Coverage of cervical cancer screening in 57 countries: low average levels and large inequalities
Published in PLoS Medicine, June 2008
Cervical cancer is a leading cause of mortality worldwide, and research by IHME shows that effective coverage of cervical cancer screening is lacking, particularly in developing countries. The study, Coverage of cervical cancer screening in 57 countries: low average levels and large inequalities, showed that outside of developed countries, women at the highest risk of developing cervical cancer are among the least likely to be screened. This study presents estimates in cervical cancer screening from 57 countries across all levels of economic development, and discusses the policy implications of inadequate screening.
The researchers found that the rates of crude and effective coverage of cervical cancer screening across all countries were 68% and 40%, respectively. Among 30 developing countries, however, these rates were much lower (45% and 19%, respectively), with the rates of effective coverage as low as 1% or less in Bangladesh, Ethiopia, and Myanmar. In many countries, crude coverage was substantially higher than effective coverage (for example, in Georgia, 67% of women have had a pelvic exam, but only 11% had an accompanying Pap smear in the preceding three years). In 16 of the 57 countries analyzed, more than half of women had never had a pelvic exam.
The researchers also found that coverage rates begin to decline for women over 45 years of age in developing countries and 55 years of age in developed countries, which corresponds with the age at which incidence rates and mortality rise sharply. Additionally, poverty has a profound effect on coverage rates, with the poorest women being nearly seven times less likely to have been screened effectively than their wealthier counterparts. Even in wealthier countries, where crude coverage of cervical cancer screening is high, effective coverage rates are very low.
The researchers analyzed population-based household surveys implemented in 57 countries by the World Health Organization in 2002. Specifically, they targeted two measures: crude coverage (proportion of eligible women who report having had a pelvic exam) and effective coverage (proportion of women who report having had a pelvic exam and Pap smear in the past three years). Crude and effective coverage rates were calculated by global wealth deciles and a relative wealth index for each country as well as age.
In developed countries, widespread cervical cancer screening has resulted in large declines in cervical cancer mortality. In developing countries, however, it is unclear whether improved rates of cervical cancer screening can be replicated. Additionally, data from the developing world are limited to a few countries and subnational surveys. This study provides additional evidence to substantiate the claim that screening coverage in the developing world is low, and identifies policy options to improve these rates. This research is part of ongoing work by IHME to track the impact of interventions to understand the progress being made in health.
Recommendations for future work
This study suggests that multiple cervical cancer prevention strategies are needed to improve the rates of cervical cancer screening globally. In developed countries, targeting subgroups of women who are not effectively screened may be a successful strategy. In some middle-income and former communist countries, opportunities to provide effective screening to a larger number of women should be explored, including the promotion of organized programs with follow-up and surveillance. In developing countries, cervical cancer deaths could be reduced with improved screening, especially for women over 35 years of age. Improving access to health care and exploring strategies such as human papillomavirus vaccination should also be considered.
Citation: Gakidou E, Nordhagen S, Obermeyer Z. Coverage of cervical cancer screening in 57 countries: Low average levels and large inequalities. PLoS Medicine. 2008 Jun 17; 5(4):e132.