PERCHLOROETHYLENE IN DRINKING WATER AND CANCER RISK

四氯乙烯，也称为全氯乙烯或PCE)是一种溶剂 通常用于减少操作和用作干洗剂。它是 也是公共饮用水供应中的一种常见污染物。两者都有 流行病学和毒理学数据表明，四氯乙烯是一种致癌物质。 我们之前的研究表明，受PCE污染的饮用水可能 与乳腺癌风险增加有关。我们进行了一次 258例乳腺癌人群病例对照研究 诊断时间为1983至1986年。当受试者接触到四氯乙烯时， 从饮用水配水管道的塑料内衬中渗出 20世纪60年代末到70年代。调整后的乳房相对危险度 当潜伏期为1.3时，高度暴露的受试者患癌症的比例为1.3 当应用9年潜伏期时忽略为2.4。然而，增加的 风险在统计上并不显著，因为暴露在 受试者很小，特别是当潜伏期较长时 假设的。因此，最近诊断的更大规模的病例对照研究 需要案例来准确估计不同延迟的风险 假设。 拟议的流行病学研究将检验PCE在 科德角地区的公共饮用水供应系统 马萨诸塞州地区与乳腺癌有关。这将是 通过开展以人群为基础的病例对照研究来实现，包括 1987至1995年间确诊的1170例病例和对照1170例，以及：(1) 使用一口井估计乳腺癌病例和对照人群中的四氯乙烯暴露 建立了暴露模型；(2)确定乳房与乳房之间的关系 控制混杂因素时的癌症风险和估计的四氯乙烯暴露 变量；以及(3)评估居民用水的影响 饮酒、烹饪和洗澡与乳腺癌的关系 风险和估计的四氯乙烯暴露。

Tetrachloroethylene also called perchlorethylene or PCE) is a solvent commonly used for decreasing operation and as a dry cleaning agent. It is also a common contaminant in public drinking water supplies. Both epidemiological and toxicological data implicate PCE as a carcinogen. Our prior research suggests that PCE-contaminated drinking water may be associated with an increased risk of breast cancer. We conducted a population-based case-control study including 258 breast cancer cases diagnosed from 1983 through 1986. Subjects were exposed to PCE when it leached from the plastic lining of drinking water distribution pipes from the late 1960s through the 1970s. The adjusted relative risks of breast cancer among "highly' exposed subjects ranged from 1.3 when latency was ignored to 2.4 when 9 years of latency was applied. However, the increased risks were not statistically significant because th proportion of exposed subjects was small, particularly when long latent periods were hypothesized. Thus, a larger case-control study of more recently diagnosed cases is needed to estimate precisely the risk for different latency assumptions. The proposed epidemiologic study will test the hypothesis that PCE found in the distribution systems of public drinking water supplies in the Cape Cod region of Massachusetts is associated with breast cancer. This will be accomplished by conducting a population-based case-control study including 1,170 cases diagnosed from 1987 through 1995 and 1,170 controls and: (1) Estimating PCE exposure in breast cancer cases and controls using a well- developed exposure model; (2) Determining the relationship between breast cancer risk and estimated PCE exposure while controlling for confounding variables; and (3) Evaluating the impact of residential water use for drinking, cooking, and bathing on the relationship between breast cancer risk and estimated PCE exposure.