Introduction To evaluate the long-term safety of ovarian cystectomy in patients with stage I unilateral borderline ovarian tumors (BOTs) who desire preserved fertility.

Methods This retrospective study included 309 patients with stage I unilateral BOTs who underwent fertility-sparing surgery between 1990 and 2015. Patients were divided into two groups according to the type of adnexal surgery: unilateral oophorectomy or salpingo-oophorectomy (USO group) and unilateral ovarian cystectomy (UOC group). Surgical, oncological, and reproductive outcomes were compared.

Results A total of 263 patients (85.1%) underwent USO and 46 (14.9%) underwent UOC. After a median of 53 months of follow-up (range: 6–249), 13 patients in the USO group (4.9%) and 4 patients in the UOC group (8.9%), respectively, had recurrent disease (P = 0.288), and three (1.1%) and none (0%), respectively, died of disease (P > 0.999). Two patients from the UOC group had recurrence on the same side of the ovary, and two had recurrence in the opposite ovary. All patients underwent a successful salvage operation.

Conclusion/Implications The recurrence rate after UOC in women with stage I unilateral BOTs was higher than that after USO. However, the difference was not significant, and all recurrences were successfully salvaged by secondary surgery. Overall survival was not compromised after UOC. Therefore, UOC can be considered in patients with stage I unilateral BOT who do not have other options for fertility preservation.