Lancet. 2011 Nov 12;378(9804):1707-16. doi: 10.1016/S0140-6736(11)61629-2. Epub 2011 Oct 19.
After breast-conserving surgery, radiotherapy reduces recurrence and breast cancer death, but it may do so more for some groups of women than for others. We describe the absolute magnitude of these reductions according to various prognostic and other patient characteristics, and relate the absolute reduction in 15-year risk of breast cancer death to the absolute reduction in 10-year recurrence risk.
We undertook a meta-analysis of individual patient data for 10,801 women in 17 randomised trials of radiotherapy versus no radiotherapy after breast-conserving surgery, 8337 of whom had pathologically confirmed node-negative (pN0) or node-positive (pN+) disease.
Overall, radiotherapy reduced the 10-year risk of any (ie, locoregional or distant) first recurrence from 35·0% to 19·3% (absolute reduction 15·7%, 95% CI 13·7-17·7, 2p<0·00001) and reduced the 15-year risk of breast cancer death from 25·2% to 21·4% (absolute reduction 3·8%, 1·6-6·0, 2p=0·00005). In women with pN0 disease (n=7287), radiotherapy reduced these risks from 31·0% to 15·6% (absolute recurrence reduction 15·4%, 13·2-17·6, 2p<0·00001) and from 20·5% to 17·2% (absolute mortality reduction 3·3%, 0·8-5·8, 2p=0·005), respectively. In these women with pN0 disease, the absolute recurrence reduction varied according to age, grade, oestrogen-receptor status, tamoxifen use, and extent of surgery, and these characteristics were used to predict large (≥20%), intermediate (10-19%), or lower (<10%) absolute reductions in the 10-year recurrence risk. Absolute reductions in 15-year risk of breast cancer death in these three prediction categories were 7·8% (95% CI 3·1-12·5), 1·1% (-2·0 to 4·2), and 0·1% (-7·5 to 7·7) respectively (trend in absolute mortality reduction 2p=0·03). In the few women with pN+ disease (n=1050), radiotherapy reduced the 10-year recurrence risk from 63·7% to 42·5% (absolute reduction 21·2%, 95% CI 14·5-27·9, 2p<0·00001) and the 15-year risk of breast cancer death from 51·3% to 42·8% (absolute reduction 8·5%, 1·8-15·2, 2p=0·01). Overall, about one breast cancer death was avoided by year 15 for every four recurrences avoided by year 10, and the mortality reduction did not differ significantly from this overall relationship in any of the three prediction categories for pN0 disease or for pN+ disease.
After breast-conserving surgery, radiotherapy to the conserved breast halves the rate at which the disease recurs and reduces the breast cancer death rate by about a sixth. These proportional benefits vary little between different groups of women. By contrast, the absolute benefits from radiotherapy vary substantially according to the characteristics of the patient and they can be predicted at the time when treatment decisions need to be made.
Cancer Research UK, British Heart Foundation, and UK Medical Research Council.
保乳手术后，放疗可降低局部复发和乳腺癌死亡风险，但对于某些女性群体而言，其效果可能更为显著。我们根据各种预后和其他患者特征，描述了这些降低幅度的绝对值，并将 15 年乳腺癌死亡风险的绝对降低与 10 年复发风险的绝对降低进行了关联。
我们对 17 项保乳手术后放疗与不放疗的随机临床试验中的 10801 名女性患者的个体患者数据进行了荟萃分析，其中 8337 名患者为病理证实的淋巴结阴性（pN0）或淋巴结阳性（pN+）疾病。
总体而言，放疗使任何（即局部区域或远处）首次复发的 10 年风险从 35.0%降至 19.3%（绝对降低 15.7%，95%CI 13.7-17.7，2p<0.00001），使 15 年乳腺癌死亡风险从 25.2%降至 21.4%（绝对降低 3.8%，1.6-6.0，2p=0.00005）。在 pN0 疾病患者（n=7287）中，放疗使这些风险从 31.0%降至 15.6%（绝对复发降低 15.4%，13.2-17.6，2p<0.00001）和从 20.5%降至 17.2%（绝对死亡率降低 3.3%，0.8-5.8，2p=0.005）。在这些 pN0 疾病患者中，绝对复发降低幅度因年龄、分级、雌激素受体状态、他莫昔芬使用情况和手术范围而异，这些特征可用于预测 10 年复发风险的大幅（≥20%）、中度（10-19%）或较小（<10%）的绝对降低。在这三个预测类别中，15 年乳腺癌死亡风险的绝对降低幅度分别为 7.8%（95%CI 3.1-12.5）、1.1%（-2.0-4.2）和 0.1%（-7.5-7.7）（绝对死亡率降低趋势 2p=0.03）。在少数 pN+疾病患者（n=1050）中，放疗使 10 年复发风险从 63.7%降至 42.5%（绝对降低 21.2%，95%CI 14.5-27.9，2p<0.00001），使 15 年乳腺癌死亡风险从 51.3%降至 42.8%（绝对降低 8.5%，1.8-15.2，2p=0.01）。总体而言，每避免 10 年复发 4 次，就可避免 15 年乳腺癌死亡 1 例，且在任何 pN0 疾病或 pN+疾病的三个预测类别中，死亡率降低与这种总体关系无显著差异。
保乳手术后，对保留乳房进行放疗可将疾病复发率降低一半，并将乳腺癌死亡率降低约六分之一。这些比例效益在不同女性群体中差异不大。相比之下，放疗的绝对获益在很大程度上取决于患者的特征，并且可以在需要做出治疗决策时进行预测。
英国癌症研究中心、英国心脏基金会和英国医学研究理事会。
