Correction to: An analysis of 11.3 million screening tests examining the association between recall and cancer detection rates in the English NHS breast cancer screening programme.

The original version of this article, published on 04 February 2019, unfortunately contained a mistake.

An analysis of 11.3 million screening tests examining the association between recall and cancer detection rates in the English NHS breast cancer screening programme.

OBJECTIVE: To develop methods to model the relationship between cancer detection and recall rates to inform professional standards. METHODS: Annual screening programme information for each of the 80 English NHSBSP units (totalling 11.3 million screening tests) for the seven screening years from 1 April 2009 to 31 March 2016 and some Dutch screening programme information were used to produce linear and non-linear models. The non-linear models estimated the modelled maximum values (MMV) for cancers detected at different grades and estimated how rapidly the MMV was reached (the modelled 'slope' (MS)). Main outcomes include the detection rate for combined invasive/micro-invasive and high-grade DCIS (IHG) detection rate and the low/intermediate grade DCIS (LIG) detection rate. RESULTS: At prevalent screens for IHG cancers, 99% of the MMV was reached at a recall rate of 7.0%. The LIG detection rate had no discernible plateau, increasing linearly at a rate of 0.12 per 1000 for every 1% increase in recall rate. At incident screens, 99% of the MMV for IHG cancer detection was 4.0%. LIG DCIS increased linearly at a rate of 0.18 per 1000 per 1% increase in recall rate. CONCLUSIONS: Our models demonstrate the diminishing returns associated with increasing recall rates. The screening programme in England could use the models to set recall rate ranges, and other countries could explore similar methodology. KEY POINTS: • Question: How can we determine optimum recall rates in breast cancer screening? • Findings: In this large observational study, we show that increases in recall rates above defined levels are almost exclusively associated with false positive recalls and a very small increase in low/intermediate grade DCIS. • Meaning: High recall rates are not associated with increases in detection of life-threatening cancers. The models developed in this paper can be used to help set recall rate ranges that maximise benefit and minimise harm.

Disability and participation in breast and bowel cancer screening in England: a large prospective study.

BACKGROUND: There is limited information about participation in organised population-wide screening programmes by people with disabilities. METHODS: Data from the National Health Service routine screening programmes in England were linked to information on disability reported by the Million Women Study cohort participants. RESULTS: Of the 473 185 women offered routine breast or bowel cancer screening, 23% reported some disability. Women with disabilities were less likely than other women to participate in breast cancer screening (RR=0.64, 95% CI: 0.62-0.65) and in bowel cancer screening (RR=0.75, 0.73-0.76). Difficulties with self-care or vision were associated with the greatest reduction in screening participation. CONCLUSION: Participation in routine cancer screening programmes in England is reduced in people with disabilities and participation varies by type of disability.

Nationwide bowel cancer screening programme in England: cohort study of lifestyle factors affecting participation and outcomes in women.

BACKGROUND: In 2006, the National Health Service Bowel Cancer Screening Programme in England (NHSBCSP) began offering routine population-based biennial faecal occult blood testing (FOBt) at ages 60-69. There is, however, limited information on how characteristics of individuals affect participation and outcomes of screening, and we studied this association by linking NHSBCSP data to a large prospective cohort of women. METHODS: Electronic linkage of the NHSBCSP and Million Women Study records identified 899 166 women in the study cohort with at least one invitation for screening. NHSBCSP provided information on screening acceptance, FOBt results, screen-detected colorectal cancer and other outcomes. The Million Women Study provided prospectively collected information on personal and lifestyle factors. Multiple regression was used to estimate relative risks (RRs) of factors associated with acceptance and outcomes of screening. RESULTS: Overall, 70% of women (628 976/899 166) accepted their first invitation for bowel cancer screening, of whom 9133 (1.5%) were FOBt-positive, 743 (0.1%) had screen-detected colorectal cancer and 3056 (0.5%) had screen-detected colorectal adenoma. Acceptance was lower in women from the most than the least deprived tertile, in South Asians and in Blacks than in Whites, in current than in never smokers and in obese than in normal weight women: adjusted RRs (95% confidence interval) for acceptance vs not, 0.90 (0.90-0.90); 0.77 (0.75-79); 0.94 (0.92-0.96); 0.78 (0.77-0.78); and 0.88 (0.88-0.89), respectively: P<0.001 for each. These factors were also associated with an increased risk of being FOBt-positive and of having screen-detected adenoma, but were not strongly associated with the risk of screen-detected colorectal cancer. Relative risks for screen-detected adenoma were 1.22 (1.12-1.34), 2.46 (1.75-3.45), 1.61 (1.05-2.48), 1.53 (1.38-1.68) and 1.77 (1.60-1.95), respectively (P<0.001 for all, except for Blacks vs Whites P=0.03). Use of hormone therapy for menopause was associated with reduced risk of screen-detected adenoma, RR ever vs never use, 0.87 (0.81-0.93), P<0.001 and colorectal cancer, 0.78 (0.68-0.91), P=0.001. INTERPRETATION: Among women in England, socioeconomic and lifestyle factors strongly affect participation in routine bowel cancer screening, risk of being FOBt-positive and risk of having screen-detected colorectal adenoma. However, screen-detected colorectal cancer risk is not strongly related to these factors.

Is the increased risk of preterm birth following excision for cervical intraepithelial neoplasia restricted to the first birth post treatment?

OBJECTIVE: To explore whether the increased risk of preterm birth following treatment for cervical disease is limited to the first birth following colposcopy. DESIGN: Nested case-control study. SETTING: Twelve NHS hospitals in England. POPULATION: All nonmultiple births from women selected as cases or controls from a cohort of women with both colposcopy and a hospital birth. Cases had a preterm (20-36 weeks of gestation) birth. Controls had a term birth (38-42 weeks) and no preterm. METHODS: Obstetric, colposcopy and pathology details were obtained. MAIN OUTCOME MEASURES: Adjusted odds ratio of preterm birth in first and second or subsequent births following treatment for cervical disease. RESULTS: A total of 2798 births (1021 preterm) from 2001 women were included in the analysis. The risk of preterm birth increased with increasing depth of treatment among first births post treatment [trend per category increase in depth, categories <10 mm, 10-14 mm, 15-19 mm, ≥20 mm: odds ratio (OR) 1.23, 95% confidence interval (95% CI) 1.12-1.36, P < 0.001] and among second and subsequent births post treatment (trend OR 1.34, 95% CI 1.15-1.56, P < 0.001). No trend was observed among births before colposcopy (OR 0.98, 95% CI 0.83-1.16, P = 0.855). The absolute risk of a preterm birth following deep treatments (≥15 mm) was 6.5% among births before colposcopy, 18.9% among first births and 17.2% among second and subsequent births post treatment. Risk of preterm birth (once depth was accounted for) did not differ when comparing first births post colposcopy with second and subsequent births post colposcopy (adjusted OR 1.15, 95% CI 0.89-1.49). CONCLUSIONS: The increased risk of preterm birth following treatment for cervical disease is not restricted to the first birth post colposcopy; it remains for second and subsequent births. These results suggest that once a woman has a deep treatment she remains at higher risk of a preterm birth throughout her reproductive life.

Guaiac faecal occult blood test performance at initial and repeat screens in the English Bowel Cancer Screening Programme.

BACKGROUND: In many countries, screening for colorectal cancer (CRC) relies on repeat testing using the guaiac faecal occult blood test (gFOBT). This study aimed to compare gFOBT performance measures between initial and repeat screens. METHODS: Data on screening uptake and outcomes from the English Bowel Cancer Screening Programme (BCSP) for the years 2008 and 2011 were used. An existing CRC natural history model was used to estimate gFOBT sensitivity and specificity, and the cost-effectiveness of different screening strategies. RESULTS: The gFOBT sensitivity for CRC was estimated to decrease from 27.35% at the initial screen to 20.22% at the repeat screen. Decreases were also observed for the positive predictive value (8.4-7.2%) and detection rate for CRC (0.19-0.14%). Assuming equal performance measures for both the initial and repeat screens led to an overestimate of the cost effectiveness of gFOBT screening compared with the other screening modalities. CONCLUSIONS: Performance measures for gFOBT screening were generally lower in the repeat screen compared with the initial screen. Screening for CRC using gFOBT is likely to be cost-effective; however, the use of different screening modalities may result in additional benefits. Future economic evaluations of gFOBT should not assume equal sensitivities between screening rounds.

Reduction in interval cancer rates following the introduction of two-view mammography in the UK breast screening programme.

BACKGROUND: The introduction of two-view mammography at incident (subsequent) screens in the National Health Service Breast Screening Programme (NHSBSP) has led to an increased number of cancers detected at screen. However, the effect of two-view mammography on interval cancer rates has yet to be assessed. METHODS: Routine screening and interval cancer data were collated from all screening programmes in the United Kingdom for women aged 50-64, screened between 1 April 2003 and 31 March 2005. Interval cancer rates were compared based on whether two-view mammography was in use at the last routine screen. RESULTS: The reduction in interval cancers following screening using two-view mammography compared with one view was 0.68 per 1,000 women screened. Overall, this suggests the introduction of two-view mammography at incident screen was accompanied by a 15-20% reduction in interval cancer rates in the NHSBSP. CONCLUSION: The introduction of two-view mammography at incident screens is associated with a reduction in incidence of interval cancers. This is consistent with previous publications on a contemporaneous increase in screen-detected cancers. The results provide further evidence of the benefit of the use of two-view mammography at incident screens.

A randomised trial of weekend and evening breast screening appointments.

BACKGROUND: There is a need to research interventions that improve access to and convenience of breast cancer screening services. METHODS: We conducted a randomised trial comparing invitations to out-of-hours appointments with standard office hour appointments. Women who were to be invited for routine breast screening were randomised (3 : 1 : 1 : 1) to one of these screening invitations: standard office hour appointment, office hour appointment with the option to change to an out-of-hours appointment, weekday evening appointment, or weekend appointment. RESULTS: A total of 9410 women were invited to an office hour, 3519 to an office hour with the option to change, 3271 to a weekday evening, and 3162 to a weekend appointment. The offer of an initial out-of-hours appointment was associated with a non-significant decrease in attendance rates (73.7% vs 74.1%). The highest attendance was observed in the group offered an initial office hour appointment with the option to change to out-of-hours (76.1% vs 73.3% for standard office hour, P=0.001), with 7% of invitees exercising the option to change. CONCLUSION: The optimum strategy for improving attendance at breast screening is to offer a traditional office hour appointment and including in the letter of invitation an option to change to an evening or weekend appointment if wished.

Longer mean colonoscopy withdrawal time is associated with increased adenoma detection: evidence from the Bowel Cancer Screening Programme in England.

BACKGROUND AND STUDY AIMS: Increasing colonoscopy withdrawal time (CWT) is thought to be associated with increasing adenoma detection rate (ADR). Current English guidelines recommend a minimum CWT of 6 minutes. It is known that in the Bowel Cancer Screening Programme (BCSP) in England there is wide variation in CWT. The aim of this observational study was to examine the relationship between CWT and ADR. PATIENTS AND METHODS: The study examined data from 31 088 colonoscopies by 147 screening program colonoscopists. Colonoscopists were grouped in four levels of mean CWT ( < 7, 7 - 8.9, 9 - 10.9, and ≥ 11 minutes). Univariable and multivariable analysis (binary logistic and negative binomial regression) were used to explore the relationship between CWT, ADR, mean number of adenomas and number of right-sided and advanced adenomas. RESULTS: In colonoscopists with a mean CWT < 7 minutes, the mean ADR was 42.5 % compared with 47.1 % in the ≥ 11-minute group (P < 0.001). The mean number of adenomas detected per procedure increased from 0.77 to 0.94, respectively (P < 0.001). The increase in adenoma detection was mainly of subcentimeter or proximal adenomas; there was no increase in the detection of advanced adenomas. Regression models showed an increase in ADR from 43 % to 46.5 % for mean CWT times ranging from 6 to 10 minutes. CONCLUSIONS: This study demonstrates that longer mean withdrawal times are associated with increasing adenoma detection, mainly of small or right-sided adenomas. However, beyond 10 minutes the increase in ADR is minimal. Mean withdrawal times longer than 6 minutes are not associated with increased detection of advanced adenomas. Withdrawal time remains an important quality metric of colonoscopy.

European guidelines for quality assurance in colorectal cancer screening and diagnosis: overview and introduction to the full supplement publication.

Population-based screening for early detection and treatment of colorectal cancer (CRC) and precursor lesions, using evidence-based methods, can be effective in populations with a significant burden of the disease provided the services are of high quality. Multidisciplinary, evidence-based guidelines for quality assurance in CRC screening and diagnosis have been developed by experts in a project co-financed by the European Union. The 450-page guidelines were published in book format by the European Commission in 2010.  They include 10 chapters and over 250 recommendations, individually graded according to the strength of the recommendation and the supporting evidence. Adoption of the recommendations can improve and maintain the quality and effectiveness of an entire screening process, including identification and invitation of the target population, diagnosis and management of the disease and appropriate surveillance in people with detected lesions. To make the principles, recommendations and standards in the guidelines known to a wider professional and scientific community and to facilitate their use in the scientific literature, the original content is presented in journal format in an open-access Supplement of Endoscopy. The editors have prepared the present overview to inform readers of the comprehensive scope and content of the guidelines.

CT colonography in the English Bowel Cancer Screening Programme: national survey of current practice.

AIM: To obtain information regarding the provision of computed tomography colonography (CTC) services to the National Health Service (NHS) Bowel Cancer Screening Programme (BCSP). MATERIALS AND METHODS: Specialist screening practitioners at the 58 BCSP screening centres and lead BCSP radiologists at 110 hospitals performing CTC for the Programme were contacted and completed a semi-structured questionnaire administered by telephone. Responses were collated and descriptive statistics derived. RESULTS: One hundred and seven (98%) SSPs and 103 (94%) radiologists were surveyed. All screening centres had access to CTC at 110 hospital sites. All sites used CTC for failed or contraindicated colonoscopy, 24% used it for patients taking anticoagulants, and 17% for those with fear of colonoscopy. Patient preference was not an indication at any site. Multidetector CT (100%), carbon dioxide insufflators (94%), and CTC software (95%) were almost universal. Ninety-one percent of radiographers and 98% of radiologists were trained in CTC image acquisition and interpretation, respectively. Seventy-five percent of the radiologists were gastrointestinal subspecialists and two-thirds had interpreted more than 300 examinations in clinical practice, although 5% had interpreted fewer than 100. Eighty-one percent of radiologists favoured some form of accreditation for CTC interpretation. CONCLUSIONS: CTC is widely available to the BCSP. Appropriate hardware and software is almost ubiquitous. Most radiographers and radiologists offering CTC to the BCSP have received specific training. Formal service evaluation is patchy. The majority of radiologists would welcome national accreditation for CTC.

A prospective study of human papillomavirus (HPV) testing to resolve uncertainty in colposcopy.

OBJECTIVE: UK colposcopy services are seeing increased workloads, a large proportion of which are follow-up appointments. The English Cervical Screening Programme HPV Special Interest Group identified five subcategories of colposcopy clinic patients who often require prolonged follow-up regimes for low-grade abnormalities. Human papillomavirus (HPV) testing has a high negative predictive value, meaning that HPV-negative women are at very low risk of underlying disease. Our objectives were to quantify the number of HPV-negative women in each study subcategory and to evaluate the number who could potentially be discharged from colposcopy on the basis of their results. METHODS: Four colposcopy clinics prospectively identified women according to five categories over 12 months. All women underwent cytological testing and high-risk HPV (hrHPV) testing using the Hybrid Capture 2 test. Management outcomes and decisions based on a knowledge of the HPV status were recorded. RESULTS: Data available on 755 women showed that 422/755 (55.9%) and 260/755 (34.4%) had persistent cervical intraepithelial neoplasia grade 1 (CIN1) (Category 1) or a minor abnormality following treatment (Category 2), respectively. In Categories 1 and 2, 51.7% and 60.2%, respectively, were hrHPV negative. The rates with biopsies of CIN2 or worse (CIN2+) across the two categories were 3/355 (0.8%) and 21/291 (7.0%) for hrHPV-negative and hrHPV-positive women, respectively. CONCLUSION: The incorporation of hrHPV testing within organized cervical screening programmes has been widely accepted. hrHPV testing for the clinical scenarios outlined in this study detects women who are hrHPV negative and therefore at low risk of underlying disease, potentially reducing anxiety and inconvenience for women and costs to colposcopy services.

Performance measures in three rounds of the English bowel cancer screening pilot.

OBJECTIVES: To compare performance measures across all three rounds of the English bowel cancer screening faecal occult blood test pilot and their relation to social deprivation and ethnicity. METHODS: In each round in three primary care trusts, data for a restricted population of over 48,500 aged 60-69 years were analysed. Individual-based data included postcode linked to area-based data on the Index of Multiple Deprivation (IMD) 2004, and ethnicity. Outcomes were the rates of screening and colonoscopy uptake, positivity and detection of neoplasia (adenomas or bowel cancer) and bowel cancer, and the positive predictive values (PPVs) of a positive test for neoplasia and bowel cancer. Sensitivity was calculated by the proportional incidence method using data on interval cancers identified from cancer registrations. RESULTS: The overall uptake rate was 61.8%, 57.0% and 58.7% in the first, second and third rounds, respectively. Although the PPV for cancer decreased over the course of the three rounds (10.9% in the 1st round, 6.5% in 3rd round), the PPV for all neoplasia remained relatively constant (42.6% in 1st round, 36.9% in 3rd round). Deprivation and non-white ethnic background (principally Indian subcontinent in the pilot region) were associated with low screening and colonoscopy uptake rates, and this changed little over the three screening rounds. Uptake was lower in men, although differences in uptake between men and women decreased over time. Non-participation in previous rounds was a strong predictor of low uptake. CONCLUSIONS: Performance measures are commensurate with expectations in a screening programme reaching its third round of screening, but a substantial ongoing effort is needed, particularly to address the effects of deprivation and ethnicity in relation to uptake.

Cost and logistics of alternative roll-out options for implementing human papillomavirus testing as a triage in cervical screening: results of the sentinel sites study.

BACKGROUND: Previous studies have indicated that human papillomavirus (HPV) testing as a triage for managing equivocal cytology is cost-effective. The aim of this study was to assess the costs of alternative roll-out options. METHODS: Detailed cost estimates were collected from six laboratories where HPV triage had been implemented. Costs were assessed for the two different service delivery models that were implemented; a 'hub and spoke model' of central HPV testing in a microbiology laboratory with separate cytology laboratories, and an 'integrated model' where HPV testing was conducted within the cytology laboratory. RESULTS: Comparison of alternative delivery models indicated that setting up HPV processing within existing cytology laboratory, i.e., an 'integrated cytology/HPV laboratory' generated savings in staff time amounting to between £2.54 and 4.86 per sample processed. Running full HPV testing batches was also an important consideration. For full batches to be run on a twice weekly basis requires having no more than two laboratories per Strategic Health Authority. CONCLUSIONS: To be cost-efficient, and to meet turn-around times, HPV testing needs to be conducted at integrated cytology/HPV testing centres with sufficient throughput to run full batches of HPV tests.

A retrospective observational study examining the characteristics and outcomes of tumours diagnosed within and without of the English NHS Bowel Cancer Screening Programme.

BACKGROUND: Colorectal cancer is common in England and, with long-term survival relatively poor, improving outcomes is a priority. A major initiative to reduce mortality from the disease has been the introduction of the National Health Service (NHS) Bowel Cancer Screening Programme (BCSP). Combining data from the BCSP with that in the National Cancer Data Repository (NCDR) allows all tumours diagnosed in England to be categorised according to their involvement with the BCSP. This study sought to quantify the characteristics of the tumours diagnosed within and outside the BCSP and investigate its impact on outcomes. METHODS: Linkage of the NCDR and BCSP data allowed all tumours diagnosed between July 2006 and December 2008 to be categorised into four groups; screen-detected tumours, screening-interval tumours, tumours diagnosed in non-participating invitees and tumours diagnosed in those never invited to participate. The characteristics, management and outcome of tumours in each category were compared. RESULTS: In all, 76 943 individuals were diagnosed with their first primary colorectal cancer during the study period. Of these 2213 (2.9%) were screen-detected, 623 (0.8%) were screening-interval cancers, 1760 (2.3%) were diagnosed in individuals in non-participating invitees and 72 437 (94.1%) were diagnosed in individuals not invited to participate in the programme due to its ongoing roll-out over the time period studied. Screen-detected tumours were identified at earlier Dukes' stages, were more likely to be managed with curative intent and had significantly better outcomes than tumours in other categories. CONCLUSION: Screen-detected cancers had a significantly better prognosis than other tumours and this would suggest that the BCSP should reduce mortality from colorectal cancer in England.

Are women ready for the new cervical screening protocol in England? A systematic review and qualitative synthesis of views about human papillomavirus testing.

BACKGROUND: A new protocol for human papillomavirus (HPV) testing within the UK cervical screening programme commenced in April 2011, creating new patient experiences. This is the first review to synthesise a substantial body of international evidence of women's information needs, views and preferences regarding HPV testing. We aimed to inform the development of educational materials to promote informed choice, reduce anxiety and improve disease control. METHODS: We searched 12 bibliographic databases. Two reviewers independently screened papers and assessed study quality; disagreements were resolved by discussion. Results were extracted verbatim and authors' findings treated as primary data. Studies were synthesised collaboratively using framework methods. RESULTS: We synthesised findings from 17 studies. Women had overwhelmingly negative concerns; an HPV diagnosis was daunting, had associated problems of disclosure of a sexually transmitted infection (STI), impacted on relationships and provoked fear of stigmatisation. Nevertheless, many thought HPV testing could be a preferable alternative to repeat cytology. Knowledge was poor; women struggled to interpret limited information in the context of existing knowledge about STIs and cervical cancer. CONCLUSION: Women are likely to be poorly informed, have limited understanding and many unanswered questions. This could increase anxiety and reduce ability to make informed choices, presenting a substantial challenge for those who design and provide information.

European guidelines for quality assurance in colorectal cancer screening and diagnosis. First Edition--Executive summary.

Multidisciplinary, evidence-based guidelines for quality assurance in colorectal cancer screening and diagnosis have been developed by experts in a project coordinated by the International Agency for Research on Cancer. The full guideline document covers the entire process of population-based screening. It consists of 10 chapters and over 250 recommendations, graded according to the strength of the recommendation and the supporting evidence. The 450-page guidelines and the extensive evidence base have been published by the European Commission. The content of the executive summary is presented here to promote international discussion and collaboration by making the principles and standards recommended in the new EU Guidelines known to a wider professional and scientific community. Following these recommendations has the potential to enhance the control of colorectal cancer through improvement in the quality and effectiveness of screening programmes and services.

Review of cytology and histopathology as part of the NHS Cervical Screening Programme audit of invasive cervical cancers.

OBJECTIVE: To audit pathology slide reporting in the Cervical Screening Programme in England by reviewing cytology and histology slides from women subsequently diagnosed with invasive cervical cancer. METHODS: Between April 2007 and March 2010, 6113 women diagnosed with cervical cancer were identified. Cervical cytology and histology slides taken within 10 years of diagnosis were identified and where possible reviewed after a nationally agreed protocol. Reviewers were not blinded to the original reading of each sample. Most cytology samples before 2005 were conventional, most after 2007 liquid based. RESULTS: Of 13,745 cytology results from women developing cervical cancer, 55% were reviewed. The review result was identical for 55% of slides. Of 3759 originally normal slides, only 45% were normal on review: 11% were inadequate, 21% low grade (borderline or mild dyskaryosis) and 23% high grade (moderate dyskaryosis or worse). Of tests originally normal taken over 5.5 years before diagnosis, 14% were upgraded to high grade compared with 37% within 3.5 years of diagnosis. Of 5159 histology specimens recorded within 10 years of diagnosis of a cancer, 3895 were reviewed. Overall, 94% of samples reviewed retained the original diagnosis. One per cent (33/3012) of cancers were downgraded and 5% (6/112) of negative samples were upgraded to cancer upon review (four of which were taken within 2 months of diagnosis). In comparison, 15% (14/91) of cervical glandular intraepithelial neoplasia (CGIN) and 12% (38/314) of cervical intraepithelial neoplasia grade 3 (CIN3) were upgraded to cancer. CONCLUSIONS: In spite of the excellent quality of cytology in England, a high proportion of negative cytology taken up to three and a half years before diagnosis were considered to contain abnormal cells by reviewers informed of the subsequent cancer. Continuing these reviews, with a strong focus on education, will ensure a clear understanding of these slides and further reduce the risk of developing cervical cancer.

HPV testing as a triage for borderline or mild dyskaryosis on cervical cytology: results from the Sentinel Sites study.

BACKGROUND: Earlier pilot studies of human papillomavirus (HPV) triage concluded that HPV triage was feasible and cost-effective. The aim of the present study was to study the impact of wider rollout of HPV triage for women with low-grade cytology on colposcopy referral and outcomes. METHODS: Human papillomavirus testing of liquid-based cytology (LBC) samples showing low-grade abnormalities was used to select women for colposcopy referral at six sites in England. Samples from 10,051 women aged 25-64 years with routine call or recall cytology reported as borderline or mild dyskaryosis were included. RESULTS: Human papillomavirus-positive rates were 53.7% in women with borderline cytology and 83.9% in those with mild dyskaryosis. The range between sites was 34.8-73.3% for borderline cytology, and 73.4-91.6% for mild dyskaryosis. In the single site using both LBC technologies there was no difference in rates between the two technologies. The positive predictive value of an HPV test was 16.3% for CIN2 or worse and 6.1% for CIN3 or worse, although there was considerable variation between sites. CONCLUSION: Triaging women with borderline cytological abnormalities and mild dyskaryosis with HPV testing would allow approximately a third of these women to be returned immediately to routine recall, and for a substantial proportion to be referred for colposcopy without repeat cytology. Variation in HPV-positive rates results in differing colposcopy workload.