Ewing sarcoma is the second most prevalent primary bone cancer in adolescents and young adults, with a median age of 15 years, accounting for less than 5% of all soft tissue sarcomas. ¹ There are around 200 cases of Ewing sarcoma identified in children each year in the United States, which accounts for one percent of all malignancies diagnosed in children. ² Based on the statistics provided by the Bone Cancer Research Trust (BCRT) in the United Kingdom, the number of reported instances of Ewing Sarcoma in the country are about 100 annually. ³ An analysis of data and trends derived from the National Cancer Registry Programme spanning the years 1982 to 2011 revealed that Ewing Sarcoma constituted around 15% of the total cases of bone malignancies in India. ⁴ Disparities in the features and outcomes were observed among patients with ES ¹ belonging to various racial and ethnic groups. Specifically, when compared to white non-Hispanic patients, black patients exhibited significantly elevated rates of soft tissue tumours; it was observed that the occurrence of soft tissue tumours exhibited an intermediate prevalence among Asian and white Hispanic individuals. ⁵ This prevalence differs from that observed in white non-Hispanic patients. ⁵ Notably, white Hispanic patients demonstrated a higher proportion of larger tumours upon initial presentation than white non-Hispanic patients. ⁵

Ewing sarcoma is a prototypical translocation sarcoma, and it was one of the first tumours in this category to be pathologically recognized as a single entity. ⁶ Chromosome translocations that fuse a gene from the ETS family of transcription factors with EWS

(EWSR1), located at 22q12, gives rise to Ewing sarcoma, the fusion gene EWS-FLI1 consisting of the N-terminal component of EWS and the C-terminal section of FLI1, together with the ETS DNA-binding domain, is present in approximately 90% of the cases instances. ⁶ It has an intricate array of conditions that require the coordination of numerous signalling pathways to manifest. ⁶ Without no precursor lesions, this unusual round cell creates an environment for the intricate transcriptional dysregulation controlled by EWSR1/FLI1, making illness detection and treatment difficult. ⁷ A periodic acid-Schiff stain can be used to detect glycogen, which is typically present in the sparse, eosinophilic, diastase-degradable cytoplasm; the cell nuclei are round, have one or more small nucleoli, and finely distributed chromatin. ⁸ Rosette formation observed. No matrix is generated by the EFT. ⁸ EFT cells show membranous expression of CD99 or MIC2 on doing immunohistochemistry analysis. ⁸

Diagnosis is most commonly made following local symptoms such as pain, stiffness, or swelling, which are secondary to tumour growth. ¹ After obtaining a patient's medical history and performing a physical examination, the doctor may order a radiograph to inspect the area. In Imaging investigations of Ewing sarcoma family of tumours (ESFT) affecting bone are characterised by a damaging neoplastic proliferation originating from the diaphysis or middle region of the bone. ⁹ As mentioned by Biermann et al. (2017, as cited in Durer and Shaikh 2022) the 2017 revision of the National Comprehensive Cancer Network (NCCN) guideline, imaging of main locations should include MRI either with or without CT, with or without contrast being of utmost significance. ¹ In order to ascertain the possible sites of metastasis, supplementary imaging modalities, such as computed tomography (CT) of the thorax, positron emission tomography/CT (PET/CT), bone scans, and magnetic resonance imaging (MRI) of the spine and pelvis, may be utilised. ¹⁰ To ascertain the possible sites of metastasis, supplementary imaging modalities, such as computed tomography (CT) of the thorax, positron emission tomography/CT (PET/CT), bone scans, and magnetic resonance imaging (MRI) of the spine and pelvis, may be utilised. ¹⁰ Further biopsy (either a biopsy (needle or surgical) is performed to ascertain if the cells are malignant and what type of cancer it is, and gene testing is also done to confirm the diagnosis. ¹¹ Once the diagnosis s confirmed, a treatment plan.

Chemotherapy, surgery, and radiotherapy are currently used as part of ES treatment. ¹² For all individuals with Ewing tumours, systemic combination chemotherapy is a necessary component of treatment. ¹³ The treatment of an Ewing tumour (Ewing sarcoma) is primarily determined by its location in the body and the extent of its propagation when it is first discovered. ¹⁴ 1.

For localised Ewing Sarcoma: Neoadjuvant chemotherapy is given, It is determined after nine weeks, if the tumour is shrinking and if a surgery can be done/is required. ¹⁴ Consolidation chemotherapy is given post primary treatment and might be accompanied by radiation therapy if cancer cells are discovered at or around the edges of surgical specimens. ¹⁴

Other novel treatment options, including targeted therapy and immunotherapy (including CAR-T cell therapy for recurrent Ewing sarcoma), are under clinical trials.

The utilisation of induction therapy involving vincristine, ifosfamide, doxorubicin, and etoposide (VIDE), followed by consolidation therapy with vincristine, actinomycin D, and either ifosfamide or cyclophosphamide (VAI or VAC), or alternatively, busulfan and melphalan (BuMel), continues to be the prevailing and widely accepted initial treatment approach for Ewing sarcoma in Europe. Conversely, in the United States, the established standard of medical care entails interval-compressed cycles of cyclophosphamide, doxorubicin, and vincristine (VDC), in conjunction with ifosfamide and etoposide (IE). ¹⁵ For the purpose of this systematic review, we focus on induction chemotherapy for Ewing Sarcoma, as it is one of the most significant components in the treatment, and it is important to either understand the reason for the two different approaches, or to bridge the gap in the absence of reasoning.

A systematic review (SR) is built on a specific and well-defined subject, and the PICO technique was used to construct the key question:

Patient/Population: Adults and/or children diagnosed with Ewing Sarcoma

Intervention: Usage of VDC/IE (or VAC/IE) for chemotherapy

Comparison: VIDE regimen

Outcome: Overall survival

Secondary outcome is Event Free Survival

A research protocol was registered with Prospero - crd.york.ac.uk/PROSPERO/display_record.php?RecordID=405442

Randomied control/clinical trials, case-control studies, and collective cohort studies were selected as the apt form for this systematic review, and any other type of study including secondary sources (reviews and meta-analysis), commentaries/letters to the editor, conference abstracts, and chapters from books were set for exclusion. Studies in languages other than English or animal studies were excluded as well. Studies comparing VIDE regimes.

Vincristine, Ifosfamide, Doxorubicin and Etoposide drug combination) to VDC/IE (or VAC/IE) (Vincristine, Doxorubicin (Adriamycin), and Cyclophosphamide drug combination) for induction chemotherapy were selected. Studies were disregarded if one or more drugs were replaced. Only studies/trials where VDC/IE and VIDE were compared head-on were considered (as stated in the Prospero protocol). No age restriction was imposed, and studies focusing on both adults and children were included.

Databases were searched for the application of unique structured search strategies for every database. Databases including Embase, Medline, and Web of Science. Informal searches of several trial registries and preprint servers were also done.

The search strategy used for searching the Embase, Medline, and Web of Sciences databases can be found under extended data section.

Research studies were located using the search strategy and loaded into Microsoft Excel before being copied to Google sheets for further work. After importing the studies to Google sheet, the process of deduplication was carried out. The process of deduplication is important because many databases frequently contain the same study, which results in the existence of many versions of the same paper. Deduplication was split into two phases: the first phase was auto deduplication, in which duplicates with identical titles were eliminated using a Google Doc add-on (while maintaining the original copy), and the filtrate was copied to another sheet. The second phase is that of manual deduplication, which is useful but not error-free, and is why a manual process is necessary. A manual deduplication process was used to ensure that no studies were counted more than once. The title field was used to sort the studies, and duplicates were eliminated. Duplicate entries were swiftly eliminated by arranging titles alphabetically.

The protocol's inclusion and exclusion criteria were then used to compare and scan the studies ( Figure 1). Each study was scanned by two independent reviewers; in case of disagreement, a decision was made post discussion and agreement on an explanation. Scanning against inclusion and exclusion criteria was done in two stages- a)

Title and abstract screening: Studies that had no link to the review question or PICO framework were disregarded at this initial stage.

Researchers have employed the evaluation of internal validity protections put in place to look at the potential trustworthiness of evidence produced within a study; such an evaluation has historically been referred to as a quality assessment since these protections defend against systematic error. ¹⁶ A risk of bias assessment is when the findings of a quality assessment are translated through the possible risk of bias using an empirical concept. ¹⁶ For this systematic review, the JBI Critical Appraisal Tools was used, the JBI checklist for randomised.

The control trial and JBI checklist for cohort studies were the specific tools which were used.

Two critical appraisers independently and rigorously evaluated the papers selected for inclusion. Differences in ROB assessments were reviewed in a discussion between the appraisers, following which a final outcome was generated.

Post this process three studies were found to be suitable for inclusion: a)

(Brennan et al., 2022) ¹⁷

All studies were determined to possess a sufficiently low risk of bias and were, hence, included. For the completed assessments, refer to extended data.

(This table has been adapted from Page et. al 2021 which is an This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited).

Data was extracted using Microsoft Excel. Fields including median age, gender distribution, Hazard Ratio and Confidence Interval were extracted from Brennan et al. (2022), ¹⁷ for both overall survival and event-free survival. Umeda et al. (2020) ¹⁹ and Umeda et al. (2021). ²⁰ compared multiple regimens and provided an aggregate overall survival outcome, but did not provide a direct comparison between the VIDE and VDC/IE regimes. As no data for the chosen measure of the effect was available, no data extraction was done for the two studies. The authors were contacted by the team. Qualitative evidence was considered for analysis.

The median age of the patients in the Umeda group was 13.5 years and 57.9% of patients were males. There was a lack of quantitative synthesis with respect to the outcome this systematic review has targeted, narratively, there is no significant difference between overall survival when either regimen is administered. ¹⁷ In contrast, Brennan et al. (2022) found that “Event-free survival at 3 years was 61% with group 1 and 67% with group 2 (adjusted hazard ratio [HR] 0·71 [95% credible interval 0·55–0·92 in favour of group 1)” with group 1 receiving the VIDE regime and group 2 receiving VDC/IE. ¹⁷ In the VIDE group, the overall survival at 3 years was 74%, but in the VDC plus IE group, it was 82% (HR 0:62, 95% CI: 0:46-0:85). ¹⁷

The group meticulously reviewed the research using a strict sc. Nevertheless, we were only able to locate three studies, and the majority of our research was based on Brennan and their team's previous work. Despite the limited number of studies available, the inclusion of a substantial number of patients in the study by Brennan et al. (2022) provides a strong foundation for our findings. Additionally, the consistency and reliability of Brennan et al. 's previous work further support the validity of our results.