<p>Despite major advancements in surgery, chemotherapy, radiotherapy, and immunotherapy, cancer remains a critical global health threat. Conventional therapies often falter due to inadequate tumor targeting, systemic toxicity, multidrug resistance, and relapse. This has fueled growing interest in nanotechnology-based precision oncology. Biogenic nanoparticles (BNPs) stand out for eco-friendly synthesis, biocompatibility, and versatile therapeutic potential. This review explores recent biosynthesised silver (Ag), gold (Au), zinc oxide (Zn/ZnO), and copper (Cu/CuO) nanoparticles for cancer detection, targeted drug delivery, imaging, photodynamic therapy, and immunomodulation. It emphasises the physicochemical features of BNPs—particle size, morphology, surface charge, and biological coronas—that dictate cellular uptake, biodistribution, and oncologic efficacy. These nanoparticles exhibit cytotoxicity across diverse cancer types, including breast, liver, lung, cervical, and colorectal. They trigger cell death via reactive oxygen species (ROS), mitochondrial disruption, DNA impairment, caspase activation, cell cycle arrest, and apoptosis. The review also addresses innovations in theranostic platforms and tailored nanomedicine that integrate gene therapy and immunotherapy. It rigorously examines patents, translational advances, biosafety, regulatory obstacles, and scalable production challenges. BNPs hold promise as safer, more selective anticancer agents, yet their clinical translation needs robust in vivo validation, standardised toxicity evaluation, and additional clinical trials.</p> Graphical Abstract <p></p>