Kim Hak Jae, Kim Suzy, Ha Sung Whan, Wu Hong-Gyun
Department of Radiation Oncology, Seoul National University College of Medicine, South Korea.
Tumori. 2008 May-Jun;94(3):327-32. doi: 10.1177/030089160809400307.
To evaluate whether doses or dose rates at International Commission on Radiation Units (ICRU) reference points are of value for predicting risks of late rectal and bladder morbidity in patients with uterine cervical cancer who have undergone external beam radiotherapy and intracavitary irradiation.
Late rectal complications and late bladder complications were evaluated in 54 patients who were treated by external beam radiotherapy followed by intracavitary irradiation between January 1996 and December 1999. External beam radiotherapy was delivered in 1.8 Gy daily fractions to a whole pelvis dose of 50.4 Gy followed by intracavitary irradiation at total point A doses ranging from 75 Gy to 85 Gy. Intracavitary irradiation was performed with dose rates of 0.5-0.7 Gy/h to point A in most patients, but 8 patients were treated at a higher dose rate (0.83-1.15 Gy/h) to shorten the hospitalization period. Biologically effective doses for the reference points were calculated using a linear quadratic model.
Grade 3 rectal and bladder morbidity by Radiation Therapy Oncology Group (RTOG) criteria developed in 4 patients (7.4%) and 1 (1.9%), respectively. An age of >60 years (P = 0.01) and a total dose to the rectal reference point of > or =80 Gy (P = 0.03) were found to be correlated with a higher rate of rectal morbidity. Total dose (> or =80 Gy), dose rate (> or = 0.75 Gy/h), and biologically effective doses (> or =135 Gy3) at the bladder reference point were found to be significant factors for the development of late bladder morbidity. By multivariate analysis, age was identified as the only significant factor of late rectal complications, and biologically effective doses at the bladder reference point was the only significant factor of late bladder complications.
RTOG grade 3 late rectal and bladder morbidity developed in respectively 7.4% and 1.9% of the patients. The significant risk factors for late rectal and bladder morbidity were old age and biologically effective doses at the bladder reference point, respectively.
评估国际辐射单位委员会(ICRU)参考点的剂量或剂量率对于预测接受体外照射和腔内照射的子宫颈癌患者晚期直肠和膀胱并发症风险是否有价值。
对1996年1月至1999年12月期间接受体外照射后再进行腔内照射治疗的54例患者的晚期直肠并发症和晚期膀胱并发症进行评估。体外照射采用每日1.8 Gy分次照射,全盆腔剂量达50.4 Gy,随后腔内照射,A点总剂量范围为75 Gy至85 Gy。大多数患者腔内照射A点剂量率为0.5 - 0.7 Gy/h,但有8例患者采用较高剂量率(0.83 - 1.15 Gy/h)以缩短住院时间。使用线性二次模型计算参考点的生物等效剂量。
根据放射治疗肿瘤学组(RTOG)标准,3级直肠和膀胱并发症分别发生在4例(7.4%)和1例(1.9%)患者中。发现年龄>60岁(P = 0.01)和直肠参考点总剂量≥80 Gy(P = 0.03)与较高的直肠并发症发生率相关。膀胱参考点的总剂量(≥80 Gy)、剂量率(≥0.75 Gy/h)和生物等效剂量(≥135 Gy³)被发现是晚期膀胱并发症发生的显著因素。多因素分析显示,年龄是晚期直肠并发症的唯一显著因素,膀胱参考点的生物等效剂量是晚期膀胱并发症的唯一显著因素。
RTOG 3级晚期直肠和膀胱并发症分别发生在7.4%和1.9%的患者中。晚期直肠和膀胱并发症的显著危险因素分别是老年和膀胱参考点的生物等效剂量。