Precision Conversion of Colorectal Cancer Lung Metastases: A Personalized Quadruplet Regimen Integrating Photodynamic Therapy with Targeted, Immunotherapy, and Chemotherapy

Colorectal cancer (CRC) has a high incidence and mortality rate, with lung metastasis being the second most common site. Current treatments have limited efficacy, and novel approaches are needed. We report a case of a middle-aged female with CRC and lung metastasis treated with four cycles of PDT and five cycles of systemic therapy, including chemotherapy, targeted therapy, and immunotherapy. After treatment, the lung metastases showed cystic changes, and the primary tumor significantly regressed (TRG: AJCC 0, Becker 1a). This multimodal therapy shows promise in CRC lung metastasis, offering new insights for treatment. This case is the first report on PDT combined with systemic therapy in this context.