Letrozole for Estrogen/Progesterone Receptor Positive Low-grade Serous Epithelial Ovarian Cancer (LEPRE Trial)

This study tests letrozole (a hormone-blocking medication usually used for breast cancer) as a maintenance treatment for a rare type of ovarian cancer called low-grade serous carcinoma. After completing standard chemotherapy, participants take letrozole long-term to try to keep the cancer from coming back. **You may be eligible if...** - You are 18 or older - You have been newly diagnosed with low-grade serous ovarian, fallopian tube, or peritoneal cancer - Your tumor is confirmed by central pathology review - Your tumor tests positive for estrogen and/or progesterone receptors - You have completed your primary surgery and chemotherapy **You may NOT be eligible if...** - Your cancer is a different type or grade of ovarian cancer - Your tumor is not hormone receptor positive - You have another active cancer - You have serious health conditions that make letrozole unsafe (e.g., severe osteoporosis) Talk to your doctor to see if this trial is right for you.