Background Anastrozole reduces breast cancer risk in women at high risk, but implementing preventive therapy in clinical practice is difficult. Here, we evaluate adherence to anastrozole in the International Breast Cancer Intervention Study (IBIS)-II prevention and ductal carcinoma in situ (DCIS) trials, and its association with early symptoms. Patients and methods In the prevention trial, 3864 postmenopausal women were randomized to placebo versus anastrozole. A total of 2980 postmenopausal women with DCIS were randomized to tamoxifen versus anastrozole. Adherence to trial medication was calculated using the Kaplan-Meier method and all P-values were two-sided. Results In the prevention trial, adherence was 65.8% [anastrozole (65.7%) versus placebo (65.9%); HR = 0.97 (0.87-1.09), P = 0.6]. Adherence was lower for those reporting arthralgia in the placebo group (P = 0.02) or gynecological symptoms in the anastrozole group (P = 0.003), compared with those not reporting these symptoms at 6 months. In the DCIS study, adherence was 66.7% [anastrozole (67.5%) versus tamoxifen (65.8%); HR = 1.06 (0.94-1.20), P = 0.4]. Hot flashes were associated with greater adherence in the anastrozole arm (P = 0.02). In both studies, symptoms were mostly mild or moderately severe, and adherence decreased with increasing severity for most symptoms. Drop-outs were highest in the first 1.5 years of therapy in both trials. Conclusions In the IBIS-II prevention and DCIS trials, over two-thirds of women were adherent to therapy, with no differences by treatment groups. Participants who reported specific symptoms in the IBIS-II prevention trial had a small but significant effect on adherence, which strengthened as severity increased. Strategies to promote adherence should target the first year of preventive therapy.

中文翻译：

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在国际乳腺癌干预研究 II 中，参与者报告的早期症状是阿那曲唑依从性的预测因素。

背景 阿那曲唑可降低高危女性患乳腺癌的风险，但在临床实践中实施预防性治疗很困难。在这里，我们评估了国际乳腺癌干预研究 (IBIS)-II 预防和导管原位癌 (DCIS) 试验中阿那曲唑的依从性，及其与早期症状的关联。患者和方法 在预防试验中，3864 名绝经后妇女被随机分配到安慰剂组和阿那曲唑组。共有 2980 名患有 DCIS 的绝经后妇女被随机分配到他莫昔芬组和阿那曲唑组。使用 Kaplan-Meier 方法计算对试验药物的依从性，所有 P 值都是双边的。结果 在预防试验中，依从率为 65.8% [阿那曲唑 (65.7%) 与安慰剂 (65.9%)；HR = 0.97 (0.87-1.09)，P = 0.6]。与 6 个月时未报告这些症状的患者相比，安慰剂组报告关节痛（P = 0.02）或阿那曲唑组妇科症状（P = 0.003）的患者的依从性较低。在 DCIS 研究中，依从性为 66.7% [阿那曲唑 (67.5%) 与他莫昔芬 (65.8%)；HR = 1.06 (0.94-1.20)，P = 0.4]。潮热与阿那曲唑组更高的依从性相关（P = 0.02）。在这两项研究中，症状大多为轻度或中度严重，大多数症状的依从性随着严重程度的增加而降低。在两项试验中，治疗前 1.5 年的辍学率最高。结论 在 IBIS-II 预防和 DCIS 试验中，超过三分之二的女性坚持治疗，治疗组之间没有差异。在 IBIS-II 预防试验中报告特定症状的参与者对依从性的影响很小但很显着，随着严重程度的增加，这种影响会加强。促进依从性的策略应针对预防性治疗的第一年。