Postoperative radiotherapy in the treatment of Ewing tumors: influence of the interval between surgery and radiotherapy

Effect of Radiotherapy Dose on Outcome in Nonmetastatic Ewing Sarcoma

Purpose

Radiation therapy (RT) is an integral part of Ewing sarcoma (EwS) therapy. The Ewing 2008 protocol recommended RT doses ranging from 45 to 54 Gy. However, some patients received other doses of RT. We analyzed the effect of different RT doses on event-free survival (EFS) and overall survival (OS) in patients with EwS.

Methods and Materials

The Ewing 2008 database included 528 RT-admitted patients with nonmetastatic EwS. Recommended multimodal therapy consisted of multiagent chemotherapy and local treatment consisting of surgery (S&RT group) and/or RT (RT group). EFS and OS were analyzed with uni- and multivariable Cox regression models including known prognostic factors such as age, sex, tumor volume, surgical margins, and histologic response.

Results

S&RT was performed in 332 patients (62.9%), and 145 patients (27.5%) received definitive RT. Standard dose ≤ 53 Gy (d1) was admitted in 57.8%, high dose of 54 to 58 Gy (d2) in 35.5%, and very high dose ≥ 59 Gy (d3) in 6.6% of patients. In the RT group, RT dose was d1 in 11.7%, d2 in 44.1%, and d3 in 44.1% of patients. Three-year EFS in the S&RT group was 76.6% for d1, 73.7% for d2, and 68.2% for d3 (P = .42) and in the RT group 52.9%, 62.5%, and 70.3% (P = .63), respectively. Multivariable Cox regression revealed age ≥ 15 years (hazard ratio [HR], 2.68; 95% confidence interval [CI], 1.63-4.38) and nonradical margins (HR, 1.76; 95% CI, 1.05-2.93) for the S&RT group (sex, P = .96; histologic response, P = .07; tumor volume, P = .50; dose, P = .10) and large tumor volume (HR, 2.20; 95% CI, 1.21-4.0) for the RT group as independent factors (dose, P = .15; age, P = .08; sex, P = .40).

Conclusions

In the combined local therapy modality group, treatment with higher RT dose had an effect on EFS, whereas higher dose of radiation when treated with definitive RT was associated with an increased OS. Indications for selection biases for dosage were found. Upcoming trials will assess the value of different RT doses in a randomized manner to control for potential selection bias.

Ewing Sarcoma-Diagnosis, Treatment, Clinical Challenges and Future Perspectives

Ewing sarcoma, a highly aggressive bone and soft-tissue cancer, is considered a prime example of the paradigms of a translocation-positive sarcoma: a genetically rather simple disease with a specific and neomorphic-potential therapeutic target, whose oncogenic role was irrefutably defined decades ago. This is a disease that by definition has micrometastatic disease at diagnosis and a dismal prognosis for patients with macrometastatic or recurrent disease. International collaborations have defined the current standard of care in prospective studies, delivering multiple cycles of systemic therapy combined with local treatment; both are associated with significant morbidity that may result in strong psychological and physical burden for survivors. Nevertheless, the combination of non-directed chemotherapeutics and ever-evolving local modalities nowadays achieve a realistic chance of cure for the majority of patients with Ewing sarcoma. In this review, we focus on the current standard of diagnosis and treatment while attempting to answer some of the most pressing questions in clinical practice. In addition, this review provides scientific answers to clinical phenomena and occasionally defines the resulting translational studies needed to overcome the hurdle of treatment-associated morbidities and, most importantly, non-survival.

Current Status of Management and Outcome for Patients with Ewing Sarcoma

Ewing sarcoma is the second most common bone sarcoma in children after osteosarcoma. It is a very aggressive malignancy for which systemic treatment has greatly improved outcome for patients with localized disease, who now see survival rates of over 70%. However, for the quarter of patients presenting with metastatic disease, survival is still dismal with less than 30% of patients surviving past 5 years. Patients with disease relapse, local or distant, face an even poorer prognosis with an event-free 5-year survival rate of only 10%. Unfortunately, Ewing sarcoma patients have not yet seen the benefit of recent years' technical achievements such as next-generation sequencing, which have enabled researchers to study biological systems at a level never seen before. In spite of large multinational studies, treatment of Ewing sarcoma relies entirely on chemotherapeutic agents that have been largely unchanged for decades. As many promising modern therapies, including monoclonal antibodies, small molecules, and immunotherapy, have been disappointing to date, there is no clear candidate as to which drug should be investigated in the next large-scale clinical trial. However, the mechanisms driving tumor development in Ewing sarcoma are slowly unfolding. New entities of Ewing-like tumors, with fusion transcripts that are related to the oncogenic EWSR1-FLI1 fusion seen in the majority of Ewing tumors, are being mapped. These tumors, although sharing much of the same morphologic features as classic Ewing sarcoma, behave differently and may require a different treatment. There are also controversies regarding local treatment of Ewing sarcoma. The radiosensitive nature of the disease and the tendency for Ewing sarcoma to arise in the axial skeleton make local treatment very challenging. Surgical treatment and radiotherapy have their pros and cons, which may give rise to different treatment strategies in different centers around the world. This review article discusses some of these controversies and reproduces the highlights from recent publications with regard to diagnostics, systemic treatment, and surgical treatment of Ewing sarcoma.

Treatment of pelvic Ewing's sarcoma: Pros and cons of chemotherapy plus definitive radiotherapy versus surgery

OBJECTIVE

The aim of this study was to compare the results of chemotherapy or combined chemotherapy-radiation therapy with surgical intervention following neodjuvant therapy in pelvic Ewing's sarcoma patients.

METHODS

The study population consisted of 39 patients with pelvic Ewing's sarcoma treated in our clinic between 1994 and 2014. Of these patients, 28 patients (11 boys and 17 girls; mean age: 19.57±6.8 years) were treated with chemotherapy and radiation therapy and the remaining 11 patients (9 boys and 2 girls; mean age: 18.64±8.1 years) patients underwent surgical intervention after neoadjuvant chemotherapy or chemotherapy plus radiation therapy. Internal hemipelvectomy was performed in 10 patients, and external hemipelvectomy was performed in one patient. Survival rates were compared between the surgical and non-surgical treatment groups. Predictive factors, such as treatment protocol (surgery, neoadjuvant chemotherapy, definitive radiotherapy), mass localisation, mass size, presence of metastasis at the time of diagnosis, and presence of late metastases were compared between the groups. The effects of each variable on survival were also examined.

RESULTS

The overall 3- and 5-year survival rates of the 28 non-surgical patients were 41.4% and 26.1%, respectively, while those of the surgical patients were 53% and 35.4%, respectively (p=0.777). Large mass size, presence of metastasis at the time of diagnosis, and presence of late metastases were significantly associated with lower survival rates.

CONCLUSION

The survival rates of the patients who underwent surgery were higher than those of non-surgical patients, although the difference was not statistically significant. Definitive radiation and chemotherapy would be preferable in selected cases, such as patients with sacral localisation, without surgical intervention.

LEVEL OF EVIDENCE

Level III, Therapeutic Study.

Management of Ewing sarcoma family of tumors: Current scenario and unmet need

Ewing sarcoma family tumors (ESFT) are heterogeneous, aggressive group of disease with peak incidence in adolescent and young adults. The outcome has been improved dramatically from 10% with surgery and radiotherapy alone to 65%-70% now, in localized disease, with the introduction of chemotherapy. Chemotherapy regimen evolved from single agent to multiagent with effort of many cooperative clinical trials over decades. The usual treatment protocol include introduction of multi-agent chemotherapy in neoadjuvant setting to eradicate systemic disease with timely incorporation of surgery and/or radiotherapy as local treatment modality and further adjuvant chemotherapy to prevent recurrence. Risk adapted chemotherapy in neoadjuvant and adjuvant setting along with radiotherapy has been used in many international collaborative trials and has resulted in improved outcome, more so in patients with localized disease. The role of high dose chemotherapy with stem cell rescue is still debatable. The outcome of patients with metastatic disease is dismal with long term outcome ranges from 20%-40% depending on the sites of metastasis and intensity of treatment. There is a huge unmet need to improve outcome further, more so in metastatic setting. Novel therapy targeting the molecular pathways and pathogenesis of ESFT is very much required. Here we have discussed the current standard of management in patients with ESFT, investigational targeted or novel therapies along with future promises.

Ewing Sarcoma: Current Management and Future Approaches Through Collaboration

Ewing sarcoma (ES) is an aggressive sarcoma of bone and soft tissue occurring at any age with a peak incidence in adolescents and young adults. The treatment of ES relies on a multidisciplinary approach, coupling risk-adapted intensive neoadjuvant and adjuvant chemotherapies with surgery and/or radiotherapy for control of the primary site and possible metastatic disease. The optimization of ES multimodality therapeutic strategies has resulted from the efforts of several national and international groups in Europe and North America and from cooperation between pediatric and medical oncologists. Successive first-line trials addressed the efficacy of various cyclic combinations of drugs incorporating doxorubicin, vincristine, cyclophosphamide, ifosfamide, etoposide, and dactinomycin and identified prognostic factors now used to tailor therapies. The role of high-dose chemotherapy is still debated. Current 5-year overall survival for patients with localized disease is 65% to 75%. Patients with metastases have a 5-year overall survival < 30%, except for those with isolated pulmonary metastasis (approximately 50%). Patients with recurrence have a dismal prognosis. The many insights into the biology of the EWS-FLI1 protein in the initiation and progression of ES remain to be translated into novel therapeutic strategies. Current options and future approaches will be discussed.

Optimal Timing of Whole-Brain Radiation Therapy Following Craniotomy for Cerebral Malignancies

BACKGROUND

For patients with cerebral metastases that are limited in number, surgical resection followed by whole-brain radiation therapy is the standard of care. In addition, for high-grade gliomas, maximal surgical resection followed by local radiotherapy is considered the optimal treatment. Radiation is known to impair wound healing, including healing of surgical incisions. Radiotherapy shortly after surgical resection would be expected to minimize the opportunity for tumor regrowth or progression. Owing to these competing interests, the purpose of this study was to shed light on the optimal timing of radiotherapy after surgical resection of brain metastasis or high-grade gliomas.

METHODS

A review of the literature was conducted on the following topics: radiation and wound healing, corticosteroid use and wound healing, radiotherapy for tumor control for cerebral metastases and high-grade gliomas, and whole-brain radiation therapy or focal radiotherapy after craniotomy with focus on the timing of radiotherapy after surgery.

RESULTS

In animal models, wound integrity and healing was less impaired by radiotherapy administered 1 week after surgery. In humans, this timing would be expected to be significantly longer, on the order of several weeks.

CONCLUSIONS

Given the limited literature, insufficient conclusions can be drawn. However, animal data suggest a period of at least 1 week (but it is likely several weeks in humans) is necessary for reconstitution of wound strength before initiation of radiation therapy. A randomized prospective study is recommended to understand better the effect of the timing of radiation therapy following surgical intervention for brain metastasis or high-grade gliomas.

Management of bone tumours in paediatric oncology

The management of bone tumours in paediatric oncology requires careful multidisciplinary planning due to the need for multimodal therapy approaches. The non-specific symptoms often lead to a delayed definitive diagnosis of a bone tumour. Imaging procedures are of major importance for an individualised and optimised treatment planning. They have to be carried out before any surgery, including biopsies. The introduction of multi-agent chemotherapy has led to a significant improvement in survival rates in patients suffering from Ewing's sarcomas and osteosarcomas. However, local therapy still remains indispensable in order to achieve long-term survival. For osteosarcoma, surgery remains the only adequate local therapy modality. Radiotherapy may be considered if surgery is not feasible. In these cases, high radiation doses need to be applied. The choice for local therapy modality is not as clear in patients with Ewing's sarcoma. Today, surgery is often preferred if a wide or at least marginal resection can be carried out. Additional radiotherapy is advised in patients with marginal/intralesional resection or poor histological response to induction chemotherapy. Definitive radiotherapy is recommended for inoperable lesions. In the future, new radiotherapy approaches, such as intensity-modulated radiotherapy or proton therapy, may yield better results with minor risks of late effects.

Post-operative radiotherapy for Ewing sarcoma: when, how and how much?

Postoperative radiotherapy in Ewing family of tumors has undergone continuous evolution over the last few decades to establish its role in the combined modality management of these tumors. The process of evolution is still far from over. This review analyzes the evidence from major multi-institutional prospective trials as well as large retrospective institutional series in Ewing tumors to determine the current standards and controversies in postoperative radiation. The indications of PORT, radiation dose-fractionation, timing, target volumes and treatment planning, as well as the late effects are reviewed. A summary of evidence based consensus is presented and unresolved aspects are discussed. Pediatr Blood Cancer 2008;51:575-580. (c) 2008 Wiley-Liss, Inc.

Current treatment for Ewing's sarcoma

Ewing's sarcoma is the second most common primary bone tumor seen in children and adolescents, and was described by James Ewing in 1921 as a diffuse endothelioma of bone. It is one of the differential diagnoses of pediatric small round blue cell tumors. This is not a single condition, but a group of morphologically and clinically closely related disorders with similar molecular biology -- expression of tumor-specific chimeric oncoproteins through balanced chromosomal translocations involving the EWS gene -- often referred to as the Ewing family of tumors. This includes Ewing's sarcoma of bone, extra-osseous Ewing's sarcoma, Askin tumor and peripheral neuroectodermal tumor. These are aggressive neoplasms with almost 25% of patients having clinically evident metastases at presentation. Ewing's sarcoma has therefore been considered as a systemic disease necessitating local as well as systemic treatment. An aggressive multidisciplinary approach has resulted in significant improvement in prognosis for patients with these tumors. Despite aggressive treatment, 20-40% of patients with localized disease and almost 80% of patients with metastatic disease at presentation succumb to the illness. Advances in understanding the molecular biology of these tumors will hopefully result in the development of novel treatment approaches. The aim of this article is to review the existing treatment methods and to highlight the more recent approaches to the treatment of this condition.

Ewing's sarcoma and primitive neuroectodermal family of tumors

Ewing's sarcoma (ES) initially was believed to be of perivascular endothelial origin. The Ewing's sarcoma family of tumors (EFT) includes ES of bone (ESB), extraosseous ES (EES), peripheral primitive neuroectodermal tumor of bone (pPNET), and malignant small-cell tumor of the thoracopulmonary region, or Askin's tumor, all of which are now known to be neoplasms of neuroectodermal origin. The degree of neuronal differentiation has been used for histopathologic subclassification of the EFT as classical ES (ESB or EES), which is characterized by minimal evidence of neural differentiation, and pPNET, which displays evidence of neural differentiation by standard microscopy, electron microscopy, or immunohistochemistry. Because the behavior, prognosis, and treatment appear to be similar for all subsets of EFT, this histopathologic subclassification may not be clinically significant, though some debate remains whether neural differentiation predicts for inferior outcome.

Ewing sarcoma: radiation dose and target volume

BACKGROUND

The outcome of children and adolescents with Ewing sarcoma is impacted by many prognostic factors and often measured by estimates of: event-free, relapse-free, disease-free, or overall survival. However, the preferred assessment following radiation therapy is local control.

PROCEDURE

A review of large group experiences over the past several decades was undertaken to assess the optimal radiation dose and volume for patients with localized, osseous Ewing sarcoma. New approaches and techniques to improve local control were also investigated.

RESULTS

With multidisciplinary therapy, 5-year overall local control rates range from 58 to 93%. Following definitive irradiation, they are 53-86%. Recommended radiation therapy doses are 55.8-60.0 Gy. In the postoperative setting, gross disease requires 55.8 Gy; microscopic disease requires 45 Gy. Altered fractionation schemes have not improved local control. The appropriate irradiated volume is an involved field to the pretreatment tumor volume plus 2.0-2.5 cm margin, followed by a boost to the post-induction chemotherapy tumor volume with margin. Good radiation quality control with central review improves local control. Use of an involved radiation field requires accuracy in defining tumor volume. Techniques to improve local control include risk-adapted multidisciplinary therapy, intraoperative boost radiation, and high radiation doses as delivered by 3-dimensional conformal radiation. Intensity modulated and proton beam radiotherapy may offer an advantage at special sites.

CONCLUSIONS

Innovative uses of radiation in the multidisciplinary setting will continue to provide excellent local control, improved function, and quality of life for young patients with localized Ewing sarcoma of bone.

Carcinomatous meningitis: are surgery or gamma knife radiosurgery treatment risk factors?

Object. The purpose of this study was to identify possible risk factors leading to carcinomatous meningitis in patients with a known brain metastasis and who were treated with gamma knife radiosurgery (GKS).

Methods. Two hundred eighty lesions in 101 patients were treated during 121 GKS procedures. The clinical and neuroimaging history, tumor histology, and follow-up studies were reviewed for all patients. Evidence as demonstrated by magnetic resonance imaging criteria and/or cerebrospinal fluid (CSF) cytology of carcinomatous meningitis was evaluated. The data were then analyzed to identify potential risk factors for the development of CSF dissemination.

Conclusions. It appears that carcinomatous meningitis is exclusively identified in patients with adenocarcinoma, in particular with primary lung cancer. Furthermore, the incidence is higher if surgery is performed and the interval to subsequent GKS is prolonged.