Injectable hydrogel: A promising frontier in cancer therapy.

The past decade has seen growing interest in injectable hydrogels for cancer therapy due to their tunable polymer backbones and high chemical versatility. Researchers are engineering injectable hydrogel platforms for chemotherapy, immunotherapy, and combination regimens to overcome limitations of conventional treatments. These materials enable localized, targeted delivery by encapsulating anti-tumor agents within a gel matrix, allowing sustained and controlled release that boosts efficacy while reducing systemic side effects. This review summarizes methods for preparing injectable hydrogels and highlights their key applications in cancer treatment, including strategies for payload loading, release modulation, and site-specific administration. We discuss how hydrogel composition, crosslinking chemistry, and microstructure govern therapeutic performance and biocompatibility, and we survey designs that integrate immune modulators, chemotherapeutics, or multi-modal agents for synergistic effects. Remaining challenges-such as predictable degradation, scalable manufacturing, in vivo stability, and regulatory translation-are examined, along with opportunities for improving targeting, responsiveness, and combination-therapy compatibility. Finally, we outline research directions needed to accelerate clinical translation, including standardized characterization, long-term safety studies, and optimized delivery protocols. By consolidating recent advances and identifying gaps, this review aims to guide future development of injectable hydrogels that can meaningfully enhance therapeutic outcomes for cancer patients.