Recent advances in organic and polymeric carriers for local tumor chemo-immunotherapy

Combination therapy involves the simultaneous administration of compounds with varying mechanisms of action that can improve the efficacy of antitumor therapy and reduce toxicity. The most widely used combination regimen is chemotherapy combined with focused immunotherapy. This is implemented to induce the apoptosis of tumor cells and can activate immune responses, improving the clearance rate of primary lesions and maintaining the resistance to postoperative tumor recurrence and metastasis. Advances in micro/nanotechnology, nanomedicine and biomaterials have contributed to the development of enhanced local drug co-delivery systems for cancer treatment, improving tumor targeting and ameliorating severe systemic complications. Carrier materials can achieve the local long-term controllable release of multiple drugs, which not only avoids rapid drug diffusion from the pathological site, but can achieve synergistic effects at lower drug concentrations. Polymeric carriers display excellent biocompatibility and biodegradability; especially, some of them also have anti-tumor effects. The aim of this article was to review recent progress in the use of organic and polymeric materials for local tumor chemo-immunotherapy, which can be used as carriers for chemotherapeutic drugs, immune adjuvants and genes, including amphiphilic nanoparticles, nanocapsules, nano-disks, nano-polyplex particles, hydrogels and implantable materials.