HPV DNA testing of self-collected vaginal samples compared with cytologic screening to detect cervical cancer

Small sample estimation of relative accuracy for binary screening tests

Comparing the accuracy of two screening tests is ideally achieved by administering both tests as well as a gold standard test to all study subjects. In practice, a more ethical screen positive study design is often used, one that requires gold standard determination only for subjects that screen positive on either test under investigation. Although it is not possible to quantify the absolute accuracy of each test with such a design,the relative accuracy of the tests can be estimated. Since relative accuracy estimation has poor small sample properties, adjusted estimators based on adding constants to the observed data have been proposed. The adjusted estimators have the advantage that they yield point and variance estimates of relative accuracy in all settings. However, we show through both theory and numerical examples that adding constants to the data can be beneficial or detrimental to small sample performance. Furthermore, the performance of the adjusted estimator depends not only on the magnitude of the constant but also on parameters that cannot be estimated with data from a screen positive study, making selection of an optimal constant difficult in practice. We also examine the performance of the adjusted estimator using data from a study comparing the accuracy of two screening tests for cervical cancer.

Human papillomavirus and cervical cancer

Of the many types of human papillomavirus (HPV), more than 30 infect the genital tract. The association between certain oncogenic (high-risk) strains of HPV and cervical cancer is well established. Although HPV is essential to the transformation of cervical epithelial cells, it is not sufficient, and a variety of cofactors and molecular events influence whether cervical cancer will develop. Early detection and treatment of precancerous lesions can prevent progression to cervical cancer. Identification of precancerous lesions has been primarily by cytologic screening of cervical cells. Cellular abnormalities, however, may be missed or may not be sufficiently distinct, and a portion of patients with borderline or mildly dyskaryotic cytomorphology will have higher-grade disease identified by subsequent colposcopy and biopsy. Sensitive and specific molecular techniques that detect HPV DNA and distinguish high-risk HPV types from low-risk HPV types have been introduced as an adjunct to cytology. Earlier detection of high-risk HPV types may improve triage, treatment, and follow-up in infected patients. Currently, the clearest role for HPV DNA testing is to improve diagnostic accuracy and limit unnecessary colposcopy in patients with borderline or mildly abnormal cytologic test results.

Risk factors related to the development and mortality from invasive cervical cancer clinical utility and impact on prevention

The focus of this article is to explore the various risk factors related to cervical cancer and the practical context in which they can be applied. The ability to link dinical outcomes (disease presence, persistence, progression, and recurrence) with antecedent risk factors is strengthened by a new understanding of the molecular mechanisms that are responsible for malignant transformation.

Efficient triage of the "screen-positive" at-risk patient

At this time little, if any, of the vast knowledge base being generated by current research is available for practical application within screening programs, although the path is opening for the development of future methodologies that might someday lead to the successful eradication of cervical cancer. Current efforts to develop a vaccine against HPV are rapidly progressing and are promising. In the meantime, a better understanding and utilization of the technologies at hand will result in a successful, organized approach to the detection of early cervical cancer and its precursors [56]. The adoption of any new screening technologies must result in a documented reduction in the incidence of cervical cancer. Until then, colposcopy and HPV DNA testing when indicated appears to remain as the undisputed gold standard in the evaluation of the patient at risk.

Tampon samplings with longer cervicovaginal cell exposures are equivalent to two consecutive swabs for the detection of high-risk human papillomavirus

BACKGROUND

Self-sampling for human papillomavirus (HPV) is useful for triage of ASCUS Papanicolaou (Pap) smears. Tampons with 10-second cervicovaginal cell exposure can detect HPV but appear to be less efficient than two consecutive swabs.

GOAL

The purpose of this study was to evaluate increased vaginal tampon exposures for detecting high-risk HPV.

STUDY DESIGN

This longitudinal cohort study followed women who self-sampled weekly with tampons for progressively longer periods of time. A tampon was inserted for 10 seconds at the office visit and 1 hour, 4 hours, and overnight for the three subsequent home samples. Two concurrent swabs were used with each tampon sampling for contemporaneous comparisons. The MY09/MY11 PCR primer system with reverse line blot detection strips was used to detect 18 distinct high-risk HPV types.

RESULTS

Of the 309 tampons and 618 swabs used at home, 83% were returned. Among normal women, the 10-second tampon detected fewer with normal histology and high-risk HPV than did its swabs ( = 0.0412), but the 1-hour, 4-hour, and overnight tampons had high-risk-HPV detection rates equal to their swabs. In women with CIN, all tampons and swabs equally identified those with high-risk HPV.

CONCLUSION

Self-sampling for HPV detection is acceptable, feasible, and technically accurate for both tampons with longer cervicovaginal exposures and swabs. The choice of technique is dependent on the woman, her culture, and her clinician.

Costs and benefits of different strategies to screen for cervical cancer in less-developed countries

BACKGROUND

About 80% of cervical cancers occur in less-developed countries. This disproportionate burden of cervical cancer in such countries is due mainly to the lack of well-organized screening programs. Several cervical cancer screening strategies have been proposed as more cost-effective than cytology screening. We compared the costs and benefits of different strategies and their effectiveness in saving lives in a less-developed country.

METHODS

We used a population-based simulation model to evaluate the incremental societal costs and benefits in Thailand of seven screening techniques, including visual inspection of the cervix after applying acetic acid (VIA), human papillomavirus (HPV) testing, Pap smear, and combinations of screening tests, and examined the discounted costs per year of life saved (LYS).

RESULTS

Compared with no (i.e., not well-organized) screening, all strategies saved lives, at costs ranging from 121 US dollars to 6720 US dollars per LYS, and reduced mortality, by up to 58%. Comparing each strategy with the next least expensive alternative, VIA performed at 5-year intervals in women of ages 35-55 with immediate treatment if abnormalities are found was the least expensive option and saved the greatest number of lives, with a cost of 517 US dollars per LYS. HPV screening resulted in similar costs and benefits, if the test cost is 5 US dollars and if 90% of women undergo follow-up after an abnormal screen. Cytology (Pap smear) was a reasonable alternative if sensitivity exceeds 80% and if 90% of women undergo follow-up. Compared with no screening, use of a combination of Pap smear and HPV testing at 5-year intervals in women of ages 20-70 could achieve greater than 90% reduction in cervical cancer mortality at a cost of 1683 US dollars per LYS, and VIA could achieve 83% reduction at 524 US dollars per LYS.

CONCLUSIONS

Well-organized screening programs can reduce cervical cancer mortality in less-developed countries at low costs. These cost-effectiveness data can enhance decision-making about optimal policies for a given setting.

Cost of screening for cancerous and precancerous lesions of the cervix

This paper is part of the cost-effectiveness study of cervical cancer screening conducted by the French Society of Clinical Cytology (SFCC). It describes the evaluation of costs of conventional smear tests, thin-layer smear tests (ThinPrep 2000 system), and viral typing by the HCS test. For 100,000 examinations per year, the average cost of a conventional smear test is 11.53 dollars in a private anatomo-pathology clinic. The cost of the thin-layer test for the same number of examinations and in the same type of clinic is 13.93 dollars. For 20,000 annual tests, the average cost of human papillomavirus (HPV) is 23.43 dollars in the public sector and 23.48 dollars in the private one. The higher price of the thin-layer method is only justifiable if this screening technique outperforms the conventional method. Furthermore, the high cost of the HPV test means that its integration into a population-based screening program must be carefully defined.

Low prevalence of abnormal cervical cytology in an institutionalized population with intellectual disability

BACKGROUND

The present study was designed to determine the prevalence of abnormal cervical cytology in an institutionalized population with intellectual disability.

METHOD

A retrospective review of charts for 162 women at a large state-owned facility was performed. Slides from 310 cervical Papanicolau smears were re-screened by a cytotechnologist and then reviewed by a pathologist.

RESULTS

The prevalence of abnormal cytology (three out of 162 participants) and biopsy confirmed that the prevalence cervical dysplasia (one out of 310 smears) was low.

CONCLUSION

The present preliminary study suggests that further investigation of the optimal interval for cervical cancer screening is warranted in this population.

Oncogenic human papillomavirus (HPV) infection and uterine cervical cancer: a screening strategy in the perspective of rural India

The predominance of cervical cancer in India can mostly be attributed to the lack of early screening. The objective of the present study has been, therefore, to determine a cost-effective oncogenic human papillomavirus (HPV)-based cervical cancer screening plan for rural Indian women. The results showed that in normal women, highest prevalence of HPV 16/18 infection was in the age group < or =23 years and lowest in > or =44 years with an insignificant change in between. HPV 16/18 infection was significantly associated with cervical erosion at age < or =23 years, but not with cytology or visual inspection with acetic acid testing at any age. The low-grade cytological lesions, however, increased only with increase in age. Fourteen per cent of the cervical malignancy was also found to be present in the age group 24-33 years with an 87% HPV infection. Here we proposed a cost-effective screening scheme in which HPV testing must be performed in women (a) < or =23 years with cervical erosion and (b) 24-43 years, as an adjunct to Pap smears (both HPV and cytology were prevalent in this group). For women > or =44 years, HPV testing might not be useful, since abnormal cytology was more prominent over the viral infection. We infer that by not performing HPV test in the group < or =23 years, approximately 76% of the high-risk HPV-infected individuals potentially "at risk" for developing cervical cancer might be missed.

Determinants of cervical cancer rates in developing countries

Although cervical cancer (CC) is a leading cause of cancer-related deaths in developing countries, incidence rates vary considerably, ranging from 3 to 61 per 10(5) females. Identifying determinants of high vs. low rates may suggest population-level prevention strategies. CC rates for 175 countries were obtained from the IARC. Country-specific behavioral, health, economic and demographic measures were obtained from United Nations agencies and other international organizations. Regression analyses performed for 127 low or medium developed countries identified both geography and religion as independently associated with high CC rates. Among behavioral measures, high fertility rates, early age at birth of first child and high teenage birth rates were significantly associated with high CC rates. Countries with high CC rates had fewer doctors per capita, less immunization coverage, more HIV infections and shorter life expectancies. CC rates also tended to be higher in countries with more spending on health and younger, less educated populations. Patterns of CC rates suggest that programmatic approaches, such as promoting delayed childbearing and sexual monogamy, may be appropriate interventions. For countries with high CC rates and some flexibility in their health-care budgets, a once-in-a-lifetime screen of women 30-50 years of age, using Pap smears, direct visual inspection and/or HPV DNA testing, may be cost-effective. Finally, relatively low immunization rates and a shortage of health-care workers in countries with high CC rates suggest potential challenges for introducing prophylactic HPV vaccines.

Human papillomavirus update with a particular focus on cervical disease

Human papillomavirus (HPV) is a common viral infection of squamous epithelial tissues, but its importance has only recently been recognised by the medical community. HPVs are now realised to consist of many genotypes and are associated with a diverse spectrum of clinical manifestations. Within the genital tract, some diseases have been recognised since antiquity; for example, genital warts which are caused by HPV types distinct from those causing genital cancer. However, others (such as cervical cancer), although recognised centuries ago as linked to sexual activity, have only been associated with oncogenic HPVs relatively recently, with the tools of molecular biology. We now understand that genital HPV infections are the most common sexually transmitted viral infections, are largely transient, asymptomatic and of no consequence. This virus manifests as more than just benign warts. Chronic carriage of with oncogenic genotypes (over years and in a minority of patients), together with other cofactors (host and/or exogenous) in complex pathways not totally understood, result in severe dysplasia or, ultimately, carcinogenesis. As it takes time for precursor lesions to develop and there are effective screening programmes for their detection and treatment, HPV-related neoplastic disease of the cervix is largely a preventable reproductive health issue of women. Yet, on a global scale, cervical cancer is the second most common cancer of women, with the majority of cases occurring in developing countries. Although HPV is noncultivatable by traditional diagnostic virological methods, successfully applied molecular biology techniques have underpinned development of vaccines which are now in phase II/III clinical trials. Successful vaccination ultimately has the greatest potential to impact upon the global burden of disease from genital HPV infection. However, the outcome from reduction in incidence of dysplasia and neoplasia will take years to eventuate; consequently, various cervical cancer prevention strategies still need to be endorsed and maintained in the meantime.

Primary screening for high risk HPV by home obtained cervicovaginal lavage is an alternative screening tool for unscreened women

BACKGROUND/AIMS

Self sampling is considered an adjuvant tool to facilitate the participation of women in cervical cancer screening programmes. This study aimed to evaluate whether cervicovaginal lavage could be an alternative for the cervical smear in cytology and human papillomavirus (HPV) testing and to assess the acceptance of the self sampling device by women.

METHODS

Fifty six women with abnormal cervical cytology (very mild dyskaryosis or worse) and 15 women with normal cervical cytology obtained a self collected cervicovaginal lavage at home and filled in a questionnaire on the use of the device. At the colposcopy clinic the gynaecologist performed the same procedure followed by a cervical smear for cytology and HPV DNA testing.

RESULTS

The self sampling device was acceptable to 88% of the women. The concordance between the cytology results in the smear and the lavage by the doctor and the patient was 54% and 41%, respectively (kappa = 0.28 and 0.14). The concordance between high risk HPV detection in the smear and the lavage by the doctor and the patient was 93% and 78%, respectively (kappa = 0.82 and 0.53). Ninety one per cent of the women with high grade cervical intraepithelial neoplasia (CIN) had a high risk HPV positive test in the smear, compared with 91% and 81% in the lavages taken by the doctor and the patient, respectively.

CONCLUSIONS

HPV DNA testing by home obtained samples is useful as a screening tool for cervical cancer, whereas cervical cytology by self sampling is not. Although the sensitivity for high grade CIN by high risk HPV testing in the lavage by the patient is not significantly lower than that in the cervical smear, self sampling for HPV DNA is a feasible alternative method in women who decline to participate in population based cervical cancer screening programmes. However, participation in the screening programme remains the best option.

Pap test results among low-income youth: prevalence of dysplasia and practice implications

OBJECTIVES

To describe Papanicolaou (Pap) test findings and identify prevalence and correlates of dysplastic cervical abnormalities in low-income adolescent females.

DESIGN AND SETTING

This cross-sectional study included a modified random sample of female students ages 16 to 25 years at 54 U.S. Job Corps centers.

PARTICIPANTS

5,734 female students enrolled in a federal job training program. Admission health records were reviewed and abstracted.

MAIN OUTCOME MEASURE

Pap test findings using the Bethesda classifications. Pap smear results indicating dysplasia (atypical squamous cells of undetermined significance [ASCUS] with dysplasia) or squamous intraepithelial lesions (low-grade squamous interepithelial lesions [LGSIL] or high-grade squamous intraepithelial lesions [HGSIL]). Participants with less severe findings were compared with those who needed follow-up.

RESULTS

For 71.4% of participants, no abnormalities were found. 15.6% had benign cellular changes, 9.2% had reactive changes, and 9.9% had epithelial cell abnormalities. Of those tested, 5.6% (+/- 0.8%) had dysplastic Pap smear findings, with 0.3% (n = 12) HGSIL. All groups were equally affected, with abnormalities not associated with race/ethnicity, age, geographic region, education level, size of city of residence, or receiving public assistance.

CONCLUSIONS

In this population, dysplastic Pap smear results were not uncommon. Findings indicate that Pap screening, alone or in combination with more sensitive tests, can identify cervical abnormalities, including HGSIL, that suggest a need for further evaluation or follow-up.

Human papillomavirus detection for cervical cancer prevention with polymerase chain reaction in self-collected samples

OBJECTIVE

We studied the usefulness of self-sampling in cervical cancer prevention.

STUDY DESIGN

A cross-sectional study was undertaken at screening services in Recife (Brazil); 253 women aged 16 to 88 years were included. Participants were randomly selected from a high-risk population for cervical neoplasia. All participants collected a self-sample with a cotton-tipped swab by rotating it against the vaginal epithelium and, possibly, the cervix. Physician-collected samples from the ectocervix and endocervix, respectively, with an Ayre's spatula and a Cytobrush endocervical brush (Medscand) were followed by thorough colposcopy. Human papillomaviruses were detected by consensus polymerase chain reaction and typed by restriction fragment length polymorphism.

RESULTS

The difference among human papillomavirus results in samples that were self-collected versus physician collected was significant (P <.03). The agreements were poor among patients with cervical intraepithelial neoplasia (CIN) grade 3 (kappa <0.29) and cervical cancer (kappa < 0.10). Self-sampling missed 50% more cancers than did physician sampling (P =.04).

CONCLUSION

Self-sampling with a cotton-tipped swab for human papillomavirus detection is not a safe method for the collection of samples that are aimed at primary cervical cancer screening.

Human papillomavirus: a review

Human papillomavirus infection remains a great source of morbidity and mortality. Progress in understanding the structure of HPV and its pathogenesis has led to a wide variety of possible new treatment modalities to combat HPV-related disease. Most HPV infections (whether high risk or low risk) resolve without any medical intervention. Persistent or progressive disease, however, remains difficult to treat. Although currently available therapies have proved efficacious and tolerable in the treatment of nongenital and genital warts, no single therapy is uniformly effective in eradicating persistent HPV infection. Cytodestructive methods, such as cryotherapy, remain the primary treatment modality for nongenital warts. Immune response modifiers, such as imiquimod, currently show the greatest promise in treating HPV-induced anogenital lesions, both with respect to complete response and in preventing recurrence. Human papillomavirus infection is one of the most common sexually transmitted diseases in the world, and cervical cancer still causes significant morbidity and mortality. Pap smear tests have greatly reduced the incidence and mortality of cervical cancer in developed countries. Additional research will focus on primary and secondary prevention strategies. Vaccines against high-risk HPV types are promising modalities currently under investigation to prevent HPV infections and possibly to treat them.

The causal relation between human papillomavirus and cervical cancer

The causal role of human papillomavirus infections in cervical cancer has been documented beyond reasonable doubt. The association is present in virtually all cervical cancer cases worldwide. It is the right time for medical societies and public health regulators to consider this evidence and to define its preventive and clinical implications. A comprehensive review of key studies and results is presented.

The Use of Urine and Self-obtained Vaginal Swabs for the Diagnosis of Sexually Transmitted Diseases

Studies have reported that self-collected specimens, such as urine or vaginal swabs, can be successfully used to diagnose sexually transmitted infections when they are used with nucleic acid amplification assays. This eliminates the necessity for a clinician-performed pelvic examination for women, or a urethral swab for men, for sample collection. These nucleic acid amplification assays used with self-collected specimens are highly sensitive and specific, and their use may be extended to broad nonclinic screening venues, where their use can augment public health programs designed to control the epidemic of sexually transmitted diseases.

The acceptability of self-collected samples for HPV testing vs. the pap test as alternatives in cervical cancer screening

OBJECTIVE

To explore the acceptability of the self-collection of samples for human papillomavirus (HPV) testing in comparison with that of the Pap test.

METHODS

The study population consisted of 1069 women 20 years and older who were eligible for coverage through the Mexican Institute of Social Security (IMSS). These women were randomly selected among participants in a larger study to evaluate the use of HPV testing as an alternative in cervical cancer screening. All participants provided a self-collected vaginal sample for HPV testing according to explicit instructions and underwent a Pap test. Afterwards, each woman was interviewed about her experience and opinion regarding the two procedures. Acceptability was measured by a calculated score based on discomfort, pain, embarrassment, privacy, perception of personal treatment during the Pap test, and understanding of how to perform the self-sampling method.

RESULTS

Ninety-three percent of women experienced sufficient privacy with the Pap test, whereas 98% of women reported that privacy with the self-sampling procedure was acceptable. The Pap test consistently provoked more discomfort, pain, and embarrassment than self-sampling. Sixty-eight percent of the women who indicated a test preference chose self-sampling. Preference for this method was positively associated with monthly household income. Women reported a preference for self-sampling because it is more comfortable (71.2%) and causes less embarrassment (55.8%).

CONCLUSIONS

Self-sampling is more acceptable than the Pap test and could improve coverage rates of early detection programs. The incorporation of self-collected samples to detect HPV could encourage participation in screening programs among those women who reject the Pap test because of the necessary pelvic examination.

Sample size calculations for comparative studies of medical tests for detecting presence of disease

Technologic advances give rise to new tests for detecting disease in many fields, including cancer and sexually transmitted disease. Before a new disease screening test is approved for public use, its accuracy should be shown to be better than or at least not inferior to an existing test. Standards do not yet exist for designing and analysing studies to address this issue. Established principles for the design of therapeutic studies can be adapted for studies of screening tests. In particular, drawing upon methods for superiority and non-inferiority studies of therapeutic agents, we propose that confidence intervals for the relative accuracy of dichotomous tests drive the design of comparative studies of disease screening tests. We derive sample size formulae for a variety of designs, including studies where patients undergo several tests and studies where patients receive only one of the tests under evaluation. Both cohort and case-control study designs are considered. Modifications to the confidence intervals and sample size formulae are discussed to accommodate studies where, because of the invasive nature of definitive testing, true disease status can only be obtained for subjects who are positive on one or more of the screening tests. The methods proposed are applied to a study comparing a modified pap test to the conventional pap for cervical cancer screening. The impact of error in the gold standard reference test on the design and evaluation of comparative screening test studies is also discussed.

Randomized clinical trial of PCR-determined human papillomavirus detection methods: self-sampling versus clinician-directed--biologic concordance and women's preferences

OBJECTIVE

The purpose of this study was to compare the high-risk human papillomavirus detection rates from self-sampled swabs and tampons with standard clinician-directed speculum sampling and to assess women's acceptance of self-sampling methods.

STUDY DESIGN

One hundred three women who required a colposcopy underwent order randomization of the human papillomavirus sampling technique. Kappa and McNemar test statistical results were used to measure the agreement between clinician-directed and self-sampling techniques for high-risk types of human papillomavirus and the acceptance of self-sampling techniques.

RESULTS

All self-directed samplings were equivalent to clinician sampling for all cervical intraepithelial neoplasia disease states. High-risk human papillomavirus was detected by self- and clinician-directed methods in 83% of the women with cervical intraepithelial neoplasia, grade 2/3. The 2 sequential swabs trend toward better detection of high-risk types of human papillomavirus than all other techniques for women with normal histologic factors (P =.0736, by McNemar's chi2 test). Ninety-four percent of women would accept self-sampling for their yearly cervical screen.

CONCLUSION

Self-sampling is equivalent to clinician sampling for the detection of high-risk human papillomavirus and is acceptable to women as a yearly screen.

Human papillomavirus in cervical cancer

Epidemiologic studies supported by molecular technology have provided sufficient evidence of the causal role of some human papillomavirus (HPV) infections in the development of cervical cancer. The finding is consistent universally, and HPV has been proposed as the first identified necessary cause of cervical cancer. Such recognition translates into the concept that cervical cancer does not develop without persistent presence of HPV DNA. In the developed parts of the world, cytologic screening programs could benefit from the addition of HPV testing to their protocols. Controlled studies and one randomized trial have shown that HPV testing is helpful in solving the ambiguous cases generated by cytology reading. In populations where cytology programs are not functional or efficient, HPV testing is being evaluated as an alternative means of primary screening. Prevention of exposure to high-risk HPV types, either by prophylactic vaccination or by combined prophylactic and therapeutic immunologic intervention, may prove to be the most efficient and logistically feasible option for the prevention of cervical cancer in developing populations.

Risk factors of invasive cervical cancer in Mali

BACKGROUND

Cervical cancer is the most common cancer in women in Mali and the second commonest cause of cancer mortality.

METHODS

As part of an international effort to evaluate the role of human papillomavirus (HPV) in the aetiology of cervical cancer, we conducted a hospital-based case-control study in three medical centres in Bamako during 1994-1995. A total of 82 cases (invasive cervical cancer patients) and 97 controls matched to the cases for age were included. Information on risk factors was collected through personal interview. Serum antibodies to HPV 16, 18 and 31 virus like particles (VLP) were detected using ELISA assays. Polymerase chain reaction was used to detect HPV DNA in frozen biopsies of cases.

RESULTS

Human papillomavirus 6, 18, 31 VLP were detected in 60.4% of cases and 45.4% of controls (P = 0.03). Overall, HPV DNA was identified in 96.9% of the cervical cancer cases. Risk factors for cervical cancer were parity >10 versus <5 children ([odds ratio] OR = 4.8, 95% CI : 1.5-14.7), never having practised vaginal douching (OR = 17.6, 95% CI : 4.2-74.7), re-using home-made feminine napkins (OR = 45.9, 95% CI : 8.8-238.7) and having a husband with more than two wives (OR = 5.3, 95% CI : 1.3-21.3).

CONCLUSIONS

These data provide further evidence on the role of HPV in cervical cancer and show that high parity and poor genital hygiene conditions were the main co-factors for cervical cancer in this population with prevalent HPV infection.

Shanxi Province Cervical Cancer Screening Study: a cross-sectional comparative trial of multiple techniques to detect cervical neoplasia

OBJECTIVE

The aim of this study was to design a cervical cancer screening algorithm for the developing world that is highly sensitive for cervical intraepithelial neoplasia (CIN) II, III, and cancer and highly specific for CIN II and III, making it possible to ablate the transformation zone without histologic confirmation.

METHODS

In rural Shanxi Province, China, we examined 1997 women ages 35-45. Each subject underwent a self-test for intermediate and high-risk HPV (by HC-II assay), fluorescence spectroscopy, a liquid-based Pap (read manually and by computer and used as a direct test for HPV), a visual inspection (VIA) diagnosis, and colposcopy with multiple cervical biopsies.

RESULTS

Mean age was 39.1 +/- 3.16 years, mean number of births was 2.6 +/- 0.93. Based on tests administered, 4.3% subjects had > or =CIN II. All subjects with > or =CIN II had either a ThinPrep Pap (> or =ASCUS) or a positive HPV direct test. The sensitivity and specificity for the detection of > or =CIN II were, respectively, 83 and 86% for the HPV self-test, 95 and 85% for the HPV direct test, 94 and 78% for the ThinPrep Pap (> or =ASCUS), 77 and 98% for the ThinPrep Pap (> or =HGSIL), 94 and 9% for fluorescence spectroscopy, 71 and 74% for VIA, and 81 and 77% for colposcopy.

CONCLUSION

Based on these data and the existing healthcare infrastructure in China, we believe that further refinement of primary HPV screening using centralized labs is indicated. Self-testing in the local villages may be effective with improvements in the devices and techniques.

Hybrid capture-II and LCR-E7 PCR assays for HPV typing in cervical cytologic samples

As part of an ongoing cohort study in the Hokuriku region of Japan, cervical cell samples from histologically confirmed normal (n = 114) or abnormal (n = 286) women were examined for the presence of HPV DNA using a second-generation hybrid capture assay (HCA-II) and LCR-E7 PCR. HCA-II detected low-risk (HPV-6, -11, -42, 43 and -44) and high-risk (HPV-16, -18, -31, -33, -35, -39, -45, -51, -52, -56, -58, -59 and -68) HPV types, while LCR-E7 PCR detected an additional 7 HPV types and some uncharacterized types. In screening of high-grade squamous intraepithelial lesions (HSILs) and invasive cervical cancer, the sensitivities of HCA-II and LCR-E7 PCR testing the high-risk HPV types were 83% and 81%, respectively, while the specificity of both assays was 93%. The sensitivity of LCR-E7 PCR increased to 87%, which was significantly higher than that in HCA-II, when testing both high-risk and other HPV types. Sixty-eight inconsistent results (17% of total tested) from HCA-II and LCR-E7 PCR were due to (i) low copy number of HPV genome (false-negative for HCA-II, 5.3% and for LCR-E7 PCR, 1.3%), (ii) infection with HPV types undetectable by HCA-II (4.8%), (iii) multiple HPV infections (5%) or (iv) unknown reasons (0.8%). LCR-E7 PCR revealed that infections with HPV-16, -18, -31, -33, -35, -51, -52, -56, -58 or -67 was a high risk for cancer since these types predominated in HSIL and invasive cervical cancer. Samples showing high relative light units (>20) with a high-risk probe in HCA-II also gave positive results in LCR-E7 PCR and were generally associated with abnormal cervical lesions. Thus, we propose that both HCA-II and LCR-E7 PCR are valuable screening tests for premalignant and malignant cervical lesions.

Current methods of testing for human papillomavirus

Human papillomavirus DNA testing is gaining wider acceptance, yet the majority of testing is still undertaken in the research setting using protocols that are unsuitable for clinical diagnostic laboratories. Large-scale clinical human papillomavirus DNA testing is likely to be introduced as an adjunct to cervical cytology, so the cytology laboratory is an appropriate place for it to be undertaken. This poses a challenge for any human papillomavirus DNA test since it will be performed by technicians not specifically trained in virology or molecular biology, and will need to produce consistently reliable results in this setting. This is only realistically possible with a standardized and quality-controlled, commercially produced human papillomavirus DNA test. There is currently only one such commercially available assay, although there are a number of research-based tests that could logically lead to additional commercial products. The technological basis of these assays, together with available performance data, is reviewed in this chapter and the clinical utility of the tests is evaluated.

An update on human papillomavirus infection and Papanicolaou smears in adolescents

Human papillomavirus infection is one of the most common sexually transmitted infections in young women, and may lead to clinical sequelae such as anogenital condylomata and cervical squamous cell carcinoma. Recent data on the biology and natural history of HPV infection in adolescents will have important implications for the development of adolescent-specific protocols for cervical cancer screening and for follow-up of abnormal cytology.

Diagnosis of human papillomavirus infection by dry vaginal swabs in military women

OBJECTIVE

Human papillomavirus (HPV) assays are likely to be used with increasing frequency in clinical management of women with abnormal Papanicolaou smears and in cervical cancer screening. Our objective was to simplify the method of collection of female genital tract specimens. The utility of vaginal dry swabs for HPV diagnosis was evaluated.

METHODS

Specimens for cytology and for HPV identification were collected by a clinician from 189 female soldiers attending a military clinic. Three methods of specimen collection for HPV identification were compared: a vaginal dry swab (v-DRY), and vaginal and cervical swabs placed into specimen transport medium (v-STM and c-STM). Swabs were shipped to a STD laboratory for processing. Specific HPV types were identified by a consensus primer based PCR based method. Results from 165 women were evaluable.

RESULTS

HPV prevalence by the three methods was similar and ranged from 44.8% to 50.9%. 53 (32.1%) women were HPV positive and 60 (36.4%) women were HPV negative by all three collection methods. With respect to the risk categories of specific HPV types, there was greater agreement between the results from the two vaginal (v-DRY and v-STM) samples (kappa values of 0.69-0.81) than between the cervical (c-STM) and either of the vaginal samples (kappa values of 0.37-0.55). The HPV yield from c-STM was somewhat greater than that from the vaginal specimens but the correlation between cytological abnormalities and HPV was high for all three methods.

CONCLUSION

A dry vaginal swab may be an acceptable method of specimen collection for HPV diagnosis.

Will New Human Papillomavirus Diagnostics Improve Cervical Cancer Control Efforts?

With the causal link between specific types of human papillomavirus (HPV) and cervical cancer firmly established, efforts have turned to assessing the relative merits of offering HPV testing in screening, triage, and posttreatment management. Many unanswered questions remain, but a growing body of evidence supports a role for HPV testing in cervical cancer prevention programs. Already, clinical centers that serve thousands of women in Europe and the United States have incorporated HPV DNA tests in triage algorithms.

Impact of New Sexually Transmitted Disease Diagnostics on Clinical Practice and Public Health Policy

Nucleic acid amplification tests (NAAT) offer enhanced sensitivity and excellent specificity for many sexually transmitted diseases. For some pathogens for which a practical diagnostic test does not exist, such as human papillomavirus (HPV), NAAT are also useful. Further, most NAAT can be applied to less "invasive" patient specimens, including urine and vaginal fluid. This dramatically increases opportunities to test persons outside of traditional clinic settings. Use of NAAT has resulted in revisions of the proportion of sexually transmitted diseases (STDs) that are asymptomatic, and has increased measured prevalence of some STDs, notably Chlamydia trachomatis. NAAT have helped to clarify the eitiologies of genital ulcer disease and urethritis, and have provided a more complete picture of the natural history of genital herpes and HPV. The ability of polymerase chain reaction to detect HPV may change the management of patients who have abnormal Pap smears. Efforts to bear the relatively high cost of NAAT, such as pooling urine, are under study. NAAT for bacterial STD should be in populations at high risk for asymptomatic STD, especially those who might not access routine STD screening at traditional settings. Working through the cost to health care systems, including the public health arena, and implementation at the laboratory level are challenges to overcome before NAAT become the standard of care in most settings.

The role of human papillomavirus in screening for cervical cancer

PURPOSE

To review the options for effectively screening for cervical cancer, including human papilloma virus (HPV) identification, cytologic screening, colposcopy, or a combination approach. Current pathophysiology, diagnostic criteria, treatment approaches, and patient preparation and education related to cervical cancer screening and prevention are also included.

DATA SOURCES

Comprehensive review of current literature, including research and review articles.

CONCLUSION

Because the Papanicolau (Pap) smear is a screening tool, not a diagnostic tool, further studies must be done to identify the actual nature of discovered abnormalities. Of particular concern is the classification of atypical squamous cells of undetermined significance (ASCUS), which may simply indicate inflammation, or may be the first indicator of serious pathology. Following ASCUS Pap smears with HPV screening will allow for a clarification of the best approach to treatment. A screening algorithm supported by a review of the literature is proposed.

IMPLICATIONS FOR PRACTICE

Cervical cancer is a preventable disease caused by certain forms of HPV. Current screening protocols are based on the use of the Pap smear; and in areas where this test is routine and available, morbidity and mortality rates have dropped dramatically. Many women throughout the world and in underserved regions of the U. S. do not have adequate access to routine screening with Pap smear technology. As long as women continue to die needlessly of cervical cancer, more comprehensive and accessible screening methods must be explored. (Cutting the unnecessary worldwide and in the U. S.).

Diagnosing human papillomaviruses: recent advances

The biological importance of a group of human papillomaviruses, known as high-risk human papillomaviruses, as the key causal agent for almost all cervical cancer has now been established. Many aspects of the natural history of high-risk human papillomaviruses as sexually transmitted infections and as oncogenic agents have been researched. Although human papillomavirus diagnosis is largely confined to DNA detection techniques in cervical smears, there is accumulating evidence that the best polymerase chain reaction and hybrid capture techniques are more sensitive and probably of similar specificity compared with cervical cytology as a triage test for women with borderline smear abnormalities and for screening older women. This is strong presumptive evidence that high-risk human papillomavirus testing could be useful in cervical screening. Current research is aimed at establishing a place for high-risk human papillomavirus testing in routine screening practice. Randomised clinical trials, long-term natural history studies, mathematical modelling, and economic and psychosocial studies are being used to demonstrate whether this testing can improve both the effectiveness and efficiency of cervical screening in a range of situations.

Cervical-cancer screening beyond the year 2000

Evidence-based studies have shown that new techniques for cervical cancer screening have a higher diagnostic yield than conventional cervical cytology (Pap test). Automated screening devices that use liquid-based, thin-layer cytology and human papillomavirus DNA testing are likely to become the standard for routine primary screening for cervical cancer and its precursors in the 21st century. The increased initial expense of the new techniques will most certainly be absorbed by instituting longer intervals for safe primary screening, in both low-risk and high-risk populations. To make modern screening programmes even more effective, we must promote extensive public awareness campaigns about cervical cancer, a preventable disease.

Prediction of high-grade cervical intraepithelial neoplasia in cytologically normal women by human papillomavirus testing

Human papillomavirus (HPV) testing has been suggested for primary screening of cervical cancer. Prediction of future high-grade cervical lesions is crucial for effectiveness and cost. We performed a case control study in a retrospective cohort of women with at least two cervical smears, all but the last one being negative, from the organized cervical screening programme in Florence, Italy. We searched for high-risk HPV in all previous, archival, smears from cases (new histologically confirmed cervical intraepithelial neoplasia (CIN) grade II or worse) and in one previous smear from each control (last smear cytologically normal, matched by age and interval (latency) from last smear). We applied polymerase chain reaction (PCR), and the b-globin gene was used as a DNA preservation marker. High-risk HPV was identified in 71/92 (77.17%) previous smears from 79 cases and 17/332 controls (5.12%). The odds ratio (OR) was 63.76 (95% CI 30.57-132.96). Among cases the proportion of HPV-positive smears declined slightly with increasing latency. Among cases, HPV was found in 81.24% (95% CI 69.93-88.96%) of smears with latency < 4 years and in 67.80% (95% CI 47.72-82.93%) of those taken at longer intervals, up to 6 years. These findings suggest that testing for high-risk HPV allows predicting 80% of CINII/III 3 years before the cytological diagnosis and two thirds 6 years before. They also suggest that testing women negative for high-risk HPV at longer interval and strictly following-up women who are HPV positive could be an effective strategy for cervical cancer screening.

[Human papillomavirus typing in routine cervical smears. Results from a series of 3778 patients]

AIM

As human papillomavirus (HPV) infection is a significant risk factor for cervical cancer, the aim of this study was to assess the efficacy of HPV detection techniques in predicting the presence or the development of a high-grade squamous intra epithelial lesion. Additional reasons for carrying out this investigation were as follows. It was considered that the clinical value of HPV typing may have been underestimated in certain previous reports, which based their findings on first-generation assays. Moreover, until the present investigation most studies only investigated the cases with abnormal smear findings and did not include long-term follow-up, nor detailed follow-up of women with a normal smear but positive HPV typing, although this patient subgroup is of particular interest. The patient population included 3778 women who underwent routine cytological cervical screening and who gave their informed consent to participate in this study, consisting of a cervical smear, HPV testing via a second-generation Hybrid Capture II assay (which is more sensitive than first-generation tests, and can detect 18 different HPV types, i.e., 13 oncogenic and five non-oncogenic types); and in the case of abnormal smear findings, colposcopic examination and directed biopsies of the sites of suspected lesions. The women with cytomorphologically normal cervical smears but which who HPV-positive were reexamined six months later.

RESULTS

HPV findings were positive in 66 cases where the initial smear indicated the presence of a high-grade lesion with the diagnosis confirmed by biopsy in 65 cases; in 155 cases (76.1%) where the initial smear indicated the presence of a low-grade lesion; in 44 (57.1%) out of 77 smears indicating the presence of ASCUS-type (atypical squamous cells of undetermined significance) lesions; and in 366 cases (10.5%) of apparently normal initial smears. After colposcopy and follow-up, a final diagnosis of high-grade lesion was made for 85 patients. All these patients were found to have high-risk (oncogene-positive) HPV at the first examination, but in only 65 cases (76.5%) was the initial smear indicative of a high-grade lesion. Finally, in the patient groups with low-grade or ASCUS-type smear findings or with an apparently normal smear, a high-grade lesion was only found in those patients with persistent high-risk HPV infection. In all, the sensitivity of the Hybrid Capture II assay in detecting high-grade lesions was 100% versus 85.9% for standard cytology. However, its specificity (86.3%) and positive predictive value were not as high as the latter.

CONCLUSION

The results of this study indicate that HPV typing via this second-generation assay displays good sensitivity for the detection of at-risk cases, i.e., those involving the presence or development of high-grade cervical lesions. However, a number of issues have to be addressed before HPV typing is adopted in clinical practice, such as the fairly high HPV prevalence in women aged over 60 years, and whether the implications of this are the same as for younger age groups. Also, the present cost of complete typing remains too high for it to be used on a widespread scale. Nevertheless, HPV typing may have a useful role to play in the detection of cervical cancer.

A systematic review of the role of human papilloma virus (HPV) testing within a cervical screening programme: summary and conclusions

A systematic review of the available evidence on the role of HPV testing in cervical screening has been published by the Health Technology Assessment Committee of the UK Department of Health. The review summarized relevant data on testing methods, natural history, and prevalence of the virus in different disease groups. Cost-effectiveness modelling was undertaken. Ten major conclusions were reached and are reported here. The key conclusions were that HPV testing was more sensitive than cytology, but that there were concerns about specificity, especially in young women. The increased sensitivity led to a recommendation that HPV testing be introduced on a pilot basis for women with borderline and mild smears. HPV testing has great potential as a primary screening test, but large trials are needed to properly evaluate this application and to determine if its introduction can reduce invasive cancer rates. There is an urgent need to undertake a large trial of HPV testing in conjunction with other new technologies (liquid-based cytology and computer-assisted cytology reading) to determine the best way to integrate them into ongoing screening programmes. A range of issues including the age to start and stop screening, the appropriate screening interval, the role of self-sampling for HPV testing and the choice of primary test (HPV and/or cytology) require further evaluation.

New technologies in cervical cancer precursor detection

The current literature reflects three routes toward improving cervical cancer screening. The first is to improve the test qualities of cytology-based screening. The use of liquid-based cytology and computerized analysis of Papanicolaou tests are examples of attempts at this approach. Secondly, through various combinations of parallel or sequential tests, either the sensitivity or the specificity of a given test could be improved depending on the tests chosen and the order in which they were performed (eg, Papanicolaou test followed by human papillomavirus [HPV] or vice versa). Several excellent studies have been published this year on the use of HPV DNA testing as a primary screening modality and as an adjunct to the triage of mildly abnormal cytologic findings. The recent literature also reflects increasing interest in visual inspection of the cervix and self-collected samples for HPV testing as an equally effective and viable alternative to cytology in low-resource settings. A third possibility is to make use of advances in digital and spectroscopic techniques. In these cost-conscious times, a significant number of articles address the cost-effectiveness of these technologies and the real value of cervical cancer screening. This article reviews the current literature concerning both the advent of new cervical cancer screening technologies and the rediscovery of old ones.