Cancer is known as the uncontrolled growth and spread of abnormal cells throughout the body, which can begin in any organ or tissue. It is the second biggest cause of death worldwide, accounting for nearly 9.6 million fatalities per year. Early detection improves the likelihood of effective treatments, boosts survival rates, and lowers treatment costs. Breast cancer, the main cause of cancer-related deaths in women, poses serious worldwide health challenges. Despite advancements in chemotherapy, radiation therapy, and surgery, non-specific drug distribution, multidrug resistance, and systemic toxicity restrict their efficacy. Metal-based nanocomposites, which have distinct physicochemical features, provide intriguing options. This research investigates the possibility of metal nanocomposites, such as gold, silver, and magnetic nanoparticles, as novel platforms for breast cancer treatment. These nanostructures, synthesized using modern techniques and functionalized with anticancer agents, improve drug stability, tumor targeting, and delivery efficiency. Nanoparticles (1–100 nm) show unique properties. Green synthesis, using biocompatible substances, offers a cost-effective, biodegradable synthesis approach. These nanoparticles have changed medicine through targeted drug delivery and personalized treatments with fewer side effects. Studies show metal nanocomposites enhance drug loading, controlled release, and tumor targeting, therefore, reducing toxicity. Gold nanoparticles excel in photothermal properties, boosting combined therapies such as photothermal and chemotherapy. These findings underscore the immense potential of metal nanocomposites as multifunctional nanotherapies for breast cancer. They address critical challenges in conventional treatments, paving the way for precise, effective, and personalized care. Further research on clinical translation, large-scale production, and regulatory approval is essential to realize their full potential.