Cervical cancer screening: a world view
Use the map to explore cervical cancer screening in different regions of the world.
Like many developed countries, the United States and Canada have, for the most part, instituted opportunistic cervical screening programs. The key difference between the two systems is that the Pap smear is the primary screening tool in Canada, while guidelines in the United States recommend hrHPV co-testing for women age 30 and older. Guidelines also vary by province in Canada, and British Columbia has implemented an organized screening program.
In Mexico, the screening policy is less developed, which may explain why the prevalence of cervical cancer is higher than in its northern neighbors.
As in many developed countries, in the United States nearly 100% of Pap cytology is performed using liquid-based cytology (LBC).1 Guidelines recommend 3-5 years as a screening interval, although women often are screened more frequently.
Screening intervals and management guidelines in the United States are based on consensus guidelines from the American Society for Colposcopy and Cervical Pathology (ASCCP). These reflect current thinking of ASCCP as well as the American Cancer Society (ACS) and American Society for Clinical Pathology (ASCP).2
Because of its larger, more heterogeneous population, the United States can provide some comparative insights about how cervical cancer affects different subpopulations of women. For example4
- Incidence is higher among Hispanic women (14.2 cases per 100,000) than African American (12.6 cases) and Caucasian (8.4 cases) women
- Incidence is higher among women with a median annual household income below $35,000 (14.8 cases per 100,000) compared with a median annual household income of at least $50,000 (9.9 cases)
Racial, ethnic, and socioeconomic disparities have been linked to the decreased likelihood of screening among these populations. As such, key focus of prevention efforts in the United States is to provide screening to these underserved populations.4
In the European Union (EU) 34,000 new cases and over 16,000 deaths due to cervical cancer are reported annually. These rates tend to be higher in new member states in Eastern Europe, particularly Romania and Lithuania.5
Conventional Pap cytology is still the cornerstone of cervical cancer prevention programs, and hrHPV triage testing is considered state-of-the-art. France and Germany use opportunistic screening, similar to the United States and most of Canada, and rely heavily on Pap cytology and more frequent screening. Other countries, such as Italy and Denmark, are considering hrHPV primary screening, and The Netherlands, in particular, is beginning to institute an organized program of HPV primary screening.5,6
A number of countries in Europe have developed organized population-based screening approaches. These efforts, as well as the systems used to classify pre-cancerous disease, vary among countries in the EU. Although the 2012 consensus guidelines proffered by the American Society for Colposcopy and Cervical Pathology (ASCCP) include input from several international organizations and influence guidelines worldwide, the guidelines are focused on opportunistic screening scenarios.1
Policies of HPV vaccination (primarily for the 16 and 18 genotypes) are more established in the EU than in other regions. However, while prophylactic vaccination, primarily in young girls, may provide important future health gains, cervical screening will need to continue because pre-cancerous lesions associated with other genotypes can still occur.
Latin America and the Caribbean
An estimated 35,322 deaths occur in Latin America and the Caribbean (LAC) each year from cervical cancer. Mortality rates are seven times higher in this region than in North America. Bolivia, Haiti and Paraguay are among the countries with the highest cervical cancer rates.9
National screening policies exist in several South American countries, and Pap cytology has been available in the region for more than 30 years. However, testing is not consistently available and results are mixed because the required training and infrastructure may be lacking in some countries. Socioeconomic factors also contribute to generally lower access to and participation in cervical cancer screening and other women’s health programs.9
Some countries, notably Bolivia, Colombia, Costa Rica, Guatemala, Mexico and Peru, are establishing programs using alternative cervical cancer screening technologies, such as visual inspection with acetic acid (VIA) and HPV testing.9
A key driver of these efforts is the Regional Strategy and Plan of Action for Cervical Cancer Prevention and Control, instituted by the Pan American Health Organization (PAHO). PAHO has instituted a number of test projects using alternative screening approaches, provides technical assistance for existing cytology screening programs and works to improve access to screening for women throughout the region.9
Australia and Asia Pacific
Australia has the second lowest incidence of cervical cancer in the world among countries with comparable screening programs. This is largely due to the National Cervical Screening Program (NCSP). Australia stands as a model of success, both in the region and among developed nations.7
Screening guidelines in Australia differ slightly from those used in other developed countries. For example, most countries recommend Pap cytology screening on a 3- to 5-year basis versus the 2-year policy in Australia.7
This may be changing, however. Recently, the Australian Medical Services Advisory Committee (MSAC) proposed a screening pathway encompassing primary HPV testing with partial HPV genotyping and reflex LBC triage, for both HPV-vaccinated and unvaccinated women ages 25 to 69 years.8 This would allow a 5-year screening interval for HPV-negative women ages 25 through 69.8
This allows the age of screening commencement in NCSP, which currently stands at 18-20 years old.7 MSAC recommends that screening reminders be mailed to women in the program and exit-testing reminders sent to women up to age 74.8
Citing several controlled trials, MSAC noted that primary HPV screening had a much higher negative predictive value than Pap cytology and improved detection of pre-cancerous neoplasia.8 HPV primary screening strategies were also found to be more cost-effective than those incorporating cytology.8
Other countries in the Asia-Pacific exhibit a mix of screening efforts, typically lacking a formal infrastructure. They also tend to disproportionately target certain socioeconomic groups. One item of note: Japan has the highest age-adjusted incidence rate of cervical cancer among developed countries (9.8 cases per 100,000 women), probably due to low participation in screening programs.4