To determine the role of adjuvant chemotherapy in stage IA G2-3 and stage IB-IC pure ovarian immature teratoma (POIT), we performed a systematic review and meta-analysis by searching PubMed, Embase, Cochrane library, Web of Science, and ClinicalTrials.gov. Randomized controlled trials or cohort studies on stage IA G2-G3 or stage IB-IC POIT between 1 January 1970 and 15 December 2022 were enrolled. The recurrence rate and mortality rate were the primary outcomes, and subgroup analysis based on the tumor stage and grade was also conducted. In total, 15 studies with 707 patients were included. Compared with surveillance, adjuvant chemotherapy significantly decreased the mortality rate (RR 0.31, 95% CI 0.11-0.88, p = 0.03), but not recurrence (RR 0.74, 95% CI 0.39-1.42, p = 0.37), in the overall population. Subgroup analysis showed no statistical difference in the recurrence rate and mortality rate between patients who received adjuvant chemotherapy and surveillance in pediatric POIT, stage IA G2-3 POIT, stage IB-IC POIT, and stage IA-IC G3 POIT (all with p > 0.05). However, patients who underwent adjuvant chemotherapy appeared to have a lower risk of both recurrence (RR 0.17, 95% CI 0.03-0.83, p = 0.03) and death (RR 0.04, 95% CI 0.00-1.00, p = 0.05) in adult POIT. Adjuvant chemotherapy significantly decreased the mortality rate in patients with stage I POIT and lowered the risk of recurrence in the adult subgroup. Surveillance administered in stage I POIT over IA G1 should be cautious, especially in adult patients.
Keywords: active surveillance; adjuvant chemotherapy; malignant germ cell tumors; ovarian immature teratoma; survival outcomes.