Objective The aims of this study were to evaluate the rate of recurrences in borderline ovarian tumors (BOTs) with microinvasion and to evaluate the possibility to enlarge fertility-sparing surgery in this group of patients.

Methods Between 1985 and 2010, 209 patients with BOTs were retrospectively divided into 2 groups: group 1 consisted of 28 women with microinvasive BOTs; group 2 consisted of 181 with BOTs without microinvasion. All of the patients were submitted to surgical treatment: in group 1, 10 patients underwent cystectomy (CYS), 11 patients underwent monolateral salpingo-oophorectomy (MSO), and 7 patients underwent bilateral oophorectomy with or without total hysterectomy (BSO); in group 2, 34 patients underwent CYS, 58 patients underwent MSO, and 89 patients underwent BSO. Specific prognostic factors such as stage, surgical approach, intraoperative spillage, histology, exophytic tumor growth, and endosalpingiosis were analyzed. Tumor recurrence rate and overall and disease-free survivals were evaluated.

Results After a mean follow-up of 53 months, relapses occurred in 21.4% of the cases in group 1 and in 12.7% of the cases in group 2 (P = 0.21). The prognostic factors had no significant differences in the 2 groups. Relapses after CYS, MSO, and BSO were observed in 30%, 27.3%, and 0%, respectively, in group 1 and in 29.4%, 12.1%, and 6.7%, respectively, in group 2. Progression-free survival was significantly longer in BOTs compared to microinvasive BOTs (P = 0.041), but overall survival did not differ.

Conclusions Although exploratory, our data suggest that BOTs with microinvasion present earlier relapses, but overall incidence of relapses and overall survival do not differ significantly from BOTs without microinvasion. Fertility-sparing surgery is feasible in this group of patients, but strict follow-up has to be suggested.