Complete second look operation and radiotherapy in locally advanced non-alveolar rhabdomyosarcoma in children: A report from the AIEOP soft tissue sarcoma committee

Localized incompletely resected standard risk rhabdomyosarcoma in children and adolescents: Results from the European Paediatric Soft Tissue Sarcoma Study Group RMS 2005 trial

BACKGROUND

The authors report the prospective evaluation of reduced dose alkylator chemotherapy combined with radiotherapy for European Pediatric Soft Tissue Sarcoma Study Group (EpSSG) standard risk nonalveolar rhabdomyosarcoma (NA-RMS).

PATIENTS AND METHODS

Localized node negative Intergroup Rhabdomyosarcoma Study (IRS) II/III NA-RMS at favorable sites (subgroup C), <25 years old, received five cycles of ifosfamide, vincristine, and dactinomycin (IVA) chemotherapy (30 g/m2 ifosfamide) and four cycles of vincristine and dactinomycin (if receiving radiotherapy), or nine cycles of IVA (54 g/m2 ifosfamide) ± radiotherapy. Delayed primary tumor excision was considered for IRS III tumors. The primary end points were event-free survival (EFS) and overall survival (OS).

RESULTS

From October 2005 to December 2016, 359 evaluable patients were recruited: orbit, 164 (45.7%); head and neck nonparameningeal, 77 (21.4%); and genitourinary non-bladder/prostate, 118 (32.9%). EFS and OS were 77.4% (95% confidence interval [CI], 72.5-81.6) and 93.5% (95% CI, 90.1-95.8), respectively. Lower dose alkylator chemotherapy and radiotherapy achieved 5-year OS of 93.7% but the difference with higher dose alkylator chemotherapy +/- radiotherapy was not significant (p = 0.8003). Adjuvant radiotherapy improved EFS with 5-year estimates of 84.7% versus 65.2% for nonirradiated (p < .0001), but not OS (p = .9298). Omitting radiotherapy for orbital tumors reduced OS (5-year was 87.1% vs. 97.3% for irradiated, p = .0257). Following R0 resection (n = 60), radiotherapy did not significantly improve EFS or OS.

CONCLUSIONS

Radiotherapy for local tumor control allows for reduction of cumulative dose of alkylators in EpSSG standard risk subgroup C RMS patients. The omission of radiotherapy did not affect OS in all patients except those with orbital RMS and was associated with inferior EFS.

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.

Recent advances in pediatric bladder malignancies

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

Treatment Approach and Outcomes in Infants With Localized Rhabdomyosarcoma: A Report From the Soft Tissue Sarcoma Committee of the Children's Oncology Group

PURPOSE

For infants with localized rhabdomyosarcoma who were enrolled on Children's Oncology Group ARST0331 and ARST0531, local therapy guidelines were provided, but adherence was not mandated because of toxicity concerns. We examined adherence to protocol for local therapy guidelines, treatment variations, and outcomes for these patients.

METHODS

Children aged ≤24 months who were enrolled on ARST0331 and ARST0531 were evaluated. Data were verified through radiologic, surgical, pathologic, and clinical records. Local therapy was assessed for adherence to protocol guidelines, with variations termed "individualized local therapy." The subdistribution hazards model assessed local failure, the Kaplan-Meier product limit method assessed event-free survival (EFS) and overall survival, and the log-rank test was used to evaluate prognostic impact.

RESULTS

The median age of the patients was 14 months, and 124 patients were eligible. Common primary sites were genitourinary (40%), parameningeal (14%), and the extremities (11%). Most patients had unresected disease (group 3, 64%) and embryonal histology (73%). Fifty-eight percent of patients received radiation therapy at a median of week 12 (weeks 1-45). The median radiation dose was 48.6 Gy (30.6-54 Gy). Forty-three percent of patients received individualized local therapy (outside protocol guidelines), typically omission or delay of radiation therapy. Delayed primary excision was performed in 28% at a median of week 14 (weeks 7-34). With a median follow-up of 5.6 years, the 5-year local failure, EFS, and overall survival rates were 24%, 68%, and 82%, respectively. Local failure was significantly higher (35%) in patients receiving individualized local therapy than in patients who received protocol-specified local therapy (16%; P = .02). The site of failure was local in 64% of patients, local and distant in 5%, and distant only in 23%. EFS was significantly higher among patients who were aged 12 to 24 months, had tumors ≤5 cm, had group 1/2 disease, and underwent protocol-specified therapy.

CONCLUSIONS

Local recurrence was the predominant pattern of failure and was more common in those receiving individualized local therapy. De-escalation of effective therapies because of concerns about treatment toxicity should be considered cautiously.

Fifty years of rhabdomyosarcoma studies on both sides of the pond and lessons learned

We review and summarize the highlights of almost five decades of cooperative group trials in rhabdomyosarcoma on both sides of the Atlantic, concentrating on chemotherapy regimens, what has been learned, and where remaining challenges are. The most important achievements have been to decrease or omit the dose of alkylator therapy for many patients, to clarify after much controversy that doxorubicin does not improve the outcome of patients even in the highest risk groups, and to show that high dose chemotherapy and stem cell rescue do not improve the outcome of the highest risk patients. In North America, vincristine/actinomycin/cyclophosphamide (VAC) remains an important part of therapy, whereas in Europe the alkylating agent of choice is ifosfamide. The highest risk patients, namely those with the poorest prognostic score, have had no improvement in outcome since the first cooperative group trial in 1972 and remain the greatest challenge. Philosophical differences between European and North American strategies still revolve somewhat around the total burden of therapy received, that is should certain groups of patients be spared aggressive local control in order to reduce late effects, recognizing that it is not possible to identify priori the children that can be cured with this approach exposing the whole population to a higher risk of relapse. Collaboration and joining resources may help answer some difficult questions.

Current standards of care in bladder and prostate rhabdomyosarcoma

Rhabdomyosarcoma (RMS) is the most common soft tissue tumor in children, and 15% to 20% arise from the genitourinary tract. Multicenter collaborative studies have improved survival substantially, and in addition to excellent oncologic control, current treatment focuses on organ preservation and minimization of late treatment effects. The multiple modalities needed to treat RMS dictate that treating physicians must be familiar with the disease as well as the goals and possible sequelae of treatment with chemotherapy, radiotherapy, and surgery. This article discusses the current standards of care for bladder and prostate RMS.

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

The majority of intermediate-risk rhabdomyosarcoma (RMS) patients have gross residual disease (Group III) after their first operative procedure. It is currently not known if local control rates can be maintained when, following induction chemotherapy, the radiation therapy (RT) dose is decreased after a delayed primary excision (DPE). To answer this question we evaluated patients enrolled on COG D9803 (1999-2005) who had Group III tumors of the bladder dome, extremity or trunk (thorax, abdomen and pelvis) were candidates for DPE at Week 12 if the primary tumor appeared resectable. RT dose was then adjusted by the completeness of DPE: no evidence of disease 36 Gy, microscopic residual 41.4 Gy and gross residual disease (GRD) 50.4 Gy. A total of 161 Group III patients were evaluated (24 bladder dome, 63 extremity and 74 trunk). Seventy-three patients (45%) underwent DPE which achieved removal of all gross disease in 61 (84%) who were then eligible for reduced RT dose (43/73 received 36 Gy, 19/73 received 41.4 Gy). The local 5-year failure rate (0% for bladder dome, 7% for extremity and 20% for trunk) was similar to IRS-IV, which did not encourage DPE and did not allow for DPE adapted RT dose reduction. In conclusion, DPE was performed in 45% of Group III RMS patients with tumors at select anatomic sites (bladder dome, extremity and trunk) and 84% of those who had DPE were eligible for RT dose reduction. Local control outcomes were similar to historic results with RT alone.

Rhabdomyosarcoma in adolescent and young adult patients: current perspectives

Rhabdomyosarcoma (RMS), a malignant tumor of mesenchymal origin, is the third most common extracranial malignant solid tumor in children and adolescents. However, in adults, RMS represents <1% of all solid tumor malignancies. The embryonal and alveolar histologic variants are more commonly seen in pediatric patients, while the pleomorphic variant is rare in children and seen more often in adults. Advances in the research of the embryonal and alveolar variants have improved our understanding of certain genes and biologic pathways that are involved in RMS, but much less is known for the other variants. Multimodality therapy that includes surgery and chemotherapy with or without radiation therapy is the mainstay of treatment for RMS. Improvements in the risk stratification of the pediatric patients based on presurgical (primary tumor site, tumor size, regional lymph node involvement, presence of metastasis) and postsurgical parameters (completeness of resection or presence of residual disease or metastasis) has allowed for the treatment assignment of patients in different studies and therapeutic trials, leading to increases in 5-year survival from 25%–70% over the past 40 years. However, for adult patients, in great part due to rarity of the disease and the lack of consensus on optimal treatment, clinical outcome is still poor. Many factors have been implicated for the differing outcomes between pediatric RMS versus adult RMS, such as the lack of standardized treatment protocols for adult RMS patients and the increased prevalence of advanced presentations. Now that there are increased numbers of survivors, we can appreciate the sequelae from therapy in these patients, such as bone growth abnormalities, endocrinopathies, and infertility. Improvements in risk stratification have led to clinical trials using lower doses of chemotherapy or radiation therapy with the intention of decreasing the incidence of side effects without compromising survival outcome.

Pediatric genitourinary oncology

Tumors of the kidney, bladder, prostate, testis, and adrenal represent a large part of the adult urologic practice, but are relatively infrequent in children. The natural history and management of these tumors in the pediatric age is different from that of the adults. As result of the successful work of several clinical trial groups in recent decades, there has been a significant improvement in their cure rates. The aim of this article is to review their most significant clinical aspects, as well as to present an update in their management.

What is new in rhabdomyosarcoma management in children?

Optimal management of rhabdomyosarcoma requires establishing the correct pathologic diagnosis, histologic sub-type, primary site, extent of disease (Stage), and extent of resection (Group). Based on these features, cooperative groups in North America and Europe have defined risk-adapted treatments that include surgery, chemotherapy, and usually radiotherapy. This article focuses on recent findings that can impact or have already impacted rhabdomyosarcoma treatment guidelines and highlights controversies that should be addressed in order to improve outcome for children with rhabdomyosarcoma. Rhabdomyosarcoma is currently sub-classified in children based on histology into the favorable embryonal/botryoid/spindle cell types and the unfavorable alveolar form. Risk group assignment depends in part on histologic sub-type. Alveolar rhabdomyosarcoma is sometimes associated with chromosomal translocations, which impact clinical behavior. An important ongoing debate is whether molecular diagnostic tools to identify chromosomal translocations and/or define gene expression profiles should be used to sub-classify rhabdomyosarcoma rather than histology. Clinical trials continue to evaluate retrospective as well as prospective cohorts in order to carefully determine the impact of histology versus biologic features on outcome in the context of specific therapeutic regimens. Most rhabdomyosarcoma recurrences involve the primary site or adjacent region. Cooperative groups continue to investigate new approaches to local control in order to reduce local recurrences and sequelae associated with local therapy. Delaying primary resection until after chemotherapy has started appears to increase the number of tumors that can be completely resected with acceptable morbidity in some primary sites. Radiation dose reductions following delayed primary resection have been investigated. Although outcomes appear similar to the conventional approach of full-dose radiotherapy without delayed primary resection, long-term effects of the two approaches have not been rigorously compared. Early evidence suggests that newer methods of delivering radiotherapy, including intensity-modulated radiotherapy (IMRT), proton beam radiotherapy, and brachytherapy maintain efficacy but may reduce long-term sequelae compared with 3-dimensional conformal radiotherapy. Chemotherapy regimens defined by the cooperative groups vary by risk group. The most commonly used regimens include vincristine and dactinomycin in combination with an alkylating agent, either cyclophosphamide or ifosfamide. In order to improve outcomes, recent clinical trials have introduced new chemotherapeutic agents (e.g. topotecan, carboplatin, or epirubicin) into the treatment regimens. However, outcomes have not been significantly impacted. Novel chemotherapy administration schedules have been tested in patients with metastatic rhabdomyosarcoma, including interval compressed dosing or maintenance therapy, and may be promising. Molecularly targeted agents are currently under investigation in combination with chemotherapy for patients with recurrent or metastatic rhabdomyosarcoma. It is hoped that these novel agents will benefit all patients with rhabdomyosarcoma in the future.

Local control with reduced-dose radiotherapy for low-risk rhabdomyosarcoma: a report from the Children's Oncology Group D9602 study

PURPOSE

To analyze the effect of reduced-dose radiotherapy on local control in children with low-risk rhabdomyosarcoma (RMS) treated in the Children's Oncology Group D9602 study.

METHODS AND MATERIALS

Patients with low-risk RMS were nonrandomly assigned to receive radiotherapy doses dependent on the completeness of surgical resection of the primary tumor (clinical group) and the presence of involved regional lymph nodes. After resection, most patients with microscopic residual and uninvolved nodes received 36 Gy, those with involved nodes received 41.4 to 50.4 Gy, and those with orbital primary tumors received 45 Gy. All patients received vincristine and dactinomycin, with cyclophosphamide added for patient subsets with a higher risk of relapse in Intergroup Rhabdomyosarcoma Study Group III and IV studies.

RESULTS

Three hundred forty-two patients were eligible for analysis; 172 received radiotherapy as part of their treatment. The cumulative incidence of local/regional failure was 15% in patients with microscopic involved margins when cyclophosphamide was not part of the treatment regimen and 0% when cyclophosphamide was included. The cumulative incidence of local/regional failure was 14% in patients with orbital tumors. Protocol-specified omission of radiotherapy in girls with Group IIA vaginal tumors (n = 5) resulted in three failures for this group.

CONCLUSIONS

In comparison with Intergroup Rhabdomyosarcoma Study Group III and IV results, reduced-dose radiotherapy does not compromise local control for patients with microscopic tumor after surgical resection or with orbital primary tumors when cyclophosphamide is added to the treatment program. Girls with unresected nonbladder genitourinary tumors require radiotherapy for postsurgical residual tumor for optimal local control to be achieved.

Selecting multimodal therapy for rhabdomyosarcoma

Rhabdomyosarcoma is a typical tumor of childhood, characterized by a high grade of malignancy, local invasiveness and a marked propensity to metastasize, but also a generally good response to chemotherapy and radiotherapy. Multimodal therapy is essential to cure rhabdomyosarcoma patients, but different uses of surgery, radiotherapy and chemotherapy, and their intensity, need to be selected and modulated to different patient risk groups. This article attempts to give an account of the current treatment options, the open and debated issues and the potential novel strategies for the near future.

Impact of tumor viability at second-look procedures performed before completing treatment on the Intergroup Rhabdomyosarcoma Study Group protocol IRS-IV, 1991-1997: a report from the children's oncology group

PURPOSES

The aims of the study were to compare results of clinical/radiographic studies before second-look procedures (SLP) with SLP specimens from patients with gross residual sarcoma at diagnosis and to relate tumor viability to outcome.

PATIENTS

Seventy-three patients underwent SLP before completing chemotherapy, with (n = 59) or without (n = 14) radiotherapy. Tumor sites were bladder/prostate (n = 27), head/orbit/parameningeal (n = 22), extremity/trunk (n = 14), and retroperitoneum/pelvis (n = 10).

RESULTS

Of 14 patients, 1 (7%) with clinical/radiographic complete response (CR) had viable tumor. Of 59 patients, 35 (59%) without CR had viable tumor. Five-year failure-free survival (FFS) rates were 81% in 37 patients without viable tumor and 53% in 36 patients with viable tumor (Cox proportional hazards adjusted P = .05). Five-year FFS rates were 67% in 15 patients with clear margins and 43% in 21 patients with tumor-involved margins (n = 18) or viable gross tumor (n = 3) (Cox proportional hazards adjusted P = .04). Five-year survival was 78% to 79% among 73 patients with and 333 patients without SLP during treatment.

CONCLUSIONS

Second-look procedures can show whether viable tumor is present and may be beneficial in selected patients with rhabdomyosarcoma. Disappearance of tumor (CR) usually correlated with no viable tumor at SLP. However, 41% of patients without CR had no viable tumor. Those without viable tumor had increased FFS but not survival compared to those with viable tumor.

Pediatric urologic rhabdomyosarcoma

PURPOSE OF REVIEW

To review on the most significant and recent developments in basic research, diagnostic, and therapeutic aspects of genitourinary rhabdomyosarcomas (RMS) in children.

RECENT FINDINGS

Collaborative studies have dramatically improved therapy of genitourinary RMS with a remarkable improvement of survival. However, refractory or relapsed disease is still the most demanding challenge. Advances in our understanding of RMS molecular biology evolve new risk stratification and new therapeutic targets such as growth factors and their receptors. High-quality imaging is crucial and integrated fluorodeoxyglucose positron emission tomography/computed tomography significantly increased sensitivity. Alternative chemotherapeutical strategies were proven. Mutilating primary surgery should be avoided. Modern irradiation modalities with decrease of local radiation dose and, therefore, less long-term effects are new tools in the therapeutic arsenal of therapists.

SUMMARY

Therapy-associated morbidity after current RMS treatment can be significantly decreased by including modern strategies, especially in the field of irradiation. However, the follow-up is too short so far to make a distinct decision. The advances in understanding tumor biology may give rise to clinically relevant new therapeutic targets in the near future.

Rhabdomyosarcoma in children

PURPOSE OF REVIEW

Rhabdomyosarcoma is a rare childhood cancer that affects only approximately 300 children per year in the United States. The purpose of this review is to provide the reader a greater understanding of the complex diagnosis, assessment and treatment of rhabdomyosarcoma in children.

RECENT FINDINGS

This review focuses on the new risk classification that is the foundation of all present rhabdomyosarcoma protocols developed by the Children's Oncology Group of the United States and Canada. The new risk classification of low, intermediate and high encompasses the staging and grouping categories that were previously utilized.

SUMMARY

This review also provides a complete list of diagnostic tests and imaging required to identify rhabdomyosarcoma in any body site. Rapid diagnosis and recognition of this rare disorder will facilitate long-term survival. Rhabdomyosarcoma today has an overall survival of 70%, depending on the site, and in orbital and other sites survival is as high as 90%. The treatment approaches that have led to this doubling in survival over the last 25 years are reviewed. For a practitioner, this review can be used as a reference when a child with a suspicious mass is encountered.

Pediatric genitourinary tumors

PURPOSE OF REVIEW

We will review the 2007/2008 literature on pediatric genitourinary tumors.

RECENT FINDINGS

Newly identified constitutional epigenetic defects in Wilms tumor genes extend the understanding of Wilms tumor risk in children lacking syndromic features, and add to the complexity of the pathogenesis of these tumor suppressor genes. Pediatric renal cell carcinoma has distinct molecular characteristics and clinical associations from the adult counterpart. The pathway from PAX3-FKHR translocation to the development of rhabdomyosarcoma tumors has been further elucidated.

SUMMARY

Therapeutic strategies continue to be driven by developments in molecular diagnostics in pediatric genitourinary tumors.