Cervical screening and cervical cancer death among older women: a population-based, case-control study

Abstract

Recent research suggests that cervical screening of older women is associated with a considerable decrease in cervical cancer incidence. We sought to quantify the efficacy of cervical cytology screening to reduce death from this disease. Among enrollees of 2 US health plans, we compared Papanicolaou smear screening histories of women aged 55-79 years who died of cervical cancer during 1980-2010 (cases) to those of women at risk of cervical cancer (controls). Controls were matched 2:1 to cases on health plan, age, and enrollment duration. Cytology screening during the detectable preclinical phase, estimated as the 5-7 years before diagnosis during which cervical neoplasia is asymptomatic but cytologically detectable, was ascertained from medical records. A total of 39 cases and 80 controls were eligible. The odds ratio of cervical cancer death associated with screening during the presumed detectable preclinical phase was 0.26 (95% confidence interval: 0.10, 0.63) after adjustment for matching characteristics, smoking, marital status, and race/ethnicity using logistic regression. We estimate that cervical cytology screening of all women aged 55-79 years in the United States could avert 630 deaths annually. These results provide a minimum estimate of the efficacy of human papillomavirus DNA screening-a more sensitive test-to reduce cervical cancer death among older women.

Keywords: Papanicolaou smear; case-control studies; screening; uterine cervical neoplasms; women's health.

Figure 1.

Screening during the detectable preclinical phase (DPP) of persons who died of their cancer (cases) and during the corresponding period among controls. The DPP is shown in bold along the x-axis. This figure assumes that the DPP is 7 years for all cases, that screening during the first 6 years of the DPP inevitably leads to the cancer being cured (i.e., odds ratio = 0), and that screening after that time is of no benefit to survival. Adapted from Weiss et al. (10).