<p>Borderline tumors (BOT) are epithelial ovarian tumors with increased proliferative activity and a lack of stromal invasion. They are treated exclusively by surgery and do not need adjuvant therapy. The recurrence rate is around 5%. Tumors with invasive implants belong to the group of low-grade serous ovarian cancers (LGSOC) and no longer to BOTs. Accordingly, they are treated in the same way as carcinomas. Almost 70% of BOTs are diagnosed in premenopausal patients. Serous BOTs can possess hormone receptors and therefore the question arises about endocrine therapy of LGSOC and also hormone replacement therapy (HRT) in premenopausal patients following bilateral salpingo-oophorectomy because of BOT. So far there are no clear recommendations for endocrine therapy in LGSOC; however, studies are currently recruiting patients with hormone receptor positive LGSOC for an endocrine maintenance therapy. There are also no clear data for HRT after BOT, but the increased morbidity and mortality in premenopausal patients after bilateral salpingo-oophorectomy are well-known, so that HRT should be recommended until the natural age of menopause (ca. 52&#xa0;years) to preserve the quality of life.</p>