PURPOSE The CALGB 9343 trial demonstrated that women age 70 or older with early-stage, estrogen receptor positive (ER +) breast cancer (BC) may safely forgo radiation therapy (RT) and be treated with breast conserving surgery followed by adjuvant endocrine therapy (AET) alone. However, most patients in this population still undergo RT in part because AET adherence is low. We sought to develop a predictive model for AET initiation and adherence in order to improve decision-making with respect to RT omission. METHODS Women ages 70 and older with early-stage, ER + BC were identified using the Surveillance, Epidemiology, and End Results (SEER)-Medicare database. Comorbidities, socioeconomic measures, prescription medications, and demographics were collected as potential predictors. Bivariate analysis was performed to identify factors associated with AET initiation and adherence. Stepwise selection of significant predictors was used to develop logistic regression classifiers for initiation and adherence. Model performance was evaluated using the c-statistic and other measures. RESULTS 11,037 patients met inclusion criteria. Within the cohort, 8703 (78.9%) patients initiated AET and 6685 (60.6%) were adherent to AET over 1 year. Bivariate predictors of AET initiation were similar to predictors of adherence. The best AET initiation and adherence classifiers were poorly predictive with c-statistics of 0.65 and 0.60, respectively. CONCLUSIONS The best models in the present study were poorly predictive, demonstrating that the reasons for initiation and adherence to AET are complex and individual to the patient, and therefore difficult to predict. Initiation and adherence to AET are important factors in decision-making regarding whether or not to forgo adjuvant RT. In order to better formulate treatment plans for this population, future work should focus on improving individual prediction of AET initiation and adherence.

中文翻译：

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预测患有早期乳腺癌的老年女性的辅助内分泌治疗开始和依从性。

目的 CALGB 9343 试验表明，70 岁或以上患有早期雌激素受体阳性 (ER +) 乳腺癌 (BC) 的女性可以安全地放弃放射治疗 (RT)，接受保乳手术和辅助内分泌治疗。 AET) 单独。然而，该人群中的大多数患者仍然接受放疗，部分原因是 AET 依从性低。我们试图开发 AET 启动和依从性的预测模型，以改进与 RT 遗漏有关的决策。方法 使用监测、流行病学和最终结果 (SEER)-Medicare 数据库确定 70 岁及以上的早期 ER + BC 女性。合并症、社会经济指标、处方药和人口统计学被收集作为潜在的预测因素。进行双变量分析以确定与 AET 启动和依从性相关的因素。显着预测因子的逐步选择用于开发用于启动和依从性的逻辑回归分类器。使用 c 统计量和其他措施评估模型性能。结果 11,037 名患者符合纳入标准。在队列中，8703 (78.9%) 名患者开始 AET，6685 (60.6%) 名患者坚持 AET 超过 1 年。AET 启动的双变量预测因子与依从性的预测因子相似。最好的 AET 启动和依从性分类器的预测性较差，c 统计量分别为 0.65 和 0.60。结论 本研究中最好的模型预测性较差，表明开始和坚持 AET 的原因复杂且因患者而异，因此难以预测。开始和坚持 AET 是决定是否放弃辅助放疗的重要因素。为了更好地为该人群制定治疗计划，未来的工作应侧重于提高个体对 AET 启动和依从性的预测。