A 48-year-old woman with stage IIIC epithelial ovarian cancer (serous histology) has completed 6 cycles of neoadjuvant chemotherapy (carboplatin + paclitaxel) and achieved a clinical complete response. She is now scheduled for interval cytoreductive surgery. Intraoperatively, the surgeon finds minimal residual disease and achieves R0 resection. What is the most appropriate next step in management?