Research progress of potential factors influencing photodynamic therapy for gastrointestinal cancer

Gastrointestinal cancer is a malignant tumor of the gastrointestinal tract and its associated digestive organs, including esophageal cancer, gastric cancer, carcinoma of the ampulla, pancreas, bile duct, intestines and rectal cancer. They account for about 30% of global cancer-related incidence and about 40% of mortality. Photodynamic therapy (PDT), as a treatment mode, has been applied to the treatment of gastrointestinal cancer due to potential advantages targeting and potentially lower toxic side effects. However, In the course of clinical treatment, we have found that different patients have various responsiveness to PDT, and even the same patients may have different clinical effects after receiving treatment in different time periods. For influencing factors, traditionally, we only focus on adjusting the dose of photosensitizer and the intensity and time of irradiation,while minimizing other potential factors.Therefore, this paper looks for factors that affect PDT from the patient's own conditions, tumor characteristics and tumor microenvironment(including:tumor acidic microenvironment,tumor hypoxic microenvironment, multi-drug resistance, different tumor characteristics and the immune status of patients) and summarizes how to potentially improve the curative effect of PDT.