Pelvic Ewing sarcomas. Three-dimensional conformal vs. intensity-modulated radiotherapy

Prognostic factors and overall survival in pelvic Ewing's sarcoma and chordoma: A comparative SEER database analysis

Background

This study aimed to develop and validate nomograms to predict overall survival (OS) for pelvic Ewing's sarcoma (EWS) and chordoma, identify prognostic factors, and compare outcomes between the two conditions.

Methods

We identified patients diagnosed with pelvic EWS or chordoma from the SEER database (2001-2019). Independent risk factors were identified using univariate and multivariate Cox regression analyses, and these factors were used to construct nomograms predicting 3-, 5-, and 10-year OS. Validation methods included AUC, calibration plots, C-index, and decision curve analysis (DCA). Kaplan-Meier curves and log-rank tests compared survival differences between low- and high-risk groups.

Results

The study included 1175 patients (EWS: 611, chordoma: 564). Both groups were randomly divided into training (70 %) and validation (30 %) cohorts. OS was significantly higher for chordoma. Multivariate analysis showed year of diagnosis, income, stage, and surgery were significant for EWS survival, while age, time to treatment, stage, and surgery were significant for chordoma survival. Validation showed the nomograms had strong predictive performance and clinical utility.

Conclusions

The nomograms reliably predict overall survival (OS) in pelvic EWS and chordoma, helping to identify high-risk patients early and guide preventive measures. The study also found that survival rates are significantly higher for chordoma, highlighting different prognostic profiles between EWS and chordoma.

En bloc resection followed by gluteal advancement flap for sacral Ewing's sarcoma: A novel technique

Ewing's sarcoma is a rare and highly aggressive bone tumor primarily affecting children and adolescents. It commonly presents in the pelvic and axial skeleton, with sacral involvement posing unique challenges due to its intricate anatomical location. This report details the case of an 18-year-old male with sacral Ewing's sarcoma, emphasizing the diagnostic, surgical, and reconstructive aspects of management. The patient presented with lower back pain, lower limb weakness, and urinary incontinence, which prompted an extensive diagnostic evaluation. Magnetic resonance imaging and computed tomography scans revealed a large lytic mass extending from the S2 vertebra to the coccyx invading the presacral space. Biopsy confirmed the diagnosis of Ewing's sarcoma, characterized by the EWS-FLI1 type 1 translocation. A multidisciplinary team comprising neurosurgeons, colorectal surgeons, and plastic surgeons was formulated. En bloc resection of the tumor, lumbopelvic fixation, and soft-tissue reconstruction using bilateral gluteus maximus advancement flaps were successfully performed. The procedure aimed to address both the oncological and functional aspects of the patient's condition. Chemotherapy and radiotherapy were administered as adjuvant therapies. At 2-year follow-up, the patient was ambulating independently with no residual tumor on imaging. This case highlights the complex nature of sacral Ewing's sarcoma and underscores the importance of a multidisciplinary approach. The described surgical technique, including the innovative use of gluteus maximus advancement flaps for soft-tissue reconstruction, contributes to reducing wound complications and promoting successful patient outcomes. The presented approach serves as a valuable addition to the armamentarium of treatment options for this challenging malignancy.

Particle Therapy in Adult Patients with Pelvic Ewing Sarcoma-Tumor and Treatment Characteristics and Early Clinical Outcomes

PURPOSE

To report dosimetric characteristics and early clinical outcomes in patients with pelvic Ewing sarcoma undergoing particle therapy.

METHODS

Patients ≥ 18 years old with pelvic Ewing sarcoma treated in adjuvant or definitive settings were considered for this retrospective analysis. Proton therapy was carried out with 45-60 Gy (RBE) (1.5-2 Gy (RBE) per fraction) and carbon ion therapy for recurrent disease with 51 Gy (RBE) (3 Gy (RBE) per fraction). Local control (LC), disease control (DC) and overall survival (OS) were calculated using the Kaplan-Meier method.

RESULTS

For our sample, 21 patients were available, 18 of whom were treated for primary, 3 for locally recurrent and 16 for inoperable disease. The median CTV and PTV were 1215 cm³ and 1630 cm³. Median Dmean values for the PTV, bladder and rectum and median V40 Gy for the bowel for patients undergoing proton therapy were 56 Gy (RBE), 0.6 Gy (RBE), 9 Gy (RBE) and 15 cm³, respectively. At the end of particle therapy, G 1-2 skin reactions (n = 16/21) and fatigue (n = 9/21) were the main reported symptoms. After a median follow-up of 21 months, the 2-year LC, DC and OS were 76%, 56% and 86%, respectively.

CONCLUSIONS

Particle therapy in adult pelvic Ewing sarcoma is feasible and provides excellent dosimetric results. First clinical outcomes are promising; however, further long-term follow-up is needed.

A novel nomogram and risk classification system predicting the Ewing sarcoma: a population-based study

Ewing sarcoma (ES) is a rare disease that lacks a prognostic prediction model. This study aims to develop a nomogram and risk classification system for estimating the probability of overall survival (OS) of patients with ES. The clinicopathological data of ES were collected from the Surveillance, Epidemiology and Final Results (SEER) database from 2010 to 2018. The primary cohort was randomly assigned to the training set and the validation set. Univariate and multiple Cox proportional hazard analyses based on the training set were performed to identify independent prognostic factors. A nomogram was established to generate individualized predictions of 3- and 5-year OS and evaluated by the concordance index (C-index), the receiver operating characteristic curve (ROC), the calibration curve, the integrated discrimination improvement (IDI) and the net reclassification improvement (NRI). Based on the scores calculated with the nomogram, ES patients were divided into three risk groups to predict their survival. A total of 935 patients were identified, and a nomogram consisting of 6 variables was established. The model provided better C-indices of OS (0.788). The validity of the Cox model assumptions was evaluated through the Schönfeld test and deviance residual. The ROC, calibration curve, IDI and NRI indicated that the nomogram exhibited good performance. A risk classification system was built to classify the risk group of ES patients. The nomogram compares favourably and accurately to the traditional SEER tumour staging systems, and risk stratification provides a more convenient and effective tool for clinicians to optimize treatment options.

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.

Reconstruction after Subtotal Sacrectomy for Sacral Ewing's Sarcoma Using Tibial Allograft Strut Grafting: A Case Report

We present the case of a 15-year-old girl. Two months after becoming aware of pain, she was diagnosed with a sacral tumor and referred to our department. She was diagnosed with a sacral Ewing's sarcoma; after chemotherapy, it was determined that the tumor could be resected, so surgical treatment was performed. The sacrum and ilium were partially resected at the lower end of S1, and the lumbar vertebrae and pelvis were fixed with a pedicle screw and two iliac screws on each side of L3, and the sacral resection was reconstructed with a tibial strut allograft. No tumor recurrence or metastasis has been observed 1 year postoperatively. She developed bladder and rectal dysfunction, but she remained independent in activities of daily living and her daily life was not limited. The bone fusion in the reconstructed area confirmed the lack of instrumentation looseness. Surgical treatment for sacral Ewing's sarcoma was performed to cure the patient. We believe that the tibial allograft contributed to the patient's ability to walk on her own due to its high mechanical stability. Postoperative bone healing was observed with the same material, suggesting that the tibial allograft is useful for similar procedures.

Impact of different treatment techniques for pediatric Ewing sarcoma of the chest wall: IMRT, 3DCPT, and IMPT with/without beam aperture

Purpose

To evaluate the dosimetric differences between photon intensity‐modulated radiation therapy (IMRT) plans, 3D conformal proton therapy (3DCPT), and intensity‐modulated proton therapy (IMPT) plans and to investigate the dosimetric impact of different beam spot size and beam apertures in IMPT for pediatric Ewing sarcoma of the chest wall.

Methods and Materials

Six proton pediatric patients with Ewing sarcoma in the upper, middle, and lower thoracic spine regions as well as upper lumbar spine region were treated with 3DCPT and retrospectively planned with photon IMRT and IMPT nozzles of different beam spot sizes with/without beam apertures. The plan dose distributions were compared both on target conformity and homogeneity, and on organs‐at‐risk (OARs) sparing using QUANTEC metrics of the lung, heart, liver, and kidney. The total integral doses of healthy tissue of all plans were also evaluated.

Results

Target conformity and homogeneity indices are generally better for the IMPT plans with beam aperture. Doses to the lung, heart, and liver for all patients are substantially lower with the 3DPT and IMPT plans than those of IMRT plans. In the IMPT plans with large spot without beam aperture, some OAR doses are higher than those of 3DCPT plans. The integral dose of each photon IMRT plan ranged from 2 to 4.3 times of proton plans.

Conclusion

Compared to IMRT, proton therapy delivers significant lower dose to almost all OARs and much lower healthy tissue integral dose. Compared to 3DCPT, IMPT with small beam spot size or using beam aperture has better dose conformity to the target.

Characteristics and prognosis of pelvic Ewing sarcoma: a SEER population-based study

Background

The pelvis is one of the primary sites of Ewing sarcoma (ES) and is associated with poorer prognoses than the extremities. Due to the rarity of this disease and limited data available, the prognostic factors of pelvic ES remain controversial. Thus, this study aimed to identify independent prognostic factors, and develop a nomogram for predicting survival rates in patients with pelvic ES.

Methods

Using data provided by the Surveillance, Epidemiology, and End Results (SEER) database, variables including age, sex, race, tumor size, tumor stage, surgery, and radiotherapy were analyzed using the Kaplan–Meier method and Cox proportional hazards regression. Based on the results of multivariate analyses, a nomogram was built to predict the overall survival (OS) of patients with pelvic ES. The performance of the nomogram was evaluated by the concordance index (C-index).

Results

A total of 267 cases diagnosed between 2004 and 2016 were included in the study. Univariate and multivariate analyses showed that patients who were younger, white, had a localized tumor stage, or underwent surgery were associated with improved prognoses, while no significant differences were observed in OS based on sex, tumor size, or radiotherapy. A nomogram was developed and the C-index was 0.728, indicating adequate performance for survival prediction.

Conclusions

Age, race, tumor stage, and surgery were identified as independent prognostic factors for the OS of pelvic ES. The nomogram developed in this study can individually predict 3- and 5-year OS in patients with pelvic ES.

UK guidelines for the management of bone sarcomas

This document is an update of the British Sarcoma Group guidelines published in 2010. The aim is to provide a reference standard for the clinical care of patients in the UK with bone sarcomas. Recent recommendations by the European Society of Medical Oncology, The National Comprehensive Cancer Network and The National Institute for Health and Care Excellence have been incorporated, and the literature since 2010 reviewed. The standards represent a consensus amongst British Sarcoma Group members in 2015. It is acknowledged that these guidelines will need further updates as care evolves. The key recommendations are that bone pain or a palpable mass should always lead to further investigation and that patients with clinico-radiological findings suggestive of a primary bone tumour at any site in the skeleton should be referred to a specialist centre and managed by a fully accredited bone sarcoma multidisciplinary team. Treatment recommendations are provided for the major tumour types and for localised, metastatic and recurrent disease. Follow up schedules are suggested.

Hepatotoxicity after liver irradiation in children and adolescents : results from the RiSK

AIM

The aim of this study was to evaluate acute and late radiotherapy-associated hepatotoxicity in consideration of dose-volume effects and liver function in childhood and adolescence.

PATIENTS AND METHODS

Since 2001, irradiated children and adolescents in Germany have been prospectively documented in the "Register of Treatment-Associated Late Effects After Radiotherapy of Malignant Diseases in Childhood and Adolescence (RiSK)" using standardized forms. Toxicity was graded according to the Radiation Therapy Oncology Group (RTOG) criteria.

RESULTS

Until April 2012, 1,392 children and adolescents from 62 radiotherapy centers were recruited. In all, 216 patients underwent irradiation of the liver (median age 9 years, range 1-18 years, 70 patients with total-body irradiation, TBI). For 75 % of patients without TBI, information on acute toxicity of the liver was available: 24 patients had acute toxicity of grade 1-4 (grade 1, 2, and 4, in 20, 3, and 1 patient, respectively), including five patients receiving simultaneous hepatotoxic chemotherapy. Information on late toxicity was documented in 465 forms from 216 patients, with a median follow-up of 2 years. A maximum grade of toxicity of ≥ 0 occurred in 18 patients over time (with grade 1, 2, and 3 toxicity occurring in 15, 2, and 1 patient, respectively), including three patients (17 %) with TBI. One of them received simultaneous hepatotoxic chemotherapy. In multivariable analysis, volume-dose correlations showed no statistically noticeable effect on acute or chronic toxicity.

CONCLUSION

Only low hepatotoxicity developed in children after irradiation of various abdominal and thoracic tumors. Due to the low radiation doses to the liver (median liver dose = 5 Gy) and the low toxicities that were consecutively observed, dose-volume curves for liver toxicity could not be established. These findings reflect the cautious attitude of radiation oncologists in terms of attributable liver doses in the treatment of the investigated tumor entities. It offers the option of increasing these conservative doses if tumor control is necessary.

Target splitting non-coplanar RapidArc radiation therapy for a diffuse sebaceous carcinoma of the scalp: a novel delivery technique

Background and purpose

To compare conventional lateral photon-electron, fixed-beam intensity modulated radiation therapy (IMRT), coplanar and non-coplanar RapidArc for the treatment of a diffuse sebaceous gland carcinoma of the scalp.

Methods

Comprehensive dosimetry comparisons were performed among 3D-CRT, IMRT and various RapidArc plans. Target coverage, conformity index (CI), homogeneity index (HI) and doses to organs at risk (OAR) were calculated. Monitor unites (MUs) and delivery time of each treatment were also recorded to evaluate the execution efficiency. The influence of target splitting technique and non-coplanar planning on plan quality was discussed.

Results

IMRT was superior to 3D-CRT concerning targets’ coverage at the sacrifice of larger irradiated brain volumes to low doses. CIs and HIs were better in coplanar RapidArc and non-coplanar RapidArc plans than 3D-CRT and IMRT. Best dose coverage and sparing of OARs were achieved in non-coplanar plans using target splitting technique. Treatment delivery time was longest in the IMRT plan and shortest in the coplanar RapidArc plan without target splitting. The 3%/3 mm gamma test pass rates were above 95% for all the plans.

Conclusions

Target splitting technique and non-coplanar arcs are recommended for total scalp irradiation.

Successful complete resection of Ewing sarcoma arising from the bladder in a 10-year-old boy after chemotherapy

Ewing sarcoma (ES) of the bladder is extremely rare. Here we report the successful treatment of the youngest case of ES arising from bladder encountered to date and a literature review. A 10-year-old boy who presented with polyuria and lower abdominal swelling was found to have a 13 cm mass arising from the bladder localized to the center of the lower abdomen. Biopsy confirmed ES. Following chemotherapy, the mass shrank to 5 cm and was found to be localized to the right side of the bladder with invasion of the right vas deferens. One-third of the right side of the bladder and part of the right vas deferens were resected. No viable cancer cells were detected in the resected specimen, and the surgical margins were reported to be negative. The patient is currently well with no recurrence or metastases after 11 months. There are 12 cases of Ewings sarcoma arising from the bladder reported in the English literature; two cases in children. Our case will be the third pediatric case and the youngest.

Optimization by visualization of indices

BACKGROUND AND PURPOSE

Physical 3D treatment planning provides a pool of parameters describing dose distributions. It is often useful to define conformal indices to enable quicker evaluation. However, the application of individual indices is controversial and not always effective. The aim of this study was to design a quick check of dose distributions based on several indices detecting underdosages within planning target volumes (PTVs) and overdosages in normal tissue.

MATERIALS AND METHODS

Dose distributions of 215 cancer patients were considered. Treatment modalities used were three-dimensional conformal radiotherapy (3DCRT), radiosurgery, intensity-modulated radiotherapy (IMRT), intensity-modulated arc therapy (IMAT) and tomotherapy. The volumes recommended in ICRU 50 and 83 were used for planning and six conformation and homogeneity indices were selected: CI, CN, CICRU, COV, C∆, and HI. These were based on the PTV, the partial volume covered by the prescribed isodose (PI; PTVPI), the treated volume (TVPI), near maximum D2 and near minimum D98. Results were presented as a hexagon-the corners of which represent the values of the indices-and a modified test function F (Rosenbrock's function) was calculated. Results refer to clinical examples and mean values, in order to allow evaluation of the power of F and hexagon-based decision support procedures in detail and in general.

RESULTS

IMAT and tomotherapy showed the best values for the indices and the lowest standard deviation followed by static IMRT. DCRT and radiosurgery (e.g. CN: IMAT 0.85 ± 0.06; tomotherapy 0.84 ± 0.06; IMRT 0.83 ± 0.07; 3DCRT 0.65 ± 0.08; radiosurgery 0.64 ± 0.11). In extreme situations, not all indices reflected the situation correctly. Over- and underdosing of PTV and normal tissue could be qualitatively assessed from the distortion of the hexagon in graphic analysis. Tomotherapy, IMRT, IMAT, 3DCRT and radiosurgery showed increasingly distorted hexagons, the type of distortion indicating exposure of normal tissue volumes. The calculated F values correlated with these observations.

CONCLUSION

An evaluation of dose distributions cannot be based on a single conformal index. A solution could be the use of several indices presented as a hexagonal graphic and/or as a test function.