Gillette S M, Gillette E L, Powers B E, Withrow S J
Department of Radiology and Radiation Biology, Colorado State University, Fort Collins 80523.
Cancer Res. 1990 Jan 1;50(1):54-7.
This report describes radiation-induced osteosarcomas in two groups of dogs. One group was given radiation therapy for spontaneous tumors and the second group of normal adult beagle dogs was given experimental intraoperative radiation therapy. Secondary tumors developed between 1.7 to 5 years after irradiation. Three of 87 spontaneous tumor-bearing dogs or 3.4% of dogs treated for soft tissue sarcomas developed osteosarcoma within the field of irradiation. Twenty-two dogs or 25% of dogs treated for soft tissue sarcomas survived 20 months. This high incidence may be due to the use of fractions in excess of 3.5 Gy. These dogs received 10 fractions in 3 weeks with fractions ranging from 3.5 to 5.0 Gy. Tumor induction may be included in the late effects of irradiation which are worsened by the use of coarse fractionation. There appeared to be a dose relationship for tumors induced after single intraoperative radiation doses combined with fractionated external beam irradiation. Seven of 27 dogs given this treatment and surviving at least 4 years developed osteosarcomas in the field of irradiation. One of 26 dogs given intraoperative radiation alone developed a tumor between 4 and 5 years. The lower incidence after intraoperative radiation alone may have been due to the lower total dose. However, the sequence of a course of fractionated irradiation followed by a large single dose seemed to enhance carcinogenicity.
本报告描述了两组犬类中的辐射诱导骨肉瘤。一组接受了针对自发性肿瘤的放射治疗，另一组正常成年比格犬接受了实验性术中放射治疗。继发性肿瘤在照射后1.7至5年之间出现。87只患有自发性肿瘤的犬中有3只，即接受软组织肉瘤治疗的犬中的3.4%，在照射区域内发生了骨肉瘤。接受软组织肉瘤治疗的22只犬，即25%，存活了20个月。这种高发病率可能是由于使用了超过3.5 Gy的分次剂量。这些犬在3周内接受了10次分次照射，分次剂量范围为3.5至5.0 Gy。肿瘤诱导可能包含在照射的晚期效应中，而粗分割的使用会使这些效应恶化。对于单次术中放射剂量联合分次外照射后诱导的肿瘤，似乎存在剂量关系。接受这种治疗且存活至少4年的27只犬中有7只在照射区域内发生了骨肉瘤。仅接受术中放射治疗的26只犬中有1只在4至5年之间发生了肿瘤。仅术中放射治疗后发病率较低可能是由于总剂量较低。然而，分次照射疗程后接着大剂量单次照射的顺序似乎增强了致癌性。
