CERVICAL CANCER SCREENING EFFICACY IN OLDER WOMEN

通过子宫颈抹片检查宫颈癌，已明显减轻了育龄妇女患宫颈癌的负担。不幸的是，在超过生育年龄的妇女中，子宫颈检查的有用性是不确定的。我们建议采用病例对照研究设计来评估老年妇女宫颈筛查的疗效。我们将比较两组老年妇女（55-79岁）在美国西北部两个大型健康维护组织中的一个登记的既往使用巴氏涂片的情况。这项建议的总体目标是评估在老年妇女中，通过巴氏涂片进行子宫颈检查能在多大程度上减少子宫颈癌的发病率。具体目的是：(1)确定在筛查阴性的老年妇女中浸润性宫颈癌的发病率；(2)比较患浸润性宫颈癌的老年妇女和其他类似的无此病史的妇女的宫颈筛查史。病例将包括1980-1997年期间在团体健康合作社或凯撒医疗机构西北注册时患上侵袭性宫颈癌的妇女。资格将仅限于连续入学七年的女性。对于每个病例，将从以前没有做过子宫切除术的登记者中随机抽取三个对照，并与年龄和健康计划登记时间相匹配。研究人员会检视研究对象的医疗纪录，以确定她们是否接受子宫颈抹片检查，以及其他与罹患子宫颈癌风险（即吸烟）有关的资料。病例和对照将比较在肿瘤侵袭前可检测阶段的筛查史。在某种程度上，筛查导致宫颈癌在这一人群中的发病率降低，筛查史-在前驱病变存在的时间内，但在癌症发展之前-在对照组中比病例中更常见。拟议的研究结果应为建议继续（或扩大）对老年妇女进行子宫颈检查或减少检查水平并将节省下来的费用用于更有效的促进健康手段提供更坚实的基础。

Screening for cervical cancer, by means of the Pap smear, has demonstrably reduced the burden of cervical cancer among women of reproductive ages. Unfortunately, in women beyond the reproductive years the usefulness of cervical screening is uncertain. We propose to evaluate the efficacy of cervical screening in older women using a case-control study design. We will compare the prior use of the Pap smear in two groups of older women (55-79 years of age) enrolled at one of two, large, health maintenance organizations in the northwestern United States. The overall goal of this proposal is to assess, in older women, the degree to which screening of the uterine cervix, by means of a Pap smear, can reduce the incidence of cancer of the cervix. The specific aims are: (1) to determine the incidence of invasive cervical cancer in older women following a negative screening exam; and (2) to compare older women who develop invasive cervical cancer and an otherwise similar group of women without this condition for a history of cervical screening. Cases will consist of those women who developed invasive cervical cancer during 1980-1997 while enrolled at either Group Health Cooperative or Kaiser Permanente Northwest. Eligibility will be restricted to women with seven years of continuous enrollment. For each case, three controls will be randomly sampled from enrollees who have not previously had a hysterectomy and matched to cases on age and duration of enrollment in the health plan. Medical records of the study subjects will be reviewed to ascertain receipt of Pap smear screening and other information relevant to the risk of developing cervical cancer (i.e., smoking). Cases and controls will be compared for a history of screening during the pre-invasive detectable phase of the tumor. To the extent that screening leads to a reduced incidence of cervical cancer in this population, a history of screening - during the time period in which the precursor lesion is present, but prior to the development of cancer - will be more common in controls than cases. The results of the proposed study should provide a more solid basis either for recommending continued (or expanded) cervical screening of older women, or instead for a reduced level of screening and an allocation of the cost savings to more productive means of health promotion.