Survival and reproductive outcomes after fertility-sparing surgery performed for borderline epithelial ovarian tumor in Japanese adolescents and young adults: Results of a retrospective nationwide study

Objective Epithelial borderline ovarian tumor (BOT) frequently occurs in young women. Because progression-free survival, overall survival, and reproductive function are important outcomes, BOT is often treated by fertility-sparing surgery (FSS). We conducted a Japan-wide study to understand post-FSS prognosis in relation to clinical characteristics and types of FSS performed. Methods We analyzed clinical and outcome data pertaining to 531 adolescent and young adult (AYA) patients (aged 15-39 years) who underwent FSS for BOT between 2009 and 2013. Results Median (range) age was 30 (15-39) years, and median observation time was 70 (2-120) months. The disease was of FIGO stage I in 492 (93%) patients. Histopathologically, tumors were of the mucinous (n = 372, 70%), serous (n = 120, 23%), seromucinous (n = 23, 4%), and other (n = 16, 3%) types. Five-year overall survival was 99.5% among patients with stage I and 100% among those with stage II-IV. Five-year progression-free survival was 96.7% and 69.3%, respectively. Multivariate analysis in cases of stage I showed a positive peritoneal cytology to be a significant risk factor for recurrence (HR, 5.199; p = 0.0188). The post-FSS pregnancy rate was relatively low for patients aged >= 30 years (OR, 0.868; 95% CI, 1.16-3.00; p = 0.0090). Conclusion Post-FFS outcomes in terms of overall and progression-free survival are favorable, especially for AYA patients with stage I BOT. However, the relapse rate is high for patients with FIGO stage II-IV and for those with stage I but a positive peritoneal cytology. A long-term prospective observation is needed before reproductive outcomes can be fully established.