Overcoming colorectal cancer and cancer stem cell resistance with photodynamic therapy: new frontiers in oncology.

Colorectal cancer (CRC) is a major global health issue characterized by abnormal cell growth leading to high morbidity and mortality rates. While conventional treatments like chemotherapy and surgery exist, they often fall short due to severe side effects and the emergence of treatment resistance, particularly from cancer stem cells (CSCs). These CSCs contribute to tumor initiation, progression, and recurrence, posing challenges for effective management. Photodynamic therapy (PDT) offers a promising alternative, leveraging light-activated photosensitizers (PSs) to selectively target and destroy tumor cells while minimizing damage to healthy tissue. Recent advancements in PDT, including the use of nanoparticles (NPs) and novel PSs, enhance its efficacy against CRC and CSCs. Preclinical studies have demonstrated PDT ability to induce apoptosis and inhibit tumor growth in various models, highlighting its potential as a therapeutic strategy. Additionally, combining PDT with immune checkpoint inhibitors may further improve treatment outcomes by activating robust immune responses. This review discusses the mechanisms of resistance in CRC, the role of CSCs, and the evolving landscape of PDT, emphasizing the need for continued research to optimize combination therapies for enhanced efficacy against colorectal cancer.