Benefit of cervical screening at different ages: evidence from the UK audit of screening histories

TLDR

Cervical screening is widely regarded as effective, yet debate persists over the optimal screening interval, with practices ranging from annual in North America to 3‑ to 5‑yearly schedules in England. The study examined screening histories of 1,305 cervical‑cancer cases and 2,532 matched controls aged 20–69 from UK programme databases, analysing time since last negative test and last smear. Five‑yearly screening protects 83% of women aged 55–69, while annual screening adds only modest benefit (87%); three‑yearly screening yields 84% protection for ages 40–54 versus 73% for five‑yearly and 88% for annual, and in women 20–39 even annual screening achieves only 76% protection, with rates returning to unscreened levels after three years, challenging a uniform 20–64‑year interval and highlighting the importance of middle‑aged screening. British Journal of Cancer 2003; 89:88‑93.

Abstract

While most experts agree that cervical screening is effective, there remains controversy over the most appropriate screening interval. Annual screening is common in North America. In England, some argue for 3-yearly screening while others believe 5-yearly screening is adequate, and the frequency varies from one part of the country to another. Screening histories of 1305 women aged 20-69 years, diagnosed with frankly invasive cervical cancer and 2532 age-matched controls were obtained from UK screening programme databases. Data were analysed in terms of time since last negative, and time since last screening smear. Five-yearly screening offers considerable protection (83%) against cancer at ages 55-69 years and even annual screening offers only modest additional protection (87%). Three-yearly screening offers additional protection (84%) over 5-yearly screening (73%) for cancers at ages 40-54 years, but is almost as good as annual screening (88%). In women aged 20-39 years, even annual screening is not as effective (76%) as 3-yearly screening in older women, and 3 years after screening cancer rates return to those in unscreened women. This calls into question the policy of having a uniform screening interval from age 20 to 64 years and stresses the value of screening in middle-aged women. British Journal of Cancer (2003) 89, 88-93. doi:10.1038/sj.bjc.6600974 www.bjcancer.com