Impact of lymphadenectomy and intraoperative tumor rupture on survival in early-stage mucinous ovarian cancers

Abstract

<h3>Objectives:</h3> Mucinous ovarian carcinoma (MOC) is a rare subtype of epithelial ovarian cancer and often presents a management conundrum. The aim of the study was to investigate the prognostic significance of lymphadenectomy and intraoperative rupture on patient survival. <h3>Methods:</h3> We conducted a retrospective cohort study of all MOCs diagnosed between 1999 and 2019 at two tertiary care cancer centers. Pathology was reviewed to rule out cases with metastasis from gastrointestinal tract primary. Baseline demographics, surgical management details, and outcomes were collected. Five-year overall survival (OS) and recurrence free survival (RFS) were calculated from Kaplan-Meier curves and comparisons made using log-rank test. Cox proportional hazard models were used to determine the association of lymphadenectomy and intraoperative rupture on survival. <h3>Results:</h3> A total of 170 women with MOC were identified, of which 149 (88%) had apparent stage I disease upon presentation. Median age was 49, (IQR 33-58) and the majority presented with low-grade unilateral ovarian masses (grade 1; 71%) with median size of 20.5cm (IQR 16-28) and had a five-year OS of 88.9% (82.9-95.3%) and RFS of 82.7% (75.7-90.3%). Forty-eight (32%; N=149) patients had a pelvic and/or para-aortic lymphadenectomy, but only 1 patient with grade 2 disease was upstaged due to positive pelvic lymph nodes. Omentectomy was carried out in 128 (86%) patients, and 2 patients with grade 2 disease were upstaged due to microscopic omental disease (1.6%). Intraoperative rupture was documented in 52 cases (35%); these were more likely to have initial surgery performed by a non-gynecologic oncologist (48% vs 11%; p<0.001). At final pathology, 137 had stage I (92%), 5 stage II (3%), 6 stage III (4%) and 1 stage IV (1%) disease. Fifteen patients (10%) received adjuvant chemotherapy; there was no significant difference in the rate of adjuvant therapy between those with or without intraoperative rupture (p=0.39). 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). Advanced stage was the only factor that was significantly associated with survival. <h3>Conclusions:</h3> For women with apparent stage I MOC, a second operative procedure for systematic lymphadenectomy has low utility, as very few patients are upstaged and recurrence typically occurs in the peritoneum. Furthermore, intraoperative rupture does not independently confer a worse survival, and therefore these women do not benefit from adjuvant treatment based on rupture alone.