Management of undifferentiated embryonal sarcoma of the liver: A Pediatric Surgical Oncology Research Collaborative study.

BACKGROUND: Undifferentiated embryonal sarcoma of the liver (UESL) is a rare tumor for which there are few evidence-based guidelines. The aim of this study was to define current management strategies and outcomes for these patients using a multi-institutional dataset curated by the Pediatric Surgical Oncology Research Collaborative. METHODS: Data were collected retrospectively for patients with UESL treated across 17 children's hospitals in North America from 1989 to 2019. Factors analyzed included patient and tumor characteristics, PRETEXT group, operative details, and neoadjuvant/adjuvant regimens. Event-free and overall survival (EFS, OS) were the primary and secondary outcomes, respectively. RESULTS: Seventy-eight patients were identified with a median age of 9.9 years [interquartile range [IQR): 7-12]. Twenty-seven patients underwent resection at diagnosis, and 47 patients underwent delayed resection, including eight liver transplants. Neoadjuvant chemotherapy led to a median change in maximum tumor diameter of 1.6 cm [IQR: 0.0-4.4] and greater than 90% tumor necrosis in 79% of the patients undergoing delayed resection. R0 resections were accomplished in 63 patients (81%). Univariate analysis found that metastatic disease impacted OS, and completeness of resection impacted both EFS and OS, while multivariate analysis revealed that R0 resection was associated with decreased expected hazards of experiencing an event [hazard ratio (HR): 0.14, 95% confidence interval (CI): 0.04-0.6]. At a median follow-up of 4 years [IQR: 2-8], the EFS was 70.0% [95% CI: 60%-82%] and OS was 83% [95% CI: 75%-93%]. CONCLUSION: Complete resection is associated with improved survival for patients with UESL. Neoadjuvant chemotherapy causes minimal radiographic response, but significant tumor necrosis.

Central Venous Catheter Consideration in Pediatric Oncology: A Systematic Review and Meta-analysis From the American Pediatric Surgical Association Cancer Committee.

BACKGROUND: Tunneled central venous catheters (CVCs) are the cornerstone of modern oncologic practice. Establishing best practices for catheter management in children with cancer is essential to optimize care, but few guidelines exist to guide placement and management. OBJECTIVES: To address four questions: 1) Does catheter composition influence the incidence of complications; 2) Is there a platelet count below which catheter placement poses an increased risk of complications; 3) Is there an absolute neutrophil count (ANC) below which catheter placement poses an increased risk of complications; and 4) Are there best practices for the management of a central line associated bloodstream infection (CLABSI)? METHODS: Data Sources: English language articles in Ovid Medline, PubMed, Embase, Web of Science, and Cochrane Databases. STUDY SELECTION: Independently performed by 2 reviewers, disagreements resolved by a third reviewer. DATA EXTRACTION: Performed by 4 reviewers on forms designed by consensus, quality assessed by GRADE methodology. RESULTS: Data were extracted from 110 manuscripts. There was no significant difference in fracture rate, venous thrombosis, catheter occlusion or infection by catheter composition. Thrombocytopenia with minimum thresholds of 30,000-50,000 platelets/mcl was not associated with major hematoma. Limited evidence suggests a platelet count <30,000/mcL was associated with small increased risk of hematoma. While few studies found a significant increase in CLABSI in CVCs placed in neutropenic patients with ANC<500Kcells/dl, meta-analysis suggests a small increase in this population. Catheter removal remains recommended in complicated or persistent infections. Limited evidence supports antibiotic, ethanol, or hydrochloric lock therapy in definitive catheter salvage. No high-quality data were available to answer any of the proposed questions. CONCLUSIONS: Although over 15,000 tunneled catheters are placed annually in North America into children with cancer, there is a paucity of evidence to guide practice, suggesting multiple opportunities to improve care. LEVEL OF EVIDENCE: III. This study was registered as PROSPERO 2019 CRD42019124077.

Effect of Early vs Late Inguinal Hernia Repair on Serious Adverse Event Rates in Preterm Infants: A Randomized Clinical Trial.

Importance: Inguinal hernia repair in preterm infants is common and is associated with considerable morbidity. Whether the inguinal hernia should be repaired prior to or after discharge from the neonatal intensive care unit is controversial. Objective: To evaluate the safety of early vs late surgical repair for preterm infants with an inguinal hernia. Design, Setting, and Participants: A multicenter randomized clinical trial including preterm infants with inguinal hernia diagnosed during initial hospitalization was conducted between September 2013 and April 2021 at 39 US hospitals. Follow-up was completed on January 3, 2023. Interventions: In the early repair strategy, infants underwent inguinal hernia repair before neonatal intensive care unit discharge. In the late repair strategy, hernia repair was planned after discharge from the neonatal intensive care unit and when the infants were older than 55 weeks' postmenstrual age. Main Outcomes and Measures: The primary outcome was occurrence of any prespecified serious adverse event during the 10-month observation period (determined by a blinded adjudication committee). The secondary outcomes included the total number of days in the hospital during the 10-month observation period. Results: Among the 338 randomized infants (172 in the early repair group and 166 in the late repair group), 320 underwent operative repair (86% were male; 2% were Asian, 30% were Black, 16% were Hispanic, 59% were White, and race and ethnicity were unknown in 9% and 4%, respectively; the mean gestational age at birth was 26.6 weeks [SD, 2.8 weeks]; the mean postnatal age at enrollment was 12 weeks [SD, 5 weeks]). Among 308 infants (91%) with complete data (159 in the early repair group and 149 in the late repair group), 44 (28%) in the early repair group vs 27 (18%) in the late repair group had at least 1 serious adverse event (risk difference, -7.9% [95% credible interval, -16.9% to 0%]; 97% bayesian posterior probability of benefit with late repair). The median number of days in the hospital during the 10-month observation period was 19.0 days (IQR, 9.8 to 35.0 days) in the early repair group vs 16.0 days (IQR, 7.0 to 38.0 days) in the late repair group (82% posterior probability of benefit with late repair). In the prespecified subgroup analyses, the probability that late repair reduced the number of infants with at least 1 serious adverse event was higher in infants with a gestational age younger than 28 weeks and in those with bronchopulmonary dysplasia (99% probability of benefit in each subgroup). Conclusions and Relevance: Among preterm infants with inguinal hernia, the late repair strategy resulted in fewer infants having at least 1 serious adverse event. These findings support delaying inguinal hernia repair until after initial discharge from the neonatal intensive care unit. Trial Registration: ClinicalTrials.gov Identifier: NCT01678638.

Children's Oncology Group's 2023 blueprint for research: Surgery.

Surgery plays a crucial role in the treatment of children with solid malignancies. A well-conducted operation is often essential for cure. Collaboration with the primary care team is important for determining if and when surgery should be performed, and if performed, an operation must be done in accordance with well-established standards. The long-term consequences of surgery also need to be considered. Indications and objectives for a procedure vary. Providing education and developing and analyzing new research protocols that include aims relevant to surgery are key objectives of the Surgery Discipline of the Children's Oncology Group. The critical evaluation of emerging technologies to ensure safe, effective procedures is another key objective. Through research, education, and advancing technologies, the role of the pediatric surgeon in the multidisciplinary care of children with solid malignancies will continue to evolve.

Management and Outcomes of Wilms Tumor With Suprarenal Intravascular Extension: A Pediatric Surgical Oncology Research Collaborative Study.

OBJECTIVE: The purpose of this study was to describe management and outcomes from a contemporary cohort of children with Wilms tumor complicated by inferior vena caval thrombus. BACKGROUND: The largest series of these patients was published almost 2 decades ago. Since then, neoadjuvant chemotherapy has been commonly used to manage these patients, and outcomes have not been reported. METHODS: Retrospective review of 19 North American centers between 2009 and 2019. Patient and disease characteristics, management, and outcomes were investigated and analyzed. RESULTS: Of 124 patients, 81% had favorable histology (FH), and 52% were stage IV. IVC thrombus level was infrahepatic in 53 (43%), intrahepatic in 32 (26%), suprahepatic in 14 (11%), and cardiac in 24 (19%). Neoadjuvant chemotherapy using a 3-drug regimen was administered in 82% and postresection radiation in 90%. Thrombus level regression was 45% overall, with suprahepatic level showing the best response (62%). Cardiopulmonary bypass (CPB) was potentially avoided in 67%. The perioperative complication rate was significantly lower after neoadjuvant chemotherapy [(25%) vs upfront surgery (55%); P =0.005]. CPB was not associated with higher complications [CPB (50%) vs no CPB (27%); P =0.08]. Two-year event-free survival was 93% and overall survival was 96%, higher in FH cases (FH 98% vs unfavorable histology/anaplastic 82%; P =0.73). Neither incomplete resection nor viable thrombus cells affected event-free survival or overall survival. CONCLUSIONS: Multimodal therapy resulted in excellent outcomes, even with advanced-stage disease and cardiac extension. Neoadjuvant chemotherapy decreased the need for CPB to facilitate resection. Complete thrombectomy may not always be necessary.

Critical elements of pediatric rhabdomyosarcoma surgery.

Rhabdomyosarcoma (RMS), the most common soft tissue sarcoma in children, requires multimodal therapy which is determined by risk group stratification. Local control may be achieved by surgical resection, radiation, or both. Resection may occur upfront or following induction chemotherapy as a delayed primary excision. An R1 resection may allow a reduction in radiation exposure; however, debulking is not indicated nor is excision of residual masses at the end of therapy. Regional lymph node assessment is an important component of surgical care, as positive nodal basins require radiation. Depending on the tumor site and biology, sentinel lymph node biopsy vs biopsy of clinically or radiographically concerning nodes is indicated. Therapeutic lymph node dissection is never indicated. Familiarity with site-specific oncologic principles for RMS and participation in a multidisciplinary team including Pediatric Oncology and Radiation Oncology are necessary components of surgical care to ensure optimal outcomes.

Fluorescent-guided surgery and the use of indocyanine green sentinel lymph node mapping in the pediatric and young adult oncology population.

BACKGROUND: Technetium-99 (99m Tc) lymphoscintigraphy with blue dye injection is an accepted method for sentinel lymph node (SLN) mapping, but blue dye has known adverse effects, and injection of 99m Tc may increase time under anesthesia for pediatric patients. Indocyanine green (ICG) may serve as an adjunct to assist with visibility and identification of SLNs. We hypothesized that sensitivity of ICG was similar to blue dye in SLN biopsies. METHODS: Thirty patients (36 procedures with 96 total specimens) underwent preoperative intradermal injection of 99m Tc, followed by intradermal injection of isosulfan blue and ICG. Test characteristics of blue dye, ICG, and 99m Tc included sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV). RESULTS: ICG had a sensitivity of 87% and PPV of 83% for detection of 99m Tc-hot lymph nodes; blue dye had a sensitivity of 44% and PPV of 97%. For detection of pathologically confirmed lymph nodes, ICG had a sensitivity of 84% and a positive predictive value (PPV) of 91%. 99m Tc had a sensitivity of 82% and a PPV of 94%. ICG had no significant difference in odds of being positive in pathology-confirmed lymph nodes compared to 99m Tc (odds ratio [OR], 0.818; 95% confidence interval [CI], 0.3-2.172; p = .823) and had higher odds than isosulfan blue (OR, 0.025, 95% CI, 0.001-0.148; p < .001). CONCLUSION: This study established the efficacy of ICG as an adjunct to SLNB in the pediatric and young adult population. ICG was safe, more efficacious than blue dye, and may obviate the need for lymphoscintigraphy in selected patients resulting in reduced time under anesthesia.

Multi-institutional assessment of the prevalence of neuroendocrine tumors in children undergoing laparoscopic appendectomy for acute appendicitis in the United States.

As non-operative management of acute appendicitis in children has become more common, missed incidental appendiceal pathology can be an unintended consequence. We assessed the prevalence of neuroendocrine tumors in appendectomy specimens from eight US children's hospitals from 2012 to 2021. The prevalence of neuroendocrine tumors (NET) was found to be 1:271, with a median age of 14 years and 62% female. Most tumors were small (median 6 mm; interquartile range [IQR]: 3-10), and no recurrence was noted during the follow-up period (median 22.5 months; IQR: 3-53). The possibility of delayed diagnosis of these tumors should be part of the discussion for non-operative management of pediatric acute appendicitis.

Implications of Immunotherapy for Pediatric Malignancies: A Summary from the APSA Cancer Committee.

Although survival for many pediatric cancers has improved with advances in conventional chemotherapeutic regimens and surgical techniques in the last several decades, it remains a leading cause of disease-related death in children. Outcomes in patients with recurrent, refractory, or metastatic disease are especially poor. Recently, the advent of alternative classes of therapies, including immunotherapies, have revolutionized systemic treatment for pediatric malignancies. Several classes of immunotherapies, including chimeric antigen receptor (CAR) T cell therapy, transgenic T-cell receptor (TCR)-T cell therapy, bispecific T-cell engagers, and monoclonal antibody checkpoint inhibitors have been FDA-approved or entered early-phase clinical trials in children and young adults. The pediatric surgeon is likely to encounter these therapies during the care of children with malignancies and should be familiar with the classes of therapy, indications, adverse events, and potential need for surgical intervention in these cases. This review from the APSA Cancer Committee offers a brief discussion of the three most encountered classes of immunotherapy in children and young adults and discusses surgical relevance. LEVEL OF EVIDENCE: IV.

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.

Feasibility of combining temsirolimus to vincristine, dactinomycin, cyclophosphamide, and vincristine and irinotecan chemotherapy for children with intermediate-risk rhabdomyosarcoma: A report from Children's Oncology Group.

BACKGROUND: Temsirolimus has shown in vivo activity against rhabdomyosarcoma (RMS). We aimed to determine the feasibility of incorporating temsirolimus within the standard Children's Oncology Group (COG) chemotherapy backbone of vincristine, actinomycin-D, and cyclophosphamide (VAC) alternating with vincristine and irinotecan (VI) in children with intermediate-risk (IR) RMS. METHODS: The feasibility phase of the COG IR-RMS trial, ARST1431 (NCT02567435), assigned 10 patients to receive 15 mg/m2 /dose (dose level 1) of temsirolimus on days 1, 8, and 15 of each of three weekly VAC and VI cycles for the first 12 weeks of induction chemotherapy. The primary endpoint of the feasibility phase was to establish the safe dose and safety of combining temsirolimus with VAC/VI. The combination regimen was deemed feasible if less than 40% of patients developed a priori defined nonhematological dose-limiting toxicities (DLTs). RESULTS: Ten patients (seven males and three females; median age = 4.5 years [range: 0.2-14.4 years]) with IR-RMS were enrolled and received dose level 1 of temsirolimus. Eight patients had FOXO1-negative disease, while two had FOXO1-positive disease. Two patients had metastatic disease. Of 10 patients, two developed DLTs: grade 3 oral mucositis and pneumonitis. Four patients (40%) had grade 4 neutropenia. No treatment-related mortality occurred. The median duration of the completion of the feasibility phase was 12.1 weeks (range: 11.7-15 weeks). CONCLUSIONS: Weekly temsirolimus at 15 mg/m2 /dose during VAC/VI chemotherapy was feasible and well tolerated. The efficacy of this regimen is currently being tested in a phase III randomized trial against VAC/VI chemotherapy alone in the ARST1431 trial.

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.

Disparities in care of pediatric, adolescent, and young adult patients with solid tumors: A systematic review.

BACKGROUND: Numerous studies have demonstrated a variety of social inequalities within pediatric and young adult patients with solid tumors. This systematic review examines and consolidates the existing literature regarding disparities in pediatric and young adult solid tumor oncology. PROCEDURE: A MeSH search was performed on the following databases: MEDLINE, PubMed, OvidSP Cochrane, Central, Embase, Cinhal, and Scopus. The systematic review was performed using Rayyan QCRI. RESULTS: Total 387 articles were found on the initial search, and 34 articles were included in final review. Twenty-seven studies addressed racial and ethnic disparities; 23 addressed socioeconomic disparities. Patients with Hispanic ethnicity, Black race, and lower socioeconomic status were more likely to present at later stages, have differences in treatments and higher mortality rates. CONCLUSION: This qualitative systematic review identified both racial and socioeconomic disparities in pediatric cancer patients across a variety of solid tumor types. Patients with Hispanic ethnicity, Black race, and lower socioeconomic status are associated with disparities in stage at presentation, treatment, and outcome. Characterization of existing disparities provides the evidence necessary to support changes at a systemic level.

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.

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.

Pediatric and Young Adult Image-Guided Percutaneous Bone Biopsy-A New Standard of Care?

BACKGROUND: There are no consensus guidelines regarding the use of percutaneous needle biopsy for the diagnosis of soft tissue and bone tumors. The aim of this study was to understand the efficacy of image-guided percutaneous biopsy for pediatric patients with soft tissue and bony masses, the role of intraoperative image guidance, and diagnostic accuracy. PATIENTS AND METHODS: A retrospective institutional chart review was performed on patients who underwent percutaneous biopsy of soft tissue or bone tumors between 2007 and 2017. Data collected included preoperative imaging, type of biopsy, demographics, insurance status, number of samples taken, and pathologic results. RESULTS: One hundred forty-one children and young adults underwent 169 biopsies. Female patients received 48.2% of biopsies. The mean age was 14.3 ± 7.0 years. Core needle biopsies made up 89.4% of procedures, while 10.6% were fine needle aspirate. The mean number of samples per patient was 3.6 ± 2.5. All patients had imaging guidance, with computed tomography used in 44.7% of patients, 9.9% using fluoroscopy, 7.1% using ultrasound for guidance, and 53 (37.6%) patients had more than one modality. Diagnostic specimens were obtained in 97.9% of biopsies. The most common overall pathology was osteoid osteoma. The most common malignant tumors were osteosarcoma and Ewing's sarcoma. CONCLUSION: Image-guided percutaneous biopsy is a safe and effective method of obtaining accurate tissue samples in children and young adults with soft tissue or bone masses. LEVEL OF EVIDENCE: Level 4-Study of diagnostic test.

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.