Anderson Christine R, McNiel Elizabeth A, Gillette Edward L, Powers Barbara E, LaRue Susan M
Department of Radiological Health Sciences, Colorado State University, Fort Collins 80523, USA.
Vet Radiol Ultrasound. 2002 Mar-Apr;43(2):187-92. doi: 10.1111/j.1740-8261.2002.tb01668.x.
When external beam radiation therapy is administered to the pelvis, normal tissues irradiated may include the colon, small intestine, urethra, bladder, bone, and spinal cord. The objectives of this retrospective study were to determine the incidence and severity of late radiation effects following pelvic irradiation in dogs and to identify factors that increase the risk of these effects. Medical records of all dogs treated with curative intent external beam radiation therapy to the pelvic region between 1993 and 1999 were reviewed. Patients with follow-up longer than 9 months or any patient that developed late complications earlier than 9 months were evaluated. Sixteen dogs met criteria for inclusion in this study. All dogs were treated with a 6-MV linear accelerator with bilaterally opposed beams. Diseases treated included transitional cell carcinoma of the bladder, transitional cell carcinoma of the prostate, and anal sac apocrine gland adenocarcinoma. Four dose/fractionation schemes were used: 49.5 Gy in 3.3 Gy fractions, 54 Gy in 3.0 Gy fractions, 54 Gy in 2.7 Gy fractions, and 18 Gy intraoperative radiation therapy followed by 43 Gy external beam radiation therapy in 2.9 Gy fractions. Implantable chemotherapy in the form of an OPLA-Pt sponge was used in six dogs as a radiation potentiator. Colitis was the major late effect following pelvic irradiation, occurring in nine dogs (56%). Colitis was characterized as mild in three dogs, moderate in one dog, and severe in five dogs. Three of the dogs with severe effects suffered gastrointestinal perforation. All dogs with severe late effects received 3 or 3.3 Gy per fraction, and 80% received radiation potentiators. In the seven dogs that received 2.7 Gy or 2.9 Gy per fraction, late effects were classified as none (n = 5), mild colitis (n = 1), and moderate colitis (n = 1). Radiation therapy can be administered to the pelvic region with a minimal risk of late effects to the colon by giving smaller doses per fraction and avoiding systemic radiation potentiators.
当对骨盆进行外照射放射治疗时，受照射的正常组织可能包括结肠、小肠、尿道、膀胱、骨骼和脊髓。这项回顾性研究的目的是确定犬类骨盆照射后迟发性放射效应的发生率和严重程度，并确定增加这些效应风险的因素。回顾了1993年至1999年间所有接受根治性外照射放射治疗骨盆区域的犬类的病历。对随访时间超过9个月的患者或任何在9个月前出现晚期并发症的患者进行了评估。16只犬符合本研究的纳入标准。所有犬均使用6兆伏直线加速器进行双侧对穿照射。治疗的疾病包括膀胱移行细胞癌、前列腺移行细胞癌和肛囊顶泌汗腺腺癌。使用了四种剂量/分割方案：3.3 Gy分割，共49.5 Gy；3.0 Gy分割，共54 Gy；2.7 Gy分割，共54 Gy；术中放疗18 Gy，随后2.9 Gy分割的外照射放疗43 Gy。6只犬使用了OPLA-Pt海绵形式的可植入化疗药物作为放射增敏剂。结肠炎是骨盆照射后的主要晚期效应，9只犬（56%）出现。3只犬的结肠炎为轻度，1只犬为中度，5只犬为重度。3只出现严重效应的犬发生了胃肠道穿孔。所有出现严重晚期效应的犬每次分割接受3或3.3 Gy照射，80%接受了放射增敏剂。在7只每次分割接受2.7 Gy或2.9 Gy照射的犬中，晚期效应分类为无（n = 5）、轻度结肠炎（n = 1）和中度结肠炎（n = 1）。通过每次给予较小剂量并避免全身放射增敏剂，对骨盆区域进行放射治疗时，结肠发生晚期效应的风险可降至最低。
