Update on the Papanicolaou smear: new issues for the 1990s

The Papanicolaou (Pap) smear is a complex examination that has undergone refinement in recent years. It is now widely accepted that a false-negative rate of perhaps 10 to 20% is inevitable for a variety of reasons. The diagnosis of "atypical cells of undetermined significance" is not a benign diagnosis and is often followed by a more severe lesion on follow-up. The Pap smear appears to be an inefficient method for detecting glandular neoplasms, and clinical features remain the most important diagnostic clue. A Pap smear and cervical biopsy should correlate in 75% or more of cases. In cases of noncorrelation, a positive Pap smear diagnosis is supported in the vast majority of cases.

Atypical squamous cells of undetermined significance. Current laboratory practices of participants in the College of American Pathologists Interlaboratory. Comparison Program in Cervicovaginal Cytology

OBJECTIVE

To evaluate current laboratory practices and rates for atypical squamous cells of undetermined significance (ASCUS), a category of epithelial cell abnormality in the Bethesda System.

DESIGN

Questionnaire surveys were mailed in December 1993 and March 1994.

SETTING

Cytopathology laboratory participants in the College of American Pathologists Interlaboratory Comparison Program in Cervicovaginal Cytology (PAP).

RESULTS

Most responding laboratories (82.5%) limited the use of "atypia" terminology to abnormalities of undetermined significance. Nearly half of the laboratories employed only the term ASCUS for squamous epithelial changes in this category. The median rate of ASCUS in 1993 was 2.8%, with 10% of laboratories reporting rates greater than 9.0%. The median squamous intraepithelial lesion rate was 2.0%, with a median ASCUS-squamous intraepithelial lesion ratio of 1.3. The majority of laboratories qualified a portion of ASCUS cases and issued recommendations for follow-up when appropriate. Fifty-six percent of laboratories surveyed included patients diagnosed with ASCUS in follow-up programs. Laboratories estimated that about 20% (median response) of patients with ASCUS smears had a squamous intraepithelial lesion or equivalent diagnosis made within a year's follow-up.

CONCLUSIONS

The ASCUS category is used by the majority of laboratories as recommended by the Bethesda System, but reporting rates vary. The results of this survey and associated surveys provide laboratories with useful benchmark figures for interlaboratory comparison of ASCUS practices.

Trends in mammography and Pap smear utilization in Canada

We have examined trends in the utilization of two preventive health procedures for women in Canada based on our analysis of the 1994 National Population Health Survey (NPHS) and comparisons with two previous large population health surveys. The NPHS provides evidence that Canadian women's use of mammography has continued to increase between 1990 and 1994, while use of Pap smears has remained steady. Increases in mammographic utilization are seen for all age groups and in all provinces of Canada. Women who are less than the recommended age of 50-69 years for screening mammography access these services in considerable numbers. Large proportions of women aged 18-24 and 65 or over have never had a Pap smear, and recency of Pap smear is associated with age. Income adequacy and educational attainment are still strong predictors of which women utilize Pap smears and mammograms. We conclude that the NPHS is sufficiently broad-based to be used in a surveillance program to track Pap smear and mammography utilization.

Have the most recent Pap smear guidelines affected GP practices?

OBJECTIVE

To assess the attitudes and knowledge of a sample of NSW general practitioners on issues concerning Papanicolaou (Pap) smear tests after the 1991 National Guidelines were established.

DESIGN

During January-March 1994, a sample of Sydney general practitioners obtained from a list from the Department of General Practice, Royal North Shore Hospital, were asked to complete a questionnaire based on Pap smear screening. Issues explored included the perceived value of Pap smears, views on recommended screening intervals and the type of patients believed to be at highest risk of developing cervical cancer.

SETTING

Northern Sydney metropolitan area.

RESULTS

Seventy of 104 general practitioners from the Department of General Practice, Royal North Shore Hospital, returned completed questionnaires. Ninety-five per cent of respondents rated the Pap-smear as an extremely valuable screening test for cervical cancer prevention. The majority of GPs surveyed tended to overscreen younger patients and underscreen both older women and those at highest risk of developing cervical cancer. Seventy-seven per cent of doctors indicated the use of a patient reminder system, in most cases provided by a pathology laboratory but 43% were unaware of the NSW Cancer Council's reminder service.

CONCLUSION

Our study suggests that Pap smears are viewed as an important means of cervical cancer prevention. Unfortunately the majority of respondents did not adhere to the recommended guidelines of 2-yearly screening. Possible changes to the current system include improved awareness of the 1991 National Guidelines, greater public awareness of the NSW Cancer Council reminder service, and the establishment of a state cytology registry.

Has the use of cervical, breast, and colorectal cancer screening increased in the United States?

This report describes trends in reported breast, cervical, and colorectal cancer screening within the US population from 1987 to 1992. Data from the 1987 and 1992 Cancer Control Supplements of the National Health Interview Survey were analyzed to determine use of Pap smears by women aged 18+; of mammography and clinical breast examination by women aged 50+; and of proctoscopy, digital rectal examination, and fecal occult blood testing among men and women aged 50+. Use of mammography doubled between 1987 and 1992 while Pap smear use changed very little. Use of the three colorectal cancer screening modalities increased but levels remained low. Usage trends were also assessed in relation to several sociodemographic factors. Disparities in screening reported in 1987 according to income and education persisted in 1992.

Family doctors and change in practice strategy since 1986

OBJECTIVES

To investigate the changes in practice strategy that have taken place since 1986.

DESIGN

Comparison of practices in 1986 and 1992.

SETTING

93% of group practices (26 practices) in a single family health services authority.

MAIN OUTCOME MEASURES

Changes in staffing, premises, equipment, clinic services, and incomes between 1986 and 1992.

RESULTS

In 1986, 28% of practices employed a nurse; in 1992, 92% did so. Between 1986 and 1992, 14 cost-rent schemes costing more than 10,000 pounds had been started. Certain practices, designated innovators, were more likely to possess specified items of equipment than other practices. Computer ownership was widespread: 77% of practices had a computer, compared with 36% in 1986. In 1992, 16 practices had a manager, compared with 10 in 1986. Clinic services provided by more than half of practices were well established services (antenatal, for example), new services for which a payment had been introduced (such as diabetes, asthma, minor surgery), or the more readily provided "new" clinic services (diet, smoking cessation). Gross income increased, but so did practice costs, especially for innovators. Practices in the more affluent area of the family health services authority were still more likely to invest in their premises and staff, and to provide more services than those in the declining area. In the more affluent area, practices had higher costs but also higher incomes.

CONCLUSION

Between 1986 and 1992, practices in this area invested heavily in equipment and services, but differences remain, depending on the location of the practice. Investment has increased, particularly in the more deprived part of the area, so that the inconsistency in standards has been much reduced. Practice incomes have risen, but so also have workload and costs.

Towards a rational cervical cytology screening strategy. Case study of a peri-urban settlement

OBJECTIVES

To assess cervical cytology screening activity in a peri-urban settlement near Cape Town, with a view to informing rational policy development.

METHOD

Total and age-specific prevalence rates of women who had been screened, relative prevalence by age group of women who had not been screened, and yield of screening were estimated from cytopathology laboratory records and available demographic data. Age-specific prevalence rates among women who had been screened were compared with age at presentation with cervical cancer at the referral hospital. Attendance for colposcopy follow-up was assessed from colposcopy clinic records.

RESULTS

The number of smears taken and the prevalence of women who had been screened peaked in the 20 - 24-year age group, and declined to low levels in those over the age of 40 years. The relative prevalence of those who had not had a smear exceeded 9 in all age groups over 39 years, compared with women of 20 - 24 years. Smears which showed signs of CIN III, malignancy or possible malignancy comprised 0.13%. Thirty-six per cent of women booked for colposcopy did not attend.

CONCLUSIONS

Efficiency of screening could be improved by emphasising coverage of higher-risk age groups, e.g. women over the age of 30 years, and better follow-up.

[The age for beginning and the frequency for performing the Pap test]

The increase in sexual activity among teenagers has been well documented. One apparent result is the increasing prevalence of cervical cytological abnormalities in this age group over the last 20 years. The adolescent cervix appears to be especially vulnerable to the initiation of carcinogenesis. Consequently, the significance of early age at first coitus is thought to be related to the biologic changes that occur in the cervix during puberty. Large epidemiologic studies have implicated sexuality as the initiator of a sequence of multistage events that destabilize the healthy cervix and culminate in cervical cancer. The median interval between age at first coitus and the development of CIN1 is 9 years, with a progressive 2.5 year increase for each degree of progression from CIN 1 through 3. Unfortunately, the precise mechanism by which that biologic variable, early age at first coitus, predisposes to CIN remains enigmatic. Nevertheless, there is no doubt that the earlier the age at first coitus, the higher the risk factor. Among virgins the incidence of cervical cancer is essentially zero. Among sexually active adolescent girl no cases of invasive carcinoma have been found, but carcinoma in situ had a prevalence rate of 2.6 per 1,000 15-19 years old, whereas cervical dysplasia ranges from 0.8 to 3.5% of screened sexually active teenagers populations. Adolescents who have never been sexually active clearly do not need to be screened for cervical cancer. On the contrary teenagers with the risk factors of sexually transmitted disease or multiple sex partners should be annually screened soon after onset of sexual activity.(ABSTRACT TRUNCATED AT 250 WORDS)

Cervical cancer screening in Western Australia in 1992: progress since 1983

OBJECTIVES

To estimate the rate of cervical cancer screening in Western Australia in 1992, and any variation by age, place of residence, and socio-economic status; and to determine the proportion of smears taken by different service providers.

DESIGN

Descriptive study; collection of data from Papanicolaou (Pap) smear request forms during one calendar month.

SETTING

All 13 cytology laboratories in Western Australia.

PARTICIPANTS

15,767 women in Western Australia aged 15 years and over having a cervical smear in March 1992.

MAIN OUTCOME MEASURES

Rates by age of cervical cancer screening per 1000 woman-years; age-standardised rate ratios for socioeconomic status and place of residence; proportion of smears taken by male and female service providers.

RESULTS

The estimated rate of Pap smears at ages 15 years and over was 303 smears per 1000 woman-years, an increase of 44% over a similar survey in 1983. The greatest increases were among women aged 50 years and over, but their rates were still well below that equivalent to three-yearly smears. Differences in the rate of screening by socioeconomic status (defined by residential postcode) were not statistically significant. The age-standardised rate ratio comparing country women with women in the Perth metropolitan area was 0.91 (95% confidence interval 0.87-0.94). General practitioners took 78% of the smears, and at least 46% of all smears were taken by female service providers. Almost all the increase in the screening rate since 1983 could be attributed to an increase in the rate of smears per 1000 woman-years taken by female general practitioners.

CONCLUSION

While there have been marked improvements in the rates of cervical screening in Western Australia over the past nine years, there are still major deficiencies in the screening coverage of women aged 50 years and over.

Predictors of abnormal cervical cytology: statistical analysis of human papillomavirus and cofactors

Reported increases in the incidence of human papillomavirus infection have generated speculation that cervical cytological abnormalities may also be increasing. A 10-year retrospective study of cervical cytology in 2,919 college women demonstrated a significant increase in the frequency and severity of cervical-cytological abnormalities (p - 0.0001). The peak year for abnormal cervical cytology coincided with the peak year for overt human papillomavirus infection. Women with papillomarivus, genital herpes and who were also smokers had mean cervical-cytology scores significantly worse than those with none of these risk factors (p - 0.00001). A stepwise regression analysis of abnormal cytology from recorded risk factors accounted for only 10 percent of the variance, with human papillomavirus accounting for 8 percent of the total. If human papillomavirus is indeed responsibile for the majority of abnormalities, this infection is not detected reliably through routine examination and cervical-cytology screening [corrected].

Cervical cancer screening: a comparison of recruitment strategies among older women

OBJECTIVE

To compare the effectiveness of different recruitment strategies in encouraging older women to have a Papanicolaou (Pap) test.

DESIGN

A 2 x 2 factorial study.

SETTING

Two rural areas of Victoria, Australia.

PARTICIPANTS

A total of 10,620 persons aged between 40 and 69 years and designated as female on electoral lists.

INTERVENTIONS

A personal letter of invitation and a community-based campaign of 4 weeks' duration alone and in combination. A control group received no active intervention.

OUTCOME MEASURE

The proportion of eligible women having a Pap test report issued by the Victorian Cytology Service during the 12 weeks after the intervention compared with the 12 weeks before the intervention, with an intervening two-week washout period.

RESULTS

The odds ratio of an eligible woman being screened during the intervention period relative to the pre-intervention period was 3.00 for women who were exposed to the campaign and sent the letter of invitation (95% confidence interval, 2.38-3.77, P less than 0.001), 1.86 for women who were exposed to the campaign (95% confidence interval, 1.49-2.33, P less than 0.001), 1.61 for women who were sent the letter of invitation (95% confidence interval, 1.34-1.92, P less than 0.001). The baseline was a control group who received no active intervention.

CONCLUSIONS

Both personal invitation letters and community-based campaigns are effective in recruiting women for Pap test screening. Combined strategies are more effective than single strategies.

The Pap smear revisited. Controversies and recent developments

Despite the widespread acceptance of the Pap smear as an effective means to reduce morbidity and mortality due to cervical carcinoma, many experts now recommend less frequent screening for women with a negative cytologic history and factors carrying a low degree of risk. This view has been countered by those who feel that less frequent screening may result in a dangerous delay in diagnosis and treatment for some women. The trend toward a longer screening interval places a burden on the primary care physician, the pathologist, and cytotechnologists to minimize false-negative smears through optimum communication, technical preparation, and quality control. In addition to the changes in thinking regarding frequency of Pap smear screening, the concept of cervical carcinogenesis is undergoing striking modification. The human papillomavirus has been associated with many lesions that have classically been considered low-grade dysplasias. Termed flat condylomas, these lesions frequently regress spontaneously but may be associated with the full spectrum of preinvasive and invasive disease. Cervical condylomas require biopsy and appropriate treatment.