Screening test accuracy studies: how valid are our conclusions? Application to visual inspection methods for cervical screening

False Negative Results in Cervical Cancer Screening-Risks, Reasons and Implications for Clinical Practice and Public Health

False negative (FN) results in cervical cancer (CC) screening pose serious risks to women. We present a comprehensive literature review on the risks and reasons of obtaining the FN results of primary CC screening tests and triage methods and discuss their clinical and public health impact and implications. Misinterpretation or true lack of abnormalities on a slide are the reasons of FN results in cytology and p16/Ki-67 dual-staining. For high-risk human papillomavirus (HPV) molecular tests, those include: truly non-HPV-associated tumors, lesions driven by low-risk HPV types, and clearance of HPV genetic material before sampling. Imprecise disease threshold definition lead to FN results in visual inspection with acetic acid. Lesions with a discrete colposcopic appearance are a source of FN in colposcopic procedures. For FAM19A4 and hsa-miR124-2 genes methylation, those may originate from borderline methylation levels. Histological misinterpretation, sampling, and laboratory errors also play a role in all types of CC screening, as well as reproducibility issue, especially in methods based on human-eye evaluation. Primary HPV-based screening combined with high quality-assured immunocytochemical and molecular triage methods seem to be an optimal approach. Colposcopy with histological evaluation remains the gold standard for diagnosis but requires quality protocols and assurance measures.

Performance of rapid IgM-IgG combined antibody tests in the occupational surveillance of COVID-19 in Colombian enterprises

Introduction: Rapid IgM-IgG combined antibody tests can play an important role in the COVID-19 surveillance by supporting the diagnosis of infection, assessing the immune response, and verifying the progress towards herd immunity. Objective: To evaluate the performance of rapid IgM-IgG combined antibody tests in COVID-19 occupational surveillance in a group of Colombian enterprises. Materials and methods: We used the occupational surveillance data from companies that had performed periodic serological tests on all personnel from the end of April to the beginning of July, 2020. Workers were organized in small groups (“social bubbles”) to prevent outbreaks and optimize surveillance. The sensitivity was estimated as if the sampling had a prospective design. We describe here the changes in serological testing through periodic rounds. Results: Data were obtained from 4,740 workers, of whom only 23 were symptomatic showing changes from IgM(-)/IgG(-) to IgM(+) and then to IgM(+)/IgG(+) and IgG(+). The sensitivity was 40.94% for IgM(+) and 47.95% for IgM(+)/IgG(+). This implies that a little less than half of the cases can be detected. Conclusion: Antibody rapid tests have a role in the diagnostic process of infection and they must be evaluated taking into account the moment of the epidemic, the type of test purchased, and the populations at risk since their results depend on the number of infections and cases. In the context of a health crisis, they can be optimized by organizing workers into “social bubbles”

Evaluation of Pulpal Involvement, Ulceration, Fistula, and Abscess Index and Periapical Index in Screening for Endodontic Disease: Reliability and Accuracy

INTRODUCTION

The pulpal involvement, ulceration, fistula, and abscess (PUFA) index was developed to screen for the clinical consequences of untreated dental caries. The aim of this study was to compare the diagnostic accuracy of the PUFA index and the periapical index (PAI) in identifying pulpal and periapical diseases.

METHODS

A cross-sectional study was conducted using consecutive sampling. Each participant went through screening using the PUFA index, orthopantomography assessment using PAI, and comprehensive clinical examination to derive pulpal and apical diagnoses. The outcomes were dichotomized. Reliability was estimated using the Cohen kappa coefficient. Sensitivity, specificity, and predictive values were calculated. The area under the receiver operating characteristic curve was compared using the chi-square test.

RESULTS

A total of 165 participants were examined, 98.2% of whom had a decayed, missing, or filled tooth index >0. Of 4115 teeth assessed, 16.2% (n = 666) were diagnosed with pulpal disease and 7.9% (n = 325) with periapical disease. Interexaminer reliability for the PUFA index and PAI was 0.87 and 0.80, respectively. Intraexaminer reliability was 0.83 and 0.76 for the PUFA index and 0.75 and 0.72 for PAI. For pulpal diagnosis, the sensitivity of the PUFA index and PAI was 67.6% and 41.7%, respectively; the specificity of the PUFA index and PAI was 99.8% and 99.2%, respectively. For apical diagnosis, the sensitivity of the PUFA index and PAI was 87.7% and 75.4%, respectively; the specificity of the PUFA index and PAI was 95.4% and 98.4%, respectively. The PUFA index is statistically more accurate than PAI for pulpal diagnosis and apical diagnosis (P < .05).

CONCLUSIONS

The PUFA index can be used in screening for pulpal and periapical diseases with some limitations.

Point of care testing for infectious diseases

Infectious diseases are caused by pathogenic microorganisms and can be transmitted between individuals and populations thus threatening the general public health and potentially the economy. Efficient diagnostic tools are needed to provide accurate and timely guidance for case identification, transmission disruption and appropriate treatment administration. Point of care (POC) tests provide actionable results near the patient and thereby serve as a personal "radar". In this review, we review clinical needs for POC testing for several major pathogens, including malaria parasites, human immunodeficiency virus (HIV), human papillomavirus (HPV), dengue, Ebola and Zika viruses and Mycobacterium tuberculosis (TB). We compare different molecular approaches, including pathogen nucleic acid and protein, circulating microRNA and antibodies, used in the POC tests. Finally, we review recent advances in novel POC technologies focusing on microfluidic and plasmonic-based approaches.

Factors associated with a cervical high-grade lesion on cytology or a positive visual inspection with acetic acid among more than 3300 Tanzanian women

OBJECTIVES

Cervical cancer screening by visual inspection with acetic acid (VIA) is a widely used alternative to cytology in developing countries. This study aimed to evaluate risk factors associated with a positive VIA test and with cervical high-grade lesions on cytology.

METHODS

We conducted a large cross-sectional study among 3339 women from urban and rural Tanzania. Study participants were interviewed about socio-demographic, reproductive and lifestyle factors. Blood samples were tested for HIV, and a gynaecological examination was performed. Human papillomavirus (HPV) status was determined by Hybrid Capture 2, and HPV genotyping was done using the LiPA Extra test. We used multivariable logistic regression to estimate adjusted odds ratios (ORs) and confidence intervals (CIs).

RESULTS

The strongest risk factors for VIA positivity were positivity to HIV (OR = 3.48; 95% CI: 2.34-5.17) or to high-risk HPV (HrHPV) (OR = 1.97; 95% CI: 1.37-2.85). HrHPV was by far the strongest predictor of high-grade cytology (OR = 110.1; 95% CI: 50.4-240.4), while there was no significant association with HIV in the multivariable analysis (OR = 1.27; 95% CI: 0.78-2.08). After adjustment for HrHPV, HIV and age, the risk of high-grade cytology also increased with increasing age, number of births and low body mass index (BMI), while high BMI decreased the risk of VIA positivity.

CONCLUSIONS

Infection with HrHPV is a major risk factor for high-grade cytology, while VIA positivity is associated with HIV and to a lesser extent with HrHPV.

Implementing community-based cervical cancer screening programs using visual inspection with acetic acid in India: A systematic review

The objective of this review was to systematically appraise the existing published literature about community-based cervical cancer screening programs that have used visual inspection methods using acetic acid (VIA) in India. All peer reviewed journal articles till December 2015 were searched per PRISMA guidelines. Articles reporting results from cervical cancer screening programs in community-based settings, conducted in India, and using VIA were included in this review. The search resulted in 20 articles to be included in the review with a total of 313,553 women at 12 unique urban and rural sites across India. Seventeen (85%) studies were cross-sectional and three studies were randomized controlled trials; most studies compared accuracy of VIA with other screening tests such as visual inspection using Lugol's Iodine (VILI), HPV DNA, and cytology. Of studies that reported test accuracy for CIN Grade 2+, the VIA sensitivity values ranged from 16.6-82.6% and specificity ranged from 82.1-96.8%. Women between age groups of 30-59 years were recruited using motivational one-on-one counseling and local support staff. All studies conducted diagnostic follow-up using colposcopy and guided biopsies, when necessary. Three major themes were identified that facilitated implementation of screening programs in a community-based setting: standardized training that maintained competency of test providers; collaborations with community-based organizations that used health education for recruitment of participants; and employing the screen-and-treat method to reduce loss to follow-up. Summarized evidence presented in this review could substantially influence future implementation and sustainment of cervical cancer screening programs at a national level.

Point-of-care test for cervical cancer in LMICs

Cervical cancer screening using Papanicolaou's smear test has been highly effective in reducing death from this disease. However, this test is unaffordable in low- and middle-income countries, and its complexity has limited wide-scale uptake. Alternative tests, such as visual inspection with acetic acid or Lugol's iodine and human papillomavirus DNA, are sub-optimal in terms of specificity and sensitivity, thus sensitive and affordable tests with high specificity for on-site reporting are needed. Using proteomics and bioinformatics, we have identified valosin-containing protein (VCP) as differentially expressed between normal specimens and those with cervical intra-epithelial neoplasia grade 2/3 (CIN2/CIN3+) or worse. VCP-specific immunohistochemical staining (validated by a point-of-care technology) provided sensitive (93%) and specific (88%) identification of CIN2/CIN3+ and may serve as a critical biomarker for cervical-cancer screening. Future efforts will focus on further refinements to enhance analytic sensitivity and specificity of our proposed test, as well as on prototype development.

VIA/VILI is more suitable for cervical cancer prevention in Chinese poverty-stricken region: a health economic evaluation

Background

Screening is the main preventive method for cervical cancer in developing countries, but each type of screening has advantages and disadvantages. To investigate the most suitable method for low-income areas in China, we conducted a health economic analysis comparing three methods: visual inspection with acetic acid and Lugol’s iodine (VIA/VILI), ThinPrep cytology test (TCT), and human papillomavirus (HPV) test.

Methods

We recruited 3086 women aged 35–65 years using cluster random sampling. Each participant was randomly assigned to one of three cervical cancer screening groups: VIA/VILI, TCT, or HPV test. In order to calculate the number of disability-adjusted life years (DALYs) averted by each screening method, we used Markov models to estimate the natural development of cervical cancer over a 15-year period to estimate the age of onset and duration of each disease stage. The cost-effectiveness ratios (CERs), net present values (NPVs), benefit-cost ratios (BCRs), and cost-utility ratios (CURs) were used as outcomes in the health economic analysis.

Results

The positive detection rate in the VIA/VILI group was 1.39%, which was 4.6 and 2.0 times higher than the rates in the TCT and HPV test groups, respectively. The positive predictive value of VIA/VILI (10.53%) was highest while the rate of referral for colposcopy was lowest for those in the HPV + TCT group (0.60%). VIA/VILI performed the best in terms of health economic evaluation results, as the cost of per positive case detected was 8467.9 RMB, which was 24503.0 RMB lower than that for TCT and 5755.9 RMB lower than that for the HPV test. In addition, the NPV and BCR values were 258011.5 RMB and 3.18 (the highest), and the CUR was 2341.8 RMB (the lowest). The TCT performed the worst, since its NPV was <0 and the BCR was <1, indicative of being poorly cost-beneficial.

Conclusions

With the best economic evaluation results and requiring minimum medical resources, VIA/VILI is recommended for cervical cancer screening in poverty-stricken areas in China with high incidence of cervical cancer and lack of medical resources.

Determinants of Cervical Cancer Screening Accuracy for Visual Inspection with Acetic Acid (VIA) and Lugol's Iodine (VILI) Performed by Nurse and Physician

BACKGROUND

Visual inspection with acetic acid (VIA) and Lugol's iodine (VILI) are used to screen women for cervical cancer in low-resource settings. Little is known about correlates of their diagnostic accuracy by healthcare provider. We examined determinants of VIA and VILI screening accuracy by examiner in a cross-sectional screening study of 1528 women aged 30 years or older in a suburb of Kinshasa, Democratic Republic of Congo.

METHODS

We used a logistic regression model for sensitivity and specificity to estimate the diagnostic accuracy of VIA and VILI, independently performed by nurse and physician, as a function of sociodemographic and reproductive health characteristics.

RESULTS

Nurses rated tests as positive more often than physicians (36.3% vs 30.2% for VIA, 26.2% vs 25.2% for VILI). Women's age was the most important determinant of performance. It was inversely associated with sensitivity (nurse's VIA: p<0.001, nurse's VILI: p = 0.018, physician's VIA: p = 0.005, physician's VILI: p = 0.006) but positively associated with specificity (all four combinations: p<0.001). Increasing parity adversely affected sensitivity and specificity, but the effects on sensitivity were significant for nurses only. The screening performance of physician's assessment was significantly better than the nurse's (difference in sensitivity: VIA = 13%, VILI = 16%; difference in specificity: VIA = 6%, VILI = 1%).

CONCLUSIONS

Age and parity influence the performance of visual tests for cervical cancer screening. Proper training of local healthcare providers in the conduct of these tests should take into account these factors for improved performance of VIA and VILI in detecting cervical precancerous lesions among women in limited-resource settings.

Molecular analysis of human Papillomavirus detected among women positive for cervical lesions by visual inspection with acetic acid/Lugol's iodine (VIA/VILI) in Libreville, Gabon

Background

The human papillomavirus (HPV) is the causative agent of cervical cancer, which is the leading cancer-related cause of death for women in Sub-Saharan Africa. In 2013, the Gabonese Ministry of Health and the Sylvia Bongo Ondimba Foundation implemented cervical cancer screening programs based on the detection of cancerous lesions by visual inspection with acetic acid and/or Lugol’s iodine (VIA/VILI). This pilot study was set up to determine the HPV profile and analyze the nucleotide sequence variation of HPV16 circulating in patients with cervical abnormalities detected by VIA/VILI testing.

Methods

The cervical abnormalities observed upon VIA/VILI were confirmed by liquid-based cytology for all tested women. Nested PCR using the MY09/11 and GP5+/6+ primer sets was used to detect HPVs present in the extracted DNA. HPV genotypes were determined after sequencing of amplicons based on a high-throughput sequencing approach. For isolates of the HPV16 genotype, the E6 gene and the long control region (LCR) were directly sequenced using Sanger method.

Results

The study included 87 women who showed a positive VIA/VILI result. Cervical abnormalities were found in 40.23 % of women and 40 % were classified as high-grade lesions. The HPV detection rate was 82.9 % among women with abnormal cytology. Among all the identified high-risk HPV genotypes, HPV16, 18 and 33 were the most frequent. Multiple HPV infections were observed in 42.31 % of HPV-infected women. Analysis of the HPV16 sequence variation in the E6 gene and in the LCR showed that 85.3 and 14.7 % belonged to the African and European lineages, respectively. Among the African branch variants, Af2 was the most frequently identified in this study.

Conclusion

This study offers the first report of the HPV detection rate and molecular epidemiology among Gabonese women with a positive result in a VIA/VILI screening test. Moreover, data on the HPV16 sequence variation confirm the predominance of African variants in high-grade lesions.

Electronic supplementary material

The online version of this article (doi:10.1186/s13027-016-0098-1) contains supplementary material, which is available to authorized users.

Evaluation of several screening approaches for detection of cervical lesions in rural Shandong, China

PURPOSE

The study was designed to: (1) investigate the prevalence of high-risk human papillomavirus (HR- HPV) infection and cervical neoplasia; and (2) evaluate clinical performance of visual inspection with acetic acid/ Lugol's iodine (VIA /VILI), Pap smear, high-risk human papillomavirus (HR-HPV) DNA test for detecting cervical intraepithelial neoplasia grade 2 or worse (CIN2+) and (3) explore appropriate screening approach in rural areas of Shandong Province.

MATERIALS AND METHODS

A total of 3,763 eligible women from Yiyuan County in Yimeng mountainous areas of rural Shandong, China, were enrolled and underwent Pap smear, HR-HPV DNA testing by Hybrid Capture 2 (HC2), and VIA /VILI tests. Women positive in any test were referred to colposcopy and biopsy as indicated.

RESULTS

The prevalence of HR-HPV infection among all enrolled women was 11.1% and that in healthy women was 9.9%. In total 33 cases of CIN1, 16 cases of CIN2, 6 cases of CIN3 but none of cervical cancer were detected and the crude prevalence of CIN2+ was 0.58%. For detecting CIN2+, the sensitivity of HR-HPV DNA testing, VIA/VILI, Pap smear was 90.9%, 77.3%, 81.8%, respectively. Pap smear had the best specificity of 98.2%, followed by HR-HPV DNA testing with specificity of 89.4%, VIA/VILI had the lowest specificity of 81.2%. Colposcopy referral rate of HR-HPV DNA testing, VIA/VILI, Pap smear was 11.1%, 18.5%, 2.3%, respectively.

CONCLUSIONS

Our results suggest that HR-HPV DNA testing alone might be appropriate for primary cervical cancer screening in rural low-resource areas of Shandong Province, China.

Prevalence and factors associated with VIA positive result among clients screened at Family Guidance Association of Ethiopia, south west area office, Jimma model clinic, Jimma, Ethiopia 2013: a cross-sectional study

Background

Cervical cancer is the 2nd most frequent and top killer cancer among women in Ethiopia. Prevalence and factors associated with visual inspection with acetic acid (VIA) positive result is not studied yet at the study area.

Methods

A cross-sectional study was conducted at Jimma model clinic of Family Guidance Association of Ethiopia, from September 11, 2013 to October 11, 2013. Pertinent data of 334 screened clients were transferred to Epidata version3.1 using checklist, double data entry verification done and exported to SPSS version16.0. After cleaning the data, descriptive analysis was done and logistic regression model employed to identify predictors of VIA positive result. Statistical significance was declared at P < 0.05.

Results

Out of 334 screened clients, 43 (12.9 %) had VIA positive result. Initiation of sexual intercourse earlier than 16 years was found to be an independent predictor increasing the risk of VIA positive by 2.2 times as compared to clients who started at the age of 16 or more years (AOR [95 % CI] = 2.2 [1.1, 4.3]).

Conclusions

Early initiation of sexual intercourse was an independent predictor of VIA positive result in this study. Thus, any cervical cancer prevention and control effort at the study area should address the problem of early initiation of sexual intercourse.

Electronic supplementary material

The online version of this article (doi:10.1186/s13104-015-1594-x) contains supplementary material, which is available to authorized users.

Optimizing technology for cervical cancer screening in high-resource settings

Although historically successful in reducing the burden of cervical cancer, Papanicolaou (Pap) testing faces numerous limitations. A growing body of evidence suggests that modern screening practice will benefit from primary screening for high-risk human papillomavirus (HPV) infection, the causative agent of cervical cancer. Molecular tests detecting the presence of HPV nucleic acids consistently demonstrate high sensitivity relative to Pap testing, and provide reliable, dichotomous results. Pap cytology is ideally suited to triage HPV-positive cases owing to its high test specificity, and the accuracy of cytological readings will be maximized in high-prevalence conditions. This algorithm of primary HPV testing with Pap triage has been shown to maintain the high sensitivity of HPV testing without compromising Pap cytology's strong ability to rule out falsely positive diagnoses. Given the anticipated decline of high-risk HPV-16 and -18 infections in the emergent post-HPV vaccination era, highly sensitive primary HPV testing is especially warranted. Novel screening technologies that identify HPV viral gene expression continue to emerge and seek to complement current HPV testing by identifying those women who may be at risk of progressive disease. How to best incorporate these new technologies into clinical practice presents our next great challenge. Implementation of novel algorithms for cervical screening is not a trivial task. Avoidance of exceedingly complex screening algorithms is an important priority.

Risk factors for VIA positivity and determinants of screening attendances in Dar es Salaam, Tanzania

Background

Tanzania is among the countries in the world where the cervical cancer incidence is estimated to be highest. Acknowledging an increase in the burden of cervical cancer, VIA was implemented as a regional cervical cancer screening strategy in Tanzania in 2002. With the aim of describing risk factors for VIA positivity and determinants of screening attendances in Tanzania, this paper present the results from a comparative analysis performed among women who are reached and not reached by the screening program”.

Methods

14 107 women aged 25–59 enrolled in a cervical cancer screening program in Dar es Salaam in the period 2002 – 2008. The women underwent VIA examination and took part in a structured questionnaire interview. Socioeconomic characteristics, sexual behavior, HIV status and high-risk (HR) HPV infection were determined in a subpopulation of 890 who participated and 845 who did not participate in the screening.

Results

Being widowed/separated OR=1.41 (95% CI: 1.17-1.66), of high parity OR=3.19 (95% CI: 1.84-5.48) of low education OR= 4.30 (95% CI: 3.50-5.31) and married at a young age OR=2.17 (95% CI: 1.37-3.07) were associated with being VIA positive. Women who participated in the screening were more likely to be HIV positive OR= 1.59 (95% CI. 1.14-2.25) in comparison with women who had never attended screening, while no difference was found in the prevalence of HR-HPV infection among women who had attended screening and women who had not attended screening.

Conclusion

Women who are widowed/separated, of high parity, of low education and married at a young age are more likely to be VIA positive and thus at risk of developing cervical cancer. The study further documents that a referral linkage between the HIV care and treatment program and the cervical cancer screening program is in place in the setting studied, where HIV positive were more likely to participate in the cervical cancer screening program than HIV negative women.

Looking ahead: a case for human papillomavirus testing of self-sampled vaginal specimens as a cervical cancer screening strategy

Even in the era of highly effective human papillomavirus (HPV) prophylactic vaccines, substantial reduction in worldwide cervical cancer mortality will only be realized if effective early detection and treatment of the millions of women already infected and the millions who may not receive vaccination in the next decade can be broadly implemented through sustainable cervical cancer screening programs. Effective programs must meet three targets: (i) at least 70% of the targeted population should be screened at least once in a lifetime, (ii) screening assays and diagnostic tests must be reproducible and sufficiently sensitive and specific for the detection of high-grade precursor lesions (i.e., CIN21), and (iii) effective treatment must be provided. We review the evidence that HPV DNA screening from swabs collected by the women in their home or village is sufficiently sound for consideration as a primary screening strategy in the developing world, with sensitivity and specificity for detection of CIN21 as good or better than Pap smear cytology and VIA. A key feature of a self-collected HPV testing strategy (SC-HPV) is the move of the primary screening activities from the clinic to the community. Efforts to increase the affordability and availability of HPV DNA tests, community education and awareness, development of strong partnerships between community advocacy groups, health care centers and regional or local laboratories, and resource appropriate strategies to identify and treat screen-positive women should now be prioritized to ensure successful public health translation of the technologic advancements in cervical cancer prevention.

Accuracy of visual inspection with acetic acid for cervical cancer screening

OBJECTIVE

To provide an updated estimation of the accuracy of visual inspection with acetic acid (VIA) in detecting true disease.

METHODS

A PubMed search provided original studies on VIA accuracy in which the gold standard for confirmatory testing was histology alone or colposcopy followed by biopsy. The numbers of true-positive, false-positive, false-negative, and true-negative results were extracted from each study. Meta-analyses were then performed with different categories of studies according to confirmatory diagnosis threshold, category of women who received confirmatory testing, and whether a medical condition that could affect VIA accuracy was present at screening. The reference category consisted of 26 studies in which VIA was performed on asymptomatic women who all underwent confirmatory testing and in which the disease threshold was cervical intraepithelial neoplasia grade 2.

RESULTS

We report an 80% sensitivity (range, 79%-82%) and a 92% specificity (range, 91%-92%) for VIA. Study region, capacity of screener, or size of the study population did not modify VIA accuracy. The positive predictive value was 10% (range, 9%-10%).

CONCLUSION

Screening for precancerous and cancerous cervical lesions using VIA is a simple, low-cost, and efficient alternative to cytologic testing in low-resource areas.

Effectiveness of VIA, Pap, and HPV DNA testing in a cervical cancer screening program in a peri-urban community in Andhra Pradesh, India

Background

While many studies have compared the efficacy of Pap cytology, visual inspection with acetic acid (VIA) and human papillomavirus (HPV) DNA assays for the detection cervical intraepithelial neoplasia and cancer, few have evaluated the program effectiveness.

Methods and Findings

A population-based sample of 5603 women from Medchal Mandal in Andhra Pradesh, India were invited to participate in a study comparing Pap cytology, VIA, and HPV DNA screening for the detection of CIN3+. Participation in primary screening and all subsequent follow-up visits was rigorously tracked. A 20% random sample of all women screened, in addition to all women with a positive screening test result underwent colposcopy with directed biopsy for final diagnosis. Sensitivity, specificity, positive and negative predictive values were adjusted for verification bias. HPV testing had a higher sensitivity (100%) and specificity (90.6%) compared to Pap cytology (sensitivity  =  78.2%; specificity = 86.0%) and VIA (sensitivity = 31.6%; specificity = 87.5%). Since 58% of the sample refused involvement and another 28% refused colposcopy or biopsy, we estimated that potentially 87.6% of the total underlying cases of CIN3 and cancer may have been missed due to program failures.

Conclusions

We conclude that despite our use of available resources, infrastructure, and guidelines for cervical cancer screening implementation in resource limited areas, community participation and non-compliance remain the major obstacles to successful reduction in cervical cancer mortality in this Indian population. HPV DNA testing was both more sensitive and specific than Pap cytology and VIA. The use of a less invasive and more user-friendly primary screening strategy (such as self-collected swabs for HPV DNA testing) may be required to achieve the coverage necessary for effective reduction in cervical cancer mortality.

Determinants of VIA (Visual Inspection of the Cervix After Acetic Acid Application) positivity in cervical cancer screening of women in a peri-urban area in Andhra Pradesh, India

OBJECTIVES

Visual inspection of the cervix after acetic acid application (VIA) is widely recommended as the method of choice in cervical cancer screening programs in resource-limited settings because of its simplicity and ability to link with immediate treatment. In testing the effectiveness of VIA, human papillomavirus DNA testing, and Pap cytology in a population-based study in a peri-urban area in Andhra Pradesh, India, we found the sensitivity of VIA for detection of cervical intraepithelial neoplasia grade 2 and worse (CIN2+) to be 26.3%, much lower than the 60% to 90% reported in the literature. We therefore investigated the determinants of VIA positivity in our study population.

METHODS

We evaluated VIA positivity by demographics and reproductive history, results of clinical examination, and results from the other screening methods.

RESULTS

Of the 19 women diagnosed with CIN2+, only 5 were positive by VIA (positive predictive value, 3.1%). In multivariate analysis, VIA positivity (12.74%) was associated with older age, positive Pap smear, visually apparent cervical inflammation, and interobserver variation. Cervical inflammation of unknown cause was present in 21.62% of women. In disease-negative women, cervical inflammation was associated with an increase in VIA positivity from 6.1% to 15.5% (P<0.001). Among the six gynecologists who performed VIA, the positivity rate varied from 4% to 31%.

CONCLUSIONS

The interpretation of VIA is subjective and its performance cannot be readily evaluated against objective standards.

IMPACT

VIA is not a robust screening test and we caution against its use as the primary screening test in resource-limited regions.

Screening for bladder cancer: theoretical and practical issues in considering the treated and untreated natural history of the various forms of the disease

Screening is used to detect disease earlier in its course, allow earlier treatment, and presumably decrease morbidities and potential mortality associated with the later expression of more advanced disease and presumably more complex treatments consequently required. Judicious screening in bladder cancer depends on an understanding of how the different forms of bladder cancer express their biological potential, whether the tools available for screening have sufficient sensitivity and specificity to have accurate predictive value in accurately diagnosing and assessing each cancer diathesis earlier in its course, and how this may influence the morbidities and mortality associated with each. The principles of screening, potential biases that can affect their accuracy and the interpretation of outcomes, tools currently available for screening, their efficacies and pitfalls, and lessons learned from studies of the role of screening in prostate cancer will be reviewed to offer an understanding of the potential role that screening may play in the different forms of bladder cancer in the context of their preclinical and treated natural history.

Different cervical cancer screening approaches in a Chinese multicentre study

To evaluate alternative cervical cancer screening methods, digital colposcopy and collection of cervical exfoliated cells for liquid-based cytology (LBC) and hybrid capture 2 (HC2) testing were performed among 2562 women aged 15–59 years in three study sites in the People's Republic of China (rural Shanxi province, Shenyang city in Liaoning province and Shenzhen city in Guangdong province). Visual inspection with acetic acid (VIA) was also evaluated independently from colposcopy. A total of 74 cases of histologically confirmed cervical intraepithelial neoplasia grade 2 or worse (CIN2+) were identified, and 16 CIN2+ cases were imputed among unbiopsied women to correct for verification bias. Corrected sensitivity for CIN2+ was 37% for VIA, 54% for colposcopy, 87% for LBC with a threshold of atypical cells of undetermined significance (LBC⩾ASCUS), 90% for HC2, 84% for LBC using HC2 to triage ASCUS and 96% for positivity to LBC⩾ASCUS or HC2. For VIA, sensitivity was much lower among women ⩾40 years (12%) than those aged ⩽39 years (50%). Specificity varied from 77% for positivity to LBC⩾ASCUS or HC2, up to 94% for LBC using HC2 to triage ASCUS. In conclusion, LBC, HC2 and their combinations performed well, whereas VIA missed a majority of CIN2+, particularly in older women. Digital colposcopy performed better than VIA, but still missed nearly half of CIN2+ in this study.

Comparative study of four candidate strategies to detect cervical cancer in different health care settings

AIM

Considering the differing but potentially supplementary properties of visual inspection of the cervix with acetic acid (VIA) and the cytological examination (CYTO) of cervical smears for the screening of cervical cancers, we examined the performance of these two tests and their combinations for the screening of cervical cancer in different health care settings.

METHODS

In this cross-sectional diagnostic test performance evaluation study of 4235 female subjects in the reproductive age group, we assessed the screening performance of four strategies: VIA alone, CYTO alone, VIA and CYTO combined in a parallel fashion, and VIA and CYTO combined in tandem. Subjects were recruited from three settings: Hospital, Urban Community and Rural Community. Colposcopy was used as the reference standard. Screening performance was assessed using sensitivity, specificity, post-test probabilities and likelihood ratios (LR), diagnostic odds, area under receiver operating characteristic curve and LR chi(2).

RESULTS

Both VIA and CYTO when used alone had a low sensitivity but high specificity, especially in the Rural Community setting. A combination of the results of VIA and CYTO improved the diagnostic accuracy but the strategy using a parallel combination of VIA and CYTO was the most accurate. In general, all screening strategies using VIA and CYTO showed a modest screening performance.

CONCLUSIONS

In the settings of varying levels of health care and low resources, caution is needed for a generalized use of VIA for cervical cancer screening. Further evaluation of the cost-effective ways of combining VIA and CYTO is needed in these circumstances.

Visual inspection with acetic acid as a cervical cancer test: accuracy validated using latent class analysis

Background

The purpose of this study was to validate the accuracy of an alternative cervical cancer test – visual inspection with acetic acid (VIA) – by addressing possible imperfections in the gold standard through latent class analysis (LCA). The data were originally collected at peri-urban health clinics in Zimbabwe.

Methods

Conventional accuracy (sensitivity/specificity) estimates for VIA and two other screening tests using colposcopy/biopsy as the reference standard were compared to LCA estimates based on results from all four tests. For conventional analysis, negative colposcopy was accepted as a negative outcome when biopsy was not available as the reference standard. With LCA, local dependencies between tests were handled through adding direct effect parameters or additional latent classes to the model.

Results

Two models yielded good fit to the data, a 2-class model with two adjustments and a 3-class model with one adjustment. The definition of latent disease associated with the latter was more stringent, backed by three of the four tests. Under that model, sensitivity for VIA (abnormal+) was 0.74 compared to 0.78 with conventional analyses. Specificity was 0.639 versus 0.568, respectively. By contrast, the LCA-derived sensitivity for colposcopy/biopsy was 0.63.

Conclusion

VIA sensitivity and specificity with the 3-class LCA model were within the range of published data and relatively consistent with conventional analyses, thus validating the original assessment of test accuracy. LCA probably yielded more likely estimates of the true accuracy than did conventional analysis with in-country colposcopy/biopsy as the reference standard. Colpscopy with biopsy can be problematic as a study reference standard and LCA offers the possibility of obtaining estimates adjusted for referent imperfections.

Screening for cervical carcinoma using visual inspection with acetic acid

OBJECTIVE

To assess the performance of visual inspection with acetic acid (VIA) as a screening test for early detection of cervical carcinoma in the Dakahlia Governorate in Egypt.

METHODS

Diluted acetic acid (5%) was applied to the cervix during routine gynecologic examination. Women with positive results were referred for colposcopy. Those with negative results were referred for colposcopy only when they had clinical indications.

RESULTS

Among the 5,000 women who were screened using VIA, 409 were referred for colposcopy. Cervical intraepithelial neoplasia (CIN) was diagnosed in 151 (60%) of the 253 women with positive screening results and in 4 of the 156 women with negative screening results. There were 39 women with high-grade and 116 with low-grade CIN. The sensitivity and negative predictive value of the VIA screening test was 97%. Its positive predictive value was 60% for all grades of CIN and 90% for high-grade CIN.

CONCLUSION

Visual inspection with acetic acid, although associated with a relatively high rate of false-positive results, is a valuable test for the screening of cervical carcinoma.

Identification of high-grade cervical dysplasia by the detection of p16INK4a in cell lysates obtained from cervical samples

BACKGROUND

Current cervical cancer screening approaches are based on cytology supplemented by human papillomavirus (HPV) testing in some settings. Whereas cytology is laborious and depends on the cytologists' experience, HPV testing has limited specificity when it is used to detect high-grade lesions. A dichotomous test to identify high-grade lesions with greater specificity may be a useful tool for cervical cancer screening. p16(INK4a) is a cell-cycle regulator that has demonstrated strong overexpression in cervical precancer cells and cervical cancer induced by the deregulated expression of HPV oncogenes.

METHODS

The authors used a sandwich enzyme-linked immunosorbent assay (ELISA) to quantify the amount of solubilized p16(INK4a) protein in lysates that were prepared from cervical samples to detect high-grade cervical lesions. In total, 187 specimens that were obtained after sampling for conventional cytology in women who attended a cervical colposcopy clinic were analyzed. Seventy-six women underwent a biopsy, and 45 of those women showed histologically confirmed, high-grade cervical intraepithelial neoplasia.

RESULTS

For 76 women with biopsy-proven diagnoses, receiver operating characteristic (ROC) analysis of different cutoff values showed an area under the ROC curve of 0.89 for the detection of high-grade cervical dysplasia. At a cutoff value of 8 U/mL, the sensitivity of the p16(INK4a) ELISA for detecting high-grade dysplastic cervical lesions was 96%.

CONCLUSIONS

The data obtained in this study suggested that ELISA-based quantification of solubilized p16(INK4a) protein may have high sensitivity for detecting cervical precancer. Further population-based studies will be necessary to analyze the specificity and predictive values of p16(INK4a) protein quantification in cervical samples.