Evaluation of Vaginal Dose in Cervical Cancer Patients Treated With Radiotherapy

Cervical cancer is the most common malignant in women with the average five-year overall survival rate as high as 70%. Radiation therapy is the main treatment for cervical cancer. Vagina is one of the important organ at risk and also a target organ in the treatment of cervical cancer patients. Vaginal radiation has serious related complications that affect the quality of life of patients and therefore needs much clinical attention. But due to lack of sufficient evidence, the clinical dose to the vagina is limited. ICRU-89 defined the recto-vaginal reference point (R-V) as a reference point for vaginal dose assessment. However, the R-V position is affected by applicator placement, vaginal packing and other factors hence the dose point only do not represent the entire vaginal radiation dose resulting in some clinical limitations. The latest research in Europe proposed that PIBS(Posterior-Inferior Border of Symphysis) / PIBS ± 2cm and VRL (vaginal reference length) may be more reasonable to use to assess vagina radiation doses, but it remains to be further clinically investigated. Therefore, this study intends to perform radical radiotherapy in cervical cancer patients and also by recruiting local and foreign hospitals into this study by recording its PIBS/ PIBS ± 2cm, VRL, R-V point dose, acute and chronic radiation injury incidence of vagina and other useful data. T-test and chi-square will be used to compare the data between Asian and European women. Correlation analysis will be used to determine if there is a relation between R-V and PIBS point dose. Furthermore, logic and or COX regression model to evaluate PIBS / PIBS ± 2cm and R-V point doses of vaginal radiation injury relationships, while exploring other relevant factors causing vaginal radiation injury. This is eventually expected to provide a scientific, simple and reliable reference point for vaginal dose assessment and clinical dose limit.