Clinicopathological Determinants of Recurrence Risk and Survival in Mucinous Ovarian Carcinoma

SIMPLE SUMMARY: Mucinous ovarian carcinoma (MOC) is a unique type of ovarian cancer. While many MOC patients have excellent survival, patients who experience recurrence have extremely poor prognosis. Identifying patients at the highest risk of recurrence is important for identifying which patients need the most aggressive treatment, and to identify where new treatment strategies are needed to improve survival. We use a large cohort of MOC patients to identify factors associated with high and low risk of recurrence. We show that once patients reach 5 years from diagnosis, their risk of recurrence is low. Patients with more advanced-stage disease and higher pathological grade of disease are more likely to experience recurrence, and their survival is significantly shorter. For early-stage MOC patients, survival time was similar whether they were treated with surgery plus chemotherapy, or whether they only had surgery. Patient survival time following recurrence is extremely poor (median 5 months); new treatment options are urgently needed to improve their survival. ABSTRACT: Mucinous ovarian carcinoma (MOC) is a unique form of ovarian cancer. MOC typically presents at early stage but demonstrates intrinsic chemoresistance; treatment of advanced-stage and relapsed disease is therefore challenging. We harness a large retrospective MOC cohort to identify factors associated with recurrence risk and survival. A total of 151 MOC patients were included. The 5 year disease-specific survival (DSS) was 84.5%. Risk of subsequent recurrence after a disease-free period of 2 and 5 years was low (8.3% and 5.6% over the next 10 years). The majority of cases were FIGO stage I (35.6% IA, 43.0% IC). Multivariable analysis identified stage and pathological grade as independently associated with DSS (p < 0.001 and p < 0.001). Grade 1 stage I patients represented the majority of cases (53.0%) and demonstrated exceptional survival (10 year DSS 95.3%); survival was comparable between grade I stage IA and stage IC patients, and between grade I stage IC patients who did and did not receive adjuvant chemotherapy. At 5 years following diagnosis, the proportion of grade 1, 2 and 3 patients remaining disease free was 89.5%, 74.9% and 41.7%; the corresponding proportions for FIGO stage I, II and III/IV patients were 91.1%, 76.7% and 19.8%. Median post-relapse survival was 5.0 months. Most MOC patients present with low-grade early-stage disease and are at low risk of recurrence. New treatment options are urgently needed to improve survival following relapse, which is associated with extremely poor prognosis.