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作为干洗剂。 是 也是公共饮用水供应中的常见污染物。 两 流行病学和毒理学数据表明，四氯乙烯是一种致癌物质。 我们先前的研究表明，受PCE污染的饮用水可能是 与乳腺癌风险增加有关。 我们进行了一项 一项基于人群的病例对照研究，包括258例乳腺癌病例 从1983年到1986年被诊断出来 受试者暴露于PCE时， 从饮用水分配管道的塑料衬里中滤出， 60年代末到70年代。 调整后的乳腺癌相对风险 “高度”暴露受试者的癌症范围从1.3，当潜伏期为 当应用9年的延迟时忽略到2.4。 然而，增加 风险没有统计学意义，因为暴露的比例 受试者很小，特别是当长潜伏期 假设的 因此，一个更大的病例对照研究， 需要精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 科德角的公共饮用水供应分配系统 马萨诸塞州的一个地区与乳腺癌有关。 这将是 通过进行基于人群的病例对照研究完成，包括 1987年至1995年诊断的1，170例病例和1，170例对照，以及：（1） 使用一个良好的模型估计乳腺癌病例和对照中的PCE暴露量- 建立暴露模型;（2）确定乳腺癌与乳腺癌之间的关系 癌症风险和估计的PCE暴露，同时控制混杂因素 变量;（3）评价居民用水对 饮酒、烹饪和洗澡与乳腺癌之间的关系 风险和估计的PCE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.