Delayed primary excision with subsequent modification of radiotherapy dose for intermediate-risk rhabdomyosarcoma: a report from the Children's Oncology Group Soft Tissue Sarcoma Committee

Treatment of nasolabial fold rhabdomyosarcoma in children: A single-institution experience

OBJECTIVES

To summarize the clinical characteristics and prognosis of children with nasolabial fold rhabdomyosarcoma (RMS).

METHODS

Retrospective review of children treated for nasolabial fold RMS from January 2014 to September 2019.

RESULTS

Of 21 patients with nasolabial fold RMS, 90.48% were alveolar subtype, in which PAX3/7-FOXO1 fusion positive accounted for 87.5%. Ten patients (47.62%) had nodals invasion. Almost all patients received comprehensive treatment (chemotherapy [100%], radiation therapy [100%], and surgery [95.24%]). The median follow-up time was 34.3 months. The 3-year overall survival (OS) and event-free survival (EFS) was 67.7% ± 14.1% and 42.1% ± 13.5%, respectively. Four patients had regional lymph node relapse (NR), all in the ipsilateral submandibular lymph node region.

CONCLUSION

Majority of the patients with RMS in the nasolabial fold area were alveolar subtype and had positive PAX3/7-FOXO1 gene fusion. In addition, the nasolabial fold RMS had a high probability of regional lymph node metastasis in the submandibular area. To maintain the facial aesthetics and functions, the surgical area for nasolabial fold RMS is often very conservative and restricted. This could be one of the contributors for the poor prognosis of nasolabial fold RMS beside its worse pathological subtype and gene fusion.

Local Treatment of Children Suffering From Parameningeal Rhabdomyosarcoma: A Retrospective Single-Center Study From China

BACKGROUND

Treatment for parameningeal rhabdomyosarcoma (PM-RMS) has been a challenge since local control is difficult. The goal of this study was to analyse the impact of different local treatment approaches on childhood PM-RMS patients and help dispel the doubt that whether secondary radical surgery (SRS) should be encouraged in the management of PM-RMS.

METHODS

A total of 17 children with PM-RMS who received unified systemic chemotherapy and individualized local therapy such as radiotherapy (RT) and/or SRS were included in this retrospective study. The overall survival (OS) and event free survival (EFS) were compared between groups adopting different local strategies.

RESULTS

The 3-year OS and EFS of our PM-RMS patients was 75.5% and 56.5% respectively. The OS and EFS of patients who received SRS were both significantly lower than that of the non-SRS group (3-year OS: 50.0% vs 90.0%, P = .031; 3-year EFS: 33.3% vs 60.6%, P = .020). The OS and EFS of the patients who received RT was higher than that of the patients of the non-RT group (3-year OS: 85.6% vs 0%, P = .001; 3-year EFS: 64.0% vs 0%, P = .011).

CONCLUSION

This study illustrates that SRS was associated with poor prognosis of PM-RMS and should not be routinely performed. Optimized RT strategies along with more intensive chemotherapy may be alternative options to improve the survival of patients with PM-RMS. Multi-center, large sample and prospective studies are needed to further validate these findings.

Common queries in managing rhabdomyosarcoma in low- and middle-income countries: An Indo-North American collaboration

Rhabdomyosarcoma (RMS) is the most common soft tissue sarcoma among children and adolescents. The management of RMS involves risk stratification of the patients based on various clinicopathological characteristics. The multimodality treatment approach requires chemotherapy, surgery, and/or radiation. The treatment of RMS necessitates the involvement of multiple disciplines, such as pathology, pediatric oncology, surgery, and radiation oncology. The disease heterogeneity, molecular testing, evolving treatment regimens, and limited resources are some of the challenges faced by clinicians while treating a patient with RMS in low- and middle-income countries (LMICs). In this review, we endeavor to bring experts from varying fields to address clinicians' common questions while managing a child or adolescent with RMS in LMICs. This review is most applicable to level 2 centers in LMICs as per the levels of services described by the Adapted Treatment Regimens Working Group of the Pediatric Oncology in Developing Countries committee of the International Society of Pediatric Oncology.

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.

Current topics and management of head and neck sarcomas

Given the low incidence, variety of histological types, and heterogeneous biological features of head and neck sarcomas, there is limited high-quality evidence available to head and neck oncologists. For resectable sarcomas, surgical resection followed by radiotherapy is the principle of local treatment, and perioperative chemotherapy is considered for chemotherapy-sensitive sarcomas. They often originate in anatomical border areas such as the skull base and mediastinum, and they require a multidisciplinary treatment approach considering functional and cosmetic impairment. Moreover, head and neck sarcomas may exhibit different behaviour and characteristics than sarcomas of other areas. In recent years, the molecular biological features of sarcomas have been used for the pathological diagnosis and development of novel agents. This review describes the historical background and recent topics that head and neck oncologists should know about this rare tumour from the following five perspectives: (i) epidemiology and general characteristics of head and neck sarcomas; (ii) changes in histopathological diagnosis in the genomic era; (iii) current standard treatment by histological type and clinical questions specific to head and neck; (iv) new drugs for advanced and metastatic soft tissue sarcomas; and (v) proton and carbon ion radiotherapy for head and neck sarcomas.

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.

Analysis of the Pediatric Radiotherapy Landscape in Mexico and a Subsequent Educational e-Contouring Intervention

PURPOSE

Mexico and Central America have the highest childhood cancer incidence in the West. Pediatric-specific oncology knowledge contributes to the disparity. We sought to (1) determine the self-identified treatment patterns and needs of Mexican pediatric radiation oncologists and (2) pilot a workshop to improve contouring accuracy.

MATERIALS AND METHODS

Partnering with local experts and the Sociedad Mexicana de Radioterapeutas (SOMERA), a 35-question survey was designed to ascertain pediatric radiotherapy capacity and distributed through the SOMERA listserv. The most challenging malignancies were selected for workshop. Participants received precontouring and postcontouring homework to assess improvement per the Dice metric. The Wilcoxon sign-rank test was used for comparative statistics.

RESULTS

Ninety-four radiation oncologists attempted and 79 completed the survey. Forty-four (76%) felt comfortable treating a pediatric patient, and 36 (62%) were familiar with national protocols for pediatric treatment. Most had access to nutrition, rehabilitation, endocrinology, and anesthesia; 14% had access to fertility services and 27% to neurocognitive support; 11% noted no support, and only one respondent had child-life support. The postsurvey contouring workshop was conducted for high-grade glioma, medulloblastoma, and Hodgkin lymphoma. Significant improvements were seen in all target volumes.

CONCLUSION

We present the first national survey of Mexico's pediatric radiotherapy capacity and Latin American e-contouring educational intervention with preworkshop and postworkshop Dice metrics, noting statistically significant improvement in all target volumes. Participation improved compared with prior experience through SOMERA partnership and Continuing Medical Education incentivization.

Surgical management of extremity rhabdomyosarcoma: A consensus opinion from the Children's Oncology Group, the European Pediatric Soft-Tissue Sarcoma Study Group, and the Cooperative Weichteilsarkom Studiengruppe

The treatment of extremity rhabdomyosarcoma remains a challenge due to several adverse prognostic factors frequently associated with this tumor site. The International Soft-Tissue Sarcoma Database Consortium (INSTRuCT) is a collaboration of the Children's Oncology Group Soft-Tissue Sarcoma Committee, the European Pediatric Soft-Tissue Sarcoma Study Group, and the Cooperative Weichteilsarkom Studiengruppe. The INSTRuCT surgical committee developed an internationally applicable consensus opinion document for the surgical treatment of extremity rhabdomyosarcoma. This document addresses surgical management, including biopsy, nodal staging, timing of therapy, resection and reexcision, reconstruction, and surgical approach at relapse.

Local control of parameningeal rhabdomyosarcoma: An expert consensus guideline from the International Soft Tissue Sarcoma Consortium (INSTRuCT)

The International Soft Tissue Sarcoma Database Consortium (INSTRuCT) consists of a collaboration between the Children's Oncology Group (COG) Soft Tissue Sarcoma Committee, the European pediatric Soft Tissue Sarcoma Study Group (EpSSG), and the Cooperative Weichteilsarkom Studiengruppe (CWS). As part of the larger initiative of INSTRuCT to provide consensus expert opinions for clinical treatment of pediatric soft tissue sarcoma, we sought to provide updated, evidenced-based consensus guidelines for local treatment of parameningeal rhabdomyosarcoma using both existing literature as well as recommendations from the relevant cooperative group clinical trials. Overall, parameningeal rhabdomyosarcoma represents a distinctly challenging disease to treat, given its location near many critical structures in the head and neck, frequently advanced local presentation, and predilection for local failure. Definitive chemoradiation remains the standard treatment approach for parameningeal rhabdomyosarcoma, with surgery often limited to biopsy or salvage therapy for recurrent disease. In this consensus paper, we specifically discuss consensus guidelines and evidence for definitive local management with radiotherapy, with a focus on imaging for radiotherapy planning, dose and timing of radiation, approach for nodal irradiation, various radiation techniques, including proton therapy, and the limited role of surgical resection.

Surgical Management of Rhabdomyosarcoma of the Nasal Cavity and Paranasal Sinuses: Analysis of Operative Indications, Settings, and Outcomes

Objectives The role of surgery in management of sinonasal rhabdomyosarcoma (SNRMS) has traditionally been limited, owing to anatomic and technological challenges and the established role of systemic therapy. Herein, we report our institutional experience with surgical management of SNRMS, with a particular focus on operative approaches, extent and outcomes.

Design This study is a retrospective cohort study.

Setting This study was conducted at a single-institution, academic center.

Participants Patients of any age with histologically confirmed RMS of the nasal cavity, maxillary, ethmoid, frontal, or sphenoid sinus, nasolacrimal duct, or nasopharynx presenting between 1994 and 2020 were included in this study.

Main Outcome Measures Demographics, tumor characteristics, operative settings, complications and recurrence, and survival outcomes were the primary outcomes of this study.

Results Our study cohort comprised of 29 patients (mean [range] age: 27.0 [3.1–65.7], n = 12 [41%] female). Tumors of the nasal cavity (n = 10, 35%) and ethmoid sinuses (n = 10, 35%) and those with alveolar histology (n = 21, 72%) predominated. Patients who had surgery as part of their treatment (n = 13, 45%) had improved distant metastasis-free survival (DMFS) overall (hazard ratio [HR]: 0.32, 95% CI: 0.11, 0.98, p = 0.05) as compared with those who did not have surgery. Surgical approaches included open (n = 7), endoscopic (n = 4), and combined (n = 2). Eight of these 13 patients (62%) had an R0 resection. Additionally, surgical salvage of recurrent disease was employed in five patients (17%).

Conclusion SNRMS is an aggressive malignancy with a high rate of recurrence and spread requiring a multidisciplinary approach for optimal outcomes. Our data supports an expanding role for surgery for SNRMS given its feasibility, tolerability, and potential to improve outcomes.

Durability of oncological outcomes of combination chemotherapy as a monotherapy for a select patient subset with non-metastatic non-alveolar bladder/prostate rhabdomyosarcoma

INTRODUCTION AND OBJECTIVES

We aim to assess the long-term oncological outcomes of children with bladder/prostate rhabdomyosarcoma (B/P RMS) treated with multiagent chemotherapy as a monotherapy. We hypothesize that a highly select patient subset can be treated with multiagent chemotherapy as a monotherapy and spared the morbidity of local treatment with similar oncological outcomes.

METHODS

Patients (≤21-year-old) treated for non-metastatic non-alveolar B/P RMS at a tertiary center and followed for>one year, were retrospectively reviewed. After pathological confirmation, patients received 12 weeks of induction VAC chemotherapy (IC) followed by second-look biopsies. Between 1996 and 2006 (group A), patients with>50% tumor size reduction and negative second-look biopsies following IC were spared local treatment and followed-up closely. Between 2007 and 2020 (group B), local treatment was routinely given at 12 weeks according to the COG protocols, irrespective of IC response. For all patients, consolidation chemotherapy was administered for additional 12-18 months.

RESULTS

Between 1996 and 2020, 27 patients (10 stage II, 17 stage III) with a median age of 3(1-21) years were included. Median follow-up was 87.5(15.3-247.1) months. Among 15 patients in group A, 3 were ineligible for the monotherapy protocol and received local treatment. The remaining 12 patients [9 complete (CR) and 3 incomplete response (IR) to IC] were treated exclusively with chemotherapy, of whom 9 were alive free of relapse at last follow-up. Two patients with IR to IC had disease relapse: one had pulmonary relapse at 8.2 months and one had local relapse at 35 months. The 5-year OS and EFS of group A were 86.7% and 80%, respectively. Analyzing survival according to IC response, CR to IC was achieved in 10 patients (9 group A and one group B) and was associated with significantly better OS and EFS than IR(p = 0.026 and 0.004, respectively) (Summary figure). All patients with CR to IC were alive free of relapse at last follow-up.

DISCUSSION

Treatment of RMS is traditionally multimodal. Local treatment of B/P RMS is associated with significant patient morbidity. In this study, CR to IC predicted better OS and EFS. Patients who achieved CR (radiological and pathological) to IC remained alive free of relapse irrespective of local treatment.

CONCLUSIONS

Our results suggest that patients with non-metastatic non-alveolar B/P RMS who achieve CR to IC can be treated with combination chemotherapy as a monotherapy and spared the morbidity of local treatment with durable survival outcomes. Prospective validation in a larger patient cohort is needed to support our hypothesis.

Rhabdomyosarcoma

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

Management of Rhabdomyosarcoma in Pediatric Patients

Rhabdomyosarcoma is the commonest soft tissue sarcoma in children. Clinicians need vigilance to recognize the different signs and symptoms this tumor can present with because of variable sites of origin. Diagnosis requires a safe biopsy that obtains sufficient tissue for pathologic, genetic, and biological characterization of the tumor. Treatment depends on accurate staging with imaging and surgical sampling of draining lymph nodes. A multidisciplinary team assigns patients to risk-based therapy. Patients require chemotherapy and usually a combination of complex, site-specific surgery and/or radiotherapy. Outcomes for localized rhabdomyosarcoma continue to improve but new treatments are required for metastatic and relapsed disease.

Benefit of delayed primary excision in rhabdomyosarcoma: A report from the Children's Oncology Group

BACKGROUND

Most children with intermediate-risk rhabdomyosarcoma (RMS) have gross disease (group III) at the initiation of chemotherapy. Delayed primary excision (DPE) after induction chemotherapy allows for a reduction in adjuvant radiation dose, but with the risk of potential surgical morbidity. The objectives of this study were to compare outcomes in children with group III RMS who did and did not undergo DPE and to assess surgical morbidity.

METHODS

The study included 369 patients who had clinical group III RMS at sites amenable to DPE from intermediate-risk Children's Oncology Group studies D9803 (encouraged DPE) and ARST0531 (discouraged DPE).

RESULTS

The primary tumor site was bladder/prostate (136 patients; 37%), extremity (97 patients; 26%), trunk (24 patients; 7%), retroperitoneum (91 patients; 25%), or intrathoracic/perineum/perianal (21 patients; 6%). In total, 112 patients (53.9%) underwent DPE in D9803, and 26 patients (16.2%) underwent DPE in ARST0531 (P < .001), with loss of vital organ or function in 30 of 138 patients (22%). DPE allowed for a reduced radiation dose in 110 of 135 patients (81%; 51% were reduced to 36 Gy, and 30% were reduced to 42 Gy). Patients who underwent DPE had improved unadjusted overall survival (P = .013). In adjusted regression analysis, the risk of death (hazard ratio, 0.71; 95% CI 0.43-1.16) was similar for patients who did and did not undergo DPE and was improved for the subset of patients who had tumors of the trunk and retroperitoneum (hazard ratio, 0.44; 95% CI, 0.20-0.97).

CONCLUSIONS

Children with group III RMS have equivalent or improved outcomes with DPE and can receive a decreased radiation dose for definitive local control. The choice of local control modality should weigh the potential morbidity of surgery versus that of higher dose irradiation.

Advances in the management of pediatric genitourinary rhabdomyosarcoma

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

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.

Rhabdomyosarcoma associated with germline TP53 alteration in children and adolescents: The French experience

OBJECTIVE

To describe the clinical characteristics and outcome of patients with Li-Fraumeni-associated rhabdomyosarcoma (RMS).

METHOD

Retrospective analysis of data from 31 French patients with RMS diagnosed before the age of 20 years associated with a TP53 pathogenic germline variant. Cases were identified through the French Li-Fraumeni database. Central histologic review was performed in 16 cases.

RESULTS

The median age at diagnosis was 2.3 years, and the median follow-up was 9.1 years (0.3-34.8). The main tumor sites were head and neck (n = 13), extremities (n = 8), and trunk (n = 8). The local pathology report classified the 31 tumors in embryonal (n = 26), alveolar (n = 1), pleomorphic (n = 1), and spindle-cell (n = 1) RMS (missing = 2). After histological review, anaplasia (diffuse or focal) was reported in 12/16 patients. Twenty-five patients had localized disease, three had lymph node involvement, and three distant metastases. First-line therapy combined surgery (n = 27), chemotherapy (n = 30), and radiotherapy (n = 14) and led to RMS control in all, but one patient. Eleven patients relapsed, and 18 patients had second malignancies. The 10-year event-free, progression-free, and overall survival rates were 36% (95% CI: 20-56), 62% (95% CI: 43-77) and 76% (95% CI: 56-88), respectively. The 10-year cumulative risk of second malignancies was 40% (95% CI: 22-60).

CONCLUSION

The high incidence of multiple primary tumors strongly influences the long-term prognosis of RMS associated with TP53 pathogenic germline variants. Anaplastic RMS in childhood, independently of the familial history, should lead to TP53 analysis at treatment initiation to reduce, whenever possible, the burden of genotoxic drugs and radiotherapy in carriers and to ensure the early detection of second malignancies.

Role of Surgery in Rhabdomyosarcoma of the Head and Neck in Children

OBJECTIVES

Rhabdomyosarcoma (RMS) is the most common soft tissue sarcoma in children. The goal of this research is to analyze the role of surgery in the management of pediatric parameningeal (PM) and non-PM head and neck RMS (HNRMS).

STUDY DESIGN

Retrospective review.

METHODS

Retrospective chart review of patients <20 years of age treated for HNRMS between 1970 and 2015. Clinical presentation, tumor characteristics, treatment, recurrence, follow-up, and outcome data were collected.

RESULTS

Of 97 patients with HNRMS, 56% were male. Overall median (IQR: interquartile range) age at diagnosis was 5.8 (3.3-9.8) years. Sixty-five patients (67%) had PM tumors. Of 75 patients with histologic subtype identified, 51 (53%) had embryonal and 20 (21%) alveolar RMS. Almost all patients received chemotherapy (99%) and radiotherapy (95%). Forty-four patients (45%) underwent surgery. Surgery was more likely to be conducted in patients with lesions of a non-PM site. Median follow-up time was 3.4 years (IQR: 1.1-10.8). In 5 years of follow-up, 20% (17 of 85) died and 29% (20 of 70) had recurrence. The estimated 5-year survival rate was 72% (95% CI, 57.8, 81.5%). Surgery was associated with a reduced risk of mortality after accounting for TNM stage 4 and tumor site (adjusted HR 0.24; 95% CI, 0.07, 0.79; P = .02). The association between surgery and risk of mortality was similar in PM and non-PM tumors.

CONCLUSION

A multimodal protocol for treatment including chemotherapy, surgery, and radiotherapy is the mainstay for management of children with HNRMS. While surgery is more commonly used to treat non-PM HNRMS, patients who are able to undergo surgery have significantly higher 5-year survival.

LEVEL OF EVIDENCE

4 Laryngoscope, 131:E984-E992, 2021.

Relationship between tumor response at therapy completion and prognosis in patients with Group III rhabdomyosarcoma: A report from the Children's Oncology Group

A subset of patients with initially unresected (Clinical Group III) rhabdomyosarcoma achieve less than a complete response (CR) despite multimodal therapy. We assessed outcome based upon tumor response at the completion of all planned therapy. We studied 601 Clinical Group III participants who completed all protocol therapy without developing progressive disease on two Children's Oncology Group studies ARST0531 (n = 285) and D9803 (n = 316). Response was defined by imaging and categorized by response; complete resolution (CR), partial response (PR) or no response (NR). Failure-free survival (FFS) and overall survival (OS) between response groups were compared using the log-rank test. We found that radiographic response was CR in 393 (65.4%) and PR/NR in 208 (34.6%) patients. Achieving CR status was associated with study D9803, nonparameningeal (PM) primary sites, tumors ≤5 cm, noninvasive tumors and alveolar histology/FOXO fusion-positive tumors. The overall 5-year FFS was 75% for those achieving CR and 66.5% in those with PR/NR (adj. p = 0.094). Patients with PM primary site who achieved CR had significantly improved FFS (adj. p = 0.037) while those with non-PM primary sites had similar outcomes (adj. p = 0.47). Radiographic response was not associated with OS (adj. p = 0.21). Resection of the end-of-therapy mass did not improve FFS (p = 0.12) or OS (p = 0.37). In conclusion, CR status at the end of protocol therapy in patients with PM Clinical Group III RMS was associated with improved FFS but not OS. Efforts to understand the biology and treatment response in patients with PM primary site are under investigation.

Recent progress in pediatric soft tissue sarcoma therapy

Soft tissue sarcomas of childhood are a heterogenous group of tumors with a wide spectrum of presentations and outcomes. Most patients require multimodal therapy with chemotherapy, surgery and/or radiation. Improved outcomes in recent decades have been achieved through improvements in the comprehensive care of these children through large cooperative group studies, even as little progress has been made in the standard chemotherapy backbone. A thorough understanding of the nuances of surgical therapy for these children is required to minimize both the risk of local failure and the possibility of loss of vital form or function.

Increased local failure for patients with intermediate-risk rhabdomyosarcoma on ARST0531: A report from the Children's Oncology Group

BACKGROUND

The objective of this study was to evaluate local control for patients with intermediate-risk rhabdomyosarcoma (RMS) treated on Children's Oncology Group (COG) protocol ARST0531.

METHODS

This study analyzed 424 patients with intermediate-risk RMS. Patients were randomized to chemotherapy with either vincristine, dactinomycin, and cyclophosphamide (VAC) or VAC alternating with vincristine and irinotecan. With the goal of improving local control, radiation therapy (RT) was delivered early at week 4 and was concurrent with irinotecan in the experimental arm. Individualized local control plans for children 24 months old or younger were allowed. Local failure on ARST0531 was compared with local failure on the preceding COG intermediate-risk study, D9803.

RESULTS

For patients with group I/II alveolar RMS (n = 55), the 5-year cumulative incidence of local failure was 13.4%; for group III alveolar RMS (n = 141), it was 20.2%; and for group III embryonal RMS (n = 228), it was 27.9% (P = .03). Among patients with group III disease, local failure did not differ by histology, site, nodal status, RT modality, or treatment arm. Local failure was worse for a tumor size >5 cm (32.3% vs 16.7%; P = .001). Among patients with group III embryonal RMS, local failure was higher on ARST0531 than D9803 (27.9% vs 19.4%; P = .03). After the exclusion of patients 24 months old or younger or patients who did not receive radiation, local failure remained significantly increased on ARST0531 (P = .02). After adjustments for clinical prognostic factors, event-free survival and overall survival were worse on ARST0531 (P = .004 and P = .05, respectively).

CONCLUSIONS

Despite interventions designed to enhance local control, local control was inferior on ARST0531 in comparison with D9803. The reason for this is unclear, but it could be the reduced cyclophosphamide dose on ARST0531.

Rhabdomyosarcoma

Rhabdomyosarcoma (RMS) is the most common soft tissue sarcoma in children and represents a high-grade neoplasm of skeletal myoblast-like cells. Decades of clinical and basic research have gradually improved our understanding of the pathophysiology of RMS and helped to optimize clinical care. The two major subtypes of RMS, originally characterized on the basis of light microscopic features, are driven by fundamentally different molecular mechanisms and pose distinct clinical challenges. Curative therapy depends on control of the primary tumour, which can arise at many distinct anatomical sites, as well as controlling disseminated disease that is known or assumed to be present in every case. Sophisticated risk stratification for children with RMS incorporates various clinical, pathological and molecular features, and that information is used to guide the application of multifaceted therapy. Such therapy has historically included cytotoxic chemotherapy as well as surgery, ionizing radiation or both. This Primer describes our current understanding of RMS epidemiology, disease susceptibility factors, disease mechanisms and elements of clinical care, including diagnostics, risk-based care of newly diagnosed and relapsed disease and the prevention and management of late effects in survivors. We also outline potential opportunities to further translate new biological insights into improved clinical outcomes.

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.

Addition of Vincristine and Irinotecan to Vincristine, Dactinomycin, and Cyclophosphamide Does Not Improve Outcome for Intermediate-Risk Rhabdomyosarcoma: A Report From the Children's Oncology Group

Purpose Intermediate-risk rhabdomyosarcoma (RMS) includes patients with either nonmetastatic, unresected embryonal RMS (ERMS) with an unfavorable primary site or nonmetastatic alveolar RMS (ARMS). The primary aim of this study was to improve the outcome of patients with intermediate-risk RMS by substituting vincristine and irinotecan (VI) for half of vincristine, dactinomycin, and cyclophosphamide (VAC) courses. All patients received a lower dose of cyclophosphamide and earlier radiation therapy than in previous trials. Patients and Methods Patients were randomly assigned at study entry to either VAC (cumulative cyclophosphamide dose, 16.8 g/m²) or VAC/VI (cumulative cyclophosphamide dose, 8.4 g/m²) for 42 weeks of therapy. Radiation therapy started at week 4, with individualized local control plans permitted for patients younger than 24 months. The primary study end point was event-free survival (EFS). The study design had an 80% power (5% one-sided α-level) to detect an improved long-term EFS from 65% (with VAC) to 76% (with VAC/VI). Results A total of 448 eligible patients were enrolled in the study. At a median follow-up of 4.8 years, the 4-year EFS was 63% with VAC and 59% with VAC/VI ( P = .51), and 4-year overall survival was 73% for VAC and 72% for VAC/VI ( P = .80). Within the ARMS and ERMS subgroups, no difference in outcome by treatment arm was found. Severe hematologic toxicity was less common with VAC/VI therapy. Conclusion The addition of VI to VAC did not improve EFS or OS for patients with intermediate-risk RMS. VAC/VI had less hematologic toxicity and a lower cumulative cyclophosphamide dose, making VAC/VI an alternative standard therapy for intermediate-risk RMS.

The Children's Oncology Group Radiation Oncology Discipline: 15 Years of Contributions to the Treatment of Childhood Cancer

PURPOSE

Our aim was to review the advances in radiation therapy for the management of pediatric cancers made by the Children's Oncology Group (COG) radiation oncology discipline since its inception in 2000.

METHODS AND MATERIALS

The various radiation oncology disease site leaders reviewed the contributions and advances in pediatric oncology made through the work of the COG. They have presented outcomes of relevant studies and summarized current treatment policies developed by consensus from experts in the field.

RESULTS

The indications and techniques for pediatric radiation therapy have evolved considerably over the years for virtually all pediatric tumor types, resulting in improved cure rates together with the potential for decreased treatment-related morbidity and mortality.

CONCLUSIONS

The COG radiation oncology discipline has made significant contributions toward the treatment of childhood cancer. Our discipline is committed to continuing research to refine and modernize the use of radiation therapy in current and future protocols with the goal of further improving the cure rates and quality of life of children with cancer.

Local control for vaginal botryoid rhabdomyosarcoma with pre-rectal transperineal surgical resection and autologous buccal graft vaginal replacement: A novel, minimally invasive, radiation-sparing approach

PURPOSE

Localized vaginal rhabdomyosarcoma (RMS) is associated with a favorable prognosis, but strategies for local control remain controversial. The use of radiotherapy (RT) can have important long-term sequelae, while traditional resection involves major reconstructive surgery. We describe a new surgical approach employing a minimally-invasive resection and immediate reconstruction.

MATERIALS AND METHODS

Records from 4 consecutive patients with localized vaginal RMS managed in 4 major pediatric referral centers were reviewed. All cases were performed with a standardized technique.

RESULTS

Patients were diagnosed at a median age of 24months. Each underwent a total/subtotal vaginectomy with autologous buccal graft vaginal replacement. Final margins were focally positive in one patient and negative in three. None received radiotherapy. To date, all patients have patent buccal neovaginas, enjoy a favorable aesthetic result, and remain disease-free at a median follow-up of 35months.

CONCLUSIONS

We report 4 cases of localized vaginal RMS successfully treated with a minimally invasive surgical approach. All patients have avoided radiation and remain disease-free. Our initial data suggest that surgical local control and immediate reconstruction are feasible and can spare these patients the long-term complications of RT. Longer follow-up is critical to ensure disease-free survival with a functional, successfully reconstructed neovagina.

TYPE OF STUDY

Case series.

LEVEL OF EVIDENCE

Level IV.

Excessive Treatment Failures in Patients With Parameningeal Rhabdomyosarcoma With Reduced-dose Cyclophosphamide and Delayed Radiotherapy

Pediatric patients with parameningeal rhabdomyosarcoma and high-risk features are recommended to receive radiotherapy at initiation of protocol therapy due to concerns about the increased risk of local and leptomeningeal failure from treatment delay. We report our early experience on a multi-institutional prospective trial incorporating delayed primary site radiation and reduced dose cyclophosphamide in all patients with parameningeal tumors. We observed an excessive number of locoregional treatment failures following this approach and have subsequently amended our trial to move radiation therapy upfront for those patients with high-risk features. We suggest that investigators should be vigilant for treatment failure given our early prospective experience with delayed radiotherapy and reduced dose cyclophosphamide.

Management of Low and Intermediate Risk Adult Rhabdomyosarcoma: A Pooled Survival Analysis of 553 Patients

This is the second-largest retrospective analysis addressing the controversy of whether adult rhabdomyosarcoma (RMS) should be treated with chemotherapy regimens adopted from pediatric RMS protocols or adult soft-tissue sarcoma protocols. A comprehensive database search identified 553 adults with primary non-metastatic RMS. Increasing age, intermediate-risk disease, no chemotherapy use, anthacycline-based and poor chemotherapy response were significant predictors of poor overall and progression-free survival. In contrast, combined cyclophosphamide-based, cyclophosphamide + anthracycline-based, or cyclophosphamide + ifosfamide + anthracycline-based regimens significantly improved outcomes. Intermediate-risk disease was a significant predictor of poor chemotherapy response. Overall survival of clinical group-III patients was significantly improved if they underwent delayed complete resection. Non-parameningeal clinical group-I patients had the best local control, which was not affected by additional adjuvant radiotherapy. This study highlights the superiority of chemotherapy regimens –adapted from pediatric protocols- compared to anthracycline-based regimens. There is lack of data to support the routine use of adjuvant radiotherapy for non-parameningeal group-I patients. Nonetheless, intensive local therapy should be always considered for those at high risk for local recurrence, including intermediate-risk disease, advanced IRS stage, large tumors or narrow surgical margins. Although practically difficult (due to tumor’s rarity), there is a pressing need for high quality randomized controlled trials to provide further guidance.

Consensus and controversies regarding the treatment of rhabdomyosarcoma

Optimal treatment of rhabdomyosarcoma (RMS) requires multidisciplinary approach, incorporating chemotherapy with local control. Although current therapies are built on cooperative group trials, a comprehensive standard of care to guide clinical decision making has been lacking, especially for relapsed patients. Therefore, we assembled a panel of pediatric and adolescent and young adult sarcoma experts to develop treatment guidelines for managing RMS and to identify areas in which further research is needed. We created algorithms incorporating evidence-based care for patients with RMS, emphasizing the importance of clinical trials and close integration of all specialties involved in the care of these patients.

Rhabdomyosarcoma of the Head and Neck: A Multimodal Approach

Head and neck rhabdomyosarcoma (HNRMS) is a uniquely challenging site to treat given the young patient age and critical anatomy of the head and neck region. We review the characteristics, management, and future directions in the treatment of HNRMS. Most patients who present with HNRMS have unresectable disease due to functional and/or cosmetic constraints. However, surgical resection and brachytherapy serve a critical role in select patients. The treatment paradigm for the majority of patients with HNRMS consists of definitive chemotherapy and radiation therapy. As the incidence of late toxicities increases with improved survival, modern efforts must focus on ways to decrease long-term morbidity. We recommend a multimodal approach emphasizing the preservation of form and function for the treatment of HNRMS.

Impact of Surgical Margin in Skull Base Surgery for Head and Neck Sarcomas

Objective  This study aimed to determine the adequate resection margin in skull base surgery for head and neck sarcoma. Design  We retrospectively reviewed 22 sarcomas with skull base invasion. Induction chemotherapy, followed by surgery and postoperative radiotherapy and adjuvant chemotherapy, was performed in 18 patients with chemosensitive sarcomas, and surgery with or without postoperative radiotherapy was performed in four patients with chemoresistant sarcomas. Radical resection was performed in patients with chemosensitive sarcomas with a poor response to induction chemotherapy and in patients with chemoresistant sarcomas. Conservative resection with close surgical margin was performed in patients with chemosensitive sarcomas with a good response to induction chemotherapy. Setting and Participants  This single-centered retrospective study included patients from the National Cancer Center Hospital, Japan. Results  The response to induction chemotherapy was significantly associated with the 3-year local control rate (LCR; good response versus poor response: 100% versus 63%, p  = 0.048). Patients with a good response to chemotherapy had a favorable local prognosis even when the local therapy was conservative resection. In radical skull base surgery, patients whose surgical margins were classified as "wide margin positive" had significantly poorer 3-year LCR than did patients with "margin negative" or "micro margin positive" margins (25% versus 83%, p  = 0.014). Conclusion  Conservative resection with close surgical margins might be acceptable for chemosensitive sarcomas with a good response to chemotherapy. Resection margin status was an important predictive factor for local recurrence after radical skull base surgery. Microscopic microresidual tumor might be controlled by postoperative treatment.

Reduction of cyclophosphamide dose for patients with subset 2 low-risk rhabdomyosarcoma is associated with an increased risk of recurrence: A report from the Soft Tissue Sarcoma Committee of the Children's Oncology Group

BACKGROUND

Failure-free survival (FFS) and overall survival (OS) rates were found to improve on Intergroup Rhabdomyosarcoma Study (IRS) IV (IRS-IV) compared with IRS-III for patients with subset 2 (IRS stage 1, group III nonorbit or stage 3, group I/II) low-risk embryonal rhabdomyosarcoma with the addition of cyclophosphamide (total cumulative cyclophosphamide dose of 26.4 g/m² ) to the combination of vincristine and dactinomycin (VAC). The goal of Children's Oncology Group ARST0331 for subset 2 low-risk patients was to reduce the total cumulative cyclophosphamide dose without compromising FFS.

METHODS

Therapy included 4 cycles of VAC (total cumulative cyclophosphamide dose of 4.8 g/m² ) followed by 12 cycles of vincristine and dactinomycin over 46 weeks. Patients with group II or III tumors received radiotherapy, except for girls with group III vaginal tumors who enrolled before September 2009 and achieved a complete response with chemotherapy with or without delayed surgical resection.

RESULTS

Among 66 eligible patients who were followed for a median of 3.5 years, there were 20 failures versus 10.53 expected failures. The estimated 3-year FFS and OS rates were 70% (95% confidence interval [95% CI], 57%-80%) and 92% (95% CI, 83%-97%), respectively. The estimated 3-year FFS rate was 57% (95% CI, 33%-75%) for girls with subset 2 genital tract embryonal rhabdomyosarcoma (21 patients) and 77% (95% CI, 61%-87%) for all other subset 2 patients (45 patients) (P = .02).

CONCLUSIONS

The authors observed suboptimal FFS among patients with subset 2 low-risk rhabdomyosarcoma using reduced total cyclophosphamide. Eliminating radiotherapy for girls with group III vaginal tumors in combination with reduced total cyclophosphamide appeared to contribute to the suboptimal outcome. Cancer 2017;123:2368-2375. © 2017 American Cancer Society.

What is new in pediatric surgical oncology?

PURPOSE OF REVIEW

As pediatric oncology has become more complex, designing and maintaining pediatric surgical protocols require greater expertise. The primary purpose of this review is to summarize the changes in protocols and new study findings, which have changed surgical practice for children with solid tumors.

RECENT FINDINGS

The most common solid tumors treated by surgery are reviewed. There are new methods of surgical techniques such as the use of sentinel lymph node techniques for the assessment of lymph nodes in pediatric sarcoma. New studies showing excellent outcomes for the nonoperative treatment for young patients with neuroblastoma are discussed. Surgical quality with the prevention of tumor rupture and the assessment of lymph nodes is essential for good outcomes in patients with Wilm's tumor. The international collaborations within germ cell and liver tumors have provided excellent new study regimens and welcomed a new era of studies that are robust and have the power to change the outcomes for these rare tumors.

SUMMARY

Surgical practice is evolving with the molecular advances in pediatric oncology. Technical advances and quality improvement endeavors to ensure protocol adherence are essential. International partnerships have allowed for greater advances particularly for rare tumors and improve overall surgical outcomes.

Rhabdomyosarcoma

A malignant tumor of striated muscle origin, rhabdomyosarcoma (RMS) is a childhood tumor that has benefited from nearly 30 years of multimodality therapy, culminating in a >70% overall 5-year survival. Prognosis for RMS is dependent on primary tumor site, age, completeness of resection, presence and number of metastatic sites, histology, and biology of the tumor cells. Multimodality treatment is based on risk stratification according to pre-treatment stage, postoperative group, histology, and site. Unique to RMS is the concept of postoperative clinical grouping that assesses the completeness of disease resection and takes into account lymph node evaluation at both the regional and metastatic basins. At all sites, if complete operative resection of disease is accomplished, including microscopic disease, survival is improved. Therefore, the surgeon plays a vital role in determining risk stratification for treatment, local control of the primary tumor and overall outcome for the patient with RMS.

Significance of delayed primary excision in localized nonmetastatic adult head and neck rhabdomyosarcoma

Adult rhabdomyosarcoma (RMS) is a highly aggressive tumor. Multidisciplinary treatment is important. However, the role of surgery is controversial. The purpose of this study was to reveal the role of a delayed primary excision (DPE) after induction chemotherapy (IC) in localized nonmetastatic adult head and neck RMS. We retrospectively reviewed 24 adult head and neck RMS. Treatment was classified into the following two groups: the DPE group, who received IC followed by surgery, postoperative radiotherapy, and adjuvant chemotherapy (17 patients); the chemoradiotherapy (CRT) group, who received IC followed by chemoradiotherapy (seven patients). We analyzed the efficacy of IC, local control rate (LCR), and overall survival (OS). In the DPE group, 10 patients (59%) underwent complete surgical resection. In the evaluation of the surgical specimens, 14 patients (82%) had residual viable tumors after IC. The response to IC was significantly associated with the 3‐year LCR (CR/PR vs. SD/PD: 100% vs. 33%, P = 0.0014). In patients with good response to chemotherapy, the DPE group had a significantly better 3‐year LCR compared with that of the CRT group (DPE group vs. CRT group, 100% vs. 44%, P = 0.018). However, the treatment modalities were not associated with OS (DPE group vs. CRT group, 65% vs. 57%: P = 0.98). The recurrence patterns differed according to treatments, and distant metastases were more frequent in the DPE group. DPE may impact local control of localized nonmetastatic adult head and neck RMS. Poor response to IC is a risk factor for local recurrence.

Local Control for Intermediate-Risk Rhabdomyosarcoma: Results From D9803 According to Histology, Group, Site, and Size: A Report From the Children's Oncology Group

PURPOSE

To determine local control according to clinical variables for patients with intermediate-risk rhabdomyosarcoma (RMS) treated on Children's Oncology Group protocol D9803.

PATIENTS AND METHODS

Of 702 patients enrolled, we analyzed 423 patients with central pathology-confirmed group III embryonal (n=280) or alveolar (group III, n=102; group I-II, n=41) RMS. Median age was 5 years. Patients received 42 weeks of VAC (vincristine, dactinomycin, cyclophosphamide) or VAC alternating with VTC (T = topotecan). Local therapy with 50.4 Gy radiation therapy with or without delayed primary excision began at week 12 for group III patients. Patients with group I/II alveolar RMS received 36-41.4 Gy. Local failure (LF) was defined as local progression as a first event with or without concurrent regional or distant failure.

RESULTS

At a median follow-up of 6.6 years, patients with clinical group I/II alveolar RMS had a 5-year event-free survival rate of 69% and LF of 10%. Among patients with group III RMS, 5-year event-free survival and LF rates were 70% and 19%, respectively. Local failure rates did not differ by histology, nodal status, or primary site, though there was a trend for increased LF for retroperitoneal (RP) tumors (P=.12). Tumors ≥5 cm were more likely to fail locally than tumors <5 cm (25% vs 10%, P=.0004). Almost all (98%) RP tumors were ≥5 cm, with no difference in LF by site when the analysis was restricted to tumors ≥5 cm (P=.86).

CONCLUSION

Local control was excellent for clinical group I/II alveolar RMS. Local failure constituted 63% of initial events in clinical group III patients and did not vary by histology or nodal status. The trend for higher LF in RP tumors was related to tumor size. There has been no clear change in local control over RMS studies, including IRS-III and IRS-IV. Novel approaches are warranted for larger tumors (≥5 cm).

Rhabdomyosarcoma of the head and neck in children: review and update

OBJECTIVE

To review the clinical presentation, histology, staging, treatment modalities, and survival for pediatric head and neck rhabdomyosarcoma (non-orbital).

STUDY DESIGN

Retrospective chart review at a tertiary pediatric hospital of children treated over 18 years (1996-2014) for primary head and neck non-orbital rhabdomyosarcoma.

METHODS

Medical charts were examined for clinical presentation, staging, histology, genetic abnormalities, treatment modalities, recurrence and complications from treatment.

RESULTS

Our cohort was 17 children (7 male, 10 female) with rhabdomyosarcoma with a median age of 6.3 years (range <1-19). The majority of tumors were of parameningeal location (13/17) with embryonal histology (11/17). Twenty-nine percent (5/17) demonstrated advanced metastatic disease at initial referral. Fifty-three percent (9/17) had skull base erosion and/or cranial nerve deficits. PET CT scan was performed in 4 patients. The overall survival was 75% for the duration of the study. Primary surgical excision was performed in all 4 patients with nonparameningeal tumors as compared to only 1 patient with a parameningeal tumor. All received chemotherapy and radiotherapy, as none had completely resectable disease.

CONCLUSION

Pediatric non-orbital primary rhabdomyosarcoma of the head and neck usually has a rapid onset and presents with advanced disease. Our analysis found that the majority of patients in our series had a cranial neuropathy at presentation, which highlights how advanced the disease is in these patients at presentation. The first mode of surgical intervention should be directed toward biopsy in junction with a metastatic work-up. Primary excision with negative microscopic margins for nonparameningeal rhabdomyosarcoma is ideal to spare radiotherapy but was not achievable in our cohort. The benefits of second-look biopsy after chemotherapy and radiation are still unproven; however, we believe that it was beneficial in two patients in our review for further resection thus decreasing subsequent radiation. Fluorodeoxy-d-glucose positron emission tomography (PET) to evaluate disease post treatment may further define the role for second look surgery.

Recent advances in understanding and managing rhabdomyosarcoma

Rhabdomyosarcoma is the most common childhood soft tissue sarcoma and the fourth most common pediatric solid tumor. For most patients, treatment consists of a multimodality approach, including chemotherapy, surgery, and/or radiotherapy. To guide treatment, patients with rhabdomyosarcoma are risk stratified based on a number of factors. These factors include clinical group, which depends largely on the extent of resection and nodal involvement, and stage, which takes into account tumor size, invasion, nodal involvement, and disease site. Histology of the tumor and age at diagnosis are also factored into risk stratification. Recent advances in understanding the biology of the disease have allowed for the further sub-classification of rhabdomyosarcoma. In addition, elucidation of additional clinical features associated with poor prognosis has allowed for better understanding of risk and provides more clarity regarding those patients who require more intensive therapy. Many areas of active investigation are ongoing, including the following: further delineation of the biological underpinnings of the various disease subtypes with the possibility of molecularly targeted therapy; a better understanding of clinical risk factors, including the evaluation and management of potentially involved lymph nodes; determination of the appropriate role of post-treatment imaging and assessment of response to therapy; and incorporation of advanced radiotherapeutic techniques, including conformal intensity-modulated photon and proton therapy.