Experience with a thin-layer, liquid-based cervical cytologic screening method

OBJECTIVE

To assess the utility of a thin-layer cytology system for cervicovaginal screening in clinical practice.

STUDY DESIGN

Twenty-five hundred cervicovaginal split samples were processed with the traditional direct smearing method and with the ThinPrep Pap Test (Cytyc Corp., Boxborough, Massachusetts, U.S.A.) method and evaluated according to the Bethesda system, focusing mainly on the cytomorphologic features.

RESULTS

The ThinPrep Pap Test yielded improved specimen adequacy and an increased detection rate of squamous abnormalities, which resulted in a decrease in the ASCUS/SIL ratio. Moreover, the thin-layer system provided adequate material for concomitant HPV testing, mainly in the LSIL and the ASCUS favor SIL cases, with satisfactory results, as well as for cell block preparations in a few selected cases that presented diagnostic difficulties. Furthermore, the morphologic features of the LSIL cases were virtually identical on both preparations, while in the HSIL cases, distinct features were noted on ThinPrep.

CONCLUSION

The ThinPrep Pap Test is significantly more effective than the conventional smear in clinical practice. However, training and experience are necessary to take full advantage of this promising new technology.

Clonality analysis of archival cervical smears. Correlation of monoclonality with grade and clinical behavior of cervical intraepithelial neoplasia

OBJECTIVE

To establish a polymerase chain reaction (PCR)-based clonality assay for archival cervical smears and examine its value in the detection of cervical intraepithelial neoplasia (CIN) and prediction of its clinical behavior.

STUDY DESIGN

Dyskaryotic cells were microdissected from archival cervical smears of 33 cases and subjected to PCR-based clonality analysis of the androgen receptor gene. High-risk HPV subtypes were screened by PCR.

RESULTS

Monoclonal patterns were found in 9/9 CIN 3 and 15/21 CIN 2, while polyclonal patterns were observed in the remaining 6 CIN 2 and 3/3 CIN 1. All patients with monoclonal CIN lesions, including 15 CIN 2, showed recurrence of the disease despite treatment. The original CIN 2 and recurrent CIN lesion in each of the 6 examined cases showed the same monoclonal pattern, suggesting a clonal link. In contrast, the patients with polyclonal CIN 1 or 2 became negative and remained disease free. High-risk HPV subtypes were found in all monoclonal CIN lesions, including 9 CIN 3 and 15 CIN 2, and in 4/6 polyclonal CIN 2 but not in CIN 1 lesions.

CONCLUSION

Clonality analysis of cervical smears is potentially valuable in the identification of true neoplastic cells and prediction of clinical behavior of CIN 2 lesions.

Willingness to pay for new Papanicolaou test technologies

The amount of money a woman is willing to pay for liquid-based cytology technology has not been measured. In the present study, 175 women answered a questionnaire asking how much they would pay to decrease their risk of dying of cervical cancer if a new (liquid-based) Papanicolaou (Pap) test was used in place of the conventional smear. When women assumed that the new Pap test reduced the risk of dying of cervical cancer from 1 in 37,000 to 1 in 50,000, the mean amount they were willing to pay was $237. If women had more than 2 children, they were willing to pay more for the new Pap test than women with 2 or fewer children. These data indicate that liquid-based and conventional Pap tests are undervalued and that cost-effectiveness studies generally have not taken into account the preference of women for new Pap test technologies.

Progress in cancer screening over a decade: results of cancer screening from the 1987, 1992, and 1998 National Health Interview Surveys

BACKGROUND

Screening to detect cancer early, an increasingly important cancer control activity, cannot be effective unless it is widely used.

METHODS

Use of Pap smears, mammography, fecal occult blood tests (FOBTs), sigmoidoscopy, and digital rectal examination (DRE) was evaluated in the 1987, 1992, and 1998 National Health Interview Surveys. Levels and trends in screening use were examined by sex, age, and racial/ethnic group. The effects of income, educational level, and health care coverage were examined within age groups. Logistic regression analyses of 1998 data were used to develop a parsimonious, policy-relevant model.

RESULTS

Use of all screening modalities increased over the period examined; for mammography and DRE, the increase was more rapid in the first half of the decade; for the Pap test and sigmoidoscopy, the increase was more rapid in the second half of the decade. Levels of colorectal cancer screening (both sigmoidoscopy and FOBTs) in 1998 were less than the level that prevailed a decade earlier for mammography. Patterns of change for all screening modalities differed between age, sex, and racial/ethnic groups, but prevalence of use during the study, within recommended time intervals, was consistently lower among groups with lower income and less education. Logistic regression analyses indicated that insurance coverage and, to a greater extent, usual source of care had strong independent associations with screening usage when age, sex, racial/ethnic group, and educational level were taken into account.

CONCLUSIONS

While cancer screening is generally increasing in the United States, usage is relatively low for colorectal cancer screening and among groups that lack health insurance or a usual source of care.

Measurement of young women's attitudes about communication with providers regarding Papanicolaou smears

PURPOSE

To describe the psychometric properties of a scale created to measure communication with the provider regarding Papanicolaou (Pap) smears.

METHODS

A scale based on expectancy-value theory was developed and administered to 490 young women aged 12 to 24 years in an urban adolescent clinic. Psychometric properties were assessed using factor analysis to evaluate latent variables, intraclass correlation coefficient to evaluate test-retest reliability, and Cronbach coefficient alpha to evaluate internal consistency reliability. Content validity was assessed by qualitative interviews, feedback on a pilot survey, and expert review. Construct validity was evaluated by examining whether relevant health care characteristics, knowledge, and attitudes were significantly associated with perceived communication.

RESULTS

Mean respondent age was 18.2 +/- 2.1 years; 50% were black and 22% Hispanic. The scale items loaded on one factor. The intraclass correlation coefficient was 0.83 and Cronbach alpha 0.95. Report of a consistent provider, report that a provider recommended a Pap smear, knowledge of Pap smears and Human Papillomavirus (HPV), intention to return for follow-up Pap smears, and positive attitudes about Pap follow-up were significantly associated with good communication.

CONCLUSIONS

The scale appears to be reliable and valid as a measure of young women's communication with providers regarding Pap smears. Future research should focus on whether this newly developed scale is useful in the design and evaluation of cervical cancer prevention programs for young women.

Rapid rescreen: a viable alternative to 1:10?

A rapid screen of those Pap smears designated as within normal limits is a quality control requirement of all UK laboratories. However in the United States standard QC involves a combination of 1:10 and selective rescreening procedures. Forty participants at the joint ASCT/ACP meeting in Las Vegas rapid screened 50 slides as part of a rapid screening workshop. They used different patterns of screening but were allowed only 60 seconds for each slide. Thirty of the slides contained abnormal cells but all had originally been called negative or unsatisfactory and as such were "false negatives". Ability to identify the abnormal smears varied considerably between individuals but overall rapid screening correctly identified 54% of the ascus or LGSIL cases and 61% of the HGSIL cases. The results demonstrate the superiority of such a rapid screen over 1:10 and question what if any role this outdated practice should have.

New technologies in gynecologic cytology

New technologies are trying to make significant changes in the way we perform the Pap smear test, a test that has undergone no significant modification since its inception. Efforts have focused on improving sampling with liquid-based methods, improving detection of abnormal cells with automated screening and improving the detection of human papillomavirus with assays practical for use in routine clinical material. This article reviews the performance of the new technologies to date, with an emphasis on those that are currently approved for cervical cytology testing. In the aggregate, these technologies can have a positive impact on cervical disease detection and intervention.

Trends in the frequency and predictive value of reporting high grade abnormalities in cervical smears

BACKGROUND

The "organized approach" to cervical screening in Australia includes standardized quality assurance measures for laboratories. This study examines changes in the frequency and the positive predictive value of reporting severe abnormalities in cervical smears over a 3-year period as a guide to the effects of implementing these measures.

METHODS

The results of screening in 6-month periods from January 1995 to December 1997 were determined. Biopsy follow-up for results in the high grade epithelial abnormality ("HGEA") and "inconclusive: possible HGEA" categories was obtained from the Western Australian Cervical Cytology Registry (CCR).

RESULTS

Approximately 40,000 smears were examined in each 6-month period. The frequencies of reporting HGEA were 0.47%, 0.59%, 0.79%, 0.85%, and 0.84%, and 0.91% for the study periods (P < 0.001). For the inconclusive category, they were 0.24%, 0.18%, 0.24%, 0.31%, 0.38%, and 0.35% (P < 0.001). Biopsy follow-up was available for 83. 9%, 80.5%, 89.9%, 92.4%, 93.1%, and 90.3% of the HGEA results and for 78.6%, 71.7%, 80.5%, 75.0%, 87.1%, and 85.9% of the inconclusive results over the study periods. The yield of high grade lesions for the biopsied cases was 82.6%, 82.3%, 83.1%, 79.5%, 80.9%, and 79% for HGEA cases and 58.2%, 41.9%, 60.6%, 52.8%, 47.5%, and 54.1% for inconclusive cases.

CONCLUSIONS

There was a doubling in the reporting of HGEA results, whereas the positive predictive value for biopsied cases remained at about 80%. Reporting rates for inconclusive: possible HGEA cases also doubled, but the yield of biopsy-proven, high grade lesions remained at about 50%. These changes occurred in the absence of ancillary testing and with targeted rescreening methods. A high rate of reporting HGEA, in combination with a high positive predictive value, is among the most important indicators of cervical cytology laboratory performance. Large improvements in results may occur using conventional methods of quality assurance. Cancer (Cancer Cytopathol)

Clinical and cost implications of new technologies for cervical cancer screening: the impact of test sensitivity

OBJECTIVE

To compare the available techniques for cervical cancer screening, including several new technologies, using actual program utilization patterns.

STUDY DESIGN

Longitudinal cohort model.

PATIENTS AND METHODS

The model followed a cohort of 100,000 women who underwent screening from age 20 through 65 years. The model was run with a weighted average of screening intervals to model the actual utilization of the cervical cancer screening program in the United States.

RESULTS

The model demonstrated that new technologies with significantly increased test sensitivity have the potential to reduce the number of cancers by 45% to 60% depending on the screening frequency in fully compliant populations. At screening intervals of 2 years or more, these new technologies had cost-effectiveness ratios below $50,000 per life-year saved. Assuming existing utilization patterns, the model predicted there would be 13.2 cancers per year in the 100,000 women screened with the conventional Pap smear, and new technologies with increased test sensitivity could reduce the annual incidence to 9.5 cancers per 100,000 women screened.

CONCLUSIONS

The model suggests that to achieve further dramatic reduction in cervical cancer mortality, significant improvements in test sensitivity, as reflected in the new screening technologies, may be the most realistic and cost-effective approach.

Molecular Papanicolaou tests in the twenty-first century: molecular analyses with fluid-based Papanicolaou technology

OBJECTIVE

This study was undertaken to demonstrate the feasibility of performing molecular analyses at the deoxyribonucleic acid, ribonucleic acid and protein levels of cervical cytologic examination with a methanol fluid-based Papanicolaou specimen collection system.

STUDY DESIGN

Genomic deoxyribonucleic acid and total ribonucleic acid were extracted from cell pellets obtained from the residual fluid-based Papanicolaou specimen collection buffer after clinical processing. Genomic and human papillomavirus deoxyribonucleic acid polymerase chain reaction and reverse transcriptase-polymerase chain reaction were performed. Messenger ribonucleic acid transcript analysis and human papillomavirus 16 E6 mutational analysis were also performed. Methylation-specific polymerase chain reaction was used to evaluate hypermethylation status of the p16 gene and the gene for E-cadherin. Immunohistochemical staining for protein expression was performed on the processed monolayer slides.

RESULTS

Cell pellets from the residual fluid-based cytologic specimen yielded good quality deoxyribonucleic acid and ribonucleic acid. Molecular analyses of genomic deoxyribonucleic acid were successful for the identification of human papillomavirus E6 and p53 polymorphism status by means of restriction enzyme digestion and direct sequencing. Methylation status of the promotor regions of the p16 tumor suppressor gene and the gene for E-cadherin were also successfully identified. Ribonucleic acid was used as the template for transcript analysis and mutational analysis of the corresponding complementary deoxyribonucleic acid of the p53 gene. Protein expression analysis was demonstrated by immunohistochemical staining for carcinoembryonic antigen.

CONCLUSION

It is feasible to conduct multiple molecular analyses at the deoxyribonucleic acid, ribonucleic acid, and protein levels of the cervicovaginal cell pellets from the residual fluid-based Papanicolaou cytologic specimen. This relatively simple and widely used collection system will allow significant advances in molecular epidemiology and eventual development of a molecular Papanicolaou test.

Advances in cervical screening technology

The Pap smear unquestionably is a successful screening test for cervical cancer. However, recent advances in technology have raised questions regarding whether the conventional Pap smear is still the standard of care. This article relates issues of screening and cost-effectiveness to the state of the art in thin layer preparations, cytology automation, human papillomavirus screening, human papillomavirus vaccines, and other cervical screening adjuncts. Perhaps nowhere in medicine is clinical decision making being more strongly influenced by market and other external forces than in cervical cytopathology.

New technologies in cervical cytology screening: a word of caution

Nearly 5000 women in the United States will die of cervical cancer this year and many of those deaths could be prevented. Most incident cases (60%) are associated with absent or deficient screening. Approximately 25% of screening failures are due to errors in cervical sampling or smear interpretation. New techniques for cytology screening such as liquid-based smears and computerized rescreening of slides are being promoted to physicians and the lay public despite limited scientific evaluation. Improving the validity of screening tests is important, but shifting resources for this purpose might cause net harm if the result is fewer screening opportunities for high-risk women. New screening technologies do not address this utilization gap and might widen it by driving the cost of screening out of the reach of high-risk women. Greater decreases in cervical cancer morbidity and mortality would likely result if the same resources were invested in a comprehensive national screening program that targeted women at highest risk.

[Cervical screening--its essence and quality-control methodology in cytology laboratories]

The essence and importance of the quality control in the activity of the cytological laboratories, fulfilling the 1st step of the cervical screening are discussed. The methodology is presented, as well as the possibilities of the different kinds of internal and external control and the place of the introduced in the practice of the developed countries automated analyzing systems are under consideration.

Thin-layer cytology meets viral hybrid capture

This commentary addresses the benefits of liquid-based thin-layer cervical cytology, and the applicability of residual samples for human papilloma virus assay. The potential for use of this technology in wide-scale screening as well as the many unanswered issues, in particular cost-benefit ratio and financing, are also discussed.