Surgical components
Three studies (n = 1230) reported the uterus’s tumor positivity and four the upstaging rate (n = 1326). The uterus was positive for a tumor in 6.2% (95%Cl: 1.8-10.7%) of the cases, with a corresponding upstaging rate of 5.9% (95%Cl: 1.4-10.4%) (Figure 1; see Appendix Figure S5 and S6).
Five studies (n = 1753) reported the tumor positivity of cytology from ascites or peritoneal washings and seven (n = 1986) on its upstaging rate. Cytology was positive for tumor cells in 18.4% (95%CI: 13.8-22.9%) (Figure 1; see Appendix Figure S7). Patients get upstaged due to positive cytology in 8.5% of the cases (95%CI: 1.8-15.2%) (Figure 1: see Appendix Figure S8).
Four studies (n = 415) investigated the tumor positivity of the peritoneum, whereas 7 (n = 928) reported the contribution of peritoneal biopsies in the upstaging rate (Figure 1: see appendix Figure S9 and S10). Positive peritoneal biopsies were found in 9.7% (95%CI: 3.8-15.6%) of the patients, but in 3.5% (95%CI: 1.0-6.0%) did this led to upstaging.
From 8 studies (n = 2085), the omentum was tumor positive in 5.2% (95%CI: 1.7-8.8%) of the patients, with an upstaging rate of 3.9% (95%CI: 1.4-6.3%) derived from 11 studies (n = 2412) (Figure 1; see Appendix Figure S11 and S12).
Three studies (n = 407) reported a tumor positive appendix in 3.6% (95%CI: 0.0-7.5%) of patients (Figure 1; see Appendix Figure S13). One study, Gouy et al., reported no appendiceal involvement was observed among their 24 included clinically stage I mucinous EOC patients who had undergone an appendectomy. No data specifically on the mucinous subgroup is available from the other included studies. Four (n = 507) evaluated the upstaging rate of early-stage EOC patients due to appendiceal involvement (Figure 1; see Appendix Figure S14), with a pooled result of 1.6% (95%CI: 0.0-3.4%).