**Letrozole in Uterine Leiomyosarcoma Study** This study is testing a medicine called letrozole to see if it can help people with a specific type of cancer called uterine leiomyosarcoma (LMS). LMS is a rare tumor in the uterus. The study's main question is whether letrozole can help stop the cancer from growing longer. Participants will take a 2.5 mg pill of letrozole each day. To join the study, you must have a type of LMS limited to the uterus and have had surgery to remove the uterus and ovaries. You must also be at least 18 years old and able to swallow pills. Doctors will check your health to make sure it's safe for you to participate. **Key Points:** - **Duration & Visits:** Participants will be randomly assigned to either take letrozole or just have regular checkups. - **Eligibility:** Must have a specific type of uterine cancer and good overall health. - **Exclusions:** Cannot join if you have other severe diseases, have been on specific medications, or are pregnant. This study helps researchers figure out if letrozole is a good treatment for people with this type of cancer.