Singer J M, Price P, Dale R G
Department of Clinical Oncology, Hammersmith Hospital, London, UK.
Br J Cancer. 1998 Dec;78(12):1629-33. doi: 10.1038/bjc.1998.734.
A number of randomized studies have been carried out in the UK and USA to determine the optimal radiotherapy dose schedule for advanced non-small-cell lung cancer (NSCLC). We have examined eight radiotherapy regimens from data taken from four randomized phase III studies carried out in the UK (1264 patients): 10 Gy single fraction; 17 Gy in two fractions over 8 days; 30 Gy in ten fractions over 14 days; 22.5 Gy in five fractions in 5 days; 27 Gy in six fractions over 11 days; 30 Gy in six fractions over 11 days; 36 Gy in 12 fractions over 16 days; and 39 Gy in 13 fractions over 17 days. We compared the clinical results in palliation, toxicity and survival with four regimens taken from one randomized study from the USA (365 patients): 40 Gy in 20 fractions over 4 weeks; 40 Gy 'split course' in ten fractions in 4 weeks; 50 Gy in 25 fractions over 5 weeks; and 60 Gy in 30 fractions over 6 weeks. Using the linear-quadratic (LQ) radiobiological model, we have calculated the radiobiological equivalent dose (BED) for acute-reacting tissues (BED10), late-reacting tissues (BED1.7) and tumour (BED25), and related the predicted response to the observed response in each tissue. There was a good correlation between the predicted response and the reported response in the case of late-reacting tissue toxicity and tumour response. The model confirmed that, in good performance status patients, a higher value for BED25 correlated with a higher degree of local control and survival and that radiotherapy regimens with a higher value for BED1.7 were associated with five cases of cord myelopathy, if the spinal cord was not shielded. In poor performance status patients the model suggested that the optimal regimen was a single fraction of 10 Gy because this resulted in an equivalent degree of symptom control as other regimens, needed only one hospital visit and was less likely to result in cord damage, thus, allowing for the possibility of retreatment at a later date.
在英国和美国开展了多项随机研究，以确定晚期非小细胞肺癌（NSCLC）的最佳放疗剂量方案。我们从英国开展的四项随机III期研究（1264例患者）的数据中考察了八种放疗方案：单次10 Gy；8天内分两次给予17 Gy；14天内分十次给予30 Gy；5天内分五次给予22.5 Gy；11天内分六次给予27 Gy；11天内分六次给予30 Gy；16天内分十二次给予36 Gy；17天内分十三次给予39 Gy。我们将这些方案在缓解症状、毒性和生存方面的临床结果与美国一项随机研究（365例患者）中的四种方案进行了比较：4周内分20次给予40 Gy；4周内分十次给予40 Gy“分割疗程”；5周内分25次给予50 Gy；6周内分30次给予60 Gy。使用线性二次（LQ）放射生物学模型，我们计算了急性反应组织（BED10）、晚期反应组织（BED1.7）和肿瘤（BED25）的放射生物学等效剂量，并将每个组织中预测的反应与观察到的反应相关联。在晚期反应组织毒性和肿瘤反应方面，预测反应与报告反应之间存在良好的相关性。该模型证实，在身体状况良好的患者中，BED25值越高，局部控制程度和生存率越高，并且如果脊髓未得到屏蔽，BED1.7值较高的放疗方案与五例脊髓病相关。在身体状况较差的患者中，该模型表明最佳方案是单次10 Gy，因为这与其他方案在症状控制程度上相当，只需一次就诊，且导致脊髓损伤的可能性较小，从而为日后再次治疗留出了可能性。
