NHS Breast Screening Programme Research Articles

Should a standard be defined for the Positive Predictive Value (PPV) of recall in the UK NHS Breast Screening Programme?

The UK NHSBSP defines standards for both cancer detection rate and recall rate for assessment but has not explicitly set a defined standard for positive predictive value (PPV) of recall. However, as PPV is defined as the percentage of women who are recalled and have a final diagnosis of cancer, a standard for PPV is an implicit consequence of the standards for cancer detection rate and recall rate. The standards are defined in terms of a lower level of acceptability known as the 'minimum standard' and a higher level of acceptability referred to as the 'target'. The target can be shown to be a PPV of more than 5.1% for prevalent screens and more than 8.4% for incident screens. This paper will explore the role of PPV as a performance measure and show how making moderate increases in PPV for programmes with the lowest PPVs could lead to major improvements in the overall efficiency of the programme.

Evaluation of digital mammography: update on the UK position

There is general acceptance that digital mammography screening will eventually replace the current analogue systems. Before this technology is introduced more widely for breast screening, however, assurances need to be made that it can improve or at least equal, the existing system in both quality and performance [1]. It is not simply a matter of replacing the existing mammography sets with digital systems. The Advisory Committee on Breast Cancer Screening supported setting up a multiprofessional Digital Steering Group to bring together the relevant expertise in breast screening and digital systems. The aim of the group was to identify areas of work required to be undertaken prior to implementation of digital systems in the screening service. The group had representation from England, Wales, Scotland and the private sector. Six areas of work were identified: technical parameters, clinical parameters, information issues, purchasing, training, and screening on mobiles. The Digital Steering Group of the National Health Service Breast Screening Programme (NHSBSP) has concluded that all the direct digital mammography systems tested by the NHSBSP meet the image quality and dose standards in the European Guidelines for Digital Mammography [2]. Only one of the computed radiography systems tested by the NHSBSP meets these standards. However, testing and evaluation of the new designs is ongoing.

Modelling of the impact of replacing four-node sampling with sentinel lymph node biopsy within the NHS Breast Screening Programme

The aim of this study was to use the Association of Breast Surgery at the British Association of Surgical Oncology audit data to model the possible consequences of the rollout of sentinel lymph node biopsy (SLNB) across the NHS Breast Screening Programme. The lymph node status, invasive size, grade and number of operations were examined for 26,431 screen-detected invasive cancers diagnosed in women who were invited for screening between 1 April 2001 and 31 March 2004. Seventy-five per cent of screen-detected invasive breast cancer had a negative nodal status. The average number of nodes removed in these cases was 10. If these cases had had their axilla assessed using SLNB, then the majority of women diagnosed with screen-detected breast cancer would have had a minimally invasive axillary procedure. Assuming that the protocol utilised during the ALMANAC study was continued, the 25% of cases with positive lymph nodes would require a second operation to clear the axilla. This would represent a 20% increase in the number of cases requiring a second therapeutic operation. In addition, as over 80% of these cases had less than five positive nodes found, a full axillary clearance may be overtreatment. Analysis of the variation of lymph node positivity with size and grade demonstrates that these factors could be used to determine which women with a positive sentinel lymph node require a full axillary clearance and which women could be appropriately managed with a level 1 clearance, thus reducing the possible complications of lympho-edema.

Workforce issues in breast imaging: radiographers as screen readers

The expansion of the National Health Service Breast Screening Programme (NHSBSP) has increased workload, adding to existing pressure on resources due to a shortage of radiologists. As a result some units have introduced double reading by two radiographers, with arbitration by a radiologist or breast clinician. Although some experimental work has supported such a move, the Advisory Committee on Breast Cancer Screening has requested further evidence from a real-life setting to support this change in reading practice. An observational study was initiated in 2004. A questionnaire was developed to document annually the reading practices of all screening units, and number of years of experience of individual film readers. Information gathered from the questionnaires, together with routine data from the KC62s, will allow us to compare the performance of units using radiographer-only double reading with that of other units. We will also be able to compare the performance before and after the change in reading protocol for units moving to radiographer-only double reading. The main outcome measures of performance will be cancer detection rates, standardised detection ratios and recall rates.

A brief history of breast medicine

Hippocrates believed that treating 'hidden cancers' did more harm than good. Today we debate whether we are over-treating some screen-detected lesions. History really does repeat itself. A review of the history of western medicine traces the efforts of physicians to cure breast cancer: from ancient potions and poultices, through centuries of brutal but swift surgery, to the supraradical mastectomy of the early twentieth century, on to conservative surgery with adjuvant therapies. Attitudes and beliefs of patients have influenced the management of breast cancer, from quiet acceptance of extreme suffering to the vocal feminist fury against 'mutilation' by male surgeons in the 1970s. The quest for early detection and accurate diagnosis produced a variety of imaging techniques. Some of them, thankfully, have now been forgotten. The NHS Breast Screening Programme, now in its 19th year, has brought rapid and radical change to breast cancer care in the United Kingdom. The difference between brilliant advances and heroic failures can only be judged by history.

Audit of short-term recall in the National Health Service Breast Screening Programme in the West Midlands

In the NHS Breast Screening Programme, cases where some diagnostic uncertainty remains following assessment may be recalled for a further appointment. Short-term recall (STR) rates and recall periods vary between screening services. There is a lack of published material to suggest who will benefit most from an STR appointment. Data were collected from the screening folders for 110 women put on STR following assessment, and for three women put on STR from STR in the financial year 2003/2004. The data collected included radiological appearance and opinion, biopsy results, reason for STR, and outcome. The most frequent reasons for women being put on STR were patient choice (18 cases, 16%), difficulty in biopsy (11 cases, 10%) and low yield of calcification in biopsy specimens (eight cases, 7%). The most frequent characteristics were calcification, benign or uncertain radiological appearance and a B1 (normal breast tissue) biopsy. At STR, 92 cases (84%) were found to be benign and returned to routine recall. Four women (3.6%) had invasive cancer, one woman had ductal carcinoma in situ, two women had a further 12-month STR and two women had open biopsy. For nine women (8%), the outcome of the STR appointment was unknown. The four invasive tumours were all from incident screens, one each of asymmetric distortion, micro-calcification, radial mass and appearance not recorded. From the three women on STR from STR, an additional invasive cancer was found and two women were returned to routine recall.

A radiographer-delivered intervention to promote early presentation of breast cancer among women as they leave the routine protection of the NHS breast screening programme

Older age is a risk factor both for developing breast cancer and for delayed presentation of the disease. Routine breast screening on the NHSBSP, however, ends at age 70. Our aim was to develop a radiographer-delivered psycho-educational intervention to be delivered at the point when the women leave the routine protection of the NHSBSP in order to: increase women's knowledge about breast symptoms and risk, promote disclosure of symptoms to someone close, reduce perceptions of barriers and increase intentions to seek help, and counter the interpretation by older women that their risk of breast cancer diminishes once routine screening ends. The ultimate aim of the intervention is to reduce the proportion of older women with breast cancer who delay their presentation, and to thereby save lives. We report the development of two variants of the intervention: a booklet and a 10-minute, radiographer-delivered, interview plus the booklet. Both variants of the intervention have been piloted within the South East London Breast Screening Programme and been shown to be acceptable and feasible to women and the Programme. A randomised controlled trial is planned to assess the effect of the intervention on delayed presentation and survival.

Screening for breast cancer in England: past and future

The NHS Breast Screening Programme (NHSBSP) began in 1988. It aims to invite all women aged 50-70 years for mammographic screening once every three years. The programme now screens 1.3 million women each year, about 75% of those invited, and diagnoses about 10,000 breast cancers annually. Although some have questioned the value of screening for breast cancer, the scientific evidence demonstrates clearly that regular mammographic screening between the ages of 50 and 70 years reduces mortality from the malignancy. Screened women are slightly more likely than unscreened women to be diagnosed with breast cancer. The cancers in screened women are smaller and are less likely to be treated with mastectomy than they would have been if diagnosed without screening. For every 400 women screened regularly by the NHSBSP over a 10-year period, one woman fewer will die from breast cancer than would have died without screening. The current NHSBSP saves an estimated 1400 lives each year in England. The screening programme spends about pound sterling 3000 for every year of life saved.

NHS breast screening: a model national programme

The United Kingdom’s NHS Breast Screening Programme is an impressive example of a high-coverage mammography screening service. The recent report from the Advisory Committee on Breast Cancer Screening (see pages 59–61) traces the history of the programme since its inception in 1988. As it was set up, the programme offered free threeyearly, single-view mammography to women aged 50–64. It has now been expanded to offer two-view mammography to women aged 50–70, and it achieves 75% coverage of the target population. The programme is estimated to save around 1400 lives per year, one per eight women regularly screened. This is consistent with estimates of the benefit of mammography programmes in the US. The costs have been estimated as £3000 per year of life saved. While more sophisticated cost effectiveness analyses are possible, it is clear that the UK programme represents value for money in health economic terms. The screening regimen, as it was initiated in 1988, might be considered minimal, and indeed some colleagues might still consider it so in view of the three-year interscreening interval. However, its spareness and simplicity may be an important contributor to its success. In offering secondary preventive services at a national level, delicate balances have to be struck with respect to effectiveness, cost, deliverability and acceptability. The three-yearly programme is deliverable within the financial resources and the numbers of appropriately qualified staff available. It is acceptable to the public, as evidenced by the high coverage, and it is saving lives. As treatment options improve, the mutually adjusted benefits of screening and adjuvant therapies will take on some importance. These may lead to further refinement of the target population, so that screening is offered only to those most likely to benefit from it. Primary prevention strategies may also have implications for the effectiveness of screening or the appropriate target population. In the meantime, the UK’s Breast Screening Programme has led to a reduction in deaths from breast cancer, in the size of tumours at presentation and in the number of mastectomies. Indirect effects include the mass of downstream research, which has added to our understanding of breast cancer natural history and control, and to the standardization and dissemination of good practice in diagnosis and treatment of breast cancer. Other countries may do well to look to the UK programme as one to emulate. Graham A Colditz Associate Director, Channing Laboratory, Department of Medicine, Brigham and Women’s Hospital and Harvard Medical School, 181 Longwood Avenue, Boston MA 02115, USA

Over-diagnosis in screening by mammography: A follow-up of the Malmö Mammographic Screening Trial, MMST

Breast screening with full-field digital mammography (FFDM) fails to detect 15–30% of cancers. This figure is higher for women with dense breasts. A new tomographic technique in mammography has been developed — digital breast tomosynthesis (DBT) — which allows images to be viewed in sections through the breast and has the potential to improve cancer detection rates. Results from retrospective reading studies comparing DBT with FFDM have been largely favourable with improvement in sensitivity and specificity. Increases in diagnostic accuracy have been reported as being independent of breast density; however there are mixed reports regarding the detection of microcalcification. Prospective screening studies using DBT with FFDM have demonstrated increased rates in cancer detection compared with FFDM alone. A reduction in false-positive recall rates has also been shown. Screening with the addition of DBT would approximately double radiation dose; however a simulated FFDM image can be generated from a DBT scan. The combination of simulated FFDM images and DBT is being evaluated within several studies and some positive results have been published. Interval cancer rates for the UK National Health Service Breast Screening Programme (NHSBSP) demonstrate the limited sensitivity of FFDM in cancer detection. DBT has the potential to increase sensitivity and decrease false-positive recall rates. It has approval for screening and diagnostics in several countries; however, there are issues with DBT as a screening tool including additional reading time, IT storage and connectivity, over-diagnosis, and cost effectiveness. Feasibility and cost-effectiveness trials are needed before the implementation of DBT in NHSBSP can be considered.

Evaluation of hereditary risk for breast cancer

Previous studies and epidemiological data from the UK National Health Service Breast Screening Programme (NHSBSP) have indicated significantly increased sensitivity for cancer detection with two-view rather than one-view mammography screening. The radiological and pathological features of these extra cancers have not been previously reported in detail. We have studied all screen-detected cancers found as incident cases in the South West London Breast Screening Service between 1994–1997 on the second round of screening. To assess the effect of two-view versus one-view mammography on cancer detection, these cases were mixed with controls in a 1:2 ratio in nine test sets and each set read independently by three film readers. They initially read the oblique view, then the craniocaudal views, and recorded abnormalities on the films and likelihood of recall. Radiological and histological data were recorded for each case.Using two views, 8.9% (P < 0.05) more invasive cancers were detected. The sensitivity increase was highest for invasive cancers less than 1Omm (11%) and cancers of low grade (11.9%). These sensitivity increases may underestimate the increase in `real life' because of over-recalling of normal mammograms, particularly with one view, under study conditions. The most significant radiological feature of invasive cancers was an irregular mass, which, seen on one view had a positive predictive value of 82.2% and 89.9% with two views. The craniocaudal view was helpful, firstly, because some cancers were not visible on the oblique view only. Secondly, benign appearing round masses and asymmetric densities seen with the oblique view only were resolved as more suspicious irregular masses with both views, leading to recall. In conclusion, there are cancers that cannot be adequately visualized on the oblique view alone. These are most commonly the small invasive cancers, which are of the greatest prognostic significance in breast cancer screening.

Mammotome biopsy: impact on preoperative diagnosis rate

To assess the impact of mammotome biopsy on preoperative diagnosis rate. A prospective study was undertaken to examine the referral patterns, radiological abnormalities, sensitivity, specificity and outcome of the first 150 patients undergoing mammotome biopsy at our institution. Most of the referrals were from the NHS Breast Screening Programme (85/100). The commonest radiological abnormality was microcalcification (87%). The accuracy of this biopsy technique for the target lesion was over 99%. Post-biopsy, 11 patients needed to proceed to a diagnostic surgical biopsy (7%). Forty-two malignancies were identified at final histology; 41 were diagnosed preoperatively. The positive predictive of mammotome biopsy was 98% for the present study. The present results for mammotome biopsy with regard to predicting invasion were: sensitivity 71.4% (10/14); specificity 100% (0/0); positive predictive value 100% (10/10); and negative predictive value 87% (27/31). Prone mammotome biopsy has proven to be highly accurate, considerably improving the preoperative diagnosis within our unit, and obviating the majority of diagnostic excision biopsies.

Impact of a national external quality assessment scheme for breast pathology in the UK

Background: This article presents the results and observed effects of the UK National Health Service Breast Screening Programme (NHSBSP) external quality assurance scheme in breast histopathology. Aims/Methods: The major objectives...

The NHS breast screening programme (pathology) EQA: experience in recent years relating to issues involved in individual performance appraisal

Background: The original role of the National Health Service breast screening programme (pathology) external quality assessment (EQA) scheme was educational; it aimed to raise standards, reinforce use of common terminology,...

Screening for breast cancer

Breast cancer is a multifactorial disease that has a worldwide annual incidence of over 1 million cases. In the UK this equates to over 39000 new diagnoses per year. Most of these cases occur in postmenopausal women, and the incidence in both this age group and in younger women is rising. Most of the major risk factors for breast cancer such as female sex, age and a family history of the disease cannot be avoided. However, there is established evidence that earlier detection of breast cancer through mammographic screening does significantly reduce mortality, by up to 24%. Since its inception in 1989, the National Health Service Breast Screening Programme (NHSBSP) has become increasingly effective at detecting breast cancer in the target population of women aged over 50, and together with advances in surgery, chemotherapy and other adjuvant medical treatments, mortality from breast cancer is significantly decreasing. This contribution aims to explore the principles behind the NHSBSP, and will review the key evidence which supports it. The advantages and pitfalls of screening will be examined and an overview of the actual screening and assessment process is included. Screening in high-risk groups is a new and controversial area that is now gaining prominence, and new imaging techniques being used in such groups, in addition to the screening and assessment of breast cancers in the conventional age range, will be covered.

The Effect of Changing From One to Two Views at Incident (Subsequent) Screens in the NHS Breast Screening Programme in England: Impact on Cancer Detection and Recall Rates

The Effect of Changing From One to Two Views at Incident (Subsequent) Screens in the NHS Breast Screening Programme in England: Impact on Cancer Detection and Recall Rates

Mammographic screening: is the benefit worth the risk?

Justification of medical exposures is a fundamental principle of radiation protection. This principle applies to mammographic screening, both for the screened population and at an individual level. The benefit of mammographic screening may be considered to be the number of cancers detected or lives saved by breast screening. The risk is the hypothetical number of fatal cancers induced by the use of ionising radiation in screening mammography. Benefit can be deduced from the cancer detection rate in the NHS Breast Screening Programme. The number of additional lives saved by the intervention of a screening programme may be deduced from knowledge of the change in tumour size, stage and nodal status (and hence prognosis) in women with screening detected breast cancers compared with symptomatic women before screening. Calculations of benefit risk ratios to the UK population have been performed. It is concluded that breast screening is justified in radiation protection terms.

The West Midlands breast cancer screening status algorithm – methodology and use as an audit tool

To illustrate the ability of the West Midlands breast screening status algorithm to assign a screening status to women with malignant breast cancer, and its uses as a quality assurance and audit tool. Breast cancers diagnosed between the introduction of the National Health Service [NHS] Breast Screening Programme and 31 March 2001 were obtained from the West Midlands Cancer Intelligence Unit (WMCIU). Screen-detected tumours were identified via breast screening units, and the remaining cancers were assigned to one of eight screening status categories. Multiple primaries and recurrences were excluded. A screening status was assigned to 14,680 women (96% of the cohort examined), 110 cancers were not registered at the WMCIU and the cohort included 120 screen-detected recurrences. The West Midlands breast screening status algorithm is a robust simple tool which can be used to derive data to evaluate the efficacy and impact of the NHS Breast Screening Programme.

Breast cancer histological classification: agreement between the Office for National Statistics and the National Health Service Breast Screening Programme

IntroductionEpidemiological studies rely on data supplied by central cancer registration sources to be timely, accurate and complete. Validation studies of such data at a national level are limited. Data collected for the Million Women Study was used to compare the level of agreement between the Office for National Statistics (ONS) and the National Health Service Breast Screening Programme (NHSBSP) in the recording of incident screen-detected breast cancer histology between 1996 and 2001.Methods1.3 million women aged 50 to 64 years were recruited into the Million Women Study cohort via the NHSBSP. Incident screen-detected breast cancer histologies were notified separately by the ONS and NHSBSP. ICD-10 and ICD-02 ONS codes and NHSBSP histology data were similarly coded to allow for comparison in terms of cancer invasiveness and morphology. The statistical outcome measures are percentage agreement and the kappa statistic.ResultsA total of 5,886 incident screen-detected breast cancers were available for analysis. Of the 5,886 screen-detected cancers reported by the ONS and NHSBSP, 5,684 (96.6%, κ = 0.9) agreed in terms of the degree of invasiveness. Of the 5,458 cancers that had been assigned a specific morphology code, there was exact agreement between the ONS and the NHSBSP in 4,922 cases (90.2%, κ = 0.8).ConclusionThere is an excellent level of agreement between the ONS and NHSBSP in the recording of the histology of screen-detected breast cancer. From these results it is not possible to comment on which source of data is the more or less accurate, although the differences are very small.

Combined use of imaging and cytologic grading schemes for screen-detected breast abnormalities improves overall diagnostic accuracy

Numeric grading systems have been validated for the reporting of mammographic abnormalities and for breast cytology. The impact of integrating lesion grades from both disciplines on the accuracy of assessment of screen-detected lesions has not been investigated. In the current study, all lesions were prospectively classified using the Tabar radiologic grading system, as well as the National Health Service Breast Screening Programme (NHSBSP) cytologic reporting system. For lesions assessed between January 1996 and January 2003, based on final histology or 12 months of follow-up, positive predictive values (PPV) were calculated for each imaging grade and for each cytologic grouping. After integration of the data, changes in the PPV and the negative predictive values (NPV) of cytology among lesions with varying imaging grades were tracked. Data were retrieved for 4806 lesions. The differences in the rates of malignancy for lesions in the different imaging grades were significant (Grade 5, 95.8%; Grade 4, 54.6%; Grade 3, 11.6%) (P < 0.001). Similarly, the cytologic categories stratified lesions into groups with significantly different rates of malignancy (positive, 99.5%; suspicious, 89.2%; atypical, 43.4%; benign, 5.7%; inadequate, 33.3%) (P < 0.001). Integration of cytologic results with the imaging grade of lesions led to significant improvements in the PPV and NPV. Positive smears were likely to represent malignant lesions in 99.9% of Grade 5 lesions, 99.2% of Grade 4 lesions, and 95.2% of Grade 3 lesions (P < 0.0001). Similarly, negative cytology corresponded to a nonmalignant lesion in 99% of Grade 3 lesions, 81.6% of Grade 4 lesions, and in only 45.5% of Grade 5 lesions (P < 0.001). The integration of numeric grading schemes for breast imaging and cytology improves the accuracy of assessment of screen-detected lesions. Because 99.9% of Grade 5 lesions with positive cytology are malignant, core biopsy confirmation may not be required in this group.