A 58-year-old postmenopausal woman presents with progressive abdominal bloating and early satiety. On pelvic MRI, the structures marked **D** (bilateral ovaries) show a complex heterogeneous mass with solid components, ascites, and peritoneal nodules. CA-125 is elevated at 245 U/mL. Which of the following is the most appropriate next step in management after confirming the diagnosis of ovarian cancer?