Okunieff P, de Bie J, Dunphy E P, Terris D J, Höckel M
Radiation Oncology Branch, National Cancer Institute, Bethesda, MD 20892, USA.
Br J Cancer Suppl. 1996 Jul;27:S185-90.
The oxygen tension of human tumours has often been thought to alter tumour response to radiation therapy. The purpose of this analysis is to determine to what extent the observed results of radiotherapy fit predictions based on in situ human tumour pO2 distributions. The radiation dose-response curve for patients treated with radiation alone for squamous cell cancers of the cervix and oropharynx were calculated based on published data. pO2 histograms were obtained from 30 women with cervical cancer and 11 patients with neck nodes from head and neck cancers. An average of 76 +/- 35 (range 28-174) measurements were made from each patient. Hypoxia was assumed to be a purely dose-modifying factor with a maximum OER of 2.5. Assuming patients are treated with daily radiation doses of 2 Gy, the squamous cell carcinoma alpha/beta ratio is 10 Gy, and that tumours have a mean of 10(8) clonogens, it was possible to estimate tumour control probability. Tumour oxygenation was an extremely important modifier of the slope of the dose-response curve and alone was sufficient to account for the slope of the clinically observed dose-response curve for neck nodes. The response curve for uterine cervical cancers is very shallow, and the oxygen distribution did not completely account for heterogeneity of response of these tumours. The results support the conclusion that oxygen tension distribution is an important modifier of human radiation treatment response.
人们常常认为人类肿瘤的氧分压会改变肿瘤对放射治疗的反应。本分析的目的是确定放射治疗的观察结果在多大程度上符合基于原位人类肿瘤pO2分布的预测。根据已发表的数据计算了单独接受放射治疗的子宫颈和口咽鳞状细胞癌患者的放射剂量反应曲线。从30名宫颈癌女性患者和11名头颈部癌颈部淋巴结患者中获取了pO2直方图。每位患者平均进行了76±35次（范围为28 - 174次）测量。假设缺氧是一个纯粹的剂量修正因子，最大氧增强比为2.5。假设患者每天接受2 Gy的放射剂量，鳞状细胞癌的α/β比值为10 Gy，且肿瘤平均有10⁸个克隆源性细胞，则有可能估计肿瘤控制概率。肿瘤氧合是剂量反应曲线斜率的一个极其重要的修正因子，仅凭它就足以解释临床上观察到的颈部淋巴结剂量反应曲线的斜率。子宫颈癌的反应曲线非常平缓，氧分布并不能完全解释这些肿瘤反应的异质性。这些结果支持了氧分压分布是人类放射治疗反应的一个重要修正因子这一结论。
