Diagnosis & Screening
Cervical Screening (Pap smear, HPV DNA test)
Cervical cancer screening includes the Pap smear and the human papillomavirus (HPV) DNA test, both of which contribute to reducing mortality from this malignancy. The Pap smear is a method used to examine cervical cells and detect abnormal changes. The HPV DNA test involves collecting a cervical sample during a pelvic examination to analyze and determine the viral genotype using molecular techniques.
Screening Guidelines by Region (IARC Models)
The International Agency for Research on Cancer (IARC) has developed models for cervical cancer screening tailored to the resources and infrastructure of different regions worldwide. These models provide recommendations regarding the appropriate age to begin screening, the interval between tests, and the most suitable screening methods for various countries.
CDC Cervical Cancer Screening Guidelines
Ages 21–29 years
Begin Pap smear screening at age 21, repeated every 3 years.
Ages 30–65 years
Co-testing with Pap smear and HPV test every 5 years, or HPV test alone every 5 years.
After age 65
Screening may be discontinued, in consultation with a physician. *
*If the following conditions are met:
- At least three negative Pap smears or two negative HPV tests within the past 10 years, and
- No history of cervical precancerous lesions, or
- Complete hysterectomy performed for non-cancerous reasons (e.g., fibroids) with total removal of the cervix.
Screening in Eastern Europe and Central Asia (EECA)
- In EECA regions, cervical cancer screening programs are implemented at the regional level but face challenges such as inadequate coverage, unequal access, limited resources, and weak organizational frameworks. Regional strategies emphasize strengthening screening programs organization and regularly updating clinical guidelines.
- Screening in EECA is often conducted through mixed or parallel approaches, including Pap smears and HPV testing. In some countries, visual inspection with acetic acid (VIA) is also applied. These programs are usually delivered through primary care, and some nations have initiated population-based screening, though full coverage and quality remain challenging.
- The typical screening age range is 30 to 60 years, though this varies among countries. According to WHO guidelines, screening intervals are recommended every 3–5 years for Pap smear and VIA, and at least every 5 years for HPV testing.
Co-testing Strategies (Pap + HPV)
Co-testing refers to the simultaneous use of the Pap smear and HPV testing. This combined approach is recommended as an advanced method for the early detection of precancerous lesions and cervical cancer, particularly in women aged 30 to 65 years.
Significance and Advantages
Enhanced diagnostic sensitivity
Combining Pap smear and HPV testing provides greater sensitivity in detecting high-grade precancerous lesions compared with either test alone. This allows for earlier diagnosis, timely treatment, and a meaningful reduction in cervical cancer mortality.
Extended screening intervals
Based on the recommendations of the American Cancer Society (ACS), the U.S. Preventive Services Task Force (USPSTF), and the American College of Obstetricians and Gynecologists (ACOG), co-testing every 5 years is sufficient for women aged 30 to 65 years with previously normal results, thereby reducing the need for frequent testing.
Detection of HPV, especially high-risk types
HPV testing can identify multiple HPV types, particularly the high-risk HPV types 16 and 18, which are responsible for approximately 70% of cervical cancer cases. In cases of positive results, immediate colposcopy is recommended.
Screening vs. Vaccination Pathways
Regular screening with Pap smear and HPV testing significantly reduces the risk of cervical cancer. Vaccination against HPV plays a complementary role by preventing high-risk viral infections and thereby lowering the incidence of cancer. The integration of vaccination and screening represents the most effective strategy to reduce disease burden.
HPV Vaccination and Screening Pathways
Human papillomavirus (HPV) is a major causative agent of cervical cancer. Two essential approaches to reduce the burden of HPV-related diseases are:
- Vaccination: A primary prevention strategy aimed at protecting individuals from HPV infection and thereby reducing the occurrence of cervical cancer.
- Regular Screening: A diagnostic approach that identifies precancerous lesions or cancer at an early stage, allowing timely and effective treatment.
The combination of widespread vaccination and Regular screening programs offers the most effective strategy for reducing HPV-related disease and cervical cancer. Vaccination lowers viral prevalence, enhances the effectiveness of screening, and reduces the need for invasive therapeutic interventions.
Screening Algorithm Visualizations
Cervical cancer screening typically begins with a Pap smear or HPV DNA test. Depending on the results of these tests, the next steps are determined. If abnormal results are found, such as the presence of atypical cells or a positive HPV DNA test, additional procedures may be required. These can include repeat testing, colposcopy, or tissue biopsy for further evaluation.
