Late rectal toxicity determined by dose-volume parameters in computed tomography-based brachytherapy for locally advanced cervical cancer

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• 作者：Yong-Chun Zhou ; Li-Na Zhao ; Ning Wang ; Jing Hu ; Xiao-Huan Sun ; Ying Zhang ; Jian-Ping Li ; Wei-Wei Li ; Jun-Yue Liu ; Li-Chun Wei and Mei Shi
• 关键词：Computed tomography-based brachytherapy ; dose-volume histogram parameters ; late side effects ; locally advanced cervical cancer ; rectum
• 刊名：Cancer Medicine
• 出版年：2016
• 出版时间：March 2016
• 年：2016
• 卷：5
• 期：3
• 页码：434-441
• 全文大小：121K
• ISSN：2045-7634

文摘

The aim of this study was to observe the relationship between dose–volume histogram (DVH) parameters and rectal late side effects (LSE) in computed tomography (CT)-based brachytherapy (BT) for patients with locally advanced cervical cancer. In total, 144 cervical cancer patients received external beam radiotherapy and CT-based BT. The data from 111 survival cases with pelvic local control (LC) were used to analyze the relationship between DVH parameters and rectal LSE. The total doses, manifesting 2, 1, and 0.1 cm³ (D_2cc, D_1cc, and D_0.1cc) of the rectum, and D₉₀ for high-risk clinical target volume (HR CTV) were computed and normalized to 2 Gy fractions (EQD2) using a linear-quadratic model. The rectal LSE were evaluated by the late effects in normal tissues-subjective, objective, management, and analytic (LENT-SOMA) scale. A dose–response relationship was evaluated by probit analyses. For all patients, the total rate of rectal LSE was 56%, and the rate of ≥Grade 2 LSE was 27.4%. For the 111 survival cases with pelvic LC, the total mean for D_2cc was 71.23 ± 5.54 Gy for the rectum, and the D_2cc, D_1cc, and D_0.1cc values for Grades 2 and 3 were higher than those for Grades 0 and 1. In addition, the number of complications increased, and the complications became more severe as the dose increased, with a dose of 73.5 Gy resulting in a 10% probability of ≥Grade 3 LSE. In conclusion, DVH parameters could predict the incidence and grades of rectal LSE in CT-based BT. D_2cc showed an excellent predictive value, and 73.5 Gy for D_2cc of the rectum might be considered as an alternative dose limit.