2.1 Search strategy
Searches were conducted in April 2020 in three publicly available
databases: PubMed; Google Scholar; and Cochrane Library. Search strategy
involved an iterative process in which keywords for searches were a
combination of one diagnosis name and one topic name. The Ewing sarcoma
family tumors (ESFT) historically included a family of morphologically
similar malignancies but with diverging names. Thus, five diagnosis
search terms were utilized: Ewing sarcoma; Ewing’s sarcoma; Peripheral
Neuroectodermal Tumor; PNET; and Askin Tumor. Alongside a diagnosis
term, 13 topic search terms were utilized: bone marrow; bone marrow
biopsy; bone marrow aspirate; Positron Emission Tomography; PET;
metastatic; metastatic pattern; metastasis; randomized; phase III;
clinical trial; staging; and diagnosis. This process resulted in 65
individual searches (5 diagnosis terms x 13 topic terms) for each of the
3 databases utilized (195 total searches across all databases). For each
search, a single reviewer documented the number of results, the number
of abstracts read and the number of articles meeting criteria to be
shared with a second reviewer for final approval. A third reviewer was
available to resolve any discrepancies. Searches resulting in
>500 results were edited to restrict specific keywords
deemed irrelevant to this study. For example, the PubMed search of
‘Primitive Neuroectodermal Tumor’ + ‘metastatic’ yielded 4,129 results.
After designating the search not return articles with keywords ‘case
report,’ ‘neuroblastoma,’ ‘medulloblastoma,’ and ‘pancreatic,’ results
decreased to 284 articles. To expand our search, references of the
retrieved articles were also screened for additional studies.