Demographic and Treatment Variables Influencing Outcome for Localized Paratesticular Rhabdomyosarcoma: Results From a Pooled Analysis of North American and European Cooperative Groups

Which Patients With Rhabdomyosarcoma Need Radiotherapy? Analysis of the Radiotherapy Strategies of the CWS-96 and CWS-2002P Studies and SoTiSaR Registry

PURPOSE

To analyze and compare the indications, doses, and application methods of radiotherapy (RT) and their influence on prognosis of patients with localized rhabdomyosarcoma (RMS).

METHODS

One thousand four hundred seventy patients with localized RMS 21 years and younger entered on CWS-96, CWS-2002P, and SoTiSaR were eligible for the analysis. The median follow-up was 6.5 years (IQR, 3.3-9.5).

RESULTS

The 5-year event-free survival (EFS) and local control survival (LCS) for 910 (62%) irradiated versus nonirradiated patients were 71% versus 69% and 78% versus 73% (P = .03), respectively. Ninety-five percent of patients in IRS I (90% embryonal RMS [eRMS]) were nonirradiated (EFS, 87%). Irradiated patients with IRS II had improved LCS (91% v 80%; P = .01) and EFS (not significant). In IRS III, EFS and LCS were significantly better for RT patients: 71% versus 56% (P = 3.1e-06) and 76% versus 61% (P = 4.1e-07). Patients with tumors in the head and neck region (orbita, parameningeal, and nonparameningeal) and in other sites had significantly better EFS and LCS and in parameningeal also overall survival (OS). The efficacy of low RT doses of 32 Gy (hyperfractionated, accelerated RT [HART]) and 36 and 41.4 Gy (conventional fractionated RT [CFRT]) in the favorable groups and higher doses of 44.8 Gy (HART) and 50.4 and 55.4 Gy (CFRT) in the unfavorable groups was comparable. Proton RT was used predominantly in head/neck-parameningeal (HN-PM) tumors, with similar EFS and LCS to photon RT.

CONCLUSION

RT can be omitted in patients with IRS I eRMS. RT improves LCS and EFS in IRS II and III. RT improves OS in patients with HN-PM, with proton RT comparable with photon RT. Doses of 32 Gy (HART) or 36 and 41.4 Gy (CFRT) had comparable efficacy in patients with favorable risk profiles and 44.8 Gy (HART) or 50.4 and 55.8 Gy (CFRT) in the unfavorable groups.

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.

Alveolar rhabdomyosarcoma of epididymis: A case report

Rhabdomyosarcoma (RMS) is a soft tissue tumor, which is the most common in the head, neck, limbs, and trunk. RMS originating from the epididymis is extremely rare. Herein, we reported a 34-year-old patient with RMS on the right epididymis. For this case, right epididymal mass resection was performed and intraoperative freezing suggested a malignant tumor. Right testicular radical resection was subsequently adopted, with right epididymal alveolar RMS being pathologically diagnosed. Alternating VAC/VI chemotherapy was given after surgery, and tumor recurrence has not been found so far.

Therapy and prognostic significance of regional lymph node involvement in embryonal rhabdomyosarcoma: a report from the European paediatric Soft tissue sarcoma Study Group

PURPOSE

Regional lymph node disease (N1) is a component of the risk-based treatment stratification in rhabdomyosarcoma (RMS). The purpose of this study was to determine the contribution of nodal disease to the prognosis of patients with non-metastatic embryonal RMS (ERMS) and analyse their outcome by treatment received.

PATIENTS AND METHODS

Between 2005 and 2016, 1294 children with ERMS were enrolled in the European paediatric Soft tissue sarcoma Study Group (EpSSG) RMS 2005 protocol, 143 patients with N1. Treatment comprised 9 cycles of ifosfamide, vincristine and dactinomycin. Some patients also received doxorubicin and/or maintenance if enrolled in the randomised studies. Local treatment was planned after 4 cycles of chemotherapy and included surgery to remove macroscopic residual tumour and/or radiotherapy (primary tumour and involved nodes).

RESULTS

N1 patients were older and presented with tumours of unfavourable size, invasiveness, site and resectability. Unlike alveolar RMS, nodal involvement was more frequent in the head and neck area and rare in extremity sites. The 5-year event-free and overall survival were 75.5% and 86.3% for patients with N0, and 65.2% and 70.7% for patients with N1, respectively. The nodal involvement and the result of surgery at diagnosis (Intergroup Rhabdomyosarcoma Study group) were independent prognostic factors on multivariate analysis. Considering only patients with N1 ERMS, we were not able to identify any treatment variables which correlated with the outcome.

CONCLUSION

In the case of nodal involvement, patients with ERMS present different characteristics and a better outcome than alveolar RMS. Regional nodal involvement is an independent prognostic factor in ERMS, therefore it is appropriate to include this population in the high-risk category.

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

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

New aspects and innovations in the local treatment of renal and urogenital pediatric tumors

Local treatment plays a key role for patients' outcome in tumors of the urogenital tract in children. Despite a great variety of different etiologies, the specific localization of pediatric urogenital tumors renders several characteristic demands to the treating personnel. Surgery and radiotherapy are the main elements of local treatment in this group of neoplasms. Numerous new guidelines and innovative technical developments of surgery and radiotherapy have recently been integrated into treatment concepts for pediatric urogenital tumors. Due to the broadness of the field it is not possible to give a full overview over all aspects. Therefore, this article highlights the most important innovations and new guidelines of surgery and radiotherapy of pediatric urogenital tumors.

EAU-ESPU pediatric urology guidelines on testicular tumors in prepubertal boys

BACKGROUND

Testicular tumors in prepubertal boys account for 1-2% of all solid pediatric tumors. They have a lower incidence, a different histologic distribution and are more often benign compared to testicular tumors in the adolescent and adult group. This fundamental difference should also lead to a different approach and treatment.

OBJECTIVE

To provide a guideline for diagnosis and treatment options in prepubertal boys with a testicular mass.

METHOD

A structured literature search and review for testicular tumors in prepubertal boys was performed. All English abstracts up to the end of 2019 were screened, and relevant papers were obtained to create the guideline.

RESULTS

A painless scrotal mass is the most common clinical presentation. For evaluation, high resolution ultrasound has a detection rate of almost 100%, alpha-fetoprotein is a tumor marker, however, is age dependent. Human chorionic gonadotropin (HCG) was not a tumor marker for testis tumors in prepubertal boys.

CONCLUSION

Based on a summary of the literature on prepubertal testis tumors, the 2021 EAU guidelines on Pediatric Urology recommend a partial orchiectomy as the primary approach in tumors with a favorable preoperative ultrasound diagnosis.

Surgical management of paratesticular rhabdomyosarcoma: A consensus opinion from the Children's Oncology Group, European paediatric Soft tissue sarcoma Study Group, and the Cooperative Weichteilsarkom Studiengruppe

The treatment of paratesticular rhabdomyosarcoma (PT-RMS) has varied over time and by cooperative group. The International Soft Tissue Sarcoma Database Consortium (INSTRuCT) is a collaboration of the Children's Oncology Group (COG) Soft Tissue Sarcoma Committee, European pediatric Soft tissue sarcoma Study Group (EpSSG), and the Cooperative Weichteilsarkom Studiengruppe (CWS). The INSTRuCT surgical committee has been given charge of the development of internationally applicable consensus guidelines for the surgical treatment of rhabdomyosarcoma. This clinical consensus opinion document addresses accepted principles and areas of controversy, such as scrotal violation and retroperitoneal nodal evaluation, providing an evidence-based guideline for the surgical treatment for PT-RMS.

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.

Alternative approaches to retroperitoneal lymph node dissection for paratesticular rhabdomyosarcoma

PURPOSE

The aim of this study was to evaluate outcomes based on surgical approach for retroperitoneal lymph node dissection (RPLND) in patients with paratesticular rhabdomyosarcoma (PT-RMS).

METHODS

Patients undergoing RPLND for PT-RMS over 10 years at a single institution were retrospectively reviewed. Length of stay (LOS), complications, oral morphine equivalents per kilogram (OME/Kg), lymph node yield, and time to chemotherapy were assessed. The surgical approaches compared were: open transabdominal, open extraperitoneal, laparoscopic, and retroperitoneoscopic. For cases with lymphatic mapping, indocyanine green (ICG) was injected into the spermatic cord.

RESULTS

Twenty patients were included: five open transabdominal, six open extraperitoneal, three laparoscopic, and six retroperitoneoscopic operations. LOS was shorter in the retroperitoneoscopic group than laparoscopic (p = 0.029) and both open groups (p < 0.001). Mean OME/kg used was lowest in the retroperitoneoscopic (0.13 ± 0.15) group compared to laparoscopic (0.68 ± 0.53, p = 0.043), open transabdominal (14.90 ± 8.87, p = 0.003), and extraperitoneal (10.11 ± 2.44, p < 0.001). Time to chemotherapy was shorter for retroperitoneoscopic patients (0.13 days ± 0.15) compared to open transabdominal (15.6 days±6.5, p = 0.005). There was no difference in lymph node yield between groups. Spermatic cord ICG demonstrated iliac lymph node avidity on near-infrared spectroscopy.

CONCLUSIONS

Minimally invasive RPLND appears to offer a faster recovery without compromising lymph node yield for patients with PT-RMS.

LEVEL OF EVIDENCE

III.

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.

Paratesticular rhabdomyosarcoma-Impact of locoregional approach on patient outcome: A report from the European paediatric Soft tissue sarcoma Study Group (EpSSG)

BACKGROUND

Paratesticular rhabdomyosarcoma (PT RMS) is rare compared to benign scrotal pathology. Inappropriate first surgery (InFS) required supplementary treatment to maintain excellent outcomes. Initial staging of regional lymph nodes is important. The aim of this study was to determine to what extent the quality of locoregional approach impacted on patient morbidity and survival.

DESIGN/METHODS

Analysis was performed on all nonmetastatic PT RMS patients enrolled in the European paediatric Soft tissue sarcoma Study Group (EpSSG) RMS 2005 protocol. Aspects assessed were adherence to surgical guidelines and impact of protocol violations, relapse analysis, and survival outcomes.

RESULTS

Analysis was performed on 237 patients, with median follow up of 67.1 months. Median age was 9.0 years. InFS occurred in 75 of 237 (32%) patients. InFS required intensified chemotherapy (10) and local therapy. After InFS, 61 required primary reexcision and five delayed surgery. Of 26 recurrences, the risk of relapse was higher in patients ≥10 years (21/26) and was mainly locoregional in 16 of 26 recurrences (± metastatic). Sixteen of 26 died with 14 of 16 patients ≥10 years. Nodal relapse neither occurred when N1 nodes were identified at diagnosis, nor after surgical staging. Five-year overall survival (OS) at age <10 years versus ≥10 years was 98.1 and 86.7%, respectively (P = .0013). Event-free survival (EFS) at age <10 years versus ≥10 years was 95.8 and 79.6%, respectively (P = .0004). OS and EFS did not highlight a significant difference in patients undergoing appropriate versus InFS (P = .8479, P = .2780, respectively).

CONCLUSIONS

InFS required intensified therapy to maintain excellent OS and EFS, so better anticipation of malignancy is required. Surgical staging of the retroperitoneal lymph nodes should be performed in patients ≥10 years old.

Impact of local control and surgical lymph node evaluation in localized paratesticular rhabdomyosarcoma: A report from the Children's Oncology Group Soft Tissue Sarcoma Committee

Paratesticular rhabdomyosarcoma (PT-RMS) carries a favorable prognosis, but questions persist regarding optimal management. Our goal was to determine the importance of primary tumor resection and surgical assessment of retroperitoneal lymph nodes during staging in patients with PT-RMS. We analyzed patients with localized PT-RMS enrolled onto one of four Children's Oncology Group studies (D9602, ARST0331, D9803 or ARST0531). Surgical resection of the primary tumor prior to chemotherapy and radiotherapy was encouraged when possible with retroperitoneal lymph node dissection (RPLND) recommended for patients ≥10 years of age. Among 279 patients (median 8.1 years old), most tumors were resected with negative margins (78.5%) and most patients did not have radiographic enlargement of regional lymph nodes (90.3%). In patients older than 10 years, imaging alone will miss over 51.5% of nodal disease. Five-year event-free survival (EFS) was 92.0% (95% CI 88.4%-95.6%). Sampling ≥7 to 12 retroperitoneal lymph nodes appeared optimal for detecting positive nodes; while there was a trend toward improved EFS among those undergoing template RPLND, this was not statistically significant (P = .068). Age (P = .28), N-stage (P = .39), T-stage (P = .11) and pathologic node involvement (P = .53) were not associated with overall survival. However, older age and larger tumor size had an additive impact on EFS (P = .027) though not overall survival (P = .13). In conclusion, outcomes for patients with PT-RMS are excellent. Reliance on imaging to detect nodal involvement will miss pathologic node involvement and may result in undertreatment. Surgical nodal staging requires at least 7 to 12 nodes to accurately identify patients with regional nodal disease.

[Retroperitoneal lymph node assessment in pediatric paratesticular rhabdomyosarcoma]

Paratesticular Rhabdomyosarcoma accounts for 7 to 11% of pediatric rhabdomyosarcomas. Children older than 10 years have a worse event-free survival (69 to 80% vs. 87 to 92%) than children younger than 10 years. In this location, the relapses are essentially in the retroperitoneal lymph nodes and are often fatal. In European protocols, the assessment of the retroperitoneal lymph nodes at diagnosis is made by imaging whereas it is performed by retroperitoneal lymph node dissection in the American protocols. This method has been proved to improve event-free survival in the group of patient older than 10 years with a tumour bigger than 5cm. In the next European protocol, when nodes will be enlarged a surgical biopsy will be performed, this will be irrespective of age or size, and when no nodes will be enlarged in patients older than 10 years, retroperitoneal lymph node assessment will be performed. Other techniques of lymph nodes assessment will be tested like sentinel node biopsies or PET-scan.

[Testicular tumors in prepubertal boys-organ preservation possible more often than expected]

In prepubertal boys, testicular tumors are rare with an incidence between 2 and 5/million. In contrast to testicular tumors in adolescents and adults, more than 2/3 of these tumors are benign. Unfortunately, in Germany in most cases, only malignant tumors (usually yolk sac tumors) are reported to the study center (MAKEI IV and now V). Therefore, the incidence in Germany is unknown. Since the introduction of polychemotherapy in the 1970s, the prognosis of malignant testicular tumors has improved enormously and has become a curable disease, even in the case of recurrence. Today the orchiectomy, which was usually carried out in the past, appears to be no longer justified in most prepubertal boys due to the high incidence of benign tumors. It has been shown in various studies that organ-sparing surgery in germ cell tumors (epidermoid cysts, teratoma); gonadal stoma tumors (Sertoli, Leydig and granulosa cell tumors) and cystic lesions (intratesticular cysts and tubular ectasia of the rete testis) is reliable and safe. In cases with preoperative significantly increased AFP (caution: norm values not valid in the first year of life) and a clear testicular tumor in the ultrasound (yolk sac tumor) or if no testicular parenchyma is sonographically detectable, orchiectomy can still be carried out. Today orchiectomies in prepubertal boys should be an exception and the reasons for an orchiectomy must be well documented.

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.

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.