The purpose of this survey is to examine the effect on quality of life (QOL) improvement and convenience of switching to leuprorelin acetate 3 months depot 11.25 milligram (mg) injection kit (Leuplin SR 11.25 mg injection kit) from a 4-week adjuvant therapy with a luteinizing hormone-releasing hormone analog (LH-RHa) 1 month depot over 48 weeks in premenopausal breast cancer participants in daily medical practice. Influence of condition of estrogen receptor expression on the efficacy and safety of leuprorelin acetate SR 11.25 mg injection kit was also evaluated.