In the middle of the twentieth century, screening for cervical cancer was heralded as the solution to a type of cancer that had hitherto been almost invariably fatal. Yet it has taken the best part of the latter half of that century to see falls in incidence and mortality in those countries that have well organised screening programmes. This chapter will address the problems and some of the solutions to running a cervical screening programme and will explore some of the recent developments that could be used to enhance the screening procedure.

Screening can be defined as the testing of people who do not have any recognisable signs of the condition in question, with the purpose of reducing risk for that individual of future ill health due to disease. Screening encompasses the whole system and is a programme not a test.¹

Screening for disease in a population might seem to offer obvious benefits, but as Raffle and Gray have stated, ‘All screening programmes do harm. Some do good as well and, of these, some do more good than harm at a reasonable cost’.¹ The aim of any screening programme is to detect disease at an earlier stage than it could have been detected by symptomatic presentation, but clearly the disease is only suitable for screening if the benefits outweigh the harms in this equation.

In order to give benefit, the test must be effective in detecting the disease. This is the sensitivity of the test. It must detect disease at a stage where intervention and treatment lead to a better outcome than if the disease had been left to present symptomatically and obviously there must be an effective treatment. In terms of harm, the screening test and follow-up investigations for those who screen positive must not confer more harm than good and this confers an ethical dilemma – is it acceptable to harm the many for the benefit of the few? Finally, the screening programme must be economically viable, and this needs to be addressed in terms of competition for resources and health priorities, albeit very different in different settings.

Cervical screening in the UK meets these criteria, and is an excellent example of a successful screening programme. However, this has not always been the case.

George Papanicolaou had described cytological changes in cervical smears in 1928² but his technique was not widely implemented for many years. It was not until the 1950s that cervical smears were first taken in the UK, but there was no properly organised programme. Screening tended to concentrate on young women attending for contraceptive and antenatal care, predominantly from higher socioeconomic groups. These women were at low risk of cervical carcinoma and women continued to die of the disease in undiminished numbers. It became apparent, however, that in areas where a well-organised programme was in place, for example Scotland,³ mortality began to fall.

This prompted the establishment of a true national screening programme, which by 1998 was producing guidance documents to standardise and improve procedures throughout the country. A national computer system (The Exeter system) was procured, which is still in use today. Computerised call and recall of women started in 1998. A national coordinating team was appointed and continued to produce documents on all aspects of the screening programme.

However, although the programme was much improved it became apparent that there were still a number of problems. A series of errors were highlighted in very critical reports, culminating in the investigation into screening services at Kent and Canterbury which was published in 1997.⁴ This defined the need for robust quality assurance (QA), which is one of the main features of the programme today.

There is now abundant evidence that the UK cervical screening programmes have greatly reduced the incidence of cervical cancer^5–7 and this reduction appears to be continuing, although the rate of improvement may be decreasing. There is also evidence that without screening, the incidence of cervical cancer would be increasing dramatically, so that it is now calculated that 75% of cases are prevented, saving thousands of lives per year in England and Wales (Figs 22.1, 22.2).⁵

Fig. 22.1 Age standardised (European) incidence rates, cervical cancer, Great Britain 1975–2006.

Fig. 22.2 Age standardised (European) mortality rates, cervical cancer, Great Britain 1975–2007.

There are three separate screening programmes in the UK, in England, Scotland and Wales, all very similar with slight differences in governance and details of policy. The information given here relates to the English programme, the National Health Service Cervical Screening Programme (NHSCSP).

Cervical screening is led by the National Screening Office, headed by a director of screening who is accountable at a high level within the Department of Health. The National Screening Office has a coordinating role, to seek expert opinion, produce national specification documents, coordinate the evaluation of all the local programmes and to assess the introduction of new technologies and screening strategies.

Delivery at a local level involves many individuals and organisations whose roles are described in Box 22.1.

The responsibility for commissioning cervical screening lies with the local Primary Care Trust (PCT), and the overseeing and performance management of this role rests with the Strategic Health Authority (SHA) for that Region. Responsibility for performance of parts of the service delivered within hospitals rests with the NHS Trust concerned, ultimately with its Chief Executive. All professionals working within the programme have a responsibility to ensure they have been adequately trained and are conversant with the programme.

Each region has a quality assurance team reporting to the Regional Director of Public Health. This is a team led by a senior individual who monitors the quality of all parts of the programme, including visits to the service at least once every 4 years. The QA process monitors procedural and outcome measurements, comparing performance to national quality specifications, and to national outcome statistics. The QA team also aims to recognise and disseminate good practice. Ultimately the purpose of the QA process is to identify potential problems early so that they can be resolved before women come to harm.

Large scale ‘look back’ exercises when mistakes emerge are very damaging to morale within the service and to uptake of screening by women, for whom there is often considerable distress. The greatest success of the QA process is that since this was fully established in 1996/1967, these enquiries have largely been avoided. Key outcome measures reviewed by the QA process are summarised in Table 22.1.

Table 22.1 Outcome measures in cervical screening quality assurance

In conclusion, the NHSCSP is a process which is specified in detail⁹ and fully quality assured. It is a national, lifelong process for women, interlinking all disciplines with fail-safe processes at every stage where intervention is required.

Cervical screening is a screening test and therefore cannot and does not prevent all cases of cervical cancer. This inevitably leads to the possibility of women or their families taking legal action for perceived failure to prevent the adverse effects of cervical cancer in cases where the system has not protected a patient adequately. These adverse effects range from loss of fertility, to postoperative morbidity and of course sometimes to death.

In the UK there are a significant number of such cases involving cervical screening each year, although the exact number is not published. The vast majority are either dropped or a settlement is reached out of court; very few have reached trial, when the details become public.

In the past, legal attention has focused on cytology laboratories but, increasingly, all parts of the programme are coming under review. It is highly likely that issues such as failure to invite women, failure to act on non-responder notifications, fail-safe failures and inadequate treatment at colposcopy could for example be the basis for litigation.

The legal principle used in the UK in many such cases is the Bolam test, which states that a course of action is not negligent if it would have been followed by a substantial body of responsible medical opinion at the time. Unfortunately, the Bolam test has proved difficult to apply to cervical cytology on those occasions where a sample reported as negative is found on review to contain abnormal cells. Although it has to be accepted that all competent screeners will occasionally miss an abnormality, this has not proved to be an acceptable defence and such cases nearly always lead to a settlement.

Since 2007, all cases of cervical cancer diagnosed in England have been subjected to a full audit, including review of the previous cytology, the histology, colposcopy and recall history. Results of this audit are offered to women. It is unclear at the time of writing whether this will result in an increase in litigation.

The NHSCSP is reputed to be one of the best screening programmes in the world but it was not the first, and is not the only successful programme. In terms of international comparison, however, the NHSCSP does have several distinguishing features.

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