Department of Obstetrics and Gynecology, Qilu Hospital, Shandong University (250012) Song Kun Kong Beihua In recent years, with the development of routine cervical cytology screening, more and more patients with CIN have been diagnosed in a timely manner.CIN is a precancerous lesion of the cervix, and the cure rate of its traditional treatments such as cold knife conization, electrocautery, freezing and laser can be as high as 90-98%, but these operations inevitably damage the cervical mesenchyme and destroy the However, these operations inevitably damage the interstitium of the cervix and destroy the integrity of the cervix, causing a decrease in the conception rate of patients. Therefore, a new therapeutic method, Photodynamic Therapy (PDT), has been tried for the treatment of CIN, with the aim of maintaining the tissue and structural integrity of the cervix while ensuring efficacy. To investigate the clinical feasibility of PDT, Dr. Bodner K recently conducted a clinical case-control study comparing the efficacy of cold knife conization with PDT in patients with HPV-positive CIN. Song Kun, Department of Gynecology, Qilu Hospital, Shandong University, studied 22 nonpregnant patients, 11 each in the treatment group (PDT group) and the control group (cold knife conization group). The mean age of the patients in both groups was not statistically different (P > 0.05), and all were confirmed to be HPV-positive CIN II by HPV-DNA testing of cervical secretions as well as Pap smear and colposcopic biopsy before treatment. acid (5-ALA), a water-soluble preparation that is metabolized intracellularly to produce protoporphyrin (PpIX), which produces a photodynamic effect by light wave irradiation and kills cells. First, a vacuum tube was attached to the cervix to generate negative pressure, and 5-ALA solution was injected into the vacuum tube, so that 5-ALA was uniformly distributed on the surface of the vaginal part of the cervix and in the cervical canal, and light irradiation was performed after 8h. The cervicovaginal surface was irradiated with red light of wavelength 600-750 nm with an intensity of 90 mW/cm2 and a field diameter of 4.5 cm; the intracervical canal was irradiated with a KTP:YAG pumped dye laser with a wavelength of 652 nm and an intensity of 300 mW/cm2. The abnormal epithelial tissue was removed and the cervical canal was scraped at the same time to prevent missing the marginal part of the CIN lesion. Both groups were retested for HPV-DNA 3 months after treatment and followed up with cervical smear and colposcopy in the outpatient clinic for 1 year. The results showed that 8 patients in both the treatment group and the control group turned negative for HPV-DNA, with a 73% conversion rate; after 1 year of follow-up, there was no recurrence of lesions in the control group, with a 100% cure rate, and a 91% cure rate in the treatment group. Statistical analysis showed that there was no statistical difference in the HPV-DNA conversion rate and the cure rate of CIN lesions between the two groups (P > 0.05). PDT uses photosensitizer molecules to receive certain wavelengths of light energy and then convert light energy into intramolecular energy through photochemical reactions and energy transfer processes to produce a variety of reactive oxygen species under aerobic conditions, which can have destructive effects on biological macromolecules such as proteins, nucleic acids and lipids, leading to apoptosis or cell death, thus providing a therapeutic effect. Since photosensitizers can selectively accumulate in abnormal proliferating tissues, such as tumor tissues, coupled with the choice of light wavelength, intensity and site, it makes PDT relatively specific, with little damage to healthy tissues and few complications and toxic side effects. The results of the above study show that local PDT treatment for HPV-positive CIN can achieve similar therapeutic effects as cold knife conization, and can maintain the integrity of the cervix without systemic and local complications, with simple and easy treatment methods, precise efficacy and outstanding advantages, which have clinical application value. Nevertheless, the application of PDT in the field of obstetrics and gynecology has just started, and many details such as the penetration of light waves and the selection of photosensitizers need to be further discussed. For patients with CIN, PDT treatment should follow the principle of individualization, and the specific treatment plan should be formulated by selecting the light source and light intensity according to the characteristics of the lesion. It is worth noting that since CIN is a precancerous lesion, a clear diagnosis should be made pathologically before treatment to exclude the possibility of the existence of invasive carcinoma so as to avoid delaying the disease.