Introduction/Background We compared outcomes between patients with stage IIIC ovarian cancer and different patterns of metastases in stage IV disease following cytoreductive surgery.

Methodology We conducted a single-centre retrospective cohort study of all patients diagnosed with FIGO stage IIIC, IVA, IVBi (extra-abdominal lymphatic metastases) and IVBii (parenchymal metastases), who underwent Primary Cytoreductive Surgery (PCS) or Interval Cytoreductive Surgery (ICS) at University College London Hospital between 2006–2019. Patients with low grade or non-epithelial histologies were excluded. Disease stage, timing of surgery, cytoreduction completeness, age, Charlson Comorbidity Index and modified-Aletti surgical complexity score were investigated in multivariable analyses.

Results 415 patients were identified for inclusion, 245 (59.0%) had stage IIIC disease, 66 (15.9%) IVA, 56 (13.5%) IVBi and 48 (11.6%) IVBii. The majority (92.0%) had high grade serous histology. Overall, 283 (68.2%) underwent ICS and 132 (31.8%) PCS; complete cytoreduction was achieved in 287 (69.3%) patients.

After 7.0 years median follow-up, median recurrence-free survival (RFS) was 12.0 months (95%CI:10.8–13.1) and median overall survival (OS) was 42.0 months (95%CI:38.0–45.9). Overall, there was no evidence of an association between disease stage and RFS (p=0.40) nor OS (p=0.20). PCS was independently associated with longer RFS (HR=0.48, 95%CI:0.37–0.62, p<0.001) and OS (HR=0.55, 95%CI:0.41–0.73, p<0.001). Patients with optimal and suboptimal resection had shorter RFS [HR=1.60 (95%CI:1.20–2.13, p<0.01] and HR=1.37 (95%CI:1.00–1.87, p=0.05) respectively) and OS [HR=1.56 (95%CI:1.17–2.09, p<0.01) and HR=1.38 (95%CI:0.99–1.92, p=0.06) respectively], compared to those with complete cytoreduction. Patients with higher surgical complexity score had shorter RFS (HR=1.07, 95%CI:1.02–1.12, p<0.01) and OS (HR=1.09, 95%CI:1.04–1.14, p<0.001).

Conclusion Similar RFS and OS were observed in stages IIIC, IVA and IVB epithelial tubo-ovarian cancer. However, timing of surgery, surgical complexity and completeness of cytoreduction were independently associated with outcomes. These data suggest that primary cytoreductive surgery should be considered for stage IV disease where complete intra-abdominal cytoreduction can be achieved.

Disclosures COI form submitted for two authors.