Lindegaard J C, Nielsen O S, Overgaard J
Department of Experimental Clinical Oncology, Radiumstationen, Aarhus, Denmark.
Int J Hyperthermia. 1991 May-Jun;7(3):519-26. doi: 10.3109/02656739109005016.
A comparison between the effect of step-down heating (SDH) obtained in a C3H mammary carcinoma grown in the feet of CDF1 mice and the skin of normal CDF1 feet is presented. Water-bath heating was used, and SDH was obtained by giving a 44.7 degrees C/10 min treatment followed by heating at 42.2 degrees C for variable times. Single heating at 42.2 degrees C and step-up heating (SUH), i.e. 42.2 degrees C followed by 44.7 degrees C/10 min, were used as controls. The endpoint was the heating time at 42.2 degrees C to obtain either a definite tumour growth time (TGT50) or a specific skin score level (RD50) in 50% of the animals. The effect of SDH and SUH was quantified by the step-down ratio (SDR), calculated as the ratio of the heating times at 42.2 degrees C to obtain the specific endpoint. In both assays the effect of SDH was seen as a significant left shift of the SDH dose-response curve compared to the curve for single heating and SUH. For the comparison of the tumour and the normal tissue response, damage levels with comparable heating times for single heating were used. The therapeutic effect was then investigated by calculating the therapeutic gain factor (TGF), where TGF = SDR(tumour)/SDR(normal tissue). Neither SUH nor SDH gave a TGF significantly different from 1. The results suggest that SDH may be used clinically to shorten the heating time without decreasing the therapeutic effect.
本文呈现了在CDF1小鼠足部生长的C3H乳腺癌与正常CDF1小鼠足部皮肤中，阶梯式降温加热（SDH）效果的比较。采用水浴加热，通过给予44.7℃/10分钟的处理，随后在42.2℃加热不同时间来获得SDH。以42.2℃单次加热和阶梯式升温加热（SUH，即42.2℃后接44.7℃/10分钟）作为对照。终点指标是在42.2℃下的加热时间，以在50%的动物中获得确定的肿瘤生长时间（TGT50）或特定的皮肤评分水平（RD50）。SDH和SUH的效果通过阶梯式降温比（SDR）进行量化，SDR计算为在42.2℃下获得特定终点的加热时间之比。在两种试验中，与单次加热和SUH的曲线相比，SDH的剂量反应曲线均显著左移。为了比较肿瘤和正常组织的反应，使用了单次加热时加热时间相当的损伤水平。然后通过计算治疗增益因子（TGF）来研究治疗效果，其中TGF = SDR（肿瘤）/SDR（正常组织）。SUH和SDH的TGF均未显著不同于1。结果表明，SDH可在临床上用于缩短加热时间而不降低治疗效果。
