The development of multifunctional theranostic agents has become an intriguing
venture for personalized oncology, because they can integrate tumor diagnosis and therapy.
One approach explored to obtain such multifunctional theranostic agents is through the
chemical conjugation of anticancer drugs and contrast agents with various cancer-targeted
ligands. The other approach is based on the nanoplatform, in which cancer-targeted nanostructures achieve
simultaneous cancer specific detection and therapeutics either by EPR effect or by conjugation of target
ligands. Interestingly, a newly emerging strategy from multifunctional small molecules to develop cancertargeted
theranostic agents has been reported recently. In consideration of the urgent need and rapid development
of theranostic agents in cancer therapy, herein we review the currently adopted and newly emerging approaches
for their preparation, and highlight the promises and challenges in each approach, hoping to offer
useful insights in developing more specific and efficient cancer theranostic agents suitable for clinical use.