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

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. 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. 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, <i>p</i> = 0.027) and subgroup (HR 10.237, 95% CI 2.175 − 48.179, <i>p</i> = 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, <i>p</i> = 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, <i>p</i> &lt; 0.001) but not the death related to POIT (<i>p</i> = 0.338). 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. Positive postoperative tumour markers and FIGO stage II–IV were the prognostic factors for pure ovarian immature teratoma. Active surveillance in stage I pure ovarian immature teratoma of any grade may be practical for those with negative postoperative tumor markers.