Risk of COVID-19 death for people with a pre-existing cancer diagnosis prior to COVID-19-vaccination: A systematic review and meta-analysis.

While previous reviews found a positive association between pre-existing cancer diagnosis and COVID-19-related death, most early studies did not distinguish long-term cancer survivors from those recently diagnosed/treated, nor adjust for important confounders including age. We aimed to consolidate higher-quality evidence on risk of COVID-19-related death for people with recent/active cancer (compared to people without) in the pre-COVID-19-vaccination period. We searched the WHO COVID-19 Global Research Database (20 December 2021), and Medline and Embase (10 May 2023). We included studies adjusting for age and sex, and providing details of cancer status. Risk-of-bias assessment was based on the Newcastle-Ottawa Scale. Pooled adjusted odds or risk ratios (aORs, aRRs) or hazard ratios (aHRs) and 95% confidence intervals (95% CIs) were calculated using generic inverse-variance random-effects models. Random-effects meta-regressions were used to assess associations between effect estimates and time since cancer diagnosis/treatment. Of 23 773 unique title/abstract records, 39 studies were eligible for inclusion (2 low, 17 moderate, 20 high risk of bias). Risk of COVID-19-related death was higher for people with active or recently diagnosed/treated cancer (general population: aOR = 1.48, 95% CI: 1.36-1.61, I2 = 0; people with COVID-19: aOR = 1.58, 95% CI: 1.41-1.77, I2 = 0.58; inpatients with COVID-19: aOR = 1.66, 95% CI: 1.34-2.06, I2 = 0.98). Risks were more elevated for lung (general population: aOR = 3.4, 95% CI: 2.4-4.7) and hematological cancers (general population: aOR = 2.13, 95% CI: 1.68-2.68, I2 = 0.43), and for metastatic cancers. Meta-regression suggested risk of COVID-19-related death decreased with time since diagnosis/treatment, for example, for any/solid cancers, fitted aOR = 1.55 (95% CI: 1.37-1.75) at 1 year and aOR = 0.98 (95% CI: 0.80-1.20) at 5 years post-cancer diagnosis/treatment. In conclusion, before COVID-19-vaccination, risk of COVID-19-related death was higher for people with recent cancer, with risk depending on cancer type and time since diagnosis/treatment.

Absolute lung cancer risk increases among individuals with >15 quit-years: Analyses to inform the update of the American Cancer Society lung cancer screening guidelines.

BACKGROUND: This report quantifies counteracting effects of quit-years and concomitant aging on lung cancer risk, especially on exceeding 15 quit-years, when the US Preventive Services Task Force (USPSTF) recommends curtailing lung-cancer screening. METHODS: Cox models were fitted to estimate absolute lung cancer risk among Prostate, Lung, Colorectal and Ovarian Cancer Screening Trial (PLCO) and National Lung Screening Trial (NLST) participants who ever smoked. Absolute lung cancer risk and gainable years of life from screening for individuals aged 50 to 80 in the US-representative National Health Interview Survey (NHIS) 2015-2018 who ever smoked were projected. Relaxing USPSTF recommendations to 20/25/30 quit-years versus augmenting USPSTF criteria with individuals whose estimated gain in life expectancy from screening exceeded 16.2 days according to the Life Years From Screening-CT (LYFS-CT) prediction model was compared. RESULTS: Absolute lung cancer risk increased by 8.7%/year (95% CI, 7.7%-9.7%; p < .001) as individuals aged beyond 15 quit-years in the PLCO, with similar results in NHIS and NLST. For example, mean 5-year lung cancer risk for those aged 65 years with 15 quit-years = 1.47% (95% CI, 1.35%-1.59%) versus 1.76% (95% CI, 1.62%-1.90%) for those aged 70 years with 20 quit-years in the PLCO. Removing the quit-year criterion would make 4.9 million more people eligible and increase the proportion of preventable lung cancer deaths prevented (sensitivity) from 63.7% to 74.2%. Alternatively, augmentation using LYFS-CT would make 1.7 million more people eligible while increasing the lung cancer death sensitivity to 74.0%. CONCLUSIONS: Because of aging, absolute lung cancer risk increases beyond 15 quit-years, which does not support exemption from screening or curtailing screening once it has been initiated. Compared with relaxing the USPSTF quit-year criterion, augmentation using LYFS-CT could prevent most of the deaths at substantially superior efficiency, while also preventing deaths among individuals who currently smoke with low intensity or long duration.

Predictors of the experience of a Cytosponge test: analysis of patient survey data from the BEST3 trial.

BACKGROUND: The Cytosponge is a cell-collection device, which, coupled with a test for trefoil factor 3 (TFF3), can be used to diagnose Barrett's oesophagus, a precursor condition to oesophageal adenocarcinoma. BEST3, a large pragmatic, randomised, controlled trial, investigated whether offering the Cytosponge-TFF3 test would increase detection of Barrett's. Overall, participants reported mostly positive experiences. This study reports the factors associated with the least positive experience. METHODS: Patient experience was assessed using the Inventory to Assess Patient Satisfaction (IAPS), a 22-item questionnaire, completed 7-14 days after the Cytosponge test. STUDY COHORT: All BEST3 participants who answered ≥ 15 items of the IAPS (N = 1458). STATISTICAL ANALYSIS: A mean IAPS score between 1 and 5 (5 indicates most negative experience) was calculated for each individual. 'Least positive' experience was defined according to the 90th percentile. 167 (11.4%) individuals with a mean IAPS score of ≥ 2.32 were included in the 'least positive' category and compared with the rest of the cohort. Eleven patient characteristics and one procedure-specific factor were assessed as potential predictors of the least positive experience. Multivariable logistic regression analysis using backwards selection was conducted to identify factors independently associated with the least positive experience and with failed swallow at first attempt, one of the strongest predictors of least positive experience. RESULTS: The majority of responders had a positive experience, with an overall median IAPS score of 1.7 (IQR 1.5-2.1). High (OR = 3.01, 95% CI 2.03-4.46, p < 0.001) or very high (OR = 4.56, 95% CI 2.71-7.66, p < 0.001) anxiety (relative to low/normal anxiety) and a failed swallow at the first attempt (OR = 3.37, 95% CI 2.14-5.30, p < 0.001) were highly significant predictors of the least positive patient experience in multivariable analyses. Additionally, sex (p = 0.036), height (p = 0.032), alcohol intake (p = 0.011) and education level (p = 0.036) were identified as statistically significant predictors. CONCLUSION: We have identified factors which predict patient experience. Identifying anxiety ahead of the procedure and discussing particular concerns with patients or giving them tips to help with swallowing the capsule might help improve their experience. Trial registration ISRCTN68382401.

Trends and predictors of hysterectomy prevalence among women in the United States.

BACKGROUND: Hysterectomy is the most common nonobstetrical medical procedure performed in US women. Evaluating hysterectomy prevalence trends and determinants is important for estimating gynecologic cancer rates and management of uterine conditions. OBJECTIVE: This study aimed to assess hysterectomy prevalence trends and determinants using the Behavioral Risk Factor Surveillance System (2006-2016). STUDY DESIGN: We estimated crude hysterectomy prevalences and multivariable-adjusted odds ratios and 95% confidence intervals for associations of race or ethnicity, age group (5-year), body mass index (categorical), smoking status, education, insurance, income, and US region with hysterectomy. Missing data were imputed. The number of women in each survey year ranged from 220,302 in 2006 to 275,631 in 2016. RESULTS: Although overall hysterectomy prevalence changed little between 2006 and 2016 (21.4% and 21.1%, respectively), hysterectomy prevalence was lower in 2016 than in 2006 among women aged ≥40 years, particularly among non-Hispanic Black and Hispanic women. Current smoking (odds ratio, 1.38; 95% confidence interval, 1.35-1.41), increasing age (odds ratio, 1.40; 95% confidence interval, 1.39-1.40), living in the South compared with the Midwest (odds ratio, 1.36; 95% confidence interval, 1.34-1.39), higher body mass index (odds ratio, 1.26; 95% confidence interval, 1.25-1.27), Black race compared with White (odds ratio, 1.10; 95% confidence interval, 1.07-1.13), and having insurance compared with being uninsured (odds ratio, 1.26; 95% confidence interval, 1.22-1.30) were most strongly associated with increased prevalence. Hispanic ethnicity and living in the Northeast were most strongly associated with decreased prevalence (odds ratio, 0.73; 95% confidence interval, 0.70-0.76; odds ratio, 0.67; 95% confidence interval, 0.65-0.69). CONCLUSION: Nationwide hysterectomy prevalence decreased among women aged ≥40 years from 2006 to 2016, particularly among non-Hispanic Black and Hispanic women. Age, non-Hispanic Black race, having insurance, current smoking, and living in the South were associated with increased odds of hysterectomy, even after accounting for possible explanatory factors. Further research is needed to better understand associations of race and ethnicity and region with hysterectomy prevalence.

Comparative performance of lung cancer risk models to define lung screening eligibility in the United Kingdom.

BACKGROUND: The National Health Service England (NHS) classifies individuals as eligible for lung cancer screening using two risk prediction models, PLCOm2012 and Liverpool Lung Project-v2 (LLPv2). However, no study has compared the performance of lung cancer risk models in the UK. METHODS: We analysed current and former smokers aged 40-80 years in the UK Biobank (N = 217,199), EPIC-UK (N = 30,813), and Generations Study (N = 25,777). We quantified model calibration (ratio of expected to observed cases, E/O) and discrimination (AUC). RESULTS: Risk discrimination in UK Biobank was best for the Lung Cancer Death Risk Assessment Tool (LCDRAT, AUC = 0.82, 95% CI = 0.81-0.84), followed by the LCRAT (AUC = 0.81, 95% CI = 0.79-0.82) and the Bach model (AUC = 0.80, 95% CI = 0.79-0.81). Results were similar in EPIC-UK and the Generations Study. All models overestimated risk in all cohorts, with E/O in UK Biobank ranging from 1.20 for LLPv3 (95% CI = 1.14-1.27) to 2.16 for LLPv2 (95% CI = 2.05-2.28). Overestimation increased with area-level socioeconomic status. In the combined cohorts, USPSTF 2013 criteria classified 50.7% of future cases as screening eligible. The LCDRAT and LCRAT identified 60.9%, followed by PLCOm2012 (58.3%), Bach (58.0%), LLPv3 (56.6%), and LLPv2 (53.7%). CONCLUSION: In UK cohorts, the ability of risk prediction models to classify future lung cancer cases as eligible for screening was best for LCDRAT/LCRAT, very good for PLCOm2012, and lowest for LLPv2. Our results highlight the importance of validating prediction tools in specific countries.

Absolute risks of cervical precancer among women who fulfill exiting guidelines based on HPV and cytology cotesting.

US guidelines recommend that most women older than 65 years cease cervical screening after two consecutive negative cotests (concurrent HPV and cytology tests) in the previous 10 years, with one in the last 5 years. However, this recommendation was based on expert opinion and modeling rather than empirical data on cancer risk. We therefore estimated the 5-year risks of cervical precancer (cervical intraepithelial neoplasia grade 3 or adenocarcinoma in situ [CIN3]) after one, two and three negative cotests among 346,760 women aged 55-64 years undergoing routine cotesting at Kaiser Permanente Northern California (2003-2015). Women with a history of excisional treatment or CIN2+ were excluded. No woman with one or more negative cotests was diagnosed with cancer during follow-up. Five-year risks of CIN3 after one, two, and three consecutive negative cotests were 0.034% (95% CI: 0.023%-0.046%), 0.041% (95% CI: 0.007%-0.076%) and 0.016% (95% CI: 0.000%-0.052%), respectively (ptrend < 0.001). These risks did not appreciably differ by a positive cotest result prior to the one, two or three negative cotest(s). Since CIN3 risks after one or more negative cotests were significantly below a proposed 0.12% CIN3+ risk threshold for a 5-year screening interval, a longer screening interval in these women is justified. However, the choice of how many negative cotests provide sufficient safety against invasive cancer over a woman's remaining life represents a value judgment based on the harms versus benefits of continued screening. Ideally, this guideline should be informed by longer-term follow-up given that exiting is a long-term decision.

Impact of screening on cervical cancer incidence: A population-based case-control study in the United States.

Cervical cancer is widely preventable through screening, but little is known about the duration of protection offered by a negative screen in North America. A case-control study was conducted with records from population-based registries in New Mexico. Cases were women diagnosed with cervical cancer in 2006-2016, obtained from the Tumor Registry. Five controls per case from the New Mexico HPV Pap Registry were matched to cases by sex, age and place of residence. Dates and results of all cervical screening and diagnostic tests since 2006 were identified from the pap registry. We estimated the odds ratio of nonlocalized (Stage II+) and localized (Stage I) cervical cancer associated with attending screening in the 3 years prior to case-diagnosis compared to women not screened in 5 years. Of 876 cases, 527 were aged 25-64 years with ≥3 years of potential screening data. Only 38% of cases and 61% of controls attended screening in a 3-year period. Women screened in the 3 years prior to diagnosis had 83% lower risk of nonlocalized cancer (odds ratio [OR] = 0.17, 95% CI: 0.12-0.24) and 48% lower odds of localized cancer (OR = 0.52, 95% CI: 0.38-0.72), compared to women not screened in the 5 years prior to diagnosis. Women remained at low risk of nonlocalized cancer for 3.5-5 years after a negative screen compared to women with no negative screens in the 5 years prior to diagnosis. Routine cervical screening is effective at preventing localized and nonlocalized cervical cancers; 3 yearly screening prevents 83% of nonlocalized cancers, with no additional benefit of more frequent screening. Increasing screening coverage remains essential to further reduce cervical cancer incidence.

A state-wide population-based evaluation of cervical cancers arising during opportunistic screening in the United States.

OBJECTIVE: Despite widespread cervical screening, an estimated 13,800 women will be diagnosed with cervical cancer in the United States in 2020. To inform improvements, the screening histories of women diagnosed with cervical cancer in New Mexico were assessed. METHODS: Data were collected on all cervical screening, diagnostic tests and treatment procedures for all women diagnosed with cervical cancer aged 25-64 yrs. in New Mexico from 2006 to 2016. Women were categorized by their screening attendance in the 5-40 months (screening interval) and 1-4 months (peri-diagnostic interval) prior to cancer diagnosis. RESULTS: Of the 504 women diagnosed between May 2009-December 2016, 64% were not screened or had only inadequate screening tests in the 5-40 months prior to diagnosis, and 90 of 182 screened women (49%) had only negative screens in this period. Only 32% (N = 162) of cervical cancers were screen-detected. Women with adenocarcinomas were more likely to have had a recent negative screen (41/57 = 722%) than women with squamous cancers (50/112 = 45%). Both older women (aged 45-64 years) and women with more advanced cancers were less likely to have been screened, and if screened, were more likely to have a false-negative outcome. Only 9% of cancers were diagnosed in women who did not attend biopsy or treatment after positive tests requiring clinical management. Screening currently prevents 35% of cancers, whereas full screening coverage could prevent 61% of cervical cancers. CONCLUSION: Improved screening coverage has the largest potential for reducing cervical cancer incidence, though there is also a role for improved recall procedures and screening sensitivity.

5-Year Prospective Evaluation of Cytology, Human Papillomavirus Testing, and Biomarkers for Detection of Anal Precancer in Human Immunodeficiency Virus-Positive Men Who Have Sex With Men.

BACKGROUND: Human papillomavirus (HPV)-related biomarkers have shown good cross-sectional performance for anal precancer detection in human immunodeficiency virus-positive (HIV+) men who have sex with men (MSM). However, the long-term performance and risk stratification of these biomarkers are unknown. Here, we prospectively evaluated high-risk (HR) HPV DNA, HPV16/18 genotyping, HPV E6/E7 messenger RNA (mRNA), and p16/Ki-67 dual stain in a population of HIV+ MSM. METHODS: We enrolled 363 HIV+ MSM between 2009-2010, with passive follow-up through 2015. All had anal cytology and a high-resolution anoscopy at baseline. For each biomarker, we calculated the baseline sensitivity and specificity for a combined endpoint of high-grade squamous intraepithelial lesion (HSIL) and anal intraepithelial neoplasia grade 2 or more severe diagnoses (HSIL/AIN2+), and we estimated the 2- and 5-year cumulative risks of HSIL/AIN2+ using logistic and Cox regression models. RESULTS: There were 129 men diagnosed with HSIL/AIN2+ during the study. HR-HPV testing had the highest positivity and sensitivity of all assays, but the lowest specificity. HPV16/18 and HPV E6/E7 mRNA had high specificity, but lower sensitivity. The 2- and 5-year risks of HSIL/AIN2+ were highest for those testing HPV16/18- or HPV E6/E7 mRNA-positive, followed by those testing dual stain-positive. Those testing HR-HPV- or dual stain-negative had the lowest 2- and 5-year risks of HSIL/AIN2+. CONCLUSIONS: HPV-related biomarkers provide long-term risk stratification for anal precancers. HR-HPV- and dual stain-negativity indicate a low risk of HSIL/AIN2+ for at least 2 years, compared with negative anal cytology; however, the high positivity of HR-HPV in HIV+ MSM may limit its utility for surveillance and management in this population.

Longitudinal Clinical Performance of the RNA-Based Aptima Human Papillomavirus (AHPV) Assay in Comparison to the DNA-Based Hybrid Capture 2 HPV Test in Two Consecutive Screening Rounds with a 6-Year Interval in Germany.

Longitudinal data on the E6/E7 mRNA-based Aptima human papillomavirus (AHPV) assay exceeding three years in comparison to the gold standard Digene Hybrid Capture 2 (HC2) test are not available. We previously reported the cross-sectional data of the German AHPV Screening Trial (GAST) in which 10,040 women were recruited and tested by liquid-based cytology, the HC2 assay, and the AHPV assay. Four hundred eleven test-positive women were followed for up to six years. In addition, 3,295 triple-negative women were screened after a median time of six years. Overall, 28 high-grade cervical intraepithelial neoplasia (CIN3) cases were detected. The absolute risk of developing high-risk HPV-positive CIN3+ over six years among those women that tested negative at baseline was 2.2 (95% confidence interval [95% CI], 1.0 to 4.9) and 3.1 (95% CI, 1.7 to 5.7) per 1,000 women screened by the HC2 and the AHPV tests; the additional risk for those with AHPV-negative compared with HC2-negative results was 0.9 (95% CI, -0.2 to 2.1) per 1,000. In comparison, the absolute risk following a negative LBC test was 9.3 (95% CI, 2.9 to 30.2). The relative sensitivity of AHPV compared to HC2 was 91.5% for CIN3+, and the negative predictive values were 99.8% (95% CI, 99.5 to 99.9%) for HC2 and 99.7% (95% CI, 99.4 to 99.8%) for AHPV. Our data show that the longitudinal performance of the AHPV test over six years is comparable to the performance of the HC2 test and that the absolute risk of CIN3+ over six years following a negative AHPV result in a screening population is low. (This study is registered at ClinicalTrials.gov under registration number NCT02634190.).

What cervical screening is appropriate for women who have been vaccinated against high risk HPV? A simulation study.

Women vaccinated against HPV16/18 are approaching the age for cervical screening; however, an updated screening algorithm has not been agreed. We use a microsimulation model calibrated to real published data to determine the appropriate screening intensity for vaccinated women. Natural histories in the absence of vaccination were simulated for 300,000 women using 10,000 sets of transition probabilities. Vaccination with (i) 100% efficacy against HPV16/18, (ii) 15% cross-protection, (iii) 22% cross-protection, (iv) waning vaccine efficacy and (v) 100% efficacy against HPV16/18/31/33/45/52/58 was added, as were a range of screening scenarios appropriate to the UK. To benchmark cost-benefits of screening for vaccinated women, we evaluated the proportion of cancers prevented per additional screen (incremental benefit) of current cytology and likely HPV screening scenarios in unvaccinated women. Slightly more cancers are prevented through vaccination with no screening (70.3%, 95% CR: 65.1-75.5) than realistic compliance to the current UK screening programme in the absence of vaccination (64.3%, 95% CR: 61.3-66.8). In unvaccinated women, when switching to HPV primary testing, there is no loss in effectiveness when doubling the screening interval. Benchmarking supports screening scenarios with incremental benefits of ≥2.0%, and rejects scenarios with incremental benefits ≤0.9%. In HPV16/18-vaccinated women, the incremental benefit of offering a third lifetime screen was at most 3.3% (95% CR: 2.2-4.5), with an incremental benefit of 1.3% (-0.3-2.8) for a fourth screen. For HPV16/18/31/33/45/52/58-vaccinated women, two lifetime screens are supported. It is important to know women's vaccination status; in these simulations, HPV16/18-vaccinated women require three lifetime screens, HPV16/18/31/33/45/52/58-vaccinated women require two lifetime screens, yet unvaccinated women require seven lifetime screens.

How confident can we be in the current guidelines for exiting cervical screening?

Current US guidelines recommend against cervical screening beyond age 65 in women who have had adequate negative screening. In anticipation of the next round of evidence review and guideline updates, we provide a critical review of the evidence supporting the exiting recommendation in the US, highlighting both practice changes and new insights into the epidemiology and natural history of HPV and cervical cancer. Current recommendations are based, by necessity, on cytology alone, and will be limited in generalizability to evolving screening strategies with co-testing and primary HPV testing. The lack of empirical data to define what constitutes 'adequate recent screening with negative results' is compounded by difficulties in predicting future risk without consideration of concepts of HPV latency and cohort effects of changing sexual behaviour in US women over time. We urge caution in extrapolating past risk experience in post-menopausal women to today's population, and suggest study designs to strengthen the evidence base in well-screened older women. We further recommend building the qualitative evidence base to better define the harms and benefits of screening among older women. Extending the lifetime of screening is a matter of finding the appropriate balance of benefits of cancer reduction and limitation of harms and costs of 'overscreening'. This will require moving beyond current emphasis on number of colposcopies as the metric of harm. Our commentary is meant to stimulate intellectual debate regarding the certainty of our existing knowledge base and set clear research priorities for the future.

Challenges in risk estimation using routinely collected clinical data: The example of estimating cervical cancer risks from electronic health-records.

Electronic health-records (EHR) are increasingly used by epidemiologists studying disease following surveillance testing to provide evidence for screening intervals and referral guidelines. Although cost-effective, undiagnosed prevalent disease and interval censoring (in which asymptomatic disease is only observed at the time of testing) raise substantial analytic issues when estimating risk that cannot be addressed using Kaplan-Meier methods. Based on our experience analysing EHR from cervical cancer screening, we previously proposed the logistic-Weibull model to address these issues. Here we demonstrate how the choice of statistical method can impact risk estimates. We use observed data on 41,067 women in the cervical cancer screening program at Kaiser Permanente Northern California, 2003-2013, as well as simulations to evaluate the ability of different methods (Kaplan-Meier, Turnbull, Weibull and logistic-Weibull) to accurately estimate risk within a screening program. Cumulative risk estimates from the statistical methods varied considerably, with the largest differences occurring for prevalent disease risk when baseline disease ascertainment was random but incomplete. Kaplan-Meier underestimated risk at earlier times and overestimated risk at later times in the presence of interval censoring or undiagnosed prevalent disease. Turnbull performed well, though was inefficient and not smooth. The logistic-Weibull model performed well, except when event times didn't follow a Weibull distribution. We have demonstrated that methods for right-censored data, such as Kaplan-Meier, result in biased estimates of disease risks when applied to interval-censored data, such as screening programs using EHR data. The logistic-Weibull model is attractive, but the model fit must be checked against Turnbull non-parametric risk estimates.

Is cervical screening preventing adenocarcinoma and adenosquamous carcinoma of the cervix?

While the incidence of squamous carcinoma of the cervix has declined in countries with organised screening, adenocarcinoma has become more common. Cervical screening by cytology often fails to prevent adenocarcinoma. Using prospectively recorded cervical screening data in England and Wales, we conducted a population-based case-control study to examine whether cervical screening leads to early diagnosis and down-staging of adenocarcinoma. Conditional logistic regression modelling was carried out to provide odds ratios (ORs) and 95% confidence intervals (CIs) on 12,418 women with cervical cancer diagnosed between ages 30 and 69 and 24,453 age-matched controls. Of women with adenocarcinoma of the cervix, 44.3% were up to date with screening and 14.6% were non-attenders. The overall OR comparing women up to date with screening with non-attenders was 0.46 (95% CI: 0.39-0.55) for adenocarcinoma. The odds were significantly decreased (OR: 0.22, 95% CI: 0.15-0.33) in up to date women with Stage 2 or worse adenocarcinoma, but not for women with Stage1A adenocarcinoma 0.71 (95% CI: 0.46-1.09). The odds of Stage 1A adenocarcinoma was double among lapsed attenders (OR: 2.35, 95% CI: 1.52-3.62) compared to non-attenders. Relative to women with no negative cytology within 7 years of diagnosis, women with Stage1A adenocarcinoma were very unlikely to be detected within 3 years of a negative cytology test (OR: 0.08, 95% CI: 0.05-0.13); however, the odds doubled 3-5 years after a negative test (OR: 2.30, 95% CI: 1.67-3.18). ORs associated with up to date screening were smaller for squamous and adenosquamous cervical carcinoma. Although cytology screening is inefficient at preventing adenocarcinomas, invasive adenocarcinomas are detected earlier than they would be in the absence of screening, substantially preventing Stage 2 and worse adenocarcinomas.

Impact of cervical screening on cervical cancer mortality: estimation using stage-specific results from a nested case-control study.

BACKGROUND: It is well established that screening can prevent cervical cancer, but the magnitude of the impact of regular screening on cervical cancer mortality is unknown. METHODS: Population-based case-control study using prospectively recorded cervical screening data, England 1988-2013. Case women had cervical cancer diagnosed during April 2007-March 2013 aged 25-79 years (N=11 619). Two cancer-free controls were individually age matched to each case. We used conditional logistic regression to estimate the odds ratio (OR) of developing stage-specific cancer for women regularly screened or irregularly screened compared with women not screened in the preceding 15 years. Mortality was estimated from excess deaths within 5 years of diagnosis using stage-specific 5-year relative survival from England with adjustment for age within stage based on SEER (Surveillance, Epidemiology and End Results, USA) data. RESULTS: In women aged 35-64 years, regular screening is associated with a 67% (95% confidence interval (CI): 62-73%) reduction in stage 1A cancer and a 95% (95% CI: 94-97%) reduction in stage 3 or worse cervical cancer: the estimated OR comparing regular (⩽5.5yearly) screening to no (or minimal) screening are 0.18 (95% CI: 0.16-0.19) for cancer incidence and 0.08 (95% CI: 0.07-0.09) for mortality. It is estimated that in England screening currently prevents 70% (95% CI: 66-73%) of cervical cancer deaths (all ages); however, if everyone attended screening regularly, 83% (95% CI: 82-84%) could be prevented. CONCLUSIONS: The association between cervical cancer screening and incidence is stronger in more advanced stage cancers, and screening is more effective at preventing death from cancer than preventing cancer itself.