Local Therapy of Breast Cancer in Community Populations

描述(由申请人提供)：早期乳腺癌治疗指南和共识声明指出：(A)保乳可提供与乳房切除术相同的存活率，(B)接受保乳手术(BCS)的患者也应接受放射治疗。这些声明是基于临床试验数据；然而，只有2.5%的癌症患者参加了临床试验，因此，试验结果并不总是为所有患者的治疗提供明确的指导。那些登记参加临床试验的人往往比其他患者更年轻、更健康，他们通常由在癌症中心执业或附属于癌症中心的提供者照顾。此外，临床试验可能不足以评估具有某些人口统计学或临床特征的患者亚群的结果。通过仔细的设计和分析，观察性数据可能会解决在随机试验背景下无法回答的有关治疗有效性的问题。在这项研究中，我们将使用倾向评分技术来检查生活在美国不同地区的社区女性队列中乳腺癌局部治疗后长达10年的存活率。我们将评估所有女性和女性亚组的结果，例如老年女性、患有更多并发症的女性和晚期肿瘤患者，这些女性几乎没有临床试验数据来指导治疗决定。这些队列包括居住在SEER地区的63,750名妇女，在1991-2002年期间被诊断为I期或II期乳腺癌，并包括在SEER-Medicare数据库中，以及明尼苏达州或马萨诸塞州的3,828名妇女，她们在1993-1995年间被诊断为I期或II期乳腺癌。具体来说，我们会： 1.评估在社区人群中，在临床上不同的早期乳腺癌患者群体中，乳房切除术与BCS加放射治疗的长期存活率是否相同。 2.评估在社区人群中接受和不接受BCS放射治疗的早期乳腺癌妇女的长期存活率是否相等。 3.使用工具变量技术评估我们对目标1和目标2的治疗效果估计的稳健性。 通过提供对治疗效果的可靠估计，拟议的工作将帮助临床医生指导早期乳腺癌妇女的治疗选择，包括几乎没有临床试验数据的妇女，如老年妇女、患有更多并发症的妇女或患有更晚期肿瘤的妇女。此外，这项工作将为分析观测数据提供不同的技术。

DESCRIPTION (provided by applicant): Guidelines and consensus statements for the treatment of early-stage breast cancer state that: (a) breast conservation offers survival rates equivalent to mastectomy and (b) patients undergoing breast-conserving surgery (BCS) should also receive radiation. These statements are based on clinical trial data; however, only 2.5% of cancer patients enroll in clinical trials, and therefore, findings from trials do not always provide definitive guidance for the treatment of all patients. Those who enroll in clinical trials tend to be younger and healthier than other patients and they are typically cared for by providers who practice at or are affiliated with cancer centers. Moreover, clinical trials may be underpowered to assess outcomes among subgroups of patients with certain demographic or clinical characteristics. Through careful design and analysis, observational data may address questions regarding treatment effectiveness that are not feasible to answer within the context of randomized trials. In this study, we will use propensity score techniques to examine survival for up to 10 years after local treatment of breast cancer among community-based cohorts of women living in various regions of the U.S. We will assess outcomes among all women and among subgroups of women, such as older women, women with more comorbid illness, and women with advanced tumors, for whom few clinical trial data are available to guide treatment decisions. The cohorts include 63,750 women living in a SEER region and diagnosed with stage I or II breast cancer during 1991-2002 and included in the SEER-Medicare database and 3,828 women in Minnesota or Massachusetts and diagnosed with stage I or II breast cancer during 1993-1995. Specifically, we will: 1. Assess whether long-term survival for mastectomy versus BCS with radiation is equivalent across clinically distinct groups of women with early-stage breast cancer in community populations. 2. Assess whether long-term survival is equivalent among women with early-stage breast cancer who do and do not undergo radiation therapy following BCS in community populations. 3. Assess the robustness of our estimates of treatment effectiveness obtained for Aim 1 and Aim 2 using instrumental variable techniques. By providing reliable estimates of treatment effectiveness, the proposed work will help clinicians guide treatment choices for women with early-stage breast cancer, including women for whom few clinical trial data are available, such as older women, women with more comorbid illness, or women with more advanced tumors. Moreover, the work will provide insight into different techniques for the analysis of observational data.