Prognostic factors for pure ovarian immature teratoma and the role of adjuvant chemotherapy in stage I diseases

Background: The prognostic factors for patients with pure ovarian immature teratoma (POIT) and the role of adjuvant chemotherapy in stage IA G2-G3 and IB-IC POIT remains controversial.Methods: We conducted a retrospective study of 155 POIT patients treated in our hospital between 2000 and 2022. The recurrence-free survival (RFS), disease-specific survival (DSS), and potential prognostic factors of POIT patients were evaluated. Subgroup analysis was conducted in stage I other than stage IA G1 POIT.Results: The median age at diagnosis was 23.0 years (range: 4.0 - 39.0), and 126 (81.3%), 2 (1.3%), 26 (16.8%), and 1 (0.6%) patients had FIGO stage I, stage II, stage III, and stage IV disease, respectively. Twenty-three patients relapsed and five died of the diseases after a median follow-up of 7.6 years, with a 5-year RFS and DSS rate of 86.0% and 97.0%, respectively. Multivariate analysis showed that positive postoperative tumour markers (TM) were the risk factor for recurrence in the overall cohort (hazard ratio [HR] 4.058, 95% CI 1.175 - 14.019, p = 0.027) and subgroup (HR 10.237, 95% CI 2.175 - 48.179, p = 0.003), and FIGO stage II-IV was the only factor for DSS in overall cohort (HR 7.751, 95% CI 1.281 - 46.895, p = 0.026). In 110 patients subjected to subgroup analysis, 29 patients received surveillance without chemotherapy and 81 patients were administered adjuvant chemotherapy. Multivariate analysis revealed active surveillance significantly increased the recurrence rate (5-year RFS of 75.7% vs. 93.6%, HR 7.562, 95% CI 2.441 - 23.424, p < 0.001) but not the death related to POIT (p = 0.338).Conclusion: Positive postoperative TM and FIGO stage II-IV were the prognostic factors for POIT. Active surveillance in stage I POIT of any grade may be practical for those with negative postoperative TM.