Effect of organized screening on the risk of cervical cancer. Evaluation of screening activity in Iceland, 1964-1991

Assessing the evidence for organised cancer screening programmes

The aim of this study was to review the evidence in the literature for organised cancer screening programmes. A Medline search for publications related to organised cancer screening programmes and their components was done. While there is a broad descriptive literature on various cancer screening programmes, there are few published studies that evaluate the impact of organised cancer screening. Most of the evidence to date is from Scandinavian cervical and breast cancer screening programmes. There is a moderate amount of literature that evaluates specific components of cancer screening programmes (such as quality control and recruitment). There is a substantial body of literature on organised cancer screening programmes. However, the studies tend to describe organised screening programmes rather than evaluate their effectiveness relative to opportunistic screening. Furthermore, most studies focus on individual components of organised screening programmes, rather than on the programmes as a whole. More research is needed that directly compares organised with opportunistic cancer screening.

HPV subtypes and immunological parameters of cervical cancer in Iceland during two time periods, 1958-1960 and 1995-1996

OBJECTIVE

Cervical cancer is a disease caused in part by an infection with an oncogenic subtype of human papillomavirus (HPV). In this study we analysed all cervical cancer samples diagnosed in Iceland during two periods, 1958-1960 and 1995-1996, and asked whether significant changes in viral or immunological parameters had occurred over a period that spanned both significant changes in sexual attitude and the implementation of organized screening for cervical cancer.

METHODS

Samples from 47 patients (46 squamous cell carcinomas (SCC) and 1 adenosquamous carcinoma (ASC)) in the first period and 30 patients (20 SCC, 4 ASC, and 6 adenocarcinomas (AC)) in the later period were analysed for viral subtype and expression of Fas, FasL, MHC class I, p53 and apoptosis.

RESULTS

AC and ASC are proportionately much more common today than 40 years ago (30% vs 2%). The distribution of HPV in cervical cancer is similar in both periods, with HPV16 found in 75% and HPV18 in 13% of cases. Other HPV types found were 31,33,45, and 59. No significant differences were found in the immunological profiles of tumors from the two periods except that a higher fraction of SCC in the later period stained positive for FasL. When SCC are compared with AC/ASC, the latter have less expression of MHC class I, less expression of Fas, and stronger FasL expression.

CONCLUSIONS

AC/ASC tumors show some immunological features that suggest that they are more resistant to immune attack than SCC.

Metaanalysis of the accuracy of rapid prescreening relative to full screening of pap smears

BACKGROUND

Efficient quality assurance and improvement measures are essential ingredients in a well organized cytology-based program for cervical carcinoma screening. Various pap smear review procedures, aiming for optimization of accuracy, are described throughout the literature. Evaluation and synthesis of those methods are needed. In a previous study, we pooled data on the diagnostic quality of rapid reviewing (RR) of cervical smears initially reported as normal or unsatisfactory. We now focus on rapid prescreening (RPS) of unreported smears.

METHODS

Six published studies on the accuracy of RPS relative to subsequent full screening were pooled using metaanalytic methods. Individual and pooled sensitivity, specificity, and predictive values were assessed using forest plots. Random effect pooling methods were used for interstudy heterogeneity. Variation in sensitivity according to influencing factors was explored by metaregression.

RESULTS

The pooled average sensitivity of RPS was 64.9% (95% confidence interval [CI] 50.7-79.1%) for all abnormalities, 72.6% (95% CI 60.6-85.2%) for low-grade lesions or more severe, and 85.7% (95% CI 77.8-93.6%) for high-grade lesions or more severe. The pooled specificity was estimated at 96.8% (CI 95.8-97.8%). The sensitivity increased significantly with duration of screening and decreased with workload. Almost 3% of all abnormal slides were detected only by RPS (2.8%; CI 0.0-5.8%). This is comparable to the proportion of false-negative smears detectable by RR.

CONCLUSIONS

Rapid prescreening has a high yield for severe dysplasia and shows diagnostic properties that support its use as a quality control procedure in cytologic laboratories. We showed previously that RR is superior to full reviewing of a 10% random sample of negative slides (10% FR). Because the yield of additional abnormalities found by RR and RPS is comparable, we expect RPS to be more efficient than 10% FR as well.

Primary prevention of uterine cervix cancer: focus on vaccine history and current strategy

Primary prevention of uterine cervix cancer spans the gamut of human papillomavirus vaccine development, dietary adjustment, chemoprevention, and risk reduction. Lifestyle and social behaviors impact on risk for cervical cancer. Before examining the growing body of molecular evidence, animal studies, and phase I clinical trials that suggest that a virus-based vaccine for cervical cancer may soon become a reality, one must reflect on what has gone before in the vaccine-based battle with viral disease.

Effects of screening on cervical cancer incidence and mortality in New South Wales implied by influences of period of diagnosis and birth cohort

STUDY OBJECTIVES

Cervical cancer incidence and mortality in NSW during 1972-1996 is examined under counterfactual assumptions to estimate the number of new cervical cancer cases averted and deaths avoided, with projections to 2006.

SETTING

Cervical cancer incident cases and deaths in NSW for 1972-96 were obtained from the NSW Central Cancer Registry, Sydney, Australia.

DESIGN

Data were analysed by age-period-cohort (APC) modelling, using Poisson regression. Projection of incidence to 2006 was based on a linear trend for period effects. A counterfactual scenario was constructed assuming stable period effects (1972-74), but modelled cohort effects. Modelled rates were converted to cases and deaths (using mortality:incidence ratios for cervical cancer), and compared with actual data to estimate cancers prevented and deaths averted due to screening.

RESULTS

Rising cohort effects with recency of birth were found after controlling for age and period of diagnosis, and declining period effects were identified after controlling for age and birth cohort. The estimated cumulated number of new cases of cervical cancer prevented during 1972-1996 was 3440. The cumulated number of averted deaths over 1972-1996, derived from incident cases, was estimated to be 1610 (including actual declines in the M/I ratio). With no change in the M/I ratio from 1972, estimated cumulated mortality averted due to cervical cancer for 1972-1996 was 1210 deaths.

CONCLUSIONS

Cervical screening has prevented a substantial number of new cases of cervical cancer and deaths. In addition, secondary prevention and improved treatment has contributed further to cervical cancer deaths averted.

Clinical studies of human papilloma vaccines in pre-invasive and invasive cancer

Cervical cancer is the second most common cause of cancer death in women worldwide. It is almost invariably associated with infection with human papilloma virus (HPV) particularly types 16 and 18. The ubiquitous expression of E6 and E7 oncogene products has been recognised as an attractive target for CTL-mediated immunotherapy. In-vivo expansion of an HPV oncogene product specific MHC class 1 restricted response has been demonstrated using intradermally administered live vaccinia virus HPV 16 and 18 E6/E7 gene construct (TA-HPV, Cantab Pharmaceuticals). Responses have been seen in 1/3 evaluable patients with advanced cervical cancer, and 3/12 CIN3 volunteers, and in 4/29 patients with early invasive cervical cancer (Rankin et al. Proceedings of 91st AACR Meeting, San Francisco, April 2000). In addition, the adoptive transfer of ex vivo HPV 16 or 18 positive autologous tumour lysate pulsed dendritic cells is currently being tested as an alternative means of expanding HPV specific CTL in advanced cervical cancer patients. So far an HLA-A*O201 restricted CD8 T cell response has been recorded in the single HLA-A*O201 patient whose tumour was shown to be HPV16 positive. It appears therefore feasible to induce HPV specific CTL responses in patients with cervical cancer using several vaccine strategies. However, further clinical trials are needed to determine the full anti-tumour potential of this vaccine based immunotherapy.

Cancer screening in the elderly population

This article reviews the current state of knowledge regarding cancer screening in the geriatric population. Care of the elderly requires knowledge of underlying physiologic changes, comorbidities, quality-of-life factors, and life expectancies. There is always the danger that ageism may prevent elderly cancer patients from receiving the proper treatment. On the other hand, overzealous treatment can lead to adverse results if elderly patients are not properly targeted based on current evidence of the benefits and risks of specific screening practices.

Attendance to cervical cancer screening in family practices in The Netherlands

BACKGROUND

The effectiveness of three different organizational approaches to cervical cancer screening (community based, family practice based, and a combination) was evaluated in nationally representative family practices.

METHOD

We selected 122 family practices with a computerized sex-age register from a database of 1, 251 family practices, representative of all 4,758 family practices in The Netherlands. Approximately 40 practices were linked with each approach. We measured the attendance, the reasons for nonattendance, and the influence of a reminder on the attendance of women invited for cervical screening in September, October, and November 1996. The patients were grouped according to age. A cross-sectional design was used for the study.

RESULTS

For younger women, the total attendance rate, coverage (percentage of women "protected" against cervical cancer), and control rate (percentage of women with medical reasons for nonattendance or postponement of the smear) were highest in practices using the family practice-based approach (68, 77, and 90%, respectively) and lowest in practices with the community-based approach (53, 62, and 68%, respectively). For older women, the family practice-based approach and the combination approach were associated with attendance rates significantly higher than those for the community-based approach (approximately 60, 80, and 80% vs 47, 67, and 70%, respectively). A reminder sent by the family physician to women not responding to an initial invitation increased the attendance rate by 7 to 11% in both age categories, depending on who had sent the first invitation.

CONCLUSION

A family practice-based cervical screening approach appeared to be the most effective at a national level, achieving the highest attendance rate, coverage, and control rate.

Screening for gynecologic cancer

Screening for cervical cancer with the Pap test has significantly reduced mortality from the disease. Although screening for ovarian and endometrial cancer is desirable, suggested strategies have not demonstrated efficacy. For the present time, educating patients with regard to the symptoms associated with these diseases and prompt evaluation of women who present with these symptoms helps limit unnecessary diagnostic delay.

Trends in cancer of the cervix uteri in Sweden following cytological screening

Trends in cervical cancer incidence following the introduction of screening have mostly been studied using cross-sectional data and not analysed separately for squamous cell cancer and adenocarcinomas. Using Swedish nationwide data on incidence and mortality, we analysed trends during more than 3 decades and fitted Poisson-based age-period-cohort models, and also investigated whether screening has reduced the incidence of adenocarcinomas of the cervix. The incidence of reported cancer in situ increased rapidly during 1958-1967. Incidence rates of squamous cell cancer, fairly stable before 1968, decreased thereafter by 4-6% yearly in women aged 40-64, with a much smaller magnitude in younger and older women. An age-cohort model indicated a stable 70-75% reduction in incidence for women born 1940 and later compared with those born around 1923. The incidence of adenocarcinomas doubled during the 35-year study period. The mortality rate increased by 3.6% before 1968 and decreased by 4.0% yearly thereafter. Although a combination of organized and opportunistic screening can reduce the incidence of squamous cell cancer substantially, the incidence of adenocarcinomas appears uninfluenced by screening.

Survival and prognostic factors of endometrial cancer patients in Iceland 1964-1985: can attendance at population-based Pap-smear screening affect survival?

After histological review of all cases registered during the period 1964-1985 at the Cancer Registry, 260 cases with endometrial carcinoma were eligible for analyses of survival rates and prognostic factors, as well as the association of Pap-smear screening attendance with these factors and survival. The total age-adjusted 5- and 10-year relative survival rates were 76% and 75%, respectively. The prognostic factors were tested by univariate analysis and simultaneously by a multivariate analysis using the Cox proportional hazards model. Factors that independently gave a less favorable prognosis were non-attendance at screening, older age at diagnosis, deep myometrial invasion, advancing stages and tumor grading, radiotherapy only, extra-genital symptoms and histology types of serous, clear cell and undifferentiated tumors (histologic type 3). Tested simultaneously with the Cox proportional hazards model, parameters that maintained a less favourable prognosis were grade 3, stage III-IV, deep myometrial invasion, older age, radiotherapy only and extra-genital symptoms. In addition, screening attendance showed significant interaction with age. In stages III and IV only grade 3 maintained a significantly less favorable prognosis. We conclude that our results indicate that attendance at Pap-smear screening (taking Pap smears and screening for genital symptoms) has a favorable prognostic value, especially among women under the age of 62.

Human papillomavirus (HPV) in an Icelandic population: the role of HPV DNA testing based on hybrid capture and PCR assays among women with screen-detected abnormal Pap smears

This study was based on 358 cases with abnormal smears referred for colposcopy and HPV DNA testing. We analysed: 1) the frequency of different grades of cyto- and histopathologic findings; 2) the frequency and relative amount of HPV DNA with the hybrid capture assay (HCA) in swabs, and the frequency of HPV with PCR in swabs (-S) and biopsies (-B); and 3) the frequency of HPV types according to the grade of the cyto- and histopathologic findings. Of all cases, 95% were positive with all HPV tests combined. The HCA (HPV: 16, 18, 31, 33, 35, 45, 51, 52 and 56) and the PCR-S and PCR-B (HPV: 16, 18, 31, 33 and 35) tests for high-risk HPV exhibited sensitivities of 57%, 56% and 48%, respectively. The high-grade smears and the high-risk PCR-S HPV had about 80% sensitivity for histologic high-grade lesions compared with around 70% for HCA and the PCR-B. Combining the high-grade smears and the high-risk HPV increased the sensitivity to 93-96%. Among the cervical intraepithelial neoplasia I (CIN I) and the atypical squamous cells of undetermined significance (ASCUS) smears the sensitivity of high-risk HPV for high-grade histologic lesions was 63% for the HCA and 79% for the PCR-S. No correlation was found between the relative amount of HPV DNA detected by HCA and the grade of cyto- and histological lesions. We conclude that the results strongly indicate that HCA is less sensitive than PCR in the diagnosis of high-risk HPV, that swabs are more sensitive than biopsies as a sampling method, that high-risk HPV and high-grade smears are complementary for the diagnosis of high-grade histologic lesions and that the present role of HPV testing in screening could be limited to identifying women with low-grade smears and koilocytotic or low-grade colposcopic biopsies that are at risk of concealing or developing high-grade histologic lesions.

Comparison of Fourier-transform infrared spectroscopic screening of exfoliated cervical cells with standard Papanicolaou screening

To compare Fourier-transform infrared (FTIR) spectroscopy in screening cervical cytology and standard Papanicolaou (Pap) screening with colposcopic directed biopsy as a "gold standard," we prospectively gathered FTIR samples and Pap smears of all patients attending our program's colposcopy clinics, from February to October 1995. We recorded demographic data for each patient including colposcopy, cytology, treatment follow-up, and histology. Using the colposcopically directed biopsy as the gold standard, exfoliated cervical cells from 301 patients were collected to compare cytology and FTIR spectroscopy. Based on previously established criteria, we provided distinctive definitions of both negative/positive FTIR, cytology, and histology. Results of 301 cases showed 196 positive and 105 negative cytologies. The sensitivity, specificity, false-negative rate, and false-positive rate for the Pap test were 86.6, 90.5, 13.4, and 9.5%, respectively. However, FTIR results versus histology showed 215 positive and 86 negative with a sensitivity of 98.6% and specificity of 98.8%. False-negative and false-positive rates were 1.4 and 1.2%, respectively. In the 12 cervical cancers there were no false-negative FTIR results but 3 false-negative Pap smears. The positive and negative predictive values for FTIR were 99.5 and 96.5% while the Pap values were 95.9 and 72.3%. Compared to standard Pap smears, FTIR has a better false-negative rate and negative predictive value in this preliminary study. Further work, to establish the range of each of the spectral criteria for different grades of dysplasia and that among various infectious effects, needs to be conducted before applying this research tool to a population-based study.

Impact of cancer screening on women's health

Worldwide, 31% of cancers in women are in the breast or uterine cervix. Prevention of cervical cancer is effective with the use of the cervical Pap smear test if applied in an organized and continuous fashion, including treatment of precancerous lesions. At best such programs have led to a 60% decrease in cervical cancer incidence and mortality in the Nordic countries. Early detection of breast cancer in a population based screening may lead to a 30% reduction of mortality from this disease in the screened population. Measures to guarantee high coverage and attendance, adequate field facilities, organized program for quality control and adequate facilities for diagnosis and treatment are prerequisites of successful programs. In absolute terms the contribution of screening to the total mortality reduction among middle-aged populations is small, much smaller than the potential gains from cancer prevention.

Effects and sustainability of a cervical screening program in remote Aboriginal Australia

We assessed the effects of an organised cervical screening program, using a population-based cervical cytology register, for Aboriginal women in the Fitzroy Valley, a remote part of the Kimberley region of Western Australia. Comparison of age-specific screening rates in the area during 1987-88, 1990-92 and 1993-94 showed that establishing the program in late 1989 was accompanied by dramatic increases in cervical screening rates, ranging from two- to over fourfold, with the largest increases in women aged 50 years and over. Following the departure of the coordinator in early 1993, screening rates decreased to between 76 per cent and 29 per cent of their 1990-92 levels, with the largest decreases occurring in the 40-49 and 60-69 years age groups. Rates were still above 1987-88 levels for most age groups. Of 545 women screened during 1991-92, 65 per cent had undergone a second Pap smear within the follow-up period of two to four years. Among women recommended for a repeat smear in two years, the probability of having a second smear was negatively associated with age (log-rank statistic = 35.58, 4 df, P < 0.0001). Follow-up of smears recommended for repeat in 12 months or earlier was less adequate in 1993-94 (46 per cent) than in 1991-92 (75 per cent). The program was successful in recruiting a large proportion of eligible women within a relatively short time, but coverage, especially of older women, was not sustained after a decline in the functioning of the recall system owing to staffing and organisational changes.

Oral contraceptive use at a young age and the risk of breast cancer: an Icelandic, population-based cohort study of the effect of birth year

The possible association between breast cancer and oral contraceptive use before the age of 20 was investigated using Icelandic population-based information from women born after 1944. The design was a nested case-control study within a cohort, using data on duration of oral contraceptive use at young ages. The availability of oral contraceptives before the age of 20 has changed dramatically and is highly dependent on birth years, with 20% and 82% starting before the age of 20 among Icelandic users born in 1945-47 and 1963-67 respectively. The association between total duration of oral contraceptive use and breast cancer was significantly dependent on year of birth. In women born in 1951-67 (based on 81 cases), the relative risk (RR) associated with use for more than 4 years was 2.0 (95% CI 1.1-3.7). The association disappeared when women born in 1945-50 were included (RR 1.1,95% CI 0.8-1.6), adding 123 cases. A significant trend of increased risk with longer duration was present only in the group born after 1950, with RR 0.9, 1.7 and 3.0 for < or = 4 years, >4-8 years and > 8 years of use respectively. The results of this study indicate an association between breast cancer and oral contraceptive use at a young age. They also stress the importance of distinguishing between groups with different opportunities for exposure at young age.

What attendance rate can be achieved for Pap smear screening? A case-control study of the characteristics of non-attenders and results of reminder efforts

OBJECTIVE

To understand participation failures in a national Pap smear screening programme by studying characteristics of non-attenders and results of further reminder efforts.

DESIGN

A case-control and an intervention study.

SETTING

The community health centre in the town of Hafnarfjördur, Iceland.

SUBJECTS

The target population comprised 2510 women aged 35-69, who were invited regularly every second year for cervical cancer screening.

MAIN RESULTS

2241 (89.3%) had attended screening during the preceding five years, 102 (4.1%) had never attended, and 167 (6.7%) had attended previously but not during the preceding five years. Women with a mental disorder and those who had never married were more likely not to attend. The most usual explanations given by non-attenders were that they did not like to participate, or they felt they did not need to, some of them because their uterus had been removed. Of the non-attenders 29 (10.8%) came for a Pap smear after repeated reminding efforts.

CONCLUSIONS

Total participation rate in cervical cancer screening programmes in Iceland is high. When efforts are taken to lower the non-attendance rate it has to be kept in mind that many women are unwilling or unable to participate in such preventive measures.

The fall in incidence of prostate carcinoma. On the down side of a prostate specific antigen induced peak in incidence--data from the Utah Cancer Registry

BACKGROUND

In the 1980s, prostate specific antigen (PSA) came into wide use as a prostate carcinoma screening and detection method in the United States. Following the introduction of PSA, the age-adjusted incidence of prostate carcinoma reported by the Surveillance, Epidemiology, and End Results (SEER) program in the United States rose rapidly (from 84.4/100,000 in 1984 to 163/100,000 in 1991). When an increase in incidence is observed following the introduction of a screening method, a subsequent decrease in incidence may be expected as prevalent cases are removed from the population (a cull effect). Incidence rates may also fall due to factors such as decreased intensity of screening. The Utah Cancer Registry data were examined for a decrease in prostate cancer incidence.

METHODS

We tracked age-adjusted prostate carcinoma incidence trends from the population-based Utah Cancer Registry and compared them with rates from the SEER national registry.

RESULTS

A rapid and highly correlated rise in prostate carcinoma incidence has been observed in both SEER and Utah incidence rates between 1988 and 1991, the last year for which SEER data are available. In 1992, Utah incidence rates peaked at 236.2 per 100,000. In 1993 and 1994, Utah incidence rates fell to 195.0, and an estimated 164.0 per 100,000, respectively.

CONCLUSIONS

Population-based data from the Utah Cancer Registry indicates that the incidence of prostate carcinoma is decreasing rapidly after a similarly rapid increase.

Screening for cervical neoplasia in Dundee and Angus: 10 years on

OBJECTIVE

To evaluate the effect of changed cervical screening policies on a steady population with low migratory tendencies.

DESIGN

A retrospective analysis study.

SETTING

Dundee and Angus, Scotland.

SUBJECTS

All women who developed cervical carcinoma between 1957 and 1992.

MAIN OUTCOME MEASURES

The incidence of and mortality from cervical cancer after the introduction of organised cervical screening in 1962, according to age, stage, histology and screening history.

RESULTS

The initial fall in incidence of cervical cancer seen in women between 35 and 54 years after the introduction of cervical screening was not sustained during the last 10 years of our study and appears to have been transferred to women aged 55 years and older instead. After 1976 an increase in the incidence of cervical cancer was seen in women under 35 years. The reduction in mortality from cervical cancer appears to have reached a plateau since 1976. No effect of cervical screening was seen on the incidence of adenocarcinoma of the cervix.

CONCLUSIONS

The effect of changed cervical screening policies has been shown for a small population for a period of 35 years. The incidence of the higher stages of squamous cervical cancer continues to fall. The increase in incidence of cervical cancer in women under 35 years confirms similar trends seen in other countries. A background mortality rate refractory to further intensification of screening appears to have been reached. Adenocarcinoma of the cervix appears to gain in importance as cervical screening policies are shown to have their effect on its squamous counterpart.

Quality assurance in cervical cancer screening: the Icelandic experience 1964-1993

Monitoring of the effectiveness of a screening programme is vital to ensure optimal use of public resources. This report correlates the results of the Icelandic cervical cancer screening programme with the results of monitoring the programme since 1964. Screening has significantly decreased both the incidence and mortality rates and greatly affected the stage distribution of squamous cell carcinomas, but not of adeno- and adenosquamous carcinomas. In the 25-64 years age group, 84% were screened, 80% of whom were in the organised screening. Smears taken outside the guidelines amounted to 10%. Sensitivity at 1 year was 93% for all smears. At 3 years it was 81% for squamous cell carcinomas, and 42% for adeno-and adenosquamous carcinomas. The rate of unsatisfactory smears was 1.3% for all smears, and 4.5% of the women had abnormal smears (7.7% in the 20-24 years age group). The specificity of the smears test was 98%. It is concluded that monitoring is vital for optimal screening results and although screening is effective in the targeted age group of 25-64 years it should preferably start sooner after age 20 years with a screening interval of 2-3 years.

Screening for ovarian, prostatic, and testicular cancers

Screening for cancer should not be offered routinely to a symptomatic people on a population basis unless it has been shown to be effective in reducing mortality in randomised controlled trials. A suitable screening test should have high sensitivity and specificity and a high positive predictive value. There is an ethical imperative to ensure that the benefit to each person from screening is likely to outweight the possible harm. Preliminary studies have identified suitable screening tests for ovarian cancer, and a randomised controlled trail is about to start. There is considerable controversy about whether to screen for prostatic cancer. Likewise, there is uncertainty about the best means of treating localised prostatic cancer. Screening for prostatic cancer raises important ethical considerations which should not be ignored. Testicular self examination is of unproved benefit. Although there is a need for education about the early signs and symptoms of testicular cancer to reduce delay at presentation, a case cannot be made for screening.

Cancer prevention in primary care. Screening for cervical cancer

Cervical screening has been shown to be effective in several countries, although not by means of randomised controlled trials. A screening programme has been in operation in the United Kingdom since 1964, but it has, in the past, been beset with problems of organisation, accountability, and commitment. The introduction in 1988 of a systematic call and recall introduction in 1988 of a systematic call and recall system and the setting up of an NHS cervical screening programme national coordinating network has brought a greater sense of coherence. Coverage of the target population in England between 1989-90 and 1992-3 increased from 61% to 83%, and there is a strong indication that cervical screening is now beginning to reach those most at risk--namely, older women from lower social classes. Primary care is central to the overall success of the cervical screening programme. General practitioners are in a unique position to invite women for a smear test, to take smears, to ensure that abnormal smear test results are followed up, and to check on reasons for non-attendance. Numerous studies have looked at the involvement of general practice in cervical screening, identifying many ways in which the programme can be improved. Many practices are now running well organised and effective programmes.