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2017年7月31日，美国临床肿瘤学会《临床肿瘤学杂志》在线发表瑞典隆德大学及其附属斯科讷医院、哥德堡大学及其附属萨尔格伦斯卡医院、哥德堡西部地区癌症中心的大型随机临床研究长期（10年）随访结果，分析了保乳术后辅助放疗对不同乳腺癌亚型的作用。 1991～1997年，瑞典乳腺癌组91放疗研究（SweBCG91-RT）将1178例淋巴结阴性I～IIA期乳腺癌患者随机分配接受保乳手术±放疗（接受全身辅助治疗仅8%：内分泌治疗6%、化疗1%、内分泌＋化疗1%），其中1003例保留了肿瘤组织，其中958例通过组织微阵列原位杂交和免疫组化染色并对所有标志评分，进行了亚型分型。 结果发现，放疗与不放疗相比，10年内首发事件为同侧乳腺癌复发（IBTR）的累积发生率：
不过，亚型之间的放疗作用总体差异证据强度不足（P=0.21）。 而且，放疗仅减少了三阴性乳腺癌的乳腺癌所致死亡率（风险比：0.35，P=0.06），未减少其他亚型乳腺癌的乳腺癌所致死亡率，亦未减少任何亚型乳腺癌的全部原因所致死亡率。 此外，对于既往假设的临床低风险组（雌激素受体阳性、淋巴结阴性、年龄≥65岁），放疗与不放疗相比，10年后首发事件为IBTR的风险减少70%（6%比20%，风险比：0.30，P=0.008），但是对于乳腺癌所致死亡率或全部原因死亡率并无影响。 因此，亚型无法预测放疗效果，不过在该研究中，HER2阳性乳腺癌似乎对放疗效果最差，而三阴性乳腺癌对乳腺癌所致死亡率影响最大。此外，放疗对假设风险较低的管腔A型乳腺癌效果优良。 J Clin Oncol. 2017 Jul 31. [Epub ahead of print] Response to Radiotherapy After Breast-Conserving Surgery in Different Breast Cancer Subtypes in the Swedish Breast Cancer Group 91 Radiotherapy Randomized Clinical Trial. Sjostrom M, Lundstedt D, Hartman L, Holmberg E, Killander F, Kovács A, Malmstrom P, Niméus E, Werner Ronnerman E, Ferno M, Karlsson P. Lund University; Skane University Hospital, Lund; Sahlgrenska University Hospital; University of Gothenburg; Regional Cancer Center West, Gothenburg, Sweden. PURPOSE: To evaluate the effect of adjuvant radiotherapy (RT) after breast conservation surgery in different breast cancer subtypes in a large, randomized clinical trial with long-term follow-up. PATIENTS AND METHODS: Tumor tissue was collected from 1,003 patients with node-negative, stage I and II breast cancer who were randomly assigned in the Swedish Breast Cancer Group 91 Radiotherapy trial between 1991 and 1997 to breast conservation surgery with or without RT. Systemic adjuvant treatment was sparsely used (8%). Subtyping was performed with immunohistochemistry and in situ hybridization on tissue microarrays for 958 tumors. RESULTS: RT reduced the cumulative incidence of ipsilateral breast tumor recurrence (IBTR) as a first event within 10 years for luminal A-like tumors (19% v 9%; P = .001), luminal B-like tumors (24% v 8%; P < .001), and triple-negative tumors (21% v 6%; P = .08), but not for human epidermal growth factor receptor 2-positive (luminal and nonluminal) tumors (15% v 19%; P = .6); however, evidence of an overall difference in RT effect between subtypes was weak (P = .21). RT reduced the rate of death from breast cancer (BCD) for triple-negative tumors (hazard ratio, 0.35; P = .06), but not for other subtypes. Death from any cause was not improved by RT in any subtype. A hypothesized clinical low-risk group did not have a low risk of IBTR without RT, and RT reduced the rate of IBTR as a first event after 10 years (20% v 6%; P = .008), but had no effect on BCD or death from any cause. CONCLUSION: Subtype was not predictive of response to RT, although, in our study, human epidermal growth factor receptor 2-positive tumors seemed to be most radioresistant, whereas triple-negative tumors had the largest effect on BCD. The effect of RT in the presumed low-risk luminal A-like tumors was excellent. PMID: 28759347 DOI: 10.1200/JCO.2017.72.7263 |
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