Biel M A, Kim T, Trump M J
Abbott Northwestern Hospital Laser Center, Minneapolis, Minnesota.
Lasers Surg Med. 1993;13(6):672-6. doi: 10.1002/lsm.1900130612.
Treatment of advanced carcinomas of the head and neck may benefit from adjuvant photodynamic therapy and brachyradiotherapy. To date, however, there has been no controlled study to evaluate whether high-dose irradiation can be safely accomplished without major tissue reaction in the presence of high circulating doses of Photofrin, the photosensitizing agent used in photodynamic therapy. Thirty adult male white rats were involved in the study. Fifteen rats received Photofrin 5 mg/kg intravenously, and 15 rats received the same volume of sterile saline intravenously. At 48 hours following injection, each rat received 1,000 cGy of radiation to a 3 x 5 cm area of dorsal skin using a cobalt linear accelerator unit. Skin changes postradiation were observed for degree of erythema, blistering, necrosis, and sloughing. Five rats from the Photofrin and control radiation groups were sacrificed on days 2, 7, and 21 postradiotherapy. Skin changes in each animal were identical with mild erythema lasting from 10-14 days postradiotherapy. There was no evidence of blistering, necrosis, or sloughing of skin in any of the animals studied. Histologic evaluation of the irradiated skin after sacrifice demonstrated no difference between the Photofrin and saline-irradiated groups. As well, the histologic recovery from acute radiation injury was also identical. This controlled study demonstrates that radiation therapy may be safely administered without increased morbidity when tissue concentrations necessary to perform photodynamic therapy are present.
头颈部晚期癌的治疗可能受益于辅助光动力疗法和近距离放射疗法。然而，迄今为止，尚无对照研究来评估在光动力疗法中使用的光敏剂Photofrin循环剂量较高的情况下，高剂量照射能否在不产生重大组织反应的情况下安全完成。30只成年雄性白色大鼠参与了该研究。15只大鼠静脉注射5mg/kg的Photofrin，15只大鼠静脉注射相同体积的无菌生理盐水。注射后48小时，使用钴直线加速器装置对每只大鼠背部3×5cm区域进行1000cGy的辐射。观察放疗后皮肤变化，包括红斑程度、水疱形成、坏死和脱屑情况。在放疗后第2天、第7天和第21天，处死Photofrin组和对照放疗组的5只大鼠。每只动物的皮肤变化均为轻度红斑，持续至放疗后10 - 14天。在所研究的任何动物中均未发现皮肤出现水疱、坏死或脱屑的迹象。处死动物后对受照射皮肤进行组织学评估，结果显示Photofrin组和生理盐水照射组之间无差异。此外，急性辐射损伤后的组织学恢复情况也相同。这项对照研究表明，当存在进行光动力疗法所需的组织浓度时，放射治疗可以安全实施，而不会增加发病率。
