Systematic search
This systematic review was developed and completed in compliance with the PRISMA and MOOSE guidelines (Appendix Table S1 and S2). PubMed (MEDLINE), Embase, and the Cochrane Library databases were systematically searched between 6 April 2020 and 15 April 2020. The search was limited to studies published between 1975 and 2020. The following terms were used: “ovarian neoplasm”, “ovarian cancer”, “neoplasm metastasis”, “tumor spread”, “pattern”, “neoplasm staging”, “TNM” and “neoplasm grading”, including their synonyms and alternative spellings (Appendix Table S3). Separate searches were performed with the MeSH terms in PubMed and the Emtree terms in Embase. Additional literature was searched through cross-examining the references of the retrieved articles.