Introduction/Background We aimed to depict the real-world surgical management of patients, with first diagnosis of FIGO stage IV primary epithelial ovarian cancer (EOC) compared to those with stage IIIC.

Methodology We conducted a retrospective analysis of all patients who underwent surgery for primary stage IIIC-IV EOC at Kliniken Essen-Mitte (KEM) from 2011–2022. Clinical parameters as time of surgery and residual tumour rates were compared between the two groups.

Results 1314 patients (median age 61; range: 21–89) underwent surgery for newly diagnosed FIGO stage IIIC or IV EOC at our centre from 2011–2022 (n=502, 38% and n=812, 62%, respectively). The tumour clearance rates at primary surgery, including procedures with no intent for complete resection, were 65% complete resection, 25% with residuals of 1–10 mm and 11% with >10 mm. The rate of interval debulking surgery (IDS) was 33% (n=163) in the IIIC cohort and 24% (n=192) in stage IV. Of note, more than 50% of IDS patients started neoadjuvant chemotherapy (NACT) prior to their referral to KEM (n=101, 62% and n=98, 51% respectively). In FIGO IIIC, complete macroscopic resection was achieved in 77% of patients who underwent NACT and in 63% of those who underwent primary surgery (PS) (p=0.002). In FIGO IV, complete resection was achieved in 72% and 66% of patients, respectively (p=0.11). The rate of complete resection did not differ between the stages (p=0.34 for PS; p=0.30 for IDS). Among patients with PS for stage IV disease, pleural involvement and lung metastasis were significantly more common in patients with residual disease as compared to those with complete resection: 32% vs. 14%; p<0.001 and 2.3% vs. 0.2%; p=0.02, respectively.

Conclusion Stage IV EOC patients have similar resection rates as patients with stage IIIC disease in both NACT and PS cohorts. Our results underline, that PS is feasible in patients with FIGO stage IV.

Disclosures COI submitted where applicable.