 Treatment: Study participants will have tests performed in advance of surgery to remove their ovaries. Surgery will be performed within four weeks of these tests. The exact day will be determined by the study participants menstrual history and by a process called randomization, which is a random decision making process to determine if each study participant will have their surgery during the first or second half of their menstrual cycle. On the day of surgery, blood will be taken immediately prior to surgery and three hours after surgery for hormone tests. After the surgery, study participants will be given tamoxifen in oral pills for daily consumption. Study participants will be asked to return to the hospital every two months for tests and distribution of additional tamoxifen tablets. Treatments will be discontinued for disease progression or unacceptable adverse effects. 