Akimoto Tetsuo, Katoh Hiroyuki, Kitamoto Yoshizumi, Tamaki Tomoaki, Harada Kosaku, Shirai Katsuyuki, Nakano Takashi
Department of Radiation Oncology, Gunma University Graduate School of Medicine, Maebashi, Gunma, Japan.
Int J Radiat Oncol Biol Phys. 2006 Jun 1;65(2):364-70. doi: 10.1016/j.ijrobp.2005.12.017.
To evaluate the incidence of Grade 2 or worse rectal bleeding after high-dose-rate (HDR) brachytherapy combined with hypofractionated external-beam radiotherapy (EBRT), with special emphasis on the relationship between the incidence of rectal bleeding and the rectal dose from HDR brachytherapy.
The records of 100 patients who were treated by HDR brachytherapy combined with EBRT for > or =12 months were analyzed. The fractionation schema for HDR brachytherapy was prospectively changed, and the total radiation dose for EBRT was fixed at 51 Gy. The distribution of the fractionation schema used in the patients was as follows: 5 Gy x 5 in 13 patients; 7 Gy x 3 in 19 patients; and 9 Gy x 2 in 68 patients.
Ten patients (10%) developed Grade 2 or worse rectal bleeding. Regarding the correlation with dosimetric factors, no significant differences were found in the average percentage of the entire rectal volume receiving 30%, 50%, 80%, and 90% of the prescribed radiation dose from EBRT between those with bleeding and those without. The average percentage of the entire rectal volume receiving 10%, 30%, 50%, 80%, and 90% of the prescribed radiation dose from HDR brachytherapy in those who developed rectal bleeding was 77.9%, 28.6%, 9.0%, 1.5%, and 0.3%, respectively, and was 69.2%, 22.2%, 6.6%, 0.9%, and 0.4%, respectively, in those without bleeding. The differences in the percentages of the entire rectal volume receiving 10%, 30%, and 50% between those with and without bleeding were statistically significant.
The rectal dose from HDR brachytherapy for patients with prostate cancer may have a significant impact on the incidence of Grade 2 or worse rectal bleeding.
评估高剂量率（HDR）近距离放射治疗联合低分割外照射放疗（EBRT）后2级或更严重直肠出血的发生率，特别关注直肠出血发生率与HDR近距离放射治疗直肠剂量之间的关系。
分析100例接受HDR近距离放射治疗联合EBRT且治疗时间≥12个月患者的记录。HDR近距离放射治疗的分割方案进行了前瞻性改变，EBRT的总辐射剂量固定为51 Gy。患者使用的分割方案分布如下：13例患者为5 Gy×5次；19例患者为7 Gy×3次；68例患者为9 Gy×2次。
10例患者（10%）出现2级或更严重直肠出血。关于与剂量学因素的相关性，出血患者和未出血患者之间，接受EBRT规定辐射剂量30%、50%、80%和90%的整个直肠体积的平均百分比无显著差异。发生直肠出血患者中，接受HDR近距离放射治疗规定辐射剂量10%、30%、50%、80%和90%的整个直肠体积的平均百分比分别为77.9%、28.6%、9.0%、1.5%和0.3%，未出血患者分别为69.2%、22.2%、6.6%、0.9%和0.4%。出血患者和未出血患者之间接受10%、30%和50%辐射剂量的整个直肠体积百分比差异具有统计学意义。
前列腺癌患者接受HDR近距离放射治疗的直肠剂量可能对2级或更严重直肠出血的发生率有显著影响。
