Hirst D G
Int J Radiat Oncol Biol Phys. 1986 Nov;12(11):2009-17. doi: 10.1016/0360-3016(86)90139-2.
Anemia may often become a problem in the treatment of the cancer patient. There are insufficient clinical data to assess the overall importance of anemia in radiotherapy, but there is clear evidence that uncorrected anemia is detrimental to local tumor control in some sites. There may be situations, however, when the transfused, previously anemic patient is at an advantage. These patients have shown a dramatically better response than non-anemic patients when radiotherapy for cancer of the cervix was given in hyperbaric oxygen. Animal experiments suggest that adaptive processes may be responsible for this effect. There is an important difference between acute and chronic anemia in their influence on the radiosensitivity of mouse tumors; while acute anemia consistently causes radioresistance, this effect is lost as the duration of the anemia prior to irradiation is prolonged. This would suggest that anemia per se should not cause tumor radioresistance in the chronically anemic patient. Blood transfusion in previously anemic animals has been shown to produce a markedly increased tumor radiosensitivity, but again this is only transient and sensitivity returns to normal when the interval between transfusion and irradiation is extended to 24 hrs. The mechanisms responsible for tumor adaptation to anemia and blood transfusion are not known, but there is evidence that changes in diffusion distances occur within tumors in response to alterations in oxygen availability and that changes in blood chemistry through the 2,3-DPG system may alter the release of oxygen to the tissues. These are complex processes and it remains to be determined what influence they have in the treatment of human cancer. However, the animal data suggest a clear benefit of blood transfusion to restore the hemoglobin level in radiotherapy, but they also emphasize the need to irradiate immediately so that adaptive mechanisms cannot erode the effect.
贫血在癌症患者的治疗中常常会成为一个问题。目前尚无足够的临床数据来评估贫血在放射治疗中的整体重要性，但有明确证据表明，未经纠正的贫血对某些部位的局部肿瘤控制是有害的。然而，在某些情况下，输血后的贫血患者可能具有优势。当在高压氧环境下对宫颈癌患者进行放射治疗时，这些患者的反应比非贫血患者明显更好。动物实验表明，适应性过程可能是造成这种效应的原因。急性贫血和慢性贫血对小鼠肿瘤放射敏感性的影响存在重要差异；虽然急性贫血始终会导致放射抗性，但随着照射前贫血持续时间的延长，这种效应会消失。这表明，在慢性贫血患者中，贫血本身不应导致肿瘤放射抗性。已证明，对先前贫血的动物进行输血可显著提高肿瘤的放射敏感性，但同样，这只是暂时的，当输血与照射之间的间隔延长至24小时时，敏感性会恢复正常。肿瘤对贫血和输血的适应机制尚不清楚，但有证据表明，肿瘤内的扩散距离会随着氧供应的改变而发生变化，并且通过2,3 - 二磷酸甘油酸（2,3-DPG）系统的血液化学变化可能会改变氧气向组织的释放。这些都是复杂的过程，它们在人类癌症治疗中的影响还有待确定。然而，动物实验数据表明输血以恢复放疗中的血红蛋白水平有明显益处，但同时也强调了需要立即进行照射，以便适应性机制不会削弱这种效果。
