Roeske J C, Mundt A J, Halpern H, Sweeney P, Sutton H, Powers C, Rotmensch J, Waggoner S, Weichselbaum R R
Department of Radiation and Cellular Oncology, University of Chicago Hospitals, IL 60637, USA.
Int J Radiat Oncol Biol Phys. 1997 Jan 15;37(2):351-8. doi: 10.1016/s0360-3016(96)00490-7.
This study attempted to correlate patient, treatment, and dosimetric factors with the risk of late rectal sequelae in patients treated with radiation therapy (RT) for cervical carcinoma.
A total of 183 patients with cervical carcinoma (67 Stage I, 93 Stage II, and 23 Stage III) treated with definitive RT with a minimum of 2 years follow-up were evaluated. Treatment consisted of external beam pelvic RT (EBRT) followed by intracavitary RT (ICRT) consisting of one or two insertions. Complications were scored and analyzed as a function of 25 patient and treatment factors. Conventional total rectal doses were obtained by adding together the EBRT and ICRT rectal doses. To account for differences in dose rate between the ICRT and EBRT, and variations in EBRT fractionation schemes, biologically equivalent rectal doses (BED) were calculated using a linear quadratic model. In addition, the influence of the varying proportions of EBRT and ICRT rectal doses were evaluated.
Twenty-eight patients (15.3%) developed late rectal sequelae (13 Grade 1, 3 Grade 2, and 12 Grade 3). Diabetes (p = 0.03), Point A dose (p = 0.04), and conventional EBRT dose (p = 0.03) were the most significant factors on multivariate analysis. Logistic regression analysis demonstrated a low risk (<10%) of late rectal sequelae below conventional and biological rectal doses of 75 Gy and 135 BED, respectively. The percentage of rectal dose delivered by the EBRT significantly influenced the dose-response relationship. A defined threshold percentage above which rectal sequelae were more common was identified over the range of doses evaluated. This threshold was 87% at a total rectal dose of 60 Gy and decreased to 60% at 80 Gy.
Diabetes, Point A, and EBRT doses are the most significant factors associated with the risk of late rectal sequelae in patients treated with RT for cervical carcinoma. The percentage of rectal dose delivered by the EBRT significantly affects the conventional and biological dose-response relationship. This suggests that the volume of rectum irradiated is an important and independent parameter in the development of late rectal sequelae.
本研究试图将患者、治疗及剂量因素与接受放射治疗（RT）的宫颈癌患者发生晚期直肠后遗症的风险相关联。
对总共183例接受根治性RT且随访至少2年的宫颈癌患者（67例I期、93例II期和23例III期）进行了评估。治疗包括盆腔外照射放疗（EBRT），随后进行腔内放疗（ICRT），ICRT由一次或两次插植组成。根据25项患者和治疗因素对并发症进行评分和分析。常规直肠总剂量通过将EBRT和ICRT直肠剂量相加获得。为了考虑ICRT和EBRT之间的剂量率差异以及EBRT分割方案的变化，使用线性二次模型计算生物等效直肠剂量（BED）。此外，评估了EBRT和ICRT直肠剂量不同比例的影响。
28例患者（15.3%）出现晚期直肠后遗症（13例1级、3例2级和12例3级）。多因素分析显示，糖尿病（p = 0.03）、A点剂量（p = 0.04）和常规EBRT剂量（p = 0.03）是最显著的因素。逻辑回归分析表明，在常规直肠剂量和生物直肠剂量分别低于75 Gy和135 BED时，晚期直肠后遗症的风险较低（<10%）。EBRT给予的直肠剂量百分比显著影响剂量反应关系。在评估的剂量范围内确定了一个明确的阈值百分比，高于该阈值直肠后遗症更常见。在直肠总剂量为60 Gy时，该阈值为87%，在80 Gy时降至60%。
糖尿病、A点和EBRT剂量是接受RT治疗的宫颈癌患者发生晚期直肠后遗症风险的最显著相关因素。EBRT给予的直肠剂量百分比显著影响常规和生物剂量反应关系。这表明照射的直肠体积是晚期直肠后遗症发生的一个重要且独立的参数。
