Objective: Although photodynamic therapy PDT has been proven effective in various tumors, it has not been widely used as a routine treatment for colorectal cancer CRC , and the characteristics of changes in the tumor microenvironment TME after PDT have not been fully elucidated. Subsequently, short-term efficacy, systemic and local immune function changes, and adverse reactions were assessed in CRC patients treated with PDT. Results: A total of 52 CRC patients were enrolled in this retrospective study from November to July , and the follow-up period ended in March No severe adverse reactions associated with PDT were observed.
It alters the TME by recruiting immune cells into tumor tissues. Colorectal cancer CRC is one of the most common gastrointestinal malignancies. According to the global cancer statistics , the overall incidence of CRC has jumped to third place, ranking second among all cancer deaths 1. In China, CRC is the second most common cancer and the fifth leading cause of cancer death, with about , new cases and , deaths.
China has become the country with the most significant number of new cases and deaths of CRC every year 1 , 2. CRC has an insidious onset, and many patients are already at an advanced stage when the tumor is detected 3 , losing the opportunity for radical surgical treatment. However, even if they are eligible for surgery, patients with low rectal cancer usually prefer to remain anal to avoid quality-of-life changes associated with a colostomy or low anterior resection syndrome 5.
Traditional CRC therapies such as chemotherapy and radiotherapy often accompany myelosuppression, non-targeting tumor-damaging normal cells, and multidrug resistance 6. Some patients may not be treated on time or give up halfway due to severe side effects and adverse events that cannot be tolerated. Additionally, cell therapy, immunotherapy, and targeted therapy have shown great potential in treating CRC, but the low benefit rate and high cost limit the number of people who benefit 6.
These current situations pose severe challenges to the current treatment of CRC. Due to a series of advantages such as high safety, robust targeting, low invasiveness, and fewer side effects, PDT may even become one of the conventional anti-tumor treatments in the future 7.
