High-grade cervical abnormalities and screening intervals in New South Wales, Australia

Abstract

Objectives This study aims to determine the association of two versus three year screening intervals with the likelihood of detection of a high-grade cervical abnormality and cervical cancer. Methods Data were obtained from the New South Wales (NSW) Papanicolaou (Pap) Test Register (PTR) and NSW Central Cancer Registry (CCR). Subjects were human papillomavirus (HPV) unvaccinated women aged 20-69 years who had a minimum of two Pap tests with a negative result at their first recorded Pap test (n ¼ 1,213,295). Logistic regression was used to determine the association between screening interval and the likelihood of: (1) a cytological prediction of high-grade abnormality, defined as cervical intraepithelial neoplasia (CIN) 2 or greater; (2) a histologically confirmed high-grade abnormality; (3) a cytological prediction of cervical cancer and (4) a confirmed diagnosis of cervical cancer, controlling for potential confounders of age and socioeconomic status (SES) of area of residence.Results For each year increase in the screening interval, the odds of a histologically confirmed highgrade abnormality increased significantly in women aged 20 -29 years (odds ratio [OR] 1.24, 95% confidence interval [CI] 1.20-1.28) and in women aged 30 -49 years (OR 1.11, 95% CI 1.06 -1.16), but not in women aged 50 -69 years (OR 1.08, 95% CI 0.89 -1.32). Similar results were observed for cytologically detected high-grade abnormalities. The screening interval was significantly and positively associated with a cytological prediction of cervical cancer (OR 1.40, 95% CI 1.28 -1.54) and a confirmed cervical cancer diagnosis (OR 1.66, 95% CI 1.33 -2.07) in women aged 20 -69 years. We estimate that if the screening interval were increased from two to three years, and the number of women participating in triennial screening participation was the same as for biennial participation in NSW, then 267 (95% CI 186-347) extra cases of highgrade abnormalities would be detected annually by cytology and 225 extra cases (95% CI 160-291) confirmed by histology, mostly confined to women aged 20 -49 years. Equivalently, 2.3 (95% CI 1.8 -2.8) and 1.9 (95% CI 1.5-2.4) extra cases of high-grade cytology and histology, respectively, would be expected per 1000 women with initially negative cytology if the screening interval were extended from two to three years. Conclusion Increasing the cervical screening interval from two to three years would be expected to significantly increase the odds of detection of a high-grade abnormality for NSW women aged 20 -49 years and cervical cancer for NSW women aged 20 -69 years. Accordingly, our study provides evidence in support of retaining the recommended cervical screening interval at two years for HPV unvaccinated, well women.

Cervical cancer screening in Australia: modelled evaluation of the impact of changing the recommended interval from two to three years

“…This is likely to be due to the longer screening interval allowing a greater fraction of high grade cases to regress naturally, whilst maintaining a similar detection rate for those high grade lesions that would have progressed to invasive cervical cancer. Our prediction of a reduced number of high grade treatments in the National Cervical Screening Program is broadly consistent with the findings of a prior analysis of NSW registry data, which predicted a statistically non-significant decrease in histologically-confirmed high grade cases, and a significant decrease in rates of high grade cytology, in the context of 3-yearly screening [19]. However, the estimates from this prior study are not directly comparable to the current evaluation because we considered the overall effects of lifetime screening behaviour in the entire population; whereas the prior study estimated the increased risk of a high grade according to screening interval in women with 2 or more cytology tests (conditional on the first test having a negative result), and applied these estimates by pro-rating the 2-yearly participation rate to a 3-yearly situation.…”

Performance of Papanicolaou Testing and Detection of Cervical Carcinoma In Situ in Participants of Organized Cervical Cancer Screening in South Korea

“…In this study, we could not identify the history of cervical cancer screening among our study subjects. Previous studies have reported that socioeconomic status is highly significantly negatively associated with a longer screening interval [49], [50]. In addition, screening interval has been shown to be significantly positively associated with a cytological prediction of diagnosis [10], [49].…”

Erratum

“…In our paper ‘High-grade cervical abnormalities and screening intervals in New South Wales, Australia‘ 1 we estimated the number of extra cases of high-grade cervical abnormality annually if the screening interval policy in New South Wales were to be changed from two to three years as 267 by cytology and 225 by histology, assuming the same number of women participated triennially as biennially. These estimates were based on modelled increased risk of a high-grade lesion with a three-year versus two-year screening interval of OR = 1.36 (95% CI:1.28–1.44) for cytology and OR = 1.47 (95% CI:1.36–1.58) for histology, and also on pro-rating the existing two-yearly screening rate to three-yearly.…”