Clinical and Pathologic Features of Patients with Rare Ovarian Tumors: Multi-Center Review of 167 Patients by the Anatolian Society of Medical Oncology

Background: Non-epithelial malignant ovarian tumors and clear cell carcinomas, Brenner tumors, transitionalcell tumors, and carcinoid tumors of the ovary are rare ovarian tumors (ROTs). In this study, our aim was todetermine the clinicopathological features of ROT patients and prognostic factors associated with survival.Materials and
Methods: A total of 167 patients with ROT who underwent initial surgery were retrospectivelyanalyzed. Prognostic factors that may influence the survival of patients were evaluated by univariate andmultivariate analyses.
Results: Of 167 patients, 75 (44.9%) were diagnosed with germ-cell tumors (GCT) and 68(40.7%) with sex cord-stromal tumors (SCST); the remaining 24 had other rare ovarian histologies. Significantdifferences were found between ROT groups with respect to age at diagnosis, tumor localization, initial surgerytype, tumor size, tumor grade, and FIGO stage. Three-year progression-free survival (PFS) rates and median PFSintervals for patients with other ROT were worse than those of patients with GCT and SCST (41.8% vs 79.6% vs77.1% and 30.2 vs 72 vs 150 months, respectively; p=0.01). Moreover, the 3-year overall survival (OS) rates andmedian OS times for patients with both GCT and SCST were better as compared to patients with other ROT,but these differences were not statistically significant (87.7% vs 88.8% vs 73.9% and 170 vs 122 vs 91 months,respectively; p=0.20). In the univariate analysis, tumor localization (p<0.001), FIGO stage (p<0.001), and tumorgrade (p=0.04) were significant prognostic factors for PFS. For OS, the univariate analysis indicated that tumorlocalization (p=0.01), FIGO stage (p=0.001), and recurrence (p<0.001) were important prognostic indicators.Multivariate analysis showed that FIGO stage for PFS (p=0.001, HR: 0.11) and the presence of recurrence (p=0.02,HR: 0.54) for OS were independent prognostic factors.
Conclusions: ROTs should be evaluated separately fromepithelial ovarian cancers because of their different biological features and natural history. Due to the rarity ofthese tumors, determination of relevant prognostic factors as a group may help as a guide for more appropriateadjuvant or recurrent therapies for ROTs.