNRMS diagnoses and have an overall survival rate between 20% and 40%. We present a case of a 46-year-old male who initially presented with nasal congestion and vision changes. Maxillofacial computed tomography and magnetic resonance imaging of the brain showed involvement of the orbital apex, abutment of the planum sphenoidale, and extension to the foramen rotundum (FR). Nasal endoscopy with biopsy confirmed the diagnosis of T2aN0M0 parameningeal HNRMS. The patient underwent induction chemotherapy, followed by endoscopic resection, which resulted in negative intraoperative margins. Subsequently, he underwent adjuvant concurrent chemotherapy and proton beam radiation after positive microscopic positive margins were found on the optic nerve. The patient did not experience any significant complications, and he is currently without radiographic or clinical recurrence 18 months after the treatment. He was able to maintain his vision throughout the treatment. In adults, HNRMS is usually treated with chemoradiotherapy based on pediatric protocols, since there are limited data available for adult treatment protocols and outcomes. Although surgery has been associated with positive outcomes in adult patients, there are no previous reports of its use with either neoadjuvant or adjuvant treatment. This type of treatment protocol has never been described for adult HNRMS. We hope that our report can add more data to the growing body of literature on HNRMS treatment protocols.

The modulation of iron metabolism affects the Rhabdomyosarcoma tumor growth in vitro and in vivo

Rhabdomyosarcoma (RMS) is an aggressive rare neoplasm that derives from mesenchymal cells, which frequently develops resistance to the current therapies and the formation of metastases. Thus, new therapies are needed. The alteration of iron metabolism in cancer cells was effective in reducing the progression of many tumors but not yet investigated in RMS. Here we investigated the effect of iron modulation in RMS both in vitro and in vivo. We first characterized the most used RMS cell lines representing the most common subtypes, embryonal (ERMS, RD cells) and alveolar (ARMS, RH30 cells), for their iron metabolism, in basal condition and in response to its modulation. Then we investigated the effects of both iron overload and chelation strategies in vitro and in vivo. RMS cell lines expressed iron-related proteins, even if at lower levels compared to hepatic cell lines and they are correctly modulated in response to iron increase and deprivation. Interestingly, the treatment with different doses of ferric ammonium citrate (FAC, as iron source) and with deferiprone (DFP, as iron chelator), significantly affected the cell viability of RD and RH30. Moreover, iron supplementation (in the form of iron dextran) or iron chelation (in the form of DFP) were also effective in vivo in inhibiting the tumor mass growth both derived from RD and RH30 with iron chelation treatment the most effective one. All the data suggest that the iron modulation could be a promising approach to overcome the RMS tumor growth. The mechanism of action seems to involve the apoptotic cell death for both iron supplementation and chelation with the concomitant induction of ferroptosis in the case of iron supplementation.

Pediatric Rhabdomyosarcomas of the Genitourinary Tract

Rhabdomyosarcoma (RMS) is the most common soft tissue sarcoma in the pediatric and adolescent population, with 350 new cases diagnosed each year. While they can develop anywhere in the body, the genitourinary tract is the second most common primary location for an RMS to develop. Overall survival has improved through the increased use of protocols and multidisciplinary approaches. However, the guidelines for management continue to change as systemic and radiation therapeutics advance. Given the relative rarity of this disease compared to other non-solid childhood malignancies, healthcare providers not directly managing RMS may not be familiar with their presentation and updated management. This review aims to provide foundational knowledge of the management of RMSs with an emphasis on specific management paradigms for those arising from the genitourinary tract. The genitourinary tract is the second most common location for an RMS to develop but varies greatly in symptomology and survival depending on the organ of origin. As the clinical understanding of these tumors advances, treatment paradigms have evolved. Herein, we describe the breadth of presentations for genitourinary RMSs with diagnostic and treatment management considerations, incorporating the most recently available guidelines and societal consensus recommendations.

Evaluation of functional and metabolic tumor volume using voxel-wise analysis in childhood rhabdomyosarcoma

BACKGROUND

Cross-sectional imaging-based morphological characteristics of pediatric rhabdomyosarcoma have failed to predict outcomes.

OBJECTIVE

To evaluate the feasibility and possible value of generating tumor sub-volumes using voxel-wise analysis of metabolic and functional data from positron emission tomography/magnetic resonance imaging (PET/MR) or PET/computed tomography (CT) and MRI in rhabdomyosarcoma.

MATERIALS AND METHODS

Thirty-four examinations in 17 patients who received PET/MRI or PET/CT plus MRI were analyzed. The volume of interest included total tumor volume before and after therapy. Apparent diffusion coefficients (ADC) and standard uptake values (SUV) were determined voxel-wise. Voxels were assigned to three different groups based on ADC and SUV: "viable tumor tissue," "intermediate tissue" or "possible necrosis." In a second approach, data were grouped into three clusters using the Gaussian mixture model. The ratio of these clusters to total tumor volume and changes due to chemotherapy were correlated with clinical and histopathological data.

RESULTS

After chemotherapy, the proportion of voxels in the different groups changed significantly. A significant reduction of the proportion of voxels assigned to cluster 1 was found, from a mean of 36.4% to 2.5% (P < 0.001). There was a significant increase in the proportion of voxels in cluster 3 following chemotherapy from 24.8% to 81.6% (P = 0.02). The proportion of voxels in cluster 2 differed depending on the presence or absence of tumor recurrence, falling from 48% to 10% post-chemotherapy in the group with no tumor recurrence (P < 0.05) and from 29% to 23% (P > 0.05) in the group with tumor recurrence.

CONCLUSION

Voxel-wise evaluation of multimodal data in rhabdomyosarcoma is feasible. Our initial results suggest that the different distribution of sub-volumes before and after therapy may have prognostic significance.

Radioresistance in rhabdomyosarcomas: Much more than a question of dose

Management of rhabdomyosarcoma (RMS), the most common soft tissue sarcoma in children, frequently accounting the genitourinary tract is complex and requires a multimodal therapy. In particular, as a consequence of the advancement in dose conformity technology, radiation therapy (RT) has now become the standard therapeutic option for patients with RMS. In the clinical practice, dose and timing of RT are adjusted on the basis of patients' risk stratification to reduce late toxicity and side effects on normal tissues. However, despite the substantial improvement in cure rates, local failure and recurrence frequently occur. In this review, we summarize the general principles of the treatment of RMS, focusing on RT, and the main molecular pathways and specific proteins involved into radioresistance in RMS tumors. Specifically, we focused on DNA damage/repair, reactive oxygen species, cancer stem cells, and epigenetic modifications that have been reported in the context of RMS neoplasia in both in vitro and in vivo studies. The precise elucidation of the radioresistance-related molecular mechanisms is of pivotal importance to set up new more effective and tolerable combined therapeutic approaches that can radiosensitize cancer cells to finally ameliorate the overall survival of patients with RMS, especially for the most aggressive subtypes.

Locally advanced cervical rhabdomyosarcoma in adults: A case report

BACKGROUND

Rhabdomyosarcoma is a soft tissue tumor of primitive mesenchymal cells origin, occurring predominantly in children and adolescents, but extremely rare in adults and the data regarding its treatment are sparse. Here, we would like to share our experience in the treatment of a locally advanced primary embryonal rhabdomyosarcoma of cervix in a 39-year-old female.

CASE SUMMARY

The patient was admitted with symptoms of intermenstrual bleeding and postcoital bleeding for six months. Physical examination revealed a friable, polyp-like mass (5 cm × 5 cm) in her cervix protruding into the vagina, while the uterus was mobile and normal-sized. Colposcopy-directed biopsy was performed, and a pathological diagnosis of embryonal rhabdomyosarcoma was made. Magnetic resonance imaging of the pelvis showed that the cervical volume was significantly increased, with a hypointense and hyperintense soft tissue mass on the right side, invading the cervical stroma; the mass was 5 cm × 5 cm with a clear boundary and confined to the cervix; there were no obvious findings indicating tumor invasion in the vaginal wall, parametrium, or pelvic wall; no enlarged lymph nodes were observed in the pelvic cavity. Based on our findings, the tumor was classified as stage IA according to the intergroup rhabdomyosarcoma studies criteria and IB3 stage according to The International Federation of Gynecology and Obstetrics 2018. The patient underwent two courses of neoadjuvant chemotherapy and a partial remission was achieved. Subsequently, she underwent laparoscopic radical hysterectomy, bilateral salpingo-oophrectomy and pelvic lymph node dissection and there were no risk factors revealed by postoperative pathological examination. Adjuvant chemotherapy was performed after surgery. The patient was disease-free until the last follow-up, 49 mo after completing the entire treatment.

CONCLUSION

Our experience suggests that neoadjuvant vincristine, dactinomycin, and cyclophosphamide chemotherapy followed by radical surgery and adjuvant chemotherapy might be reasonable therapeutic option for bulky cervical rhabdomyosarcoma in adults without fertility desire. Since large-scale studies on such rare conditions are rather impossible, further case reports and systematic reviews could help optimize the treatment of primary, bulky cervical rhabdomyosarcoma in adults.

Pediatric rhabdomyosarcoma incidence and survival in the United States: An assessment of 5656 cases, 2001-2017

BACKGROUND

While rhabdomyosarcoma (RMS) is the most common soft tissue sarcoma in children and adolescents, past epidemiology studies of this malignancy used data that covered <30% of the US population. Therefore, we evaluated RMS incidence using data from U.S. Cancer Statistics (USCS) and survival trends using the National Program of Cancer Registries (NPCR), which covers 100% and 94% of the U.S. population, respectively.

METHODS

Incidence and survival were assessed for pediatric patients diagnosed with RMS during 2003-2017 and 2001-2016, respectively. Both demographic and clinical variables were evaluated. Age-adjusted incidence rates, average annual percent change (AAPC), and 5-year relative survival (RS) were calculated, all with corresponding 95% confidence intervals (CIs). Cox regression models were used to evaluate the impact of demographic and clinical variables on survival.

RESULTS

We identified 5656 primary RMS cases in USCS during 2003-2017. The age-adjusted incidence rate was 4.58 per 1 million (95% CI: 4.46-4.70) with an AAPC of 0.3% (95% CI: -0.7 to 1.2%). In NPCR, 5-year RS for all cases was 68.0% (95% CI: 66.6-69.3%). In multivariable analyses, non-Hispanic (NH) Black cases had worse survival compared with NH White cases (hazard ratio [HR] = 1.16, 95% CI: 1.01-1.33).

CONCLUSION

The incidence and survival rates were stable in the largest and most comprehensive population-based analysis for pediatric RMS cases in the U.S. Additionally, we observed a survival disparity among NH Black cases. Findings from this study could inform interventions to address disparities, risk stratification strategies, and clinical trial design.

Rhabdomyosarcoma in children: Retrospective analysis from a single tertiary care center in Saudi Arabia

BACKGROUND

Rhabdomyosarcoma (RMS) is the most common soft tissue sarcoma in children occurring most commonly in the head and neck region. The treatment involves using a multimodality approach including chemotherapy, surgery, and radiation therapy. Survival for patients with localized disease has improved markedly, but the treatment of advanced disease remains a challenge. We report the clinical characteristics and outcome for patients treated at a tertiary care center in Saudi Arabia.

METHODS

Patients aged 0-14 years diagnosed with RMS between 2005 and 2018 were included. Statistical analysis was performed using SPSS software. Kaplan-Meier method was used to calculate overall and event free survival. Cox proportional hazards model was used for multivariate analysis.

RESULTS

One hundred and twenty-four patients were analyzed. The median age was 5.7 years with male predominance (2.4:1). The most common primary sites were head/neck (30%) and the genitourinary tract (25%). Embryonal RMS was present in 81%; alveolar in 19%. Most patients had intermediate risk disease (60%). The 5-year overall and event free survivals were 64.3% and 53.3%, respectively. Survival was influenced by primary tumor site, histology, and clinical risk group. Unfavorable primary site, high risk stratification, and poor initial response to therapy predicted a poor outcome.

CONCLUSION

This study provides an insight on the current management outcomes for our patients with RMS. Cytogenetics and molecular diagnostics need to be incorporated as standard of care in the therapeutic approach of our patients. In addition, there is a need for national collaborative efforts to improve the outcome of RMS in children and adolescents.

Sedation practices during high dose rate brachytherapy for children with urogenital and perianal rhabdomyosarcoma

BACKGROUND

A novel concept for an organ-preserving treatment of pediatric urogenital and perianal rhabdomyosarcoma includes high dose rate brachytherapy following surgical tumor resection. For the duration of the brachytherapy of 6 days plus 2-day recovery break the patients are not allowed to move and are kept under deep sedation, which can lead to difficult weaning from mechanical ventilation, withdrawal, delirium, and prolonged hospital stay. The aim of this study was to evaluate a protocol which includes a switch from fentanyl to ketamine 3 days prior to extubation to help ensure a rapid extubation and transfer from PICU.

METHODS

Patients who underwent surgical tumor resection of rhabdomyosarcoma and subsequent brachytherapy were treated according to a standardized protocol. We evaluated doses of fentanyl, midazolam and clonidine, time of extubation, length of PICU stay and occurrence of withdrawal symptoms and delirium. We compared fentanyl dose at time of extubation, duration of weaning from mechanical ventilation and time to discharge from PICU with patients after isolated severe traumatic brain injury.

RESULTS

Twentytwo patients (age 39.9 ± 29.8 months) were treated in our PICU to undergo brachytherapy. Extubation was performed 21.6 ± 13.5 h after the last brachytherapy session with an average fentanyl dose of 1.5 ± 0.5 µg/kg/h and patients were discharged from PICU 58.4 ± 30.3 h after extubation, which all is significantly lower compared to the control group (extubation after 88.0 ± 42.2 h, p < 0.001; fentanyl dose at the time of extubation 2.5 ± 0.6 µg/kg/h, p < 0.001; PICU discharge after 130.1 ± 148.4 h, p < 0.009). Withdrawal symptoms were observed in 9 patients and delirium in 13 patients.

CONCLUSION

A standardized analgesia and sedation protocol including an opioid break, scoring systems to detect withdrawal symptoms and delirium, and tapering plans contributes to successful early extubation and discharge from PICU after long-term deep sedation.

A Web-Based Prognostic Model for Pediatric Genitourinary Rhabdomyosarcoma: Analysis of Population-Based Cohort With External Validation

Background

We conduct an analysis of data from the Surveillance, Epidemiology, and End Results (SEER) database, intending to identify prognostic factors of pediatric genitourinary rhabdomyosarcoma (PGU–RMS). Prognostic nomogram and web-based calculator were developed for potential clinical use.

Methods

Data of PGU–RMS patients were extracted from the SEER database as training and internal validation cohort, patients diagnosed as PGU–RMS from 2001 to 2015 in Beijing Children's Hospital were collected as an external validation cohort. We used log-rank tests to seek risk factors on the overall survival (OS) in the overall SEER cohort, tumor site subgroups, radiation subgroups, and metastasis subgroups. The univariable and multivariate Cox regression analyses were applied to establish the prognosis model.

Results

A total of 372 PGU-RMS patients in SEER and 84 patients from our center were included. 1-, 3-, and 5-year OS of the overall SEER cohort were 95.8, 82.1, and 78.8%. Subgroup analysis indicated that tumors located in the prostate/bladder were associated with a worse prognosis than the paratesticular, female genital system, and other sites (P < 0.001). Tumors of the T1/T2 stage, without regional lymph node, involvement or metastasis, can benefit from radiotherapy (P < 0.05). For patients without metastasis, younger age, T1/T2 stage, and undergoing radiation were associated with better prognosis (P < 0.05). The prognosis nomogram was well-calibrated, the concordance index (C-index) for the OS prediction was 0.823, 0.803, and 0.768 in training, internal and external validation cohort, the area under the receiver operating characteristic curve for 3-, and 5-year OS were 0.84, 0.84 in the training cohort, 0.90, 0.84 in internal validation cohort and 0.75, 0.80 in the external validation cohort. Decision curve analysis showed good clinical utility. The predictive performance of the nomogram was higher than the Intergroup Rhabdomyosarcoma Study Group (IRSG) pretreatment stage system based on the comparison of overtime C-index, net reclassification index, and integrated discriminatory index (P < 0.001).

Conclusion

A comprehensive analysis of OS for PGU–RMS patients was conducted based on population cohort. The established prognosis nomogram has been fully validated and evaluated, exhibits better performance than the IRSG pretreatment stage system. Furthermore, a web-based risk calculator was developed to optimize clinical decisions.

Rhabdomyosarcoma in low- and middle-income countries: A report from the Asociacion de Hemato-oncología Pediatrica de Centro América (AHOPCA)

This report describes the results of an observational study dedicated to rhabdomyosarcoma developed by the Asociación de Hemato-oncología Pediatrica de Centro América (AHOPCA) between 2001 and 2018. Overall, 337 previously untreated patients < 18 years old were included in the analysis; 58% had unresected disease, and 19% were metastatic at diagnosis. With a median follow-up of 6.6 years, five-year event-free and overall survival rates were 30% and 33%, respectively. Local progression/relapse was the main cause of treatment failure.

Diagnosis and treatment of pleomorphic rhabdomyosarcoma of the uterus: a rare case report and review of the literature

Pleomorphic rhabdomyosarcomas of the uterus (PRMSu) is a rare malignant tumor of the female genital tract. Accurate diagnosis and effective treatment of PRMSu are important. We report an 81-year-old woman who was diagnosed with PRMSu. She had an extremely unusual presentation of secondary dyspnea because of an extremely large uterus (26.0 cm). Pelvic magnetic resonance imaging showed rare severe enlargement and intrauterine filling with tumor tissue, and she was initially diagnosed with uterine leiomyosarcoma. The patient underwent hysterectomy, as well as bilateral salpingo-oophorectomy and omentectomy, and was finally confirmed as having PRMSu by histopathology combined with immunohistochemistry. We performed a systematic review of the literature between 1982 and 2020 and focused on different treatment strategies and prognosis of PRMSu. A retrospective review of 28 cases was conducted and survival analysis was estimated by using the Kaplan–Meier method. We found that the accuracy of diagnosis of PRMSu completely depends on histopathology and immunohistochemistry because of no special clinical symptoms, no sensitive tumor markers, and no special imaging findings. Although there is no standardized approach for treating this rare disease, the treatment strategy of a surgical operation combined with adjuvant chemotherapy appears to be the best choice.

Radiosurgery, reirradiation, and brachytherapy

Radiosurgery and brachytherapy are potentially useful treatment techniques that are sparingly applied in pediatric oncology. They are often used in the setting of reirradiation for recurrent or metastatic tumors. Reirradiation in children with recurrent tumors is complicated by the tolerance of critical organs and the potential risks for overall long-term dose-dependent complications. We review the current literature available in support of reirradiation and the use of radiosurgery and brachytherapy in pediatric patients.

Skin Toxicity Profile of Photon Radiotherapy versus Proton Beam Therapy in Paediatric and Young Adult Patients with Sarcomas

AIMS

Radiotherapy is key in the management of patients with both Ewing sarcoma and rhabdomyosarcoma. However, there is little evidence in the literature with regards to radiation-induced skin toxicities (RISTs) for patients treated with conventional radiotherapy with X-rays (XRT) or proton beam therapy (PBT) for these two conditions. In the present study we evaluated acute and late RIST in patients treated within European protocols with either PBT or XRT, taking both clinical and dosimetric variables into consideration.

MATERIALS AND METHODS

This was a retrospective analysis of 79 paediatric/young adult patients treated with radical radiotherapy (with XRT or PBT) and concurrent chemotherapy. In all cases, radiotherapy was given in conventional fractionation (1.8 Gy/fraction). Acute and late RISTs were registered according to the Radiation Therapy Oncology Group (RTOG) scoring system.

RESULTS

With regards to acute RIST, 47.9% (23/48) of XRT patients and 48.4% (15/31) of PBT patients had acute grade 2/3 toxicity. When it comes to late RIST, 17.5% (7/40 with known toxicity profile) of XRT patients and 29.0% (9/31) of PBT patients had grade 1/2 toxicity. This difference of -11.5% (95% confidence interval -31.2 to 7.9%) in grade 1/2 toxicity between XRT and PBT was not statistically significant (P = 0.25). Regardless of the radiotherapy technique, V30Gy seems a good predictor of acute RIST. Moreover, for the same value of V30Gy, patients who receive PBT may have a higher risk of moderate-severe acute RIST. Perhaps due to the small sample, definitive conclusions on the predictive factors of late RIST could not be drawn.

CONCLUSIONS

No clinically meaningful differences in acute and late RIST were observed between PBT and XRT subgroups. Systematic differences in the modelling of the build-up region may exist between XRT and PBT algorithms, which could make the comparison of dose metrics between techniques potentially biased. A more comprehensive analysis of dosimetric data on larger patient cohorts is needed to elucidate the most relevant skin dose metrics. Dose-effect models of RIST for this unique patient population would be an invaluable tool in radiotherapy plan optimisation.

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.

Alveolar rhabdomyosarcoma with regional nodal involvement: Results of a combined analysis from two cooperative groups

BACKGROUND

Treatment of children and adolescents with alveolar rhabdomyosarcoma (ARMS) and regional nodal involvement (N1) have been approached differently by North American and European cooperative groups. In order to define a better therapeutic strategy, we analyzed two studies conducted between 2005 and 2016 by the European paediatric Soft tissue sarcoma Study Group (EpSSG) and Children's Oncology Group (COG).

METHODS

We retrospectively identified patients with ARMS N1 enrolled in either EpSSG RMS2005 or in COG ARST0531. Chemotherapy in RMS2005 comprised ifosfamide + vincristine + dactinomycin + doxorubicin (IVADo), IVA and maintenance (vinorelbine, cyclophosphamide); in ARST0531, it consisted of either vincristine + dactinomycin + cyclophosphamide (VAC) or VAC alternating with vincristine + irinotecan (VI). Local treatment was similar in both protocols.

RESULTS

The analysis of the clinical characteristics of 239 patients showed some differences between study groups: in RMS2005, advanced Intergroup Rhabdomyosarcoma Study Group (IRS) and large tumors predominated. There were no differences in outcomes between the two groups: 5-year event-free survival (EFS), 49% (95% confidence interval [CI]: 39-59) and 44% (95% CI: 30-58), and overall survival (OS), 51% (95% CI: 41-61) and 53.6% (95% CI: 40-68) in RMS2005 and ARST0531, respectively. In RMS2005, EFS of patients with FOXO1-positive tumors was significantly inferior to those with FOXO1-negative (49.3% vs 73%, P = .034). In contrast, in ARST0531, EFS of patients with FOXO1-positive tumors was 45% compared with 43.8% for those with FOXO1-negative.

CONCLUSIONS

The outcome of patients with ARMS N1 was similar in both protocols. However, patients with FOXO1 fusion-negative tumors enrolled in RMS2005 showed a significantly better outcome, suggesting that different strategies of chemotherapy may have an impact in the outcome of this subgroup of patients.

Endoglin Expression and Microvessel Density as Prognostic Factors in Pediatric Rhabdomyosarcoma

(1) Background: The study proposed to analyze microvessel density (MVD) in rhabdomyosarcoma (RMS) based on the expression of angiogenesis markers and define its prognostic role in this group of patients. (2) Methods: The study included forty-nine pediatric patients diagnosed with RMS. Tumor tissue expression of CD31, CD34, and CD105 was analyzed. MVD was calculated and correlated with clinical RMS prognostic parameters. (3) Results: CD31, CD34, and CD105 are expressed in all RMS cases. MVD/CD105 was significantly higher in the RMS group than in the control group. The mean and median values of MVD/CD105 in RMS were lower than MVD/CD31 and MVD/CD34. MVD/CD105 was significantly higher in patients with alveolar RMS and those with metastatic disease. Patients with higher levels of MVD/CD105 had a higher risk of death (HR = 1.009). (4) Conclusion: CD105 is a relevant angiogenesis marker in pediatric RMS, and MVD/CD105 is an independent risk factor of short overall survival in children with RMS.

Update on pediatric rhabdomyosarcoma: A report from the APSA Cancer Committee

BACKGROUND/PURPOSE

Rhabdomyosarcoma is the most common soft tissue sarcoma in children and young adults and requires multimodality treatment. The purpose of this review is to present an update on risk stratification as well as surgical and medical management strategies in pediatric rhabdomyosarcoma.

METHODS

A comprehensive review of the current literature on pediatric rhabdomyosarcoma, including the most recent Children's Oncology Group studies and several international collaboratives, was performed by the authors and key findings were summarized in the manuscript.

RESULTS

FOXO1 fusion status is a stronger prognostic factor than histology and is now used for risk stratification in treatment protocols. For assessment of regional nodal involvement, FDG-PET-CT shows poor sensitivity and specificity to detect histologically confirmed nodal metastasis. Thus, surgical assessment of regional lymph nodes is required for rhabdomyosarcoma of the extremities or trunk as well as paratesticular rhabdomyosarcoma in patients ≥10 years of age, although adherence to surgical guidelines remains poor. Hemiscrotectomy performed for scrotal violation in paratesticular rhabdomyosarcoma has not shown an improvement in event free survival and is not recommended.

CONCLUSIONS

Surgical and medical treatment strategies for rhabdomyosarcoma in children continue to evolve. This review provides current evidence-based treatment standards with an emphasis on surgical care.

TYPE OF STUDY

Review.

LEVEL OF EVIDENCE

Level IV.

Rare benign and malignant testicular lesions: histopathology and management

PURPOSE OF REVIEW

The presence of vascular solid tumors within the testicle is considered to be malignant until proven otherwise. However, it is prudent for clinicians to be aware of rare benign and malignant intratesticular lesions as management can differ from the established treatment algorithms for germ-cell tumors.

RECENT FINDINGS

Utilizing certain histopathologic findings can assist with the diagnosis of rare testis tumors. Often times the tumor subtypes are an important consideration in the grading and classification of the disease, which drives management. The multidisciplinary management of rare malignant testis tumors at an experienced center seems to provide optimal patient outcomes. Regardless of the primary treatment, prolonged follow-up for sex cord stromal tumors and other rare testis malignancies is advocated due to the delayed metastatic potential.

SUMMARY

The clinical presentation of rare benign and malignant testis tumors is often similar to that of germ-cell tumors. Likewise, imaging characteristics are also often indistinguishable. However, the management of these rare tumors is often different from the well established treatment algorithms of germ-cell tumors. To that end, it is important for the practicing urologist to be familiar with the current principles of these tumor characteristics and the management.

Intratumoral Translocation Positive Heterogeneity in Pediatric Alveolar Rhabdomyosarcoma Tumors Correlates to Patient Survival Prognosis

Alveolar rhabdomyosarcoma (ARMS) is characterized by one of three translocation states: t(2;13) (q35;q14) producing PAX3-FOXO1, t(1;13) (p36;q14) producing PAX7-FOXO1, or translocation-negative. Tumors with t(2;13) are associated with greater disease severity and mortality than t(1;13) positive or translocation negative patients. Consistent with this fact, previous work concluded that a molecular analysis of RMS translocation status is essential for the accurate determination of prognosis and diagnosis. However, despite this knowledge, most diagnoses rely on histology and in some cases utilize fluorescence in situ hybridization (FISH) probes unable to differentiate between translocation products. Along these same lines, diagnostic RT-PCR analysis, which can differentiate translocation status, is unable to determine intratumoral translocation heterogeneity, making it difficult to determine if heterogeneity exists and whether correlations exist between this heterogeneity and patient outcomes. Using newly developed FISH probes, we demonstrate that intratumoral heterogeneity exists in ARMS tumors with respect to the presence or absence of the translocation product. We found between 3 and 98% of cells within individual tumor samples contained a translocation event with a significant inverse correlation (R² = 0.66, p = 0.001) between the extent of intratumoral translocation heterogeneity and failure-free survival of patients. Taken together, these results provide additional support for the inclusion of the molecular analysis of these tumors and expand on this idea to support determining the extent of intratumoral translocation heterogeneity in the diagnosis of ARMS to improve diagnostic and prognostic indicators for patients with these tumors.

Primary Uterine Rhabdomyosarcoma in a 54-Year-Old Postmenopausal Woman

Rhabdomyosarcoma (RMS) is a malignant neoplasm that originates from undifferentiated myogenic progenitor cells. It is predominantly a pediatric disease, and its occurrence in adults is exceedingly rare. Adult primary RMS of gynecologic origin is an uncommon phenomenon, and the cervix is the most frequently involved site. The incidence of adult primary uterine RMS is extremely scarce. Herein, we present the case of primary uterine RMS in a 54-year-old Saudi postmenopausal woman who presented to clinic attention with a six-month history of abdominal pain and vaginal bleeding.

The Role of Adjuvant Treatment in Craniofacial Malignancy: A Critical Review

Background: Tumors originating from the craniofacial region usually present in a locally advanced stage with frequent involvement of adjacent sites and have a strong tendency for local recurrence in the absence of adjuvant therapy, even when the original surgical resection was presumed to be radical. In the past decades, several advances in the radiological diagnosis and treatment of craniofacial malignancies have been introduced. There are, however, no randomized trials that define the optimal multimodal treatment of these tumors because of their rarity as well as heterogeneity in both histology and site of origin. The aim of this study was to conduct a critical review of the role of adjuvant therapy in the treatment of craniofacial malignancy. Method: We conducted a critical review of the past and contemporary literature available, focusing on adjuvant oncological treatments of the most common craniofacial malignancies. Results: Preoperative radiotherapy can have a documented role in the treatment of olfactory neuroblastoma and soft tissue sarcoma, while preoperative chemotherapy can be advocated in the treatment of sinonasal undifferentiated carcinoma, neuroendocrine carcinoma, olfactory neuroblastoma, and craniofacial sarcoma (both soft-tissue and high-grade osteosarcoma). Postoperative radiotherapy has a well-established role in the treatment of most craniofacial malignancies. The role of postoperative chemotherapy is unclear in most histologies, but is commonly used during the treatment of well-selected cases of paranasal sinus carcinoma, olfactory neuroblastoma, mucosal melanoma, soft tissue sarcoma and high-grade craniofacial osteosarcoma. Discussion: Alongside developments in surgery, there have also been improvements in diagnostics, radiotherapy, and chemotherapy. Implementation of novel radiation techniques allows delivery of higher radiation doses while minimizing irradiation-related morbidity. Better understanding of tumor biology allows the construction of more complex treatment strategies, incorporating adjuvant chemotherapy either pre- or postoperatively. In the era of personalized targeted therapy, rapid strides are being made to identify specific tumor-targets for use of novel biologic agents, with the potential to change current management paradigms.

Impact of Rhabdomyosarcoma Treatment Modalities by Age in a Population-Based Setting

Purpose: Rhabdomyosarcoma (RMS) has a worse prognosis in adults than in children, but there is evidence of a better outcome in the former if treated using a pediatric-like approach. This study describes treatment for RMS in patients more than 10 years old and examines to what extent treatment contributes to explain the different age-related survival observed and to what extent treatment centers impact treatment appropriateness. Methods: A retrospective population-based study was developed considering 104 RMS cases (excluding the pleomorphic subtype) diagnosed in Italy between 2000 and 2015. Patients were grouped by age (10-19 vs. 20-60 years old) and scored according to whether or not their chemotherapy was consistent with the schemes used in pediatric protocols (score 1 = chemotherapy in line with pediatric protocols). Treatment centers were grouped according to whether or not they have a pediatric-dedicated unit affiliated to the national pediatric oncology network (Associazione Italiana Ematologia Oncologia Pediatrica [AIEOP]). Results: Older patients were more likely to have tumors at unfavorable sites (p = 0.045). A treatment score of 1 was assigned to 85% of younger patients, but only to 32% of older patients (p < 0.001). Furthermore, the proportion of score 1 was higher in younger patients treated in centers with an AIEOP Unit. A multivariate model confirmed age as a significant prognostic factor (Hazard rate ratio [HR] = 2.06; p = 0.04) and showed a significant impact of treatment on survival (HR = 2.13; p = 0.03). Conclusions: Adult RMS patients are still relatively unlikely to be treated with pediatric protocols and in centers with a pediatric oncology expertise. This may explain the survival gap between older and younger patients.

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.

Do children and adolescents with completely resected alveolar rhabdomyosarcoma require adjuvant radiation? A report from the Children's Oncology Group

BACKGROUND

The role of adjuvant radiotherapy (RT) remains unclear in patients with localized, completely resected (group I) alveolar rhabdomyosarcoma (ARMS).

PROCEDURE

Patients with group I ARMS enrolled on any one of three prior Children's Oncology Group (COG) clinical trials (D9602, D9803, or ARST0531) were analyzed. All patients received systemic chemotherapy and 36 Gy adjuvant RT (if given) to the primary site at week 12 or week 4 for D9602/D9803 and ARST0531, respectively.

RESULTS

Thirty-six patients with group I ARMS were treated on D9602 (n = 6), D9803 (n = 17), or ARST0531 (n = 13), of whom 24 (67%) were male. The median age was 4.1 years (range, 0.8-45.8). Twenty (56%) patients had an unfavorable primary site, and 10 (28%) had tumors > 5 cm. FOXO1-fusion status was negative, positive, and unknown in 10 (28%), 15 (42%), and 11 (30%) tumors, respectively. Twenty-two (61%) patients received RT. Overall, the four-year event-free survival (EFS) and overall survival (OS) were 70.8% and 88.3%, respectively. Patients with FOXO1 positivity who received RT had superior EFS compared with those who did not (77.8% vs 16.7%; P = 0.03). Among 10 patients who were FOXO1 negative, the outcome was similar with or without RT.

CONCLUSIONS

Although limited by a small sample size, data from this study support the routine use of adjuvant RT in patients with FOXO1-positive disease even after complete resection. Additionally, omitting adjuvant RT is rational for patients with FOXO1-negative ARMS and will be prospectively investigated in the current COG trial ARST1431.

Recent advances in pediatric bladder malignancies

Urothelial pediatric neoplasms are relatively rare. Papillary urothelial neoplasms of low malignant potential (PUNLMPs) and rhabdomyosarcoma (RMS) are the most common bladder malignancies in the pediatric population. Clinical presentation encompasses macroscopic hematuria or lower urinary tract symptoms (or both) or is detected incidentally at imaging. Tumors arising from the bladder can originate from any of its four histological layers (urothelium, lamina propria, detrusor, and adventitia) and are divided into tumors that have an epithelial origin (arising from the urothelium) and those that have a non-epithelial origin (mesenchymal neoplasms). RMS is the most common malignant tumor of the urinary bladder in children younger than 10 years. Deriving from the embryonic mesenchymal cell, the histopathologic subtypes of RMS are embryonal RMS (>90%) and alveolar histology (<10%). Pre-treatment imaging should be carried out by computed tomography (CT) or at present is more likely with magnetic resonance imaging of the pelvis. Chest CT and bone scintigraphy are used to screen for metastases. In selected cases, a positron emission tomography scan may be recommended to evaluate suspicious lesions. The current prognostic classification considers age, histologic subtype, tumor site, size, and extent (nodal or distant metastases). Staging is based on pre-operative findings, group is based on intra-operative findings and pathology, and risk stratification is derived from both stage and group data. Pre-operative chemotherapy is the most common first-line intervention for bladder/prostate RMS, before surgery or radiation therapy. Collaborative groups such as the Soft Tissue Sarcoma Committee of the Children’s Oncology Group and the European Pediatric Soft Tissue Sarcoma Study Group endorse this therapy. PUNLMPs are generally solitary, small (1–2 cm), non-invasive lesions that do not metastasize. Therapy is usually limited to a transurethral resection of the bladder tumor. About 35% are recurrent and around 10% of them increase in size if they are not treated.

Exquisite Tumor Targeting by Salmonella A1-R in Combination with Caffeine and Valproic Acid Regresses an Adult Pleomorphic Rhabdomyosarcoma Patient-Derived Orthotopic Xenograft Mouse Model

Adult pleomorphic rhabdomyosarcoma (RMS) is a rare and malignant mesenchymal tumor. Recently, we developed a patient-derived orthotopic xenograft (PDOX) model of adult pleomorphic RMS. In the present study, we evaluated the efficacy of tumor-targeting Salmonella typhimurium (S. typhimurium) A1-R combined with caffeine (CAF) and valproic acid (VPA) on the adult RMS PDOX. An adult pleomorphic RMS cell line was established from the PDOX model. Cell survival after exposure to CAF and VPA was assessed, and the IC₅₀ value was calculated for each drug. The RMS PDOX models were randomized into five groups: untreated control; tumor treated with cyclophosphamide (CPA); tumor treated with CAF + VPA; tumor treated with S. typhimurium A1-R; and tumor treated with S. typhimurium A1-R + CAF + VPA. Tumor size and body weight was measured twice a week. VPA caused a concentration-dependent cytocidal effect. A synergistic effect of combination treatment with CAF was observed against the RMS cell line. For the in vivo study, all treatments significantly inhibited tumor growth compared with the untreated control. S. typhimurium A1-R combined with VPA and CAF was significantly more effective than CPA, VPA combined with CAF, or S. typhimurium A1-R alone and significantly regressed the tumor volume compared with day 0. These results suggest that S. typhimurium A1-R together with VPA and CAF could regresses an adult pleomorphic RMS in a PDOX model and therefore has important future clinical potential.

Gene Co-Expression Networks Restructured Gene Fusion in Rhabdomyosarcoma Cancers

Rhabdomyosarcoma is subclassified by the presence or absence of a recurrent chromosome translocation that fuses the FOXO1 and PAX3 or PAX7 genes. The fusion protein (FOXO1-PAX3/7) retains both binding domains and becomes a novel and potent transcriptional regulator in rhabdomyosarcoma subtypes. Many studies have characterized and integrated genomic, transcriptomic, and epigenomic differences among rhabdomyosarcoma subtypes that contain the FOXO1-PAX3/7 gene fusion and those that do not; however, few investigations have investigated how gene co-expression networks are altered by FOXO1-PAX3/7. Although transcriptional data offer insight into one level of functional regulation, gene co-expression networks have the potential to identify biological interactions and pathways that underpin oncogenesis and tumorigenicity. Thus, we examined gene co-expression networks for rhabdomyosarcoma that were FOXO1-PAX3 positive, FOXO1-PAX7 positive, or fusion negative. Gene co-expression networks were mined using local maximum Quasi-Clique Merger (lmQCM) and analyzed for co-expression differences among rhabdomyosarcoma subtypes. This analysis observed 41 co-expression modules that were shared between fusion negative and positive samples, of which 17/41 showed significant up- or down-regulation in respect to fusion status. Fusion positive and negative rhabdomyosarcoma showed differing modularity of co-expression networks with fusion negative (n = 109) having significantly more individual modules than fusion positive (n = 53). Subsequent analysis of gene co-expression networks for PAX3 and PAX7 type fusions observed 17/53 were differentially expressed between the two subtypes. Gene list enrichment analysis found that gene ontology terms were poorly matched with biological processes and molecular function for most co-expression modules identified in this study; however, co-expressed modules were frequently localized to cytobands on chromosomes 8 and 11. Overall, we observed substantial restructuring of co-expression networks relative to fusion status and fusion type in rhabdomyosarcoma and identified previously overlooked genes and pathways that may be targeted in this pernicious disease.

Rhabdomyosarcoma of the Adult Prostate: A Case Report With Complete Molecular Profile

Primary rhabdomyosarcoma of the adult prostate is rare and associated with an aggressive clinical course. Given the limited number of cases reported about the prostate, little is known about the impact of molecular mutations on tumor biology and prognosis in adults. In this article, we present a case of primary embryonal rhabdomyosarcoma of the adult prostate with a complete molecular mutational profile of the tumor.

Sentinel lymph node biopsy in head and neck rhabdomyosarcoma

Head and neck rhabdomyosarcoma lymph node staging is challenging due to varied patterns of lymphatic drainage and the suboptimal predictive value of available imaging modalities. Furthermore, regional relapse rates are unacceptably high, and the toxicity of empiric radiation is undesirable in the pediatric and young adult population. In an attempt to improve locoregional control without excess morbidity, we have adopted routine sentinel lymph node biopsy in head and neck rhabdomyosarcoma, which is safe and feasible in pediatric patients. Of six procedures reported here, pathologic findings led to intensification of regional and/or systemic therapy in two patients.

Prognostication in Mesenchymal Tumors: Can We Improve?

Prognostication in mesenchymal tumors can be challenging. They exhibit diverse, and sometimes overlapping, histologic features that are not always predictive of their true behavior. This article highlights examples of both traditional and emerging sarcoma biomarkers.

[PRIMARY PROSTATIC RHABDOMYOSARCOMA WITH REPEATING CEREBRAL HEMORRHAGE FROM BRAIN METASTASES IN AN ADULT: A CASE REPORT]

A 28-year-old man visited a nearby doctor with a chief complaint of hematospermia. Magnetic resonance imaging showed a tumor 12-cm in diameter in his pelvis and he was introduced to our hospital. The tumor had replaced the prostate and infiltrated the rectum. He already had multiple lung, pelvic lymph, and bone metastases. He was diagnosed with embryonal rhabdomyosarcoma based on pathological findings after needle tumor biopsy. His disease was stage IV rhabdomyosarcoma according to the Intergroup Rhabdomyosarcoma Study, and he received a VAC (vincristine, actinomycin D, cyclophosphamide) chemotherapy regimen. Despite a partial response with 44% shrinkage in tumor diameter after seven cycles of chemotherapy, he experienced cerebral hemorrhage from small brain metastases during preparation for the eighth course. During gamma knife planning, the cerebral hemorrhage from small brain metastases repeated four times. The patient died 8 months after the introduction of chemotherapy.

Update on Myogenic Sarcomas

Myogenic sarcomas include soft tissue sarcomas that show skeletal muscle differentiation (rhabdomyosarcoma) and those with smooth muscle differentiation (leiomyosarcoma). Rhabdomyosarcomas are more common in the pediatric age group and leiomyosarcomas occur more often in the adult population. Based on the clinico-pathologic features and genetic abnormalities identified, the rhabdomyosarcomas are classified into embryonal, alveolar, spindle cell/sclerosing, and pleomorphic subtypes. Each subtype shows distinctive morphology and has characteristic genetic abnormalities. In this update on myogenic sarcomas, each entity is discussed with special emphasis on recent updates in genetic findings and the diagnostic approach to these tumors.

Rhabdomyosarcoma and Extraosseous Ewing Sarcoma

Rhabdomyosarcoma (RMS) is a malignant tumor that represents the most common form of pediatric soft tissue sarcoma. It arises from mesenchymal origin and forms part of the group of small round blue cell tumors of childhood. It has a constant annual incidence of 4.5 cases per 1,000,000 children. The known histological diagnosis of the two major subtypes (embryonal and alveolar) has been recently enhanced by tumor biological markers and molecular differentiation diagnostic tools that have improved not only the updated classification based on risk stratification, but also the treatment approach based on the clinical group. Ewing sarcoma (ES) is a round cell tumor, highly malignant and poorly differentiated that is currently the second most common malignant bone tumor in children. In rare instances, it develops from an extraskeletal origin, classified as extraosseous Ewing sarcoma (EES). We provide an updated, evidence-based and comprehensive review of the molecular diagnosis, clinical and diagnostic approach and a multidisciplinary medical and surgical management according to the latest standard of care for the treatment of pediatric RMS and EES.

Identification of Therapeutic Targets in Rhabdomyosarcoma through Integrated Genomic, Epigenomic, and Proteomic Analyses

Personalized cancer therapy targeting somatic mutations in patient tumors is increasingly being incorporated into practice. Other therapeutic vulnerabilities resulting from changes in gene expression due to tumor specific epigenetic perturbations are progressively being recognized. These genomic and epigenomic changes are ultimately manifest in the tumor proteome and phosphoproteome. We integrated transcriptomic, epigenomic, and proteomic/phosphoproteomic data to elucidate the cellular origins and therapeutic vulnerabilities of rhabdomyosarcoma (RMS). We discovered that alveolar RMS occurs further along the developmental program than embryonal RMS. We also identified deregulation of the RAS/MEK/ERK/CDK4/6, G₂/M, and unfolded protein response pathways through our integrated analysis. Comprehensive preclinical testing revealed that targeting the WEE1 kinase in the G₂/M pathway is the most effective approach in vivo for high-risk RMS.

Is there a role for salvage re-irradiation in pediatric patients with locoregional recurrent rhabdomyosarcoma? Clinical outcomes from a multi-institutional cohort

BACKGROUND AND PURPOSE

Limited data exist detailing the role of salvage reirradiation following local-regional recurrence (LR) in previously irradiated pediatric patients with rhabdomyosarcoma (RMS).

MATERIALS AND METHODS

We evaluated outcomes and prognostic factors in a multi-institutional cohort of 23 patients with LR-only (N = 19) or LR with distant failure (N = 4) RMS managed with (N = 12) or without (N = 11) re-irradiation who were treated from 1996 to 2012.

RESULTS

At a median follow-up of 4.6 years from LR, 7 (30%) patients were alive and 5 (22%) had no evidence of disease. Median OS and PFS from LR were 19.3 and 16.9 months, respectively. LFFS and DFFS at 3 years from relapse were 54% and 56%, respectively. Salvage re-irradiation occurred in 12 (52%) patients, with 9 (75%) receiving resection before re-irradiation. Patients classified as low-risk at diagnosis with favorable primary tumor location had improved 3-year PFS 80% (95% CI 51.6-100%) vs. 47.1% (95% CI 27.3-81.2%), p = 0.066], and OS 80% [(95% CI 22.4-100%) vs. 47.1% (95% CI 27.3-81.3%), p = 0.051] following LR. Median LFFS and OS in unirradiated vs. re-irradiated patients was 12.4 vs. 19.6 (p = 0.1) and 18.8 vs. 26.1 months (p = 0.46). No patients experienced ≥grade 4 acute toxicity from re-irradiation. LR failure was a component of cancer-related death in 60% vs. 40% of the unirradiated and re-irradiated group (p = 0.02).

CONCLUSION

Salvage re-irradiation appears tolerable with acceptable morbidity and may reduce the risk of subsequent LR as a component of death in patients with LR RMS.

Clinical outcomes of pediatric patients with newly diagnosed rhabdomyosarcoma treated by two consecutive protocols - A single institution report in Taiwan

BACKGROUND

Taiwan Pediatric Oncology Group (TPOG) initiated two consecutive protocols for treating pediatric patients with rhabdomyosarcoma since 1995. However, the results have not been analyzed and reported yet. The aim of this study is to investigate the treatment results of these two protocols in our hospital and to assess whether the results are comparable to other large-scaled studies.

METHODS

Treatment of pediatric patients with rhabdomyosarcoma according to TPOG protocols at National Taiwan University Hospital began in 1995. Between 1995 and 2006, patients were treated by TPOG RMS 95 protocol, which was based on IRS-III/IV. After 2007, patients were treated by TPOG RMS 2007 protocol which was adapted from IRS-V study. The clinical data of patients were obtained retrospectively by reviewing medical records. The date of the latest follow-up was December 31, 2016.

RESULTS

Thirty-seven patients were enrolled in this study. The 5-year overall survival (OS) and event-free survival rates of them were 54.7 ± 8.8% and 48.5 ± 8.6%, respectively. The 5-year OS rates for patients treated by TPOG RMS 95 and TPOG RMS 2007 protocols were 55.0 ± 11.1% and 55.9 ± 14.0%, respectively. Age at diagnosis of less than ten years old and receiving operation with gross total or subtotal tumor resection were identified as independent prognostic factors that predicted better outcomes in the multivariate analysis.

CONCLUSION

The clinical outcomes of pediatric patients with rhabdomyosarcoma in Taiwan improved dramatically after incorporating two consecutive protocols from TPOG. In addition, the treatment results of these two protocols were comparable to large-scale studies of other countries.

Fusion status in patients with lymph node-positive (N1) alveolar rhabdomyosarcoma is a powerful predictor of prognosis: Experience of the European Paediatric Soft Tissue Sarcoma Study Group (EpSSG)

BACKGROUND

Alveolar rhabdomyosarcoma (aRMS) with lymph node involvement (N1 classification) accounts for up to 10% of all cases of RMS. The prognosis is poor, and is comparable to that of distant metastatic disease. In the European Paediatric Soft Tissue Sarcoma Study Group (EpSSG) RMS2005 protocol, patients with a histologic diagnosis of aRMS/N1 received intensified chemotherapy with systematic locoregional treatment.

METHODS

Patients with aRMS/N1 were enrolled prospectively after primary surgery/biopsy and fusion status was assessed in tumor samples. All patients received 9 cycles of induction chemotherapy and 6 months of maintenance therapy. Local treatment included radiotherapy to the primary site and lymph nodes with or without secondary surgical resection.

RESULTS

A total of 103 patients were enrolled. The clinical characteristics of the patients were predominantly unfavorable: 90% had macroscopic residual disease after initial surgery/biopsy, 63% had locally invasive tumors, 77% had a tumor measuring >5 cm, and 81% had disease at unfavorable sites. Fusion genes involving forkhead box protein O1 (FOXO1) were detected in 56 of 84 patients. Events occurred in 52 patients: 43 developed disease recurrence, 7 had disease that was refractory to treatment, and 2 patients developed second neoplasms. On univariate analysis, unfavorable disease site, tumor invasiveness, Intergroup Rhabdomyosarcoma Study group III, and fusion-positive status correlated with worse prognosis. The 5-year event-free survival rate of patients with fusion-positive tumors was 43% compared with 74% in patients with fusion-negative tumors (P = .01). On multivariate analysis, fusion positivity and tumor invasiveness proved to be unfavorable prognostic markers.

CONCLUSIONS

Fusion status and tumor invasiveness appear to have a strong impact on prognosis in patients with aRMS/N1. Fusion status will be used to stratify these patients in the next EpSSG RMS study, and treatment will be intensified in patients with fusion-positive tumors. Cancer 2018. © 2018 American Cancer Society.

Primary rhabdomyosarcoma of the breast in a 17-year-old girl: Case report

RATIONALE

Primary rhabdomyosarcoma of the breast is very rare disease with poor prognosis and no definitive treatment has yet been established.

PATIENT CONCERNS

A 17-year-old girl presented with right breast mass without distant metastasis in image study.

DIAGNOSIS

The result of core needle biopsy was intraductal carcinoma; however, histopathologic finding after mastectomy was primary rhabdomyosarcoma of breast.

INTERVENTIONS

Adjuvant chemotherapy was recommended because resection margin was involved by tumor cells, but she did not visit the clinic anymore. Five months later, tumor recurred with local invasion and chemotherapy of vincristine, doxorubicin, and cyclophosphamide alternating with ifosfamide and etoposide (VAC/IE) was done.

OUTCOMES

In the course of chemotherapy and sequential follow-up, there was no tumor growth until now.

LESSONS

Primary breast rhabdomyosarcoma is an uncommon disease, as a result diagnosis is often delayed. For the same reason, there is little information about treatment. This report may be helpful for managing the disease.

Results for patients with sarcoma not otherwise specified and other diagnoses than Ewing sarcoma treated according to the Euro-EWING 99 trial

BACKGROUND

Euro-EWING 99 trial of the European Ewing tumor Working Initiative of National Groups (EE99) was an international phase III study in patients with Ewing sarcoma. The German Society of Pediatric Oncology and Hematology (GPOH) data center registered and followed patients with other diagnoses than Ewing sarcoma who were treated according to the EE99 protocol in an additional non-Ewing database.

PROCEDURE

Data of 27 patients with other diagnoses than Ewing sarcoma treated according to the EE99 protocol were analyzed. Patients had miscellaneous histologic diagnoses, the majority were diagnosed with sarcoma not otherwise specified (NOS) arising in bone and soft tissue (63%).

RESULTS

The median age at diagnosis was 16.9 years (range 4.5-41.4). Localized disease was diagnosed in 61.5% of the patients and 38.5% had distant metastases at time of primary diagnosis. The median follow-up time was 3.7 years (range 0.5-9.5). Patients with localized disease showed a 3-year event-free survival (EFS) of 68%, compared to 3-year EFS of 20% in patients with metastases (P = 0.042). Three-year EFS for patients with sarcoma NOS was 52%, patients with localized and metastatic disease showed 3-year EFS of 66 and 20%, respectively.

CONCLUSION

EFS in patients with other diagnoses than Ewing sarcoma treated according to EE99 was significantly higher in patients with localized than metastatic disease. Sarcomas of soft tissue and bone that cannot be classified to current diagnostic categories constitute a therapeutic challenge.

Precision Medicine and PET-Computed Tomography in Pediatric Malignancies

Fluorine-18 fluorodeoxyglucose (¹⁸F-FDG) PET-computed tomography (CT) plays a significant role in diagnosis, staging, therapy selection, and therapy assessment of multiple pediatric malignancies and facilitating precision medicine delivery in pediatric patients. In patients with Hodgkin lymphoma, interim fludeoxyglucose ¹⁸F-FDG PET/CT is highly sensitive and specific for predicting survival and multiple trials with FDG PET/CT-based adaptive therapies are currently ongoing. It is superior to iodine-131 metaiodobenzylguanidine (¹³¹I-MIBG) scintigraphy and bone scintigraphy for detecting metastases in neuroblastoma patients and sarcoma patients. It may predict histologic differentiation and neoadjuvant therapy assessment in Wilms tumor.