Cervical cancer screening in the United States and the Netherlands: a tale of two countries

Abstract

Context: This article compares cervical cancer screening intensity and cervical cancer mortality trends in the United States and the Netherlands to illustrate the potential of cross-national comparative studies. We discuss the lessons that can be learned from the comparison as well as the challenges in each country to effective and efficient screening.

Methods: We used nationally representative data sources in the United States and the Netherlands to estimate the number of Pap smears and the cervical cancer mortality rate since 1950. The following questions are addressed: How do differences in intensity of Pap smear use between the countries translate into differences in mortality trends? Can population coverage rates (the proportion of eligible women who had a Pap smear within a specified period) explain the mortality trends better than the total intensity of Pap smear use?

Findings: Even though three to four times more Pap smears per woman were conducted in the United States than in the Netherlands over a period of three decades, the two countries' mortality trends were quite similar. The five-year coverage rates for women aged thirty to sixty-four were quite comparable at 80 to 90 percent. Because screening in the Netherlands was limited to ages thirty to sixty, screening rates for women under thirty and over sixty were much higher in the United States. These differences had consequences for age-specific mortality trends. The relatively good coverage rate in the Netherlands can be traced back to a nationwide invitation system based on municipal population registries. While both countries followed a "policy cycle" involving evidence review, surveillance of screening practices and outcomes, clinical guidelines, and reimbursement policies, the components of this cycle were more systematically linked and implemented nationwide in the Netherlands than in the United States. To a large extent, this was facilitated by a public health model of screening in the Netherlands, rather than a medical services model.

Conclusions: Cross-country studies like ours are natural experiments that can produce insights not easily obtained from other types of study. The cervical cancer screening system in the Netherlands seems to have been as effective as the U.S. system but used much less screening. Adequate coverage of the female population at risk seems to be of central importance.

FIGURE 1

Number of Pap smears per 1,000 Women per year in the United States and the Netherlands, Age Standardized to the U.S. 2000 Population. Sources: United States: NHIS, see Gardner and Lyon 1977; National Center for Health Statistics 2011a, ; Swan et al. 2010. Netherlands: PALGA, see Casparie et al. 2007; Habbema et al. 1988.

FIGURE 2

Cervical Cancer Mortality Rates in the United States and in the Netherlands, Age Standardized to the U.S. 2000 Population. Sources: United States: NCHS, see Altekruse et al. 2010. Netherlands: Statistics Netherlands (CBS) 2010a.

FIGURE 3

Cervical Cancer Incidence in the United States and in the Netherlands, Age Standardized to the U.S. 2000 Population. Sources: United States: SEER, see Altekruse et al. 2010. Netherlands: Netherlands Cancer Registry 2010.

FIGURE 4

Percentage of the Female Population in the United States and the Netherlands That Received a Pap Smear in the Last Five Years, by Age Groups 20–29, 30–64, and 65+, Age Standardized to the U.S. 2000 Population. Sources: United States: NHIS, see National Center for Health Statistics 2011a, ; Swan et al. 2010. Netherlands: PALGA, see Casparie et al. 2007.

FIGURE 5

Trend in Mortality Rates in the United States and in the Netherlands by Age Group, Age Standardized to the U.S. 2000 Population. Notes: For each age group, the mortality between 1970 and 1974 is indexed at 100 for both countries. (a) <30 years, U.S. mortality in 1970: 106 cases, mortality rate = 0.68/100,000. (b) 30–64 years, U.S. mortality in 1970: 4,011 cases, mortality rate = 10.12/100,000. (c) >65 years, U.S. mortality in 1970, 2,429 cases, mortality rate = 20.84/100,000. Sources: United States: NCHS, see Altekruse et al. 2010. Netherlands: Statistics Netherlands (CBS) 2010a.