Diameter Variation of Rectum and Bladder for Prostate Cancer Radiotherapy Under Bowel Preparation Regime
T Li1,2, Y Guo1,2, X Dai1,2, L He1, X Yang1, S Huang1*, (1) Sun Yat-sen University Cancer Center; State Key Laboratory of Oncology in South China; Collaborative Innovation Center for Cancer Medicine; Guangdong Key Laboratory of Nasopharyngeal Carcinoma Diagnosis and Therapy, Guangzhou, Guangdong province, 510060, China, (2) Guangzhou Xinhua College, Guangzhou, Guangdong, 510520, China
Presentations
PO-GePV-M-330 (Sunday, 7/10/2022) [Eastern Time (GMT-4)]
ePoster Forums
Purpose: The clinically accepted rectum and bladder of prostate cancer radiotherapy under bowel and bladder preparation was analyzed retrospectively to obtain the optimal volume and diameter, providing quantitative, operable indicators suitable for rectum and bladder preparation.
Methods: 277 definitive prostate patients treated with 52~68GY followed bowel and bladder preparation in our center. Clinical Tumor Volume (CTV) includes entire prostate and seminal vesicles. Bladder volume (BV), bladder length (BL) and maximum vertical diameter(W) were measured on the sagittal plane in the midline of pubic symphysis. Rectum filling was assessed by measurement of anterior-posterior (AP) diameters (D1:at the superior of CTV; D2: at the middle of CTV, D3: the maximum AP diameter), and lateral (Lat) diameter(D4). Relation between volume and diameter of bladder and rectum was analyzed.
Results: The mean BV was 370.003 ± 110.193 cm³ and BL/W was 1.012 ± 0.251. BL/W of bladder was divided into three groups (A: X< 0.76; B: 0.76≤ X ≤0.99; C: X>0.99). The BL/W of A, B and C were 1.206±0.177, 0.881 ± 0.065, 0.651 ± 0.083, and BV of A, B and C were 396.730±106.038 cm³, 354.316±113.483 cm³, 314.431±98.860 cm³. The difference was statistically significant for Volume and BL/W of the 3 groups (p<0.05). The linear relationship between V and BL, W was V=46.844*BL+41.546*W-391.481. Rectum AP diameters D1, D2, D3 and D4 were 3.128 ± 0.889cm, 3.2856 ± 0.809cm, 3.963 ± 0.810 cm, 3.548 ± 0.834cm.
Conclusion: BV was suggested to be 260 ~ 480 cm³. The BL/W was recommended to be within 0.761~1.263, contributing to predict BV. Rectum Diameters corresponding to CTV should be less than 3.5cm and the others should be less than 4cm. The result was consistent to clinical experience and other research findings.
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