Objective The standard treatment for young patients with stage I malignant ovarian germ cell tumors, except stage I dysgerminoma and stage IA G1 immature teratoma, is unilateral salpingo-oophorectomy with complete staging surgery followed by platinum-based chemotherapy. However, the role of complete staging surgery and adjuvant chemotherapy remains controversial. The aim of this study was to investigate the role of complete staging surgery and adjuvant chemotherapy in patients with early-stage pure immature teratoma after fertility-sparing surgery.

Methods Patients with stage I pure immature teratoma who underwent fertility-sparing surgery between January 1986 and June 2018 were reviewed retrospectively. Fertility-sparing surgery was defined as preservation of the uterus and at least one adnexa. The inclusion criteria were age >18 years, stage I disease (confined to one ovary), and diagnosis of pure immature teratoma. Patients with distant metastasis or mixed ovarian germ cell tumor were excluded. Complete staging surgery was defined as peritoneal cytology examination, peritoneal biopsy, omentectomy, or omental biopsy with or without lymph node dissection. Patients designated with stage I disease without complete staging surgery were categorized as stage X. Disease-free survival was defined as the interval from the date of surgery to the date of recurrence or censoring. Disease-free survival curves were calculated using the Kaplan–Meier method and compared using the log-rank test.

Results A total of 75 patients were included in the analysis, with a median age of 26 years (range 18–40): 26 (34.7%) patients had received complete staging surgery; 51 (68%) patients received postoperative adjuvant chemotherapy while 24 (32%) underwent surgery alone; and 4 patients (5.3%) had recurrent disease during a median follow-up time of 80.2 months (range 13.7–261). The recurrence rates in the chemotherapy group and surveillance groups were 3.9% and 8.3%, respectively (p=0.46). All patients were successfully salvaged, except for one death. Tumor relapse occurred in patients with all grades of immature teratoma (G1: 1/35; G2: 2/25; G3: 1/15). Univariate analysis revealed that complete staging surgery, adjuvant chemotherapy, and tumor grade were not associated with 5 year disease-free survival (p=0.69, p=0.46, p=0.7, respectively). The 5 year disease-free survival rate was 94.6% and the overall survival rate was 98.7%.

Conclusion Adult patients with stage I pure immature teratoma had 98.7% overall survival and recurrence rates were low after fertility-sparing surgery.