Petera J, Matula P, Paluska P, Sirak I, Macingova Z, Kasaova L, Frgala T, Hodek M, Vosmik M
Department of Oncology and Radiotherapy, University Hospital Hradec Králové, Czech Republic.
Neoplasma. 2009;56(2):163-8. doi: 10.4149/neo_2009_02_163.
Low dose rate (LDR) brachytherapy is a well established treatment for the early stages of tongue cancer. High dose rate (HDR) afterloading devices have replaced LDR brachytherapy in many radiotherapy departments, but the effect and safety of HDR brachytherapy in comparison with LDR brachytherapy for interstitial applications is an unresolved question. The aim of our radiobiological study was to utilize dose volume histiograms from patients treated in our institution to simulate the risk of complication of LDR and HDR brachytherapy. Normal tissue complication probabilities (NTCP) of acute mucositis, late mucosal necrosis and osteoradionecrosis of two HDR brachytherapy schedules (18 x 3 Gy bid and 10 x 6 Gy bid) and of LDR brachytherapy with identical tumor control probability were compared using data from 8 brachytherapy applications. A linear quadratic (LQ) model was used to calculate the biologically equivalent doses, the effective volume method of Kutcher and Burman and Lyman's model was used to calculate NTCP. The Student's two-tailed test was used for statistical analysis. For 18 x 3 Gy bid the risk of acute mucositis and of late mucosal necrosis was 1.48 and 1.66 times higher with HDR in comparison with LDR brachytherapy. For 10 x 6 Gy bid the risk of acute mucositis, mucosal necrosis and osteoradionecrosis was 1.3, 3.44 and 13.18 times higher with HDR brachytherapy. All differences were statistically highly significant. Our radiobiological study supported the hypothesis that HDR has a higher risk of complication in comparison with LDR brachytherapy for the same tumor control probability.
tongue cancer, brachytherapy, low dose rate, high dose rate.
低剂量率（LDR）近距离放射治疗是舌癌早期一种成熟的治疗方法。高剂量率（HDR）后装设备已在许多放疗科室取代了LDR近距离放射治疗，但与LDR近距离放射治疗相比，HDR近距离放射治疗在间质应用中的效果和安全性仍是一个未解决的问题。我们放射生物学研究的目的是利用在我们机构接受治疗的患者的剂量体积直方图来模拟LDR和HDR近距离放射治疗的并发症风险。使用8例近距离放射治疗的数据，比较了两种HDR近距离放射治疗方案（18×3 Gy，每日两次和10×6 Gy，每日两次）以及具有相同肿瘤控制概率的LDR近距离放射治疗的急性粘膜炎、晚期粘膜坏死和放射性骨坏死的正常组织并发症概率（NTCP）。采用线性二次（LQ）模型计算生物学等效剂量，采用Kutcher和Burman的有效体积法以及Lyman模型计算NTCP。采用学生双尾检验进行统计分析。对于18×3 Gy，每日两次，与LDR近距离放射治疗相比，HDR时急性粘膜炎和晚期粘膜坏死的风险分别高1.48倍和1.66倍。对于10×6 Gy，每日两次，HDR近距离放射治疗时急性粘膜炎、粘膜坏死和放射性骨坏死的风险分别高1.3倍、3.44倍和13.18倍。所有差异均具有高度统计学意义。我们的放射生物学研究支持这样的假设，即在相同肿瘤控制概率下，与LDR近距离放射治疗相比，HDR的并发症风险更高。
舌癌；近距离放射治疗；低剂量率；高剂量率
