HORMONAL REPLACEMENT THERAPY AND RISK OF COLON CANCER

描述：结直肠癌是第三大最常见的癌症， 是西方世界女性癌症死亡的第二大原因。虽然 该机制尚未得到证实，流行病学研究和一些 动物研究的证据表明，生殖激素， 特别是雌激素，可以防止结肠的发展， 绝经后妇女的癌症。这种基于历史人口的嵌套 病例对照研究将调查过去暴露于 激素替代疗法（HRT）对结肠癌的风险。 方法：研究的源人群将是动态队列 根据萨斯喀彻温省处方药计划（SPDP）的成员资格定义。 50岁以上的结肠癌发病病例将由 1981年至1998年省级癌症登记处（n= 2，400）。四个年龄匹配的 每个病例的对照将从源人群中选择，使用 发病密度抽样详细的处方药暴露数据， HRT在诊断前至少5年，最多20年 年将从SPDP获得。也从SPDP获得， 同一时间段将是口服避孕药的处方信息 和NSAIDs。将从样本中获得潜在混杂因素的数据 1994年1月1日至1998年12月31日， 的电话采访进行盲目的疾病状态。采样 分数将根据疾病和药物暴露状态而变化， 第二阶段样本将包括约150个接触病例和对照组 以及150例未暴露病例和对照（总计=500-650例受试者）。混杂 将进行控制，并将使用逻辑分析研究效果修改 回归，对第二阶段抽样进行适当校正 阴谋 重要性：申请人处于独特的地位，可以审查 HRT暴露的剂量、持续时间和时间对风险的各自影响 早在20年前， 在指数数据之前。研究结果将详细说明风险/获益 HRT的概况，这将有助于妇女和他们的医生， 明智的决定。此外，这些结果将在 为HRT制定全面的实践指南。

DESCRIPTION: Colorectal cancer is the third most frequent cancer and the second cause of cancer mortality in women in the Western World. Although the mechanism has not been confirmed, epidemiological studies and some evidence from animal studies suggest that reproductive hormones, specifically estrogens, may protect against the development of colon cancer in post-menopausal women. This historical population-based nested case-control study will investigate the effect of past exposure to hormonal replacement therapy (HRT) on the risk of developing colon cancer. Methods: The source population for the study will be the dynamic cohort defined by membership in the Saskatchewan Prescription Drug Plan (SPDP). Incident cases of colon cancer over 50 years of age will be accrued by the provincial cancer registry from 1981 to 98 (n=2,400). Four age-matched controls per case will be selected from the source population, using incidence density sampling. Detailed prescription drug exposure data on HRT over a minimum of 5 years before diagnosis and up to a maximum 20 years will be obtained from the SPDP. Also obtained from the SPDP for this same time period will be prescription information on oral contraceptives and NSAIDs. Data on potential confounders will be obtained from a sample of the subjects accrued from January 1, 1994 to December 31, 1998 by means of telephone interviews carried out blind to disease status. The sampling fractions will vary according to disease and drug exposure status, so that the second stage sample will contain about 150 exposed cases and controls and 150 unexposed cases and controls (total=500-650 subjects). Confounding will be controlled and effect modification will be studied with logistic regression, using appropriate correction for the second stage-sampling scheme. Significance: The applicant is in a unique position to examine the respective effect of dose, duration and timing of HRT exposure on the risk of developing colon cancer, for a period of time as far back as 20 years prior to the index data. The findings will elaborate on the risk/benefit profile of HRT, which will assist women and their physicians to make informed decisions. In addition the results will be of value in the development of comprehensive practice guidelines for HRT.