曾辉   　孙梦熊   　蔡郑东

 摘要： Photodynamic therapy (PDT) is a novel method to cure cancer in recent years. Comparing with traditional therapies such as operation, radiotherapy, chemotherapy and so on, PDT has such advantages as minimal invasion, little toxic side effects, selective killing of tumor tissues without destroying normal structures nearby and so on. Photosensitizer is selectively aggregated in tumor tissues, and type I and II photochemical reactions occur under the illumination of specific wavelengths. Singlet reactive oxygen species (ROS) generated in these reactions have prominent tumor-killing effect. The anti-cancer mechanism mainly includes inducing tumor cell apoptosis and necrosis directly, destroying tumor blood supply and stimulating immune system. Due to the excessive resection of normal tissues such as blond vessels, nerves, joints and so on, the traditional bone cancer treatment methods including surgical resection, chemotherapy, radiotherapy and so on may lead to severely impaired limb function and high recurrence rates. Therefore, PDT is becoming a new treatment method for bone cancer. At present, it has been widely used in remedying malignant tumors such as skin cancer, head and neck cancer, lung cancer, breast carcinoma and so on. It has already been demonstrated by preclinical research that PDT can notably induce apoptosis in bone tumor cells in vitro, and meanwhile there are photosensitizer concentrations and laser energy density dependence for cell-killing effects mediated by PDT. In vivo study, PDT can effectively reduce local recurrence rates and metastasis rates in other places. In recent years, the operation combined with PDT can obviously reduce local recurrence rates, prolong patients’ median survival time, maintain the favorable limb function and so on. The current problem that the light penetration depth of PDT is limited can be effectively solved by low-dose X-rays, and whose anti-cancer mechanism is similar to that of PDT both in vitro and in vivo. In the treatment of metastatic bone tumors, especially metastatic spinal tumors, PDT also plays a crucial role in reducing the risk of tumor recurrence, preserving the structural stability of the spine and improving spinal function.