Brachytherapy as part of the multidisciplinary treatment of childhood rhabdomyosarcomas of the orbit

Brachytherapy for rhabdomyosarcoma: Survey of international clinical practice and development of guidelines

BACKGROUND AND PURPOSE

The purpose of this study was to address the lack of published data on the use of brachytherapy in pediatric rhabdomyosarcoma by describing current practice as starting point to develop consensus guidelines.

MATERIALS AND METHODS

An international expert panel on the treatment of pediatric rhabdomyosarcoma comprising 24 (pediatric) radiation oncologists, brachytherapists and pediatric surgeons met for a Brachytherapy Workshop hosted by the European paediatric Soft tissue Sarcoma Study Group (EpSSG). The panel's clinical experience, the results of a previously distributed questionnaire, and a review of the literature were presented.

RESULTS

The survey indicated the most common use of brachytherapy to be in combination with tumor resection, followed by brachytherapy as sole local therapy modality. HDR was increasingly deployed in pediatric practice, especially for genitourinary sites. Brachytherapy planning was mostly by 3D imaging based on CT. Recommendations for patient selection, treatment requirements, implant technique, delineation, dose prescription, dose reporting and clinical management were defined.

CONCLUSIONS

Consensus guidelines for the use of brachytherapy in pediatric rhabdomyosarcoma have been developed through multicenter collaboration establishing the basis for future work. These have been adopted for the open EpSSG overarching study for children and adults with Frontline and Relapsed RhabdoMyoSarcoma (FaR-RMS).

A systematic review of combined surgery and brachytherapy approaches for children and young people with relapsed and refractory rhabdomyosarcoma (Local-REFoRMS)

Approximately one third of children with rhabdomyosarcoma relapse or have refractory disease. Treatment approaches include a combination of systemic therapies and local therapies, directed at tumour site(s). This review was conducted to evaluate the effectiveness and safety of the combination of surgery and brachytherapy as local therapy for treating children and young people with relapsed/refractory rhabdomyosarcoma. This review identified studies based on a previous systematic review looking at the treatments for children and young people under 18 years old with relapsed/refractory rhabdomyosarcoma. Studies conducted after 2000 were included. Survival outcomes, relapse rates, adverse events and functional outcomes were extracted. From 16,965 records identified in the baseline systematic review, 205 included the words 'AMORE' or 'brachytherapy', and were screened for eligibility in this substudy. Thirteen studies met the inclusion criteria for Local-REFoRMS, including over 55 relapsed and refractory rhabdomyosarcoma patients. Most studies were retrospective cohort studies conducted within Europe. Most patients had embryonal disease within the head and neck or bladder/prostate regions, and received local therapy for first relapse. Approximately one quarter of patients relapsed following surgery and brachytherapy, with local relapses occurring more than metastatic relapse. Adverse events and functional outcomes were infrequently reported, but related to the site of surgery and brachytherapy. Study quality was limited by inconsistent reporting and potential selection bias. Outcomes following surgery and brachytherapy for a selected group of relapsed and refractory rhabdomyosarcoma show reasonable benefits, but reporting was often unclear and based on small sample sizes.

Brachytherapy for Pediatric Patients at Gustave Roussy Cancer Campus: A Model of International Cooperation for Highly Specialized Treatments

PURPOSE

Childhood cancer is rare, and treatment is frequently associated with long-term morbidity. Disparities in survival and long-term side effects encourage the establishment of networks to increase access to complex organ-conservative strategies, such as brachytherapy. We report our experience of an international cooperation model in childhood cancers.

METHODS AND MATERIALS

We examined the outcome of all children referred to our center from national or international networks to be treated according to a multimodal organ-conservative approach, including brachytherapy.

RESULTS

We identified 305 patients whose median age at diagnosis was 2.2 years (range, 1.4 months to 17.2 years). Among these patients, 99 (32.4%) were treated between 2015 and 2020; 172 (56.4%) were referred from national centers; and 133 (43.6%) were international patients from 31 countries (mainly Europe). Also, 263 patients were referred for primary treatment and 42 patients were referred for salvage treatment. Genitourinary tumors were the most frequent sites, with 56.4% bladder/prostate rhabdomyosarcoma and 28.5% gynecologic tumors. In addition to brachytherapy, local treatment consisted of partial tumor resection in 207 patients (67.9%), and 39 patients (13%) had additional external radiation therapy. Median follow-up was 58 months (range, 1 month to 48 years), 93 months for national patients, and 37 months for international patients (P < .0001). Five-year local control, disease-free survival, and overall survival rates were 90.8% (95% confidence interval [CI], 87.3%-94.4%), 84.4% (95% CI, 80.1%-89.0%), and 93.3% (95% CI, 90.1%-96.5%), respectively. Patients referred for salvage treatment had poorer disease-free survival (P < .01). Implementation of image guided pulse-dose-rate brachytherapy was associated with better local control among patients with rhabdomyosarcoma referred for primary treatment (hazard ratio, 9.72; 95% CI, 1.24-71.0). At last follow-up, 16.7% patients had long-term severe treatment-related complications, and 2 patients (0.7%) had developed second malignancy.

CONCLUSIONS

This retrospective series shows the feasibility of a multinational referral network for brachytherapy allowing high patient numbers in rare pediatric cancers. High local control probability and acceptable late severe complication probability could be achieved despite very challenging situations. This cooperation model could serve as a basis for generating international reference networks for high-tech radiation such as brachytherapy to increase treatment care opportunities and cure probability.

[Treatment and management of orbital tumors]

BACKGROUND

There are various options for the conservative treatment of the most frequent orbital tumors. These can delay, complement or be superior to the surgical approach, which is often prone to complications.

OBJECTIVE

This article gives a summary of the possible treatment options for the most common orbital tumors in childhood and adulthood.

METHODS

A literature search was carried out and the possible treatment pathways are presented.

RESULTS

1. Frequent orbital tumors in childhood: a systemic treatment with noncardioselective beta blockers is the primary treatment for capillary orbital hemangiomas. In cases of no response, steroids, interferon alpha or cyclophosphamide are treatment options. Observation is a possible option for smaller dermoid cysts, in cases of progression excision can become necessary. Symptomatic optic nerve gliomas can also be observed and in cases of progression treated with chemotherapy, mTOR/MEK inhibitors or radiotherapy (children > 5 years). Rhabdomyosarcomas are biopsied and subsequently treated by radiotherapy and chemotherapy. 2. Frequent orbital tumors in adulthood: asymptomatic cases of cavernous hemangiomas of the orbit can just be observed. Symptomatic hemangiomas can be surgically excised or treated with radiotherapy. For meningiomas of the optic nerve sheath radiotherapy is a very effective treatment. Surgical excision should be reserved for cases with no prognosis of visual acuity. There is also the option to treat with antiprogesterone. Orbital lymphomas with purely orbital involvement can be treated with radiotherapy, chemotherapy or the application of rituximab.

CONCLUSION

There are now very effective conservative treatment options for many orbital tumors. In some cases a surgical procedure can be avoided and a good visual function can be retained.

Score for the Survival Probability of Patients With Orbital Rhabdomyosarcoma After Surgery: A Long-Term and Large Cohort Study

Orbital rhabdomyosarcoma (RMS) is a relatively rare primary malignancy occurring in children. The objective of this study was to evaluate the cumulative incidence of cancer-specific death and competing risk of death among RMS patients after surgery and to build nomograms to predict overall survival (OS) and cancer-specific survival (CSS) based on a large population-based cohort. The records of 217 patients who were pathologically diagnosed with an orbital RMS between 1973 and 2015 from the Surveillance, Epidemiology, and End Results (SEER) database were retrospectively analyzed. The 10-, 20-, and 40-years OS rates and cancer-specific mortality were 82.5, 72.2, and 48.9%, respectively, and 14.8, 21.7, and 21.7%, respectively. The established nomograms were well-calibrated and validated, with a concordance index (C-index) of 0.901 and 0.944 for OS prediction, 0.923 and 0.904, for CSS prediction in the training and validation cohorts, respectively. The values of area under the receiver operating characteristic curve (AUC) for 10-, 20-, and 40-years OS and CSS prediction were 0.908, 0.826, and 0.847, and 0.924, 0.863, and 0.863, respectively. The established nomogram showed relatively good performances and could be convenient individualized predictive tools for prognostic prediction in RMS patients.

Interstitial brachytherapy for orbital soft tissue sarcoma: an innovative technique

Purpose

To report an innovative technique of interstitial brachytherapy developed for treatment of orbital soft tissue tumors.

Material and methods

A 4-month-old child diagnosed with rhabdomyosarcoma of orbit was treated with multiagent chemotherapy (CTh) and brachytherapy. Pre-planning computed tomography (CT) images were obtained and clinical target volume (CTV) was defined using the pre-treatment magnetic resonance imaging (MRI). Brachytherapy plan was generated for deciding optimal catheter placement. With the child under general anesthesia, catheter entry points were extrapolated and marked on the skin as determined from the pre-planning CT scan. Implantation of catheters was performed as per pre-determined catheter position and depths. Brachytherapy plan was generated and evaluated using dose volume histograms (DVH). A comparative external beam radiotherapy (EBRT) plan using RapidArc was also generated for the CTV with a 3 mm margin as the planning target volume (PTV).

Results

The mean CTV dose with brachytherapy was 158% compared to 101% with RapidArc. The CTV V₁₀₀ was 90% for brachytherapy vs. 95% for RapidArc. The mean dose to Lt Lens were 51% and 60%, respectively for brachytherapy and RapidArc, while the corresponding mean doses to the bony orbit were 39% and 68%, respectively. Follow-up MRI at 3 months showed complete response of the tumor.

Conclusions

Interstitial brachytherapy for orbit using this innovative technique is a safe and effective modality of local treatment for appropriately selected orbital soft tissue tumors. Brachytherapy resulted in excellent disease control with significant reduction of dose to surrounding ocular structures compared to EBRT.

Local Resection and Brachytherapy for Primary Orbital Rhabdomyosarcoma: Outcome and Failure Pattern Analysis

PURPOSE

Survival in patients with orbital rhabdomyosarcoma (RMS) is excellent. Therefore, new local treatment modalities, such as brachytherapy, have been developed to minimize adverse events. Since 1990, patients with orbital RMS and a residual tumor after induction chemotherapy were eligible for resection and brachytherapy. Otherwise patients received external beam radiotherapy. In this study, the authors describe the outcome for 20 patients with primary orbital RMS. The aim was to assess risk factors for treatment failure in this single center cohort.

METHODS

In this retrospective cohort study, the authors reviewed imaging studies, surgery reports, histology reports, and radiotherapy plans in a multidisciplinary setting. The authors included 20 consecutive patients with orbital RMS, treated between 1990 and 2007, (median age: 7.4 years, range: 0.7-16.1; median follow up: 11.5 years).

RESULTS

After induction chemotherapy, 12 patients were treated with surgery and brachytherapy, 2 with external beam radiotherapy, and in 5 patients who achieved complete remission, local treatment was withheld. In 1 patient, brachytherapy was incorrectly withheld after delayed surgery. Seven patients relapsed (no local treatment, N = 2; surgery and brachytherapy, N = 2; external beam radiotherapy, N = 2; surgery only, N = 1). The authors found no patient, tumor, or treatment characteristics that predisposed for treatment failure. Ten-year-overall survival and event-free survival were 89% and 65%, respectively.

CONCLUSIONS

Overall survival in this cohort of orbital RMS patients was good, including surgery and brachytherapy as treatment modality for orbital RMS resulted in an effective local treatment approach with fewer adverse events than external beam radiotherapy. The authors could not identify factors predisposing for treatment failure.

High-dose-rate brachytherapy of rhabdomyosarcoma limited to the external auditory canal

PURPOSE

To report on the single-catheter high-dose-rate brachytherapy treatment of a 21-month-old girl child with an embryonal, botryoid-type, rhabdomyosarcoma limited to the external auditory canal (EAC).

METHODS AND MATERIALS

A 2.4-mm diameter catheter was inserted into the right EAC and placed against the tympanic membrane. A computed tomography simulation scan was acquired. A brachytherapy treatment plan, in which 21 Gy in seven fractions was prescribed to a 1-mm depth along the distal 2 cm of the catheter, was generated. Treatments were delivered under anesthesia without complication. A dosimetric comparison between this plan and an intensity-modulated radiation therapy (IMRT) plan was then conducted. A clinical target volume (CTV), which encompassed a 1-mm margin along the distal 2 cm of the catheter, was delineated for both plans. Given positioning uncertainty under image guidance, a planning target volume (PTV = CTV + 3-mm margin) was defined for the IMRT plan. The IMRT plan was optimized for maximal CTV coverage but subsequently normalized to the same CTV volume receiving 100% of the prescription dose (V₁₀₀) of the brachytherapy plan.

RESULTS

The IMRT plan was normalized to the brachytherapy CTV V₁₀₀ of 82.0%. The PTV V₁₀₀ of this plan was 34.1%. The PTV exhibited dosimetric undercoverage within the middle ear and toward the external ear. Mean cochlea doses for the IMRT and brachytherapy plans were 26.7% and 10.5% of prescription, respectively.

CONCLUSIONS

For rhabdomyosarcomas limited to the EAC, a standard brachytherapy catheter can deliver a highly conformal radiation plan that can spare the nearby cochlea from excess radiation.

Hearing loss in survivors of childhood head and neck rhabdomyosarcoma: a long-term follow-up study

OBJECTIVES

To determine the hearing status of survivors treated for head and neck rhabdomyosarcoma (HNRMS) at long-term follow-up.

DESIGN

Cross-sectional long-term follow-up study.

SETTING

Tertiary comprehensive cancer centre.

PARTICIPANTS

Survivors treated for HNRMS during childhood in two concurrent cohorts; survivors in London had been treated with external beam radiotherapy (EBRT-based local therapy); survivors in Amsterdam were treated with AMORE (Ablative surgery, MOuld technique afterloading brachytherapy and surgical REconstruction) if feasible, otherwise EBRT (AMORE-based local therapy).

MAIN OUTCOME MEASURES

We assessed hearing status of HNRMS survivors at long-term follow-up. Hearing thresholds were obtained by pure-tone audiometry.

METHODS

We assessed the hearing thresholds, the number of patients with clinically relevant hearing loss and hearing impairment graded according to the Common Terminology Criteria for Adverse Events version 4.0 (CTCAEv4) and Boston criteria. Furthermore, we compared hearing loss between survivors treated with EBRT-based local therapy (London) and AMORE-based local therapy (Amsterdam).

RESULTS

Seventy-three survivors were included (median follow-up 11 years). We found clinically relevant hearing loss at speech frequencies in 19% of survivors. Multivariable analysis showed that survivors treated with EBRT-based treatment and those with parameningeal tumours had significantly more hearing impairment, compared to survivors treated with AMORE-based treatment and non-parameningeal tumours.

CONCLUSIONS

One in five survivors of HNRMS developed clinically relevant hearing loss. AMORE-based treatment resulted in less hearing loss compared to EBRT-based treatment. As hearing loss was highly prevalent and also occurred in survivors with orbital primaries, we recommend systematic audiological follow-up in all HNRMS survivors.

A review of the clinical experience in pulsed dose rate brachytherapy

Pulsed dose rate (PDR) brachytherapy is a treatment modality that combines physical advantages of high dose rate (HDR) brachytherapy with the radiobiological advantages of low dose rate brachytherapy. The aim of this review was to describe the effective clinical use of PDR brachytherapy worldwide in different tumour locations. We found 66 articles reporting on clinical PDR brachytherapy including the treatment procedure and outcome. Moreover, PDR brachytherapy has been applied in almost all tumour sites for which brachytherapy is indicated and with good local control and low toxicity. The main advantage of PDR is, because of the small pulse sizes used, the ability to spare normal tissue. In certain cases, HDR resembles PDR brachytherapy by the use of multifractionated low-fraction dose.

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.

Orbital rhabdomyosarcomas: A review

Rhabdomyosarcoma (RMS) is a highly malignant tumor and is one of the few life-threatening diseases that present first to the ophthalmologist. It is the most common soft-tissue sarcoma of the head and neck in childhood with 10% of all cases occurring in the orbit. RMS has been reported from birth to the seventh decade, with the majority of cases presenting in early childhood. Survival has changed drastically over the years, from 30% in the 1960's to 90% presently, with the advent of new diagnostic and therapeutic modalities. The purpose of this review is to provide a general overview of primary orbital RMS derived from a literature search of material published over the last 10 years, as well as to present two representative cases of patients that have been managed at our institute.

Endoscopic management of Ewing's sarcoma of ethmoid sinus within the AMORE framework: a new paradigm

The Ablative surgery, MOulage brachytherapy and REconstruction) (AMORE) protocol developed in the Academic Medical Center of Amsterdam has been used successfully to treat sarcomas. The use of endoscopic surgery fits well within this framework. A 6-year-old boy presented with Ewing Sarcoma of left ethmoid sinus closest to orbit. The patient underwent neoadjuvant chemotherapy followed by complete endoscopic resection, brachytherapy and reconstruction. Brachytherapy was administered by iridium catheters through limited Lynch-Howarth incision. Skull base defect was reconstructed with a galea flap. The use of endoscopic surgery complemented by neoadjuvant chemotherapy and brachytherapy might maximize tumor control while reducing morbidity.

Imaging findings in craniofacial childhood rhabdomyosarcoma

Rhabdomyosarcoma (RMS) is the commonest paediatric soft-tissue sarcoma constituting 3-5% of all malignancies in childhood. RMS has a predilection for the head and neck area and tumours in this location account for 40% of all childhood RMS cases. In this review we address the clinical and imaging presentations of craniofacial RMS, discuss the most appropriate imaging techniques, present characteristic imaging features and offer an overview of differential diagnostic considerations. Post-treatment changes will be briefly addressed.