对于 I 期雌激素受体阳性乳腺癌的老年女性，不进行内分泌治疗的放射治疗与更高的第二乳腺癌事件风险无关。

Radiation Without Endocrine Therapy in Older Women With Stage I Estrogen-Receptor-Positive Breast Cancer is Not Associated With a Higher Risk of Second Breast Cancer Events.

机构信息

Department of Radiation Oncology, NYU School of Medicine, New York, New York.

Baptist Clinical Research Institute, Memphis, Tennessee.

出版信息

Int J Radiat Oncol Biol Phys. 2022 Jan 1;112(1):40-51. doi: 10.1016/j.ijrobp.2021.04.030. Epub 2021 May 8.

DOI:10.1016/j.ijrobp.2021.04.030

PMID:33974886

Abstract

PURPOSE

The omission of radiation therapy (RT) in older women with stage 1 estrogen-receptor-positive (ER+) breast cancer receiving endocrine therapy (ET) is an acceptable strategy based on randomized trial data. Less is known about the omission of ET with or without RT.

METHODS AND MATERIALS

We analyzed surveillance, epidemiology, and end results (SEER)-Medicare data for 13,321 women age 66 years or older with stage I ER+ breast cancer from 2007 to 2012 who underwent breast-conserving surgery. Patients were classified into 4 groups: (1) ET + RT (reference); (2) ET alone; (3) RT alone; and (4) neither RT nor ET (NT). Second breast cancer events (SBCEs) were captured using the Chubak high-specificity algorithm. We used χ tests for descriptive statistics, multivariable multinomial logistic regression to estimate relative risk of undergoing a treatment, and multivariable, propensity-weighted competing-risks survival regression to estimate standardized hazard ratio (SHR) of SBCE. We set significance at P ≤ .01.

RESULTS

Most women underwent both treatments, with 44% undergoing ET + RT, 41% RT alone, 6.6% ET alone, and 8.6% NT, but practice patterns varied over time. From 2007 to 2012, RT decreased from 49% to 30%, whereas ET alone and ET + RT increased (ET alone, 5.4%-9.6%; ET + RT, 38%-51%). Compared with patients age 66 to 69 years, patients age 80 to 85 years were more likely to receive NT (odds ratio [OR], 8.9), RT (OR, 1.9), or ET (OR, 8.8) versus ET + RT (P < .01). Three percent of subjects had an SBCE (2.2% ET + RT, 3.0% RT alone, 3.2% ET alone, 7.0% NT). Relative to ET + RT, NT and ET alone were associated with higher SBCE (NT: SHR, 3.7, P < .001; ET alone: SHR, 2.2, P = .008), whereas RT was not associated with a higher SBCE (SHR 1.21; P = .137). Clinical factors associated with higher SBCE were HER2 positivity and pT1c (SHR, 1.7; P = .006).

CONCLUSIONS

Treatment with RT alone in older women with stage I ER+ disease is decreasing. RT alone is not associated with an increased risk for SBCE. By contrast, NT and ET are both associated with higher SBCE in multivariable analysis with propensity weighting. Further study of the omission of endocrine therapy in this patient population is warranted.

摘要

目的

根据随机试验数据，对于接受内分泌治疗（ET）的年龄较大的 I 期雌激素受体阳性（ER+）乳腺癌女性，省略放疗（RT）是一种可接受的策略。对于省略 ET 联合或不联合 RT 的情况，了解较少。

方法和材料

我们分析了 2007 年至 2012 年间接受保乳手术的年龄在 66 岁或以上、I 期 ER+乳腺癌的 13321 名 SEER-医疗保险数据，这些患者均患有 stage I ER+ 乳腺癌。患者分为 4 组：（1）ET+RT（参考）；（2）仅 ET；（3）仅 RT；（4）既无 RT 也无 ET（NT）。使用 Chubak 高特异性算法捕获第二原发乳腺癌事件（SBCE）。我们使用 χ2 检验进行描述性统计，多变量多项逻辑回归估计接受治疗的相对风险，多变量、倾向评分加权竞争风险生存回归估计 SBCE 的标准化风险比（SHR）。我们设定 P≤0.01 为显著性水平。

结果

大多数女性接受了两种治疗，其中 44%接受了 ET+RT，41%接受了 RT，6.6%接受了 ET，8.6%接受了 NT，但治疗模式随时间而变化。2007 年至 2012 年，RT 从 49%下降到 30%，而单独 ET 和 ET+RT 增加（单独 ET，5.4%-9.6%；ET+RT，38%-51%）。与 66-69 岁的患者相比，80-85 岁的患者更有可能接受 NT（比值比[OR]，8.9）、RT（OR，1.9）或 ET（OR，8.8）而非 ET+RT（P<.01）。3%的患者发生了 SBCE（2.2% ET+RT，3.0% RT 单独，3.2% ET 单独，7.0% NT）。与 ET+RT 相比，NT 和 ET 单独治疗与更高的 SBCE 相关（NT：SHR，3.7，P<.001；ET 单独：SHR，2.2，P=.008），而 RT 与更高的 SBCE 无关（SHR 1.21；P=.137）。与更高的 SBCE 相关的临床因素包括 HER2 阳性和 pT1c（SHR，1.7；P=.006）。