PHARMO Institute for Drug Outcomes Research, P.O. Box 85222, 3508 AE, Utrecht, The Netherlands.
Breast Cancer Res Treat. 2010 Aug;122(3):843-51. doi: 10.1007/s10549-009-0724-3. Epub 2010 Jan 8.
Observational studies on long-term endocrine treatment among breast cancer patients have presented discontinuation rates on tamoxifen, but lack information on the continuance of any endocrine treatment [both tamoxifen and aromatase inhibitors (AIs)] within the same cohort. In this study we determined switching rates from tamoxifen to AIs, discontinuation rates of tamoxifen only, discontinuation rates of any endocrine treatment and determinants of first treatment switch and treatment discontinuation. Patients with early stage breast cancer (stage I-IIIa) starting on tamoxifen were selected from the linked Eindhoven Cancer Registry-PHARMO RLS cohort in the period 1998-2006. Continuous use (allowing a 60 days gap between refills) of tamoxifen only and any endocrine treatment were determined after various follow-up periods: 1, 2, 3, 4, and 5 years. Time to first switch from tamoxifen to an AI was assessed. Cox regression was used to identify determinants of first treatment switch, discontinuation of tamoxifen, and discontinuation of any endocrine treatment. A total of 1,451 new early stage breast cancer patients started on tamoxifen. Of those, 380 had a treatment switch to an AI during follow-up. Of the patients followed for 5 years, 40% continuously used tamoxifen, which was 49% for any endocrine treatment. Older age (older than 70 versus 50-69 years) was independently associated with increased discontinuation of tamoxifen and any endocrine therapy. Patients with two or more concomitant diseases (versus no comorbidity) showed an increased likelihood to stop any endocrine treatment or switch treatment from tamoxifen to an AI. In conclusion, up to half of the breast cancer patients starting tamoxifen continued 5 years of endocrine treatment. Identification of patients at risk of discontinuation will assist in the development of interventions to improve treatment continuation comparable to that of patients included in clinical trials.
观察性研究表明，乳腺癌患者接受长期内分泌治疗时，会出现他莫昔芬停药率，但缺乏同一队列中任何内分泌治疗（包括他莫昔芬和芳香化酶抑制剂（AIs））持续使用的信息。在这项研究中，我们确定了从他莫昔芬转为使用 AI 的转换率、仅使用他莫昔芬的停药率、任何内分泌治疗的停药率，以及首次治疗转换和治疗停药的决定因素。选择了 1998 年至 2006 年期间在 EINDHOVEN 癌症登记处-PHARMO RLS 队列中开始使用他莫昔芬的早期乳腺癌（I-IIIa 期）患者。在不同的随访期间确定了仅使用他莫昔芬和任何内分泌治疗的连续使用（允许在每次续药之间有 60 天的间隔）：1、2、3、4 和 5 年。评估了从他莫昔芬首次转换为 AI 的时间。使用 Cox 回归来确定首次治疗转换、他莫昔芬停药和任何内分泌治疗停药的决定因素。共纳入 1451 例新诊断的早期乳腺癌患者开始使用他莫昔芬。其中，380 例在随访期间转为使用 AI。在随访 5 年的患者中，40%连续使用他莫昔芬，49%连续使用任何内分泌治疗。年龄较大（大于 70 岁与 50-69 岁相比）与他莫昔芬和任何内分泌治疗的停药率增加独立相关。有两种或更多并存疾病（与无合并症相比）的患者停止任何内分泌治疗或从他莫昔芬转为使用 AI 的可能性增加。总之，开始使用他莫昔芬的乳腺癌患者中，有多达一半的患者继续接受 5 年的内分泌治疗。识别有停药风险的患者，将有助于制定干预措施，以提高治疗的连续性，使其与临床试验中纳入的患者相当。
