科学家说，放射线疗法大大降低接受过乳房肿瘤切除术的乳腺癌患者肿瘤复发的风险。
牛津大学的研究人员发现，术后放疗能使乳腺癌复发的几率减少50%。研究人员在10年期间，对1万多名女性的数据进行了评估。这是同类研究中最为深入的研究之一。研究结果表明，放疗能减少癌症向身体其他部分扩散的可能性，是许多人挽救生命的重要手段。医生往往在手术后对病人实施利用高能X光的放射线疗法，杀死没有被切除的癌细胞。
此项研究的负责人萨拉·达比教授说：“一些人一直怀疑，是否所有患者都有必要在保乳术后接受放疗。我们的研究结果证实，对几组女性而言，放疗是挽救生命的重要手段。”放疗经过谨慎的设计，以确保尽可能多地杀死癌细胞，同时保护健康细胞。放疗次数取决于肿瘤的位置、肿瘤大小和类型以及患者的总体健康状况。
此项研究涉及的所有女性以前都有通过乳房肿瘤切除术就可以去除的小肿瘤。在历时10年的研究期间，患者的病情受到监控，科学家将接受过和没有接受过放疗的女性的状况进行了对比。达比教授指出，虽然自从研究开始以来，乳腺癌的治疗方法一直在发展，但了解放疗的长期益处将有助于指导今后的治疗。她还说：“只要有可能，患乳腺癌的女性都接受手术，要么是乳房切除术(切除整个乳房)，要么是保乳手术(只切除部分乳房)。”
达比教授说：“目前的原则是，接受过保乳手术的所有女性都应进行放疗。对于接受了乳房切除术的女性而言，如果肿瘤已扩散至腋下淋巴结但没有扩散至其他地方，放疗是有必要的。”
此项研究结果本周刊登在《柳叶刀》医学期刊上。托马斯·巴克霍尔兹教授评价说：“放疗降低乳腺癌复发的风险，更重要的是，放疗提高总体生存几率。”
他说：“放疗使乳腺癌复发的可能性减少50%，这或许是治疗乳腺癌最有效的方法。”（生物谷 Bioon.com）
doi:10.1016/S0140-6736(11)61629-2
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Effect of radiotherapy after breast-conserving surgery on 10-year recurrence and 15-year breast cancer death: meta-analysis of individual patient data for 10 801 women in 17 randomised trials
Early Breast Cancer Trialists' Collaborative Group (EBCTCG)‡
Background
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.
Methods
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.
Findings
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.
Interpretation
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.
Funding
Cancer Research UK, British Heart Foundation, and UK Medical Research Council.
