Recognizing that the routine use of GnRH agonist in this setting would lead to overtreatment of a small proportion of young women who do experience permanent menopause, this decision should be tailored to the individual patient’s risk of long-term amenorrhea, breast cancer risk features, and concerns regarding side effects, out-of-pocket costs, and the burden of injection visits. This evidence concerns the gene GNRH1 and breast cancer.