Ujaimi Reem, Milosevic Michael, Fyles Anthony, Beiki-Ardakani Akbar, Carlone Marco, Jiang Haiyan, Lindsay Patricia, Xie Jason, Gerber Rachel, Croke Jennifer, Skliarenko Julia, Levin Wilfred, Han Kathy
Radiation Medicine Program, Princess Margaret Cancer Centre, University Health Network, Toronto, Ontario, Canada.
Radiation Medicine Program, Princess Margaret Cancer Centre, University Health Network, Toronto, Ontario, Canada; Department of Radiation Oncology, University of Toronto, Toronto, Ontario, Canada.
Brachytherapy. 2017 Sep-Oct;16(5):968-975.e2. doi: 10.1016/j.brachy.2017.06.007. Epub 2017 Jul 27.
The dose delivered to the most exposed 2 cm [Formula: see text] of the rectum and bladder is predictive of late rectal and bladder toxicity in cervix cancer patients. We investigated the predictive value of intermediate doses to the rectum and bladder for late rectal/bladder toxicity after MRI-guided brachytherapy for patients with locally advanced cervix cancer.
Toxicity was prospectively graded using Common Toxicity Criteria for Adverse Events v4.0 and retrospectively verified for women with Stage IB-IVA cervix cancer treated consecutively with MRI-guided brachytherapy between 2008 and 2013. The minimum equivalent dose in 2 Gy fractions delivered to 0.1, 1, 2, 5, and 10 cm of the rectum and bladder and the absolute volume of the rectum receiving 55, 60, 65, 70, and 75 Gy (V) were collected. The association between dose-volume parameters and Grade 2+ rectal/bladder toxicity was examined using logistic regression.
With a median followup of 44 months, cumulative incidences of Grade 2+ rectal and bladder toxicity among the 106 patients were 29% and 15% at 3 years, respectively. All the dose-volume parameters were significantly associated with late Grade 2+ rectal and bladder toxicity (p < 0.05), except for bladder [Formula: see text] . On multivariable logistic regression, both [Formula: see text] > 70 Gy and V > 11 cm (p < 0.05) were predictive of late Grade 2+ rectal toxicity, with improved model fitting and higher area under the curve compared with the model with [Formula: see text] > 70 Gy alone.
In this study, V was predictive of late Grade 2+ rectal toxicity. Adding V to [Formula: see text] improved prediction accuracy.
直肠和膀胱最暴露的2厘米（公式：见正文）所接受的剂量可预测宫颈癌患者的晚期直肠和膀胱毒性。我们研究了局部晚期宫颈癌患者在磁共振成像引导下近距离放疗后，直肠和膀胱的中间剂量对晚期直肠/膀胱毒性的预测价值。
使用《不良事件通用毒性标准》第4.0版对毒性进行前瞻性分级，并对2008年至2013年间连续接受磁共振成像引导下近距离放疗的IB-IVA期宫颈癌女性患者进行回顾性验证。收集直肠和膀胱0.1、1、2、5和10厘米处接受的2 Gy分割的最小等效剂量，以及接受55、60、65、70和75 Gy（V）的直肠绝对体积。使用逻辑回归分析剂量体积参数与2级及以上直肠/膀胱毒性之间的关联。
中位随访44个月，106例患者中2级及以上直肠和膀胱毒性的3年累积发生率分别为29%和15%。除膀胱（公式：见正文）外，所有剂量体积参数均与晚期2级及以上直肠和膀胱毒性显著相关（p < 0.05）。在多变量逻辑回归分析中，（公式：见正文）> 70 Gy和V > 11厘米（p < 0.05）均为晚期2级及以上直肠毒性的预测因素，与仅使用（公式：见正文）> 70 Gy的模型相比，模型拟合度提高，曲线下面积更大。
在本研究中，V可预测晚期2级及以上直肠毒性。将V纳入（公式：见正文）可提高预测准确性。
