Evaluation of Vaginal Dose in Cervical Cancer Patients Treated With Radiotherapy

Overview

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.

1. a detailed record of the irradiation dose and R-V point dose for all patients PIBS / PIBS ± 2cm, VRL data were taken. 2. according to CTCAE v3.0 standard, accurate and detailed record of patient treatment, after treatment of 2 years and the incidence of vaginal complications were recorded. 3. COX regression model was used to find dose-effect relationship between the reference point and vaginal complications. Clinical Scheme: Inclusion criteria: Pathologically confirmed cervical cancer patients, FIGO stage ⅠA- ⅣA patients who underwent radical radiotherapy, Any pathological type Exclusion criteria: FIGO staging of cervical cancer ⅢA; Age \> 60 years due to vaginal stenosis during the treatment course 1. pre-treatment: Abdominal and Chest CT scan before treatment. Patients were given pelvic MRI after EBRT to measure VRL before the start of brachytherapy. 2. 3DCRT / IMRT was used and according to RTOG target outlined recommendation dose of 46-50Gy / 23-25f; recording PIBS WP and R-V WP dose. 3. Intracavitary irradiation starts at the end of the external beam radiation using image-guided CT / SIM. catheterization of full bladder. Patients were advice to have empty rectum before CT scan The first treatment method: 1. Catheterization: placement of catheter inside bladder and injection of contrast agent-containing 7ml liquid 2. Place uterine and vaginal applicator device (must double the bulb), vaginal orifices ball from 3cm, and record 3. Vaginal packing with gauze is done to keep the applicator fixed. 4. Barium into the rectum and anal canal. 5. CT/SIM (transverse axis) is done to complete 3D / 2D treatment planning. measurement VRL, PIBS and PIBS ± 2cm, R-V were recorded; 6. Brachytherapy plan: Point A: 24-30Gy / 4-5f, or 21-28Gy / 3-4f HR-CTV: ≥85Gy, IR-CTV 65Gy dose records; 4. Concurrent chemotherapy: DDP 30-40mg / m2 \* 5w or T 135mg / m2D1 + DDP 30mg / m2 d1-3; 5. vaginal washing method is every day from the beginning of radiation therapy for six months. After 6 months, it was done twice per week for 2 years. 6. vaginal radiation complications were recorded according to CTCAE 3.0 standard 7. Gynecological examination and MRI was performed before radiotherapy and brachytherapy treatment and also after the entire treatment period. Patients follow-up was done on the 1,3,6,9,12,18 and 24th month after treatment during which vaginal radiation complication were evaluated according to CTCAE 3.0 standard 8. COX regression model was used to find dose-effect relationship between the reference point and vaginal complications.