Facing the growing global challenge posed by cancer, the quest for more accurate and potent cancer diagnostic and therapeutic strategies continues to require a multidisciplinary integration approach. This review firstly summarizes various types of nanoparticles in cancer research. Subsequently, it offers a comprehensive overview of signal-enhancing techniques for visualizing in situ tumors, along with multimodal diagnostic methods for detecting metastases. As for tumor therapy, cutting-edge drug delivery methods that can cross biological barriers and the pinpoint targeting of tumor lesions for precise medical intervention are introduced. Within the domain of therapeutic diagnostics, we elucidate the theoretical underpinnings and structural paradigms that underlie a spectrum of advanced diagnostic and therapeutic modalities. Additionally, we present a compendium of publications delineating the clinical applications of each nano-based theragnostic integration platform. Finally, this comprehensive review discusses the safety concerns pertaining to the clinical application of nanoparticles and proposes some strategic recommendations to enhance the precision and safety of theragnostic-guided, nanotechnology-based clinical practices. A deeper understanding of nanomaterials, together with intimate interdisciplinary collaborations, nano-wave will most probably guide human beings to win the battle against cancers.