Keyes Mira, Spadinger Ingrid, Liu Mitchell, Pickles Tom, Pai Howard, Hayden Amy, Moravan Veronika, Halperin Ross, McKenzie Michael, Kwan Winkle, Agranovic Alexander, Lapointe Vince, Morris W James
Provincial Prostate Brachytherapy Program, British Columbia Cancer Agency, Vancouver Cancer Centre, Vancouver, British Columbia, Canada.
Brachytherapy. 2012 May-Jun;11(3):199-208. doi: 10.1016/j.brachy.2011.05.007. Epub 2011 Jul 16.
To describe the acute and late rectal toxicity in 1006 prostate brachytherapy patients implanted 1998-2003. To determine whether rectal dose-volume histogram as well as patient and treatment factors were associated with rectal toxicity.
Median followup was 60.7 months. Rectal dosimetry was calculated as dose-volume histogram of the rectum using Day 28 CT-based dosimetry and expressed as volume of the rectum in cc receiving 50%, 100%, and 150% of the prescription dose (VR(50cc), VR(100cc), and VR(150cc), respectively). Univariate and multivariate analyses were performed to examine the influence of patient, implant, dosimetry, and learning curve factors on the development of acute and late toxicities using a modified Radiation Therapy Oncology Group (RTOG) scale. Acute toxicity was analyzed using logistic regression and late toxicity using Cox proportional hazards regression. Analysis of variance was used to examine the association between rectal toxicity and rectal dose.
Rectal dosimetry in 93.5% and rectal toxicity in 96.2% have been recorded. Median VR(100)=1.05cc. Late RTOG Grades 0, 1, 2, 3, and 4 were recorded in 68%, 23%, 7.3%, 0.9%, and 0.2% patients, respectively. On multivariate analysis, acute RTOG ≥2 rectal toxicity was associated with urinary retention (p=0.036) and learning curve (p=0.015); late RTOG ≥2 was associated with the presence of acute toxicity (p=0.0074), higher VR(100) (p=0.030) and learning curve (p=0.027).
Late rectal RTOG ≥2 rectal toxicity in this cohort was 8%. Increased VR(100), presence of acute rectal toxicity, and learning curve were associated with higher rate of late RTOG ≥2 toxicity. Severe late rectal toxicity after prostate brachytherapy was rare.
描述1998年至2003年接受前列腺近距离放射治疗的1006例患者的急性和晚期直肠毒性。确定直肠剂量体积直方图以及患者和治疗因素是否与直肠毒性相关。
中位随访时间为60.7个月。直肠剂量测定采用基于第28天CT的剂量测定法计算直肠的剂量体积直方图，并表示为接受处方剂量50%、100%和150%的直肠体积（分别为VR(50cc)、VR(100cc)和VR(150cc)）。使用改良的放射肿瘤学组（RTOG）量表进行单因素和多因素分析，以检查患者、植入、剂量测定和学习曲线因素对急性和晚期毒性发生的影响。使用逻辑回归分析急性毒性，使用Cox比例风险回归分析晚期毒性。采用方差分析检查直肠毒性与直肠剂量之间的关联。
记录了93.5%的直肠剂量测定和96.2%的直肠毒性。VR(100)的中位数为1.05cc。晚期RTOG 0、1、2、3和4级分别记录在68%、23%、7.3%、0.9%和0.2%的患者中。多因素分析显示，急性RTOG≥2级直肠毒性与尿潴留（p=0.036）和学习曲线（p=0.015）相关；晚期RTOG≥2级与急性毒性的存在（p=0.0074）、较高的VR(100)（p=0.030）和学习曲线（p=0.027）相关。
该队列中晚期直肠RTOG≥2级直肠毒性为8%。VR(100)增加、急性直肠毒性的存在和学习曲线与晚期RTOG≥2级毒性的较高发生率相关。前列腺近距离放射治疗后严重的晚期直肠毒性罕见。
