The Role of Delayed Interval Debulking Surgery (DIDS) in the Surgical Treatment of Advanced Epithelial Ovarian Cancer: A Retrospective Cohort from an ESGO-Certified Center

<b>Background/Objectives</b>: Patients with advanced ovarian cancer with a high tumor burden typically undergo neoadjuvant chemotherapy (NACT) followed by interval debulking surgery. The optimal number of NACT cycles remains undefined: although three to four cycles are considered gold-standard, in real-world practice, five or more cycles are frequently administrated. This study aims to evaluate the impact of delayed interval debulking surgery (DIDS) after ≥5 cycles of NACT on the survival rates. <b>Methods</b>: We conducted a retrospective analysis of women with advanced ovarian cancer that underwent surgery in the 1st Department of Obstetrics-Gynecology Clinic from 2012 to 2022. Patient characteristics, oncological, and follow-up information were collected. <b>Results</b>: A total of 125 patients met the inclusion criteria and were divided into two groups: Group A (77 patients) received 3-4 of NACT cycles, and Group B (48 patients) ≥5 cycles. No statistically significant difference was observed between the groups concerning age, BMI, comorbidities, Aletti score, FIGO stage, pre-operative CA-125 values, surgery duration, rate of postoperative complications, hospital stay, ICU admittance, and complete gross resection (RD = 0). However, patients undergoing DIDS experienced significantly greater intraoperative blood loss. Progression-free survival did not differ between groups (IDS: 17 vs. DIDS: 18 months, <i>p</i> = 0.561), whereas overall survival was significantly lower in the DIDS group (IDS: 52 vs. DIDS: 36 months, <i>p</i> = 0.00873). This statistical significance persisted after controlling for residual disease, but was lost after adjusting for FIGO stage. <b>Conclusions</b>: DIDS may be considered for advanced ovarian cancer patients with a high tumor burden, when complete gross resection (RD = 0) cannot be achieved during IDS. Further prospective randomized trials are necessary to evaluate its oncological safety and morbidity.