Luteal v. Follicular Phase Surgical Oophorectomy & Tamoxifen in Premenopausal Women With Metastatic Hormone Receptor + Br. CA

Rationale: Previous research suggests that women who have their ovaries removed as part of
their treatment for breast cancer may live longer if the ovarian surgery is performed during
the luteal phase (last 14 days of the menstrual cycle) rather than the follicular phase (the
first 14 days of the menstrual cycle). The current study will evaluate this important
research question in premenopausal women with metastatic hormone receptor-positive breast
cancer who will be treated with surgery and tamoxifen.

Purpose: The purpose of this research is to find out if premenopausal women with breast
cancer that has spread to other parts of the body live longer if their ovaries are removed
during the second half of the menstrual cycle. This study will compare how long women live
if they have their ovaries removed during the first half of their menstrual cycle
(follicular phase) to how long women live if they have their ovaries removed during the
second half of their menstrual cycle (luteal phase). Tamoxifen will also be given to study
participants.

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 participant's 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.