Parsons J T, Bova F J, Fitzgerald C R, Mendenhall W M, Million R R
Department of Radiation Oncology, University of Florida College of Medicine, Gainesville.
Int J Radiat Oncol Biol Phys. 1994 Nov 15;30(4):765-73. doi: 10.1016/0360-3016(94)90347-6.
To investigate the risk of radiation-induced retinopathy according to total radiation dose and fraction size, based on both retrospective and prospectively collected data.
Between October 1964 and May 1989, 68 retinae in 64 patients received fractionated external-beam irradiation during the treatment of primary extracranial head and neck tumors. All patients had a minimum of 3 years of ophthalmologic follow-up (range, 3 to 26 years; mean, 9 years; median, 8 years).
Twenty-seven eyes in 26 patients developed radiation retinopathy resulting in visual acuity of 20/200 or worse. The mean and median times to the onset of symptoms attributable to retinal ischemia were 2.8 and 2.5 years, respectively. Fourteen of the injured eyes developed rubeosis iridis and/or neovascular glaucoma. Radiation retinopathy was not observed at doses below 45 Gy, but increased steadily in incidence at doses > or = 45 Gy. In the range of doses between 45 and 55 Gy, there was an increased risk of injury among patients who received doses per fraction of > or = 1.9 Gy (p = .09). There was also a trend toward increased risk of injury among patients who received chemotherapy (two of two vs. four of ten in the 45-51 Gy range; p = .23). The lowest dose associated with retinopathy was 45 Gy delivered to a diabetic patient by twice-a-day fractionation. The data did not suggest an increased risk of radiation retinopathy with increasing age.
The current study suggests the importance of total dose as well as dose per fraction, and adds support to a small body of literature suggesting that patients with diabetes mellitus or who receive chemotherapy are at increased risk of injury. A sigmoid dose-response curve is constructed from our current data and data from the literature.
基于回顾性和前瞻性收集的数据，研究根据总辐射剂量和分次剂量发生放射性视网膜病变的风险。
1964年10月至1989年5月期间，64例患者的68只视网膜在原发性颅外头颈部肿瘤治疗期间接受了分次外照射。所有患者至少有3年的眼科随访（范围3至26年；平均9年；中位数8年）。
26例患者的27只眼发生放射性视网膜病变，导致视力降至20/200或更差。视网膜缺血所致症状发作的平均时间和中位时间分别为2.8年和2.5年。14只受伤眼睛发生虹膜红变和/或新生血管性青光眼。低于45 Gy的剂量未观察到放射性视网膜病变，但剂量≥45 Gy时发病率稳步上升。在45至55 Gy的剂量范围内，每次分次剂量≥1.9 Gy的患者受伤风险增加（p = 0.09）。接受化疗的患者也有受伤风险增加的趋势（45 - 51 Gy范围内，2例中的2例 vs. 10例中的4例；p = 0.23）。与视网膜病变相关的最低剂量是一名糖尿病患者每天分两次接受的45 Gy。数据未表明放射性视网膜病变风险随年龄增加而增加。
当前研究表明了总剂量以及分次剂量的重要性，并为一小部分文献提供了支持，这些文献表明糖尿病患者或接受化疗的患者受伤风险增加。根据我们当前的数据和文献数据构建了一条S形剂量反应曲线。
