Department of Oncology, Georgetown University Medical Center and Cancer Prevention and Control Program, Georgetown-Lombardi Comprehensive Cancer Center, Washington, DC.
Departments of Family and Social Medicine and Epidemiology and Population Health, Albert Einstein College of Medicine, Bronx, NY.
J Natl Cancer Inst. 2018 Dec 1;110(12):1370-1379. doi: 10.1093/jnci/djy128.
Radiotherapy after breast conservation has become the standard of care. Prior meta-analyses on effects of radiotherapy predated availability of gene expression profiling (GEP) to assess recurrence risk and/or did not include all relevant outcomes. This analysis used GEP information with pooled individual-level data to evaluate the impact of omitting radiotherapy on recurrence and mortality.
We considered trials that evaluated or administered radiotherapy after lumpectomy in women with low-risk breast cancer. Women included had undergone lumpectomy and were treated with hormonal therapy for stage I, ER+ and/or PR+, HER2- breast cancer with Oncotype scores no greater than 18. Recurrence-free interval (RFI), type of RFI (locoregional or distant), and breast cancer-specific and overall survival were compared between no radiotherapy and radiotherapy using adjusted Cox models. All statistical tests were two-sided.
The final sample included 1778 women from seven trials. Omission of radiotherapy was associated with an overall adjusted hazard ratio of 2.59 (95% confidence interval [CI] = 1.38 to 4.89, P = .003) for RFI. There was a statistically significant increase in any first locoregional recurrence (P = .001), but not distant recurrence events (P = .90), or breast cancer-specific (P = .85) or overall survival (P = .61). Five-year RFI rate was high (93.5% for no radiotherapy vs 97.9% for radiotherapy; absolute reduction = 4.4%, 95% CI = 0.7% to 8.1%, P = .03). The effects of radiotherapy varied across subgroups, with lower RFI rates for those with Oncotype scores of less than 11 (vs 11-18), older (vs younger), and ER+/PR+ status (vs other).
Omission of radiotherapy in hormone-sensitive patients with low recurrence risk may lead to a modest increase in locoregional recurrence event rates, but does not appear to increase the rate of distant recurrence or death.
保乳术后放疗已成为标准治疗方法。先前关于放疗效果的荟萃分析早于基因表达谱（GEP）评估复发风险的应用，且并未纳入所有相关结局。本分析采用 GEP 信息和汇总的个体水平数据，评估省略放疗对复发和死亡的影响。
我们考虑了评估或在低危乳腺癌患者保乳术后给予放疗的试验。纳入的患者均接受保乳术，且接受激素治疗，为 I 期、ER+/PR+、HER2-乳腺癌，Oncotype 评分不大于 18。采用调整后的 Cox 模型比较未放疗与放疗组的无复发生存期（RFI）、RFI 类型（局部区域或远处）、乳腺癌特异性生存和总生存。所有统计检验均为双侧。
最终样本包括来自 7 项试验的 1778 例女性。与放疗相比，省略放疗的总体调整后风险比为 2.59（95%置信区间[CI] = 1.38 至 4.89，P = .003），用于 RFI。任何首次局部区域复发的发生率均显著增加（P = .001），但远处复发事件无显著增加（P = .90），乳腺癌特异性生存（P = .85）或总生存（P = .61）无显著增加。5 年 RFI 率较高（未放疗组为 93.5%，放疗组为 97.9%；绝对减少率为 4.4%，95%CI = 0.7%至 8.1%，P = .03）。放疗的效果在亚组间存在差异，对于 Oncotype 评分<11（11-18）、年龄较大（年龄较小）和 ER+/PR+状态（其他）的患者，RFI 率较低。
在激素敏感、复发风险低的患者中省略放疗可能会导致局部区域复发事件率略有增加，但似乎不会增加远处复发或死亡的风险。
