Objectives The aim of the study was to investigate the prognostic significance of lymphadenectomy and intraoperative tumor rupture in patients with apparent stage I mucinous ovarian carcinoma (MOC).

Methods We conducted a retrospective cohort study of MOCs diagnosed between 1999–2019 at two tertiary cancer centers. Pathology was reviewed to rule out metastasis from gastrointestinal tract. Clinicopathologic details, five-year overall survival (OS) and recurrence free survival (RFS) were examined. Cox proportional hazard models were used to determine the association of lymphadenectomy and intraoperative rupture on survival.

Results of 149 with apparent stage I disease, 48 (32%) had pelvic and/or para-aortic lymphadenectomy, but only 1 patient with grade 2 disease was upstaged due to positive pelvic lymph nodes. Intraoperative rupture was documented in 52 (35%); these were more likely to have initial surgery performed by a non-gynecologic oncologist (48% vs. 11%; p<0.001). There were 20 recurrences in the cohort (13%; 9 grade 1, 6 grade 2, 4 grade 3), with the vast majority peritoneal (95%). On multivariable analysis, after adjusting for age, final stage, and use of adjuvant chemotherapy, there was no significant association between intraoperative rupture with OS (HR 2.2 (0.6–8.0), p=0.25) or RFS (HR 1.3 (0.5–3.3), p=0.63) or lymphadenectomy with OS (HR 0.9 (0.3–2.8), p=0.90) or RFS (HR 1.2 (0.5–3.0), p=0.73).

Conclusions In apparent stage I MOC, systematic lymphadenectomy has low utility, as few patients are upstaged and recurrence typically occurs in the peritoneum. Furthermore, intraoperative rupture does not independently confer a worse survival.