Low-grade Serous Ovarian Carcinoma (LGSOC)

The purpose of this study is to evaluate the efficacy of addition of letrozole to the standard maintenance therapy in subjects following a primary diagnosis of Estrogen-receptor (ER) positive high and low grade epithelial ovarian cancer (including fallopian tube and primary peritoneal cancer) and subsequent primary treatment surgery and chemotherapy. Half of the participants will receive to the standard maintenance treatment, letrozole, whilst the other half receives placebo. The study's primary hypothesis is that the treatment with letrozole increases progression free survival in comparison to the maintenance standard treatment (superiority trial).