Patients with advanced-stage OCCC more frequently presented with preoperative CA125 levels of ≥114.5 U/mL, endometriosis absence, RD sized ≥1 cm, platinum–paclitaxel doublets, poor chemo-response, a PFI of <7 months, and a waiver of surgical resection. Here, MUC16 is linked to endometriosis.