已传文件：photo/1773121782.png Preventing the recurrence of cancer after surgery while preserving breast aesthetics and functionality remains a challenge. Traditional scaffold-based methods are often limited by insufficient integration with natural tissues and mismatch between the degradation rate of the materials and tissue development. Here, we report an anti-cancer drug secretion system based on engineered breast organoids for inhibiting postoperative tumor recurrence and promoting tissue reconstruction. By inducing milk secretion in breast organoids, lipid droplets form within the cells. Ph-responsive prodrugs, including all-trans retinoic acid and the chemotherapy drug doxorubicin, can easily be encapsulated in these lipid droplets. During lactation, milk fat globules rich in these drug-loaded lipid droplets are released into the residual tumor cells through the contraction of myoepithelial cells. Both mouse and human induced pluripotent stem cell-derived breast organoids have been designed as drug secretion reservoirs and have been proven effective in inhibiting tumor recurrence (reduction by 96%) in mouse breast cancer postoperative models. Moreover, the organoids can adaptively integrate with the breast and contribute to breast reconstruction, ultimately restoring the lactation ability of recipient mice.