From the Guidelines
Pap smear screening should begin at age 21 and continue every 3 years until age 65 for women with normal results, with the option of co-testing with HPV every 5 years for women aged 30-65. This recommendation is based on the most recent guidelines from the American Cancer Society, as outlined in the 2016 review of current guidelines and issues in cancer screening 1. The guidelines emphasize that women younger than 21 years should not be screened, regardless of their age of sexual initiation, and that women at any age should not be screened annually by any screening method.
Screening Schedule
The recommended screening schedule is as follows:
- Women aged 21-29 years: cytology screening every 3 years
- Women aged 30-65 years: co-testing with cytology and HPV every 5 years, or cytology alone every 3 years
- Women older than 65 years: discontinuation of screening if they have had 3 consecutive negative cytology tests or 2 consecutive negative co-test results within the 10-year period prior to ceasing screening, with the most recent test occurring within the last 5 years
Rationale
This screening schedule is effective because cervical cancer typically develops slowly over years, allowing time for detection and treatment of precancerous changes before they become invasive cancer 1. The addition of HPV testing improves detection since persistent HPV infection is the primary cause of cervical cancer. The American Cancer Society continues to monitor developments in cervical cancer screening, including the use of primary HPV testing as a screening approach 1.
Special Considerations
Women who have had a total hysterectomy (including removal of the cervix) for non-cancerous reasons generally do not need continued screening. However, those with a history of cervical cancer, high-grade precancerous lesions, or HIV infection may need more frequent screening. Recommended screening practices should not change on the basis of a woman's HPV vaccination status 1.
From the Research
Pap Smear Screening Overview
- Pap smear screening is a crucial part of preventive healthcare for women, aiming to detect cervical cancer early 2.
- The introduction of the Pap test in the 1950s has led to a significant decrease in the incidence and mortality of cervical carcinomas in industrialized countries 3.
Effectiveness of Pap Smear Screening
- The Pap test has a good specificity of 95% but a lower sensitivity of 70% 3.
- Additional immunohistochemical tests can increase the sensitivity of the Pap test up to 94% 3.
- The HPV test has a high sensitivity of 94% but a lower specificity compared to the Pap test, leading to an increased risk of unnecessary clarification and therapy 3.
Comparison of Screening Strategies
- A study compared the effectiveness of conventional Pap smear test, liquid-based cytology, and human papillomavirus testing as stand-alone or cotesting strategies 4.
- The results showed that cotesting offers no benefit in detection over stand-alone HPV testing, resulting in more false positive results and colposcopy referrals 4.
- HPV stand-alone screening offers a better balance of benefits and harms than cotesting 4.
Impact of HPV Vaccination on Pap Smear Screening
- Women who received the HPV vaccine were more likely to have a Pap smear than unvaccinated women 5.
- However, women vaccinated at ages 9-12 were less likely to participate in screening compared to those vaccinated at ages 13-23 6.
- Promoting cervical cancer screening is important not only among unvaccinated women but also among those who received the HPV vaccine at the recommended ages of 9-12 6.