Department of Radiation Oncology, University of Pittsburgh, UPMC Hillman Cancer Center, Pittsburgh, PA, USA.
Department of Radiation Oncology, Medical College of Wisconsin, Milwaukee, WI, USA.
Cancer Med. 2020 Dec;9(23):8979-8988. doi: 10.1002/cam4.3597. Epub 2020 Nov 4.
Among patients with osseous metastases, breast cancer (BC) patients typically have the best prognosis. In the palliative setting, BC is often considered a single disease, but based on receptor status there are four distinct subtypes: luminal A (LA), luminal B (LB), triple negative (TN), and HER2-enriched (HER2). We hypothesize that survival and palliative outcomes following palliative RT for osseous metastases correlate with breast cancer subtype (BCS).
We identified 3,895 BC patients with known receptor status who received palliative RT for osseous metastases from 2004-2013 in the National Cancer Database. Kaplan-Meier method with log-rank testing and univariate/multivariate Cox-regression was used to identify survival factors. Incomplete radiation courses, 30-day mortality rate, and percentage remaining life spent receiving RT (PRLSRT) were calculated.
Subtypes were 54% LA, 33% LB, 8% TN, and 5% HER2 with median survival of 34.1, 28.2, 5.3, and 15.7 months, respectively (p < 0.001). Overall 82% of patients received ≥10 fractions. Although BCS had limited effect on radiation regimens, TN received nearly twice as many single or hypofractionated (≤5 fractions) treatments, but the overall rate of these fraction schemes was low at 3.7 and 13.7%, respectively. Compared to LA and LB, TN and HER2 patients had worse palliative outcomes; higher rates of incomplete courses at 18.8% and 18.3% versus 12.7%-14.4%; higher 30-day mortality post-radiotherapy at 21.5% and 16.0% versus 6.3%-7.9%, and higher median PRLSRT of 7.7% and 3.7% versus 2.2%-2.4% for LA and LB. On multivariate analysis, BCS was associated with overall survival with TN (HR 3.7), HER2 (HR 1.75), and LB (HR 1.28) fairing worse than LA (p < 0.001).
BCS correlated with survival and palliative outcome following radiation to osseous metastases. BCS should be considered by physicians when planning palliative RT to maximize quality-of-life, avoid unnecessary treatment, and ensure palliative benefits.
在患有骨转移的患者中，乳腺癌（BC）患者通常具有最佳的预后。在姑息治疗环境中，BC 通常被认为是一种单一疾病，但根据受体状态，它有四个不同的亚型：管腔 A（LA）、管腔 B（LB）、三阴性（TN）和 HER2 丰富（HER2）。我们假设，接受姑息性放疗治疗骨转移后的生存和姑息治疗结局与乳腺癌亚型（BCS）相关。
我们从 2004 年至 2013 年在国家癌症数据库中确定了 3895 名已知受体状态的接受姑息性放疗治疗骨转移的 BC 患者。采用 Kaplan-Meier 方法结合对数秩检验和单变量/多变量 Cox 回归分析来确定生存因素。计算不完整放疗疗程、30 天死亡率和接受放疗的剩余生命百分比（PRLSRT）。
各亚型的比例分别为 54%的 LA、33%的 LB、8%的 TN 和 5%的 HER2，中位生存时间分别为 34.1、28.2、5.3 和 15.7 个月（p<0.001）。总体而言，82%的患者接受了≥10 个剂量。尽管 BCS 对放疗方案的影响有限，但 TN 接受了近两倍的单次或低分割（≤5 个剂量）治疗，但这些分割方案的总体比例较低，分别为 3.7%和 13.7%。与 LA 和 LB 相比，TN 和 HER2 患者的姑息治疗结局更差；不完全疗程的比例分别为 18.8%和 18.3%，而 12.7%-14.4%；放疗后 30 天死亡率分别为 21.5%和 16.0%，而 6.3%-7.9%；LA 和 LB 的 PRLSRT 中位数分别为 7.7%和 3.7%，而 TN 和 HER2 则分别为 3.7%和 3.7%。多变量分析显示，BCS 与整体生存相关，TN（HR 3.7）、HER2（HR 1.75）和 LB（HR 1.28）的预后均差于 LA（p<0.001）。
BCS 与骨转移放疗后的生存和姑息治疗结局相关。在计划姑息性放疗时，医生应考虑 BCS，以最大限度地提高生活质量，避免不必要的治疗，并确保姑息治疗的益处。
