Adequacy of visual inspection with acetic acid in women of advancing age

Cervical Cancer Screening and Treatment Algorithms Using Human Papillomavirus Testing-Lessons Learnt from a South African Pilot Randomized Controlled Trial

BACKGROUND

To report quantitative and qualitative results on cervical cancer human papillomavirus (HPV)-based screening and treatment algorithms, with/out triage with visual inspection after acetic acid (VIA), followed by ablative treatment (AT).

METHODS

Women 30 to 54 years old from Durban, South Africa were recruited, regardless of human immunodeficiency virus (HIV) status, randomized into one of two study arms and screened for HPV. VIA triage arm: HPV-positive women were triaged using VIA, biopsied and received AT if VIA positive and eligible; no triage arm: eligible HPV-positive women received AT. Women ineligible for AT were referred to colposcopy. Women were asked about side effects immediately and 1 week after AT. Retention to screening and treatment algorithms was compared between arms.

RESULTS

A total of 350 women [275 HIV-uninfected and 75 women living with HIV, (WLWH)] were allocated to receive HPV testing with VIA triage (n = 175) or no triage (n = 175). HPV prevalence was 28% [95% confidence interval (CI) = 23-33]; WLWH: 52% (95% CI = 40-64) versus HIV-uninfected: 21% (95% CI = 17-27; P < 0.05). Among women who underwent VIA triage with histologic diagnosis, 3/17 were VIA negative with cervical intraepithelial neoplasia (CIN)2+; 14/18 were VIA positive with

CONCLUSIONS

This pilot demonstrated the feasibility of implementing screening and treatment algorithms, including performing triage and treatment in one visit; however, VIA triage did not reduce overtreatment and missed some precancerous lesions.

IMPACT

This study reports on implementation feasibility of two World Health Organization screening and treatment algorithms (with/out VIA triage). Although the retention to screening and treatment algorithms was high in both arms, the question of how best triaging HPV-positive women deserves further consideration, particularly for WLWH. See related In the Spotlight, p. 763.

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Key Words Collapse

MESH Headings

• Humans
• Female
• Uterine Cervical Neoplasms/virology
• Uterine Cervical Neoplasms/diagnosis
• Middle Aged
• Adult
• Algorithms
• South Africa/epidemiology
• Early Detection of Cancer/methods
• Pilot Projects
• Papillomavirus Infections/diagnosis
• Papillomavirus Infections/virology
• Papillomaviridae/isolation & purification
• Triage/methods
• Colposcopy
• Uterine Cervical Dysplasia/virology
• Uterine Cervical Dysplasia/diagnosis
• Uterine Cervical Dysplasia/therapy
• Human Papillomavirus Viruses

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Grants

• 001 World Health Organization
• HRP Alliance for Research Capacity Strengthening (RCS)

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Affiliation(s)

Hannah M. Sebitloane Discipline of Obstetrics and Gynaecology, School of Clinical Medicine, College of Health Sciences, University of KwaZulu-Natal, Durban, South Africa
Mathilde Forestier Early Detection, Prevention and Infections (EPR), International Agency for Research on Cancer, Lyon, France Department of Reproductive Health and Research, World Health Organization, Geneva, Switzerland
Themba G. Ginindza Public Health Medicine, University of KwaZulu-Natal, Durban, South Africa Cancer & Infectious Diseases Epidemiology Research Unit (CIDERU), College of Health Sciences, University of KwaZulu-Natal, Durban, South Africa
Wendy Dhlomo Discipline of Obstetrics and Gynaecology, School of Clinical Medicine, College of Health Sciences, University of KwaZulu-Natal, Durban, South Africa
Eshia Moodley-Govender Discipline of Obstetrics and Gynaecology, School of Clinical Medicine, College of Health Sciences, University of KwaZulu-Natal, Durban, South Africa
Teresa M. Darragh Department of Pathology, University of California, San Francisco, California
Armando Baena Early Detection, Prevention and Infections (EPR), International Agency for Research on Cancer, Lyon, France
Rolando Herrero Early Detection, Prevention and Infections (EPR), International Agency for Research on Cancer, Lyon, France Agencia Costarricense de Investigaciones Biomedicas, San José, Costa Rica
Maribel Almonte Early Detection, Prevention and Infections (EPR), International Agency for Research on Cancer, Lyon, France Department of Reproductive Health and Research, World Health Organization, Geneva, Switzerland Department of Non-communicable Diseases, World Health Organization, Geneva, Switzerland
Nathalie Broutet Department of Reproductive Health and Research, World Health Organization, Geneva, Switzerland
Hugo De Vuyst Early Detection, Prevention and Infections (EPR), International Agency for Research on Cancer, Lyon, France Department of Reproductive Health and Research, World Health Organization, Geneva, Switzerland

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Squamocolumnar junction visibility, age, and implications for cervical cancer screening programs

Visual assessment is currently used for primary screening or triage of screen-positive individuals in cervical cancer screening programs. Most guidelines recommend screening and triage up to at least age 65 years old. We examined cervical images from participants in three National Cancer Institute funded cervical cancer screening studies: ALTS (2864 participants recruited between 1996 to 1998) in the United States (US), NHS (7548 in 1993) in Costa Rica, and the Biopsy study (684 between 2009 to 2012) in the US. Specifically, we assessed the visibility of the squamocolumnar junction (SCJ), which is the susceptible zone for precancer/cancer by age, as reported by colposcopist reviewers either at examination or review of cervical images. The visibility of the SCJ declined substantially with age: by the late 40s the majority of people screened had at most partially visible SCJ. On longitudinal analysis, the change in SCJ visibility from visible to not visible was largest for participants from ages 40-44 in ALTS and 50-54 in NHS. Of note, in the Biopsy study, the live colposcopic exam resulted in significantly higher SCJ visibility as compared to review of static images (Weighted kappa 0.27 (95% Confidence Interval: 0.21, 0.33), Asymmetry chi-square P-value<0.001). Lack of SCJ visibility leads to increased difficulty in diagnosis and management of cervical precancers. Therefore, cervical cancer screening programs reliant on visual assessment might consider lowering the upper age limit for screening if there are not adequately trained personnel and equipment to evaluate and manage participants with inadequately visible SCJ.

Squamocolumnar junction visibility among cervical cancer screening population in Peru might influence upper age for screening programs

Cervical cancer screening and treatment of screen positives is an important and effective strategy to reduce cervical cancer morbidity and mortality. In order to have an accurate cervical cancer screening and evaluation of positives, the entire Squamocolumnar Junction (SCJ) must be visible. Throughout the life course, the position of the SCJ changes and affects its visibility. SCJ visibility was analyzed among participants screened at the League Against Cancer Clinic in Lima, Peru. Of the 4247 participants screened, the SCJ was fully visible in 49.7% of participants, partially visible in 23.1%, and not visible in 27.2%. Visibility decreased with age, and by age 45 years old, the SCJ was not fully visible in over 50% of participants. Our results show that a high percentage of participants at ages still recommended for screening do not have totally visible SCJ, and we may need to reconsider the upper age limit for screening and find new strategies for evaluation of those with a positive screening test and non-visible SCJ.

Diagnostic accuracy for alternative cervical cancer screening strategies: A systematic review and meta-analysis

We performed a systematic review and meta-analysis to evaluate the accuracy of screening cervical cancer tests as alternative standalone methods. The combined estimates of sensitivity of visual inspection with acetic acid, visual inspection with lugol's iodine, conventional pap smear, liquid-based cytology, High risk HPV testing by clinician, High risk HPV testing by self- sampling, cervicography were 64%, 80%, 55%, 70%, 70% and 67% respectively; the combine values of specificity of these screening strategies were 88%, 88%, 96%, 59%, 94%, and 95% respectively. Our findings draw attention to an attractive opinion to facilitate the collection of specimens for DNA HPV by patients in settings where they don't have access to a regular screening programs.

Addressing cervical cancer screening disparities through advances in artificial intelligence and nanotechnologies for cellular profiling

Almost all cases of cervical cancer are caused by the human papilloma virus (HPV). Detection of pre-cancerous cervical changes provides a window of opportunity for cure of an otherwise lethal disease when metastatic. With a greater understanding of the biology and natural course of high-risk HPV infections, screening methods have shifted beyond subjective Pap smears toward more sophisticated and objective tactics. This has led to a substantial growth in the breadth and depth of HPV-based cervical cancer screening tests, especially in developed countries without constrained resources. Many low- and middle-income countries (LMICs) have less access to advanced laboratories and healthcare resources, so new point-of-care (POC) technologies have been developed to provide test results in real time, improve the efficiency of techniques, and increase screening adoption. In this Review, we will discuss how novel decentralized screening technologies and computational strategies improve upon traditional methods and how their realized promise could further democratize cervical cancer screening and promote greater disease prevention.

Performance of careHPV, hybrid capture 2 and visual inspection with acetic acid for detection of high-grade cervical lesion in Tanzania: A cross-sectional study

Objective

To examine the test performance of careHPV, Hybrid Capture2 (HC2) and visual inspection with acetic acid (VIA) for detection of cytologically diagnosed high-grade cervical lesions or cancer (HSIL+).

Design

Cross-sectional study.

Setting

Ocean Road Cancer Institute (ORCI) and Kilimanjaro Christian Medical Center (KCMC), Tanzania.

Population

Women attending routine cervical cancer screening.

Method

We enrolled 4080 women (25–60 years) in the study. The women were interviewed on lifestyle habits, and tested for HIV. A cervical specimen for careHPV testing (performed at ORCI and KCMC), and a liquid-based cytology sample for HPV DNA detection using HC2 (performed at Tuebingen University Hospital, Germany) and for cytology assessment (performed at Vejle Hospital, Denmark) were obtained at a gynecological examination. Subsequently, VIA was performed. With cytology as gold standard, the sensitivity and specificity of careHPV, HC2, and VIA for detection of HSIL+ were calculated.

Results

Altogether, 23.6% had a positive careHPV test, 19.1% had positive HC2 test, and 6.3% had a positive VIA test. The sensitivity/specificity was 88.9%/78.9% for careHPV and 91.1%/83.7%, for HC2. VIA showed a low sensitivity of 31.1% but a high specificity (94.6%) for detection of HSIL+. The sensitivity of careHPV, HC2 and VIA was higher among younger women, and among HIV positive women. VIA triage of careHPV positive women improved specificity, but sensitivity dropped to 27%.

Conclusion

Our results confirm the low sensitivity of VIA for detection of HSIL+ and further document that careHPV test is promising as a primary screening method for cervical-cancer prevention in low-resource regions. A suitable triage test has to be identified.

Cervical cancer prevention in El Salvador (CAPE)-An HPV testing-based demonstration project: Changing the secondary prevention paradigm in a lower middle-income country

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CareHPV tests were used to compare screen-and-treat and colposcopy management.

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Screen-and-treat strategy with HPV testing was found to be very cost-effective.

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CAPE has screened > 25,000 women in the Paracentral region.

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Over 70% of screen-positive women received recommended treatment within six months.

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CAPE is an example of public-private partnership resulting in paradigm change.

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.

Evaluation of multiple primary and combination screening strategies in postmenopausal women for detection of cervical cancer in China

As China's population ages, the importance of determining prevalence of cervical disease and accurate cervical cancer screening strategies for postmenopausal women is increasing. Seventeen population-based studies were analyzed to determine prevalence of cervical neoplasia in postmenopausal women. All women underwent HPV DNA testing, visual inspection with acetic acid (VIA) and cytology testing. Diagnostic values for primary and combinations screening methods included sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), referral rate and area under curve (AUC) were calculated using directed biopsy or four quadrants biopsy as reference standard. Premenopausal and postmenopausal women had equal HPV infection and cervical neoplasia rates (p > 0.05). HPV DNA testing CIN3+ sensitivity, specificity, PPV, NPV, referral rate and AUC were 97.9% (95% CI: 90.2-99.9%), 84.2% (95% CI: 82.8-85.5%), 9.9% (95% CI: 7.4-12.8%), 100% (95% CI: 99.8-100%), 17.2% (95% CI: 15.9-18.7%), 0.911, respectively. VIA values were 41.7% (95% CI: 28.4-55.9%), 94.5% (95% CI: 93.6-95.3%), 11.8% (95% CI: 7.5-17.3%), 98.9% (95% CI: 98.5-99.3%), 6.2% (95% CI: 5.3-7.1%) and 0.681, respectively. Values for VIA with HPV triage were 39.6% (95% CI: 26.6-53.8%), 99.2% (95% CI: 98.8-99.5%), 45.2% (95% CI: 30.8-60.4%), 98.9% (95% CI: 98.5-99.3%), 1.5% (95% CI: 1.1-2.0%) and 0.694, respectively. VIA and HPV DNA co-test values were 100% (95% CI: 94.0-100%), 79.5% (95% CI: 78.0-81.0%), 8.0% (95% CI: 6.0-10.3%), 100% (95% CI: 99.9-100%), 21.9% (95% CI: 20.4-23.4%) and 0.898, respectively. VIA sensitivity decreases significantly in postmenopausal women compared to premenopausal performance. HPV DNA testing maintains performance between pre- and postmenopausal women and is the most accurate primary modality for screening postmenopausal populations in low resource areas of China.

Resources Required for Cervical Cancer Prevention in Low- and Middle-Income Countries

BACKGROUND

Cervical cancer is the fourth leading cause of cancer death in women, with 85% of cases and deaths occurring in developing countries. While organized screening programs have reduced cervical cancer incidence in high-income countries through detection and treatment of precancerous lesions, the implementation of organized screening has not been effective in low-resource settings due to lack of infrastructure and limited budgets. Our objective was to estimate the cost of comprehensive primary and secondary cervical cancer prevention in low- and middle-income countries.

METHODS AND FINDINGS

We performed a modeling analysis to estimate 1) for girls aged 10 years, the cost of 2-dose human papillomavirus (HPV) vaccination; and 2) for women aged 30 to 49 years, the cost of cervical cancer screening (with visual inspection with acetic acid (VIA), HPV testing, or cytology) and preventive treatment in 102 low- and middle-income countries from 2015 to 2024. We used an Excel-based costing and service utilization model to estimate financial costs (2013 US$) based on prevalence of HPV, prevalence of precancerous lesions, and screening test performance. Where epidemiologic data were unavailable, we extrapolated from settings with data using an individual-based microsimulation model of cervical carcinogenesis (calibrated to 20 settings) and multivariate regression. Total HPV vaccination costs ranged from US$8.6 billion to US$24.2 billion for all scenarios considered (immediate, 5-year, or 10-year roll-out; price per dose US$4.55-US$70 by country income level). The total cost of screening and preventive treatment ranged from US$5.1 billion (10-year roll-out, screening once at age 35 years) to US$42.3 billion (immediate roll-out, high intensity screening). Limitations of this analysis include the assumption of standardized protocols by country income level that did not account for the potential presence of multiple screening modalities or management strategies within a country, and extrapolation of cost and epidemiologic data to settings where data were limited.

CONCLUSIONS

The estimated cost of comprehensive cervical cancer prevention with 2-dose HPV vaccination of 10-year-old girls and screening of women aged 30 to 49 years ranges from US$13.7 billion to US$66.5 billion, depending on speed of roll-out, vaccine price per dose, and screening test and frequency. Findings demonstrate the substantial impact of vaccine price in middle-income countries that are not eligible for assistance from Gavi, the Vaccine Alliance. Replacing routine cytology with HPV-based screening may reduce total costs. Data on the health impact and relative cost-effectiveness of strategies are needed to determine the best value for public health dollars.

Clinical Practice Guidelines on the Screening and Treatment of Precancerous Lesions for Cervical Cancer Prevention in Saudi Arabia

BACKGROUND

Cervical cancer is the third most common gynecological malignancy in Saudi women with an estimated incidence rate of 1.9 cases per 100 000 women-years. More than 40% of cervical cancer cases are diagnosed at advanced stages due to lack of a routine screening program in Saudi Arabia. Thus, national guidelines for routine screening and treatment of precancerous cervical lesions are needed.

METHODS

The Saudi Centre for Evidence-Based Healthcare invited a panel of local experts and partnered them with a team from McMaster University in Canada for methodological support, to develop national clinical practice guidelines on the screening and treatment of precancerous lesions for cervical cancer. After the panel identified key clinical questions, the McMaster University working group updated existing systematic reviews that had been used for the 2013 WHO Guidelines for screening and treatment of precancerous lesions for cervical cancer prevention. Recommendations were based on the GRADE (Grading of Recommendations, Assessment, Development and Evaluation) approach. Those recommendations took into account the available evidence, patient values and preferences, and resource use in the Saudi context. The panel provided recommendations on two major issues: screening for precancerous lesions (cervical intraepithelial neoplasia 2 & 3) and treatment of those lesions to prevent cervical cancer in women who tested positive after screening.

CONCLUSIONS

The Saudi expert panel recommends using the HPV DNA test followed by colposcopy or cytology (Pap test) followed by colposcopy to screen for CIN2+ in women at risk of cervical cancer. The panel recommends cryotherapy or loop excision electrosurgery procedure (LEEP) over cold knife cone biopsy to treat women at risk of cervical cancer that tests positive for CIN2+. Universal screening for precancerous cervical dysplasia in women in Saudi Arabia is recommended using HPV testing and or cytology. Either cryotherapy or LEEP are preferred for treatment.

LIMITATIONS

National studies on cervical cancer screening modalities and treatment of precancerous cervical lesions, including HPV prevalence and its association with cervical cancer, are scarce.

Visual Inspection of Cervix With Acetic Acid as a Screening Modality for Cervical Cancer

OBJECTIVE

To assess feasibility and suitability of visual inspection of cervix with acetic acid (VIA) in detecting cervical intraepithelial neoplasia (CIN), and compare it with Papanicolaou test.

METHODS

This was a diagnostic accuracy cross-sectional study conducted at an Egyptian teaching hospital, where 784 women were offered Papanicolaou test, VIA, colposcopy, and cervical biopsy.

RESULTS

Histopathologically confirmed CIN 2/3 was noted in 26 cases (3.3%) and cervical cancer in 3 cases (0.4%). Twenty-seven (93.1%) of these 29 cases of CIN 2+, including one invasive cancer, were suggested by VIA. The test sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) to detect CIN 2+ were 93.1%, 90.6%, 26.6%, and 99.7%, respectively. Positive likelihood ratio (LR +) and negative likelihood ratio (LR-) for VIA were 9.90 (95% confidence interval [CI], 7.77-12.62) and 0.08 (95% CI, 0.02-0.29), respectively. Twenty-six cases (89.7%) of CIN 2+ were suggested by Papanicolaou test, whereas all 3 cancers were missed by this test. Papanicolaou test sensitivity, specificity, PPV, and NPV to detect CIN 2+ were 89.7%, 99.1%, 78.8%, and 99.6%, respectively. Positive likelihood ratio and LR- for the Papanicolaou test were 96.7 (95% CI, 45.78-204.23) and 0.10 (95% CI, 0.04-0.3), respectively. Colposcopy suggested 28 cases (96.6%) of CIN 2+, including 2 cancers. Colposcopy sensitivity, specificity, PPV, and NPV to detect CIN 2+ were 96.6%, 99.2%, 82.4%, and 99.9%, respectively.

CONCLUSION

Visual inspection of the cervix with acetic acid is a feasible and suitable screening test for cervical cancer in under-resourced settings in developing countries. Its performance is comparable to the Papanicolaou test.

Accuracy of visual inspection with acetic acid and with Lugol's iodine for cervical cancer screening: Meta-analysis

The aim of this review was to provide an updated summary estimation of the accuracy of visual inspection with acetic acid (VIA) and with Lugol's iodine (VILI) in detecting cervical cancer and precancer. Studies on VIA/VILI accuracy were eligible in which VIA/VILI was performed on asymptomatic women who all underwent confirmatory testing of histology, combination of colposcopy and histology, or combination of multiple screening tests, colposcopy and histology, to detect cervical intraepithelial neoplasia grade 2 or worse (CIN2+ or CIN3+). A bivariate model was fitted to estimate the accuracy of VIA/VILI and provide estimates of heterogeneity. Subgroup analysis was used to investigate the source of heterogeneity. A total of 29 studies on VIA and 19 studies on VILI were included finally in the meta-analysis. The summary sensitivity and specificity of VIA for CIN2+ were 73.2% (95%CI: 66.5-80.0%) and 86.7% (95%CI: 82.9-90.4%), respectively, and those for VILI were 88.1% (95%CI: 81.5-94.7%) and 85.9% (95%CI: 81.7-90.0%), respectively. VIA and VILI were both more sensitive in detecting more severe outcome, although there was a slight loss in specificity. Apparent heterogeneity existed in sensitivity and specificity for both VIA and VILI. High sensitivity of both VIA and VILI for CIN2+ was found when a combination of colposcopy and histology was used as disease confirmation. VIA, VILI, even a combination of them in parallel, could be good options for cervical screening in low-resource settings. Significant differences in sensitivity between different gold standards might provide a proxy for optimization of ongoing cervical cancer screening programs.

Accuracy of visual inspection with acetic acid in detecting high-grade cervical intraepithelial neoplasia in pre- and post-menopausal Thai women with minor cervical cytological abnormalities

PURPOSE

To determine the accuracy of visual inspection with acetic acid (VIA) in detecting high-grade cervical intraepithelial neoplasia (CIN) in pre- and post-menopausal women with atypical squamous cells of undetermined significance (ASC-US) and low grade squamous intraepithelial lesion (LSIL) Papanicolaou (Pap) smears.

MATERIALS AND METHODS

Two hundred women (150 pre-menopausal and 50 post-menopausal) with ASC- US and LSIL cytology who attended the colposcopy clinic, Thammasat University Hospital, between March 2013 and August 2014 were included. All women underwent VIA testing and colposcopy by gynecologic oncologists. Diagnostic values of VIA testing including sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) for detecting high-grade CIN were determined using the histopathology obtained from colposcopic-directed biopsy as a gold standard.

RESULTS

VIA testing was positive in 54/150 (36%) pre-menopausal women and 5/50 (10%) post-menopausal women. Out of 54 pre-menopausal women with positive VIA testing, 15 (27.8%) had high-grade CIN and 39 (72.2%) had either CIN 1 or insignificant pathology. Ten (10.4%), 43 (44.8%) and 43 (44.8%) out of the remaining 96 pre-menopausal women with negative VIA testing had high- grade CIN, CIN 1 and insignificant pathology, respectively. Out of 5 post-menopausal women with positive VIA testing, there were 4 (80%) women with high-grade CIN, and 1 (20%) women with insignificant pathology. Out of 45 VIA-negative post-menopausal women, 42 (93.3%) women had CIN 1 and insignificant pathology, and 3 (6.7%) had high-grade CIN. Sensitivity, specificity, PPV and NPV of the VIA testing were 59.4%, 76.2%, 32.2% and 90.8%, respectively (60%, 68.8%, 27.8% and 89.6% in pre-menopausal women and 57.1%, 97.7%, 80% and 93.3% in post-menopausal women).

CONCLUSIONS

VIA testing may be used as a screening tool for detecting high-grade CIN in women with minor cervical cytological abnormalities in a low-resource setting in order to lower the rate of colposcopy referral.

Cervical cancer precursors and hormonal contraceptive use in HIV-positive women: application of a causal model and semi-parametric estimation methods

OBJECTIVE

To demonstrate the application of causal inference methods to observational data in the obstetrics and gynecology field, particularly causal modeling and semi-parametric estimation.

BACKGROUND

Human immunodeficiency virus (HIV)-positive women are at increased risk for cervical cancer and its treatable precursors. Determining whether potential risk factors such as hormonal contraception are true causes is critical for informing public health strategies as longevity increases among HIV-positive women in developing countries.

METHODS

We developed a causal model of the factors related to combined oral contraceptive (COC) use and cervical intraepithelial neoplasia 2 or greater (CIN2+) and modified the model to fit the observed data, drawn from women in a cervical cancer screening program at HIV clinics in Kenya. Assumptions required for substantiation of a causal relationship were assessed. We estimated the population-level association using semi-parametric methods: g-computation, inverse probability of treatment weighting, and targeted maximum likelihood estimation.

RESULTS

We identified 2 plausible causal paths from COC use to CIN2+: via HPV infection and via increased disease progression. Study data enabled estimation of the latter only with strong assumptions of no unmeasured confounding. Of 2,519 women under 50 screened per protocol, 219 (8.7%) were diagnosed with CIN2+. Marginal modeling suggested a 2.9% (95% confidence interval 0.1%, 6.9%) increase in prevalence of CIN2+ if all women under 50 were exposed to COC; the significance of this association was sensitive to method of estimation and exposure misclassification.

CONCLUSION

Use of causal modeling enabled clear representation of the causal relationship of interest and the assumptions required to estimate that relationship from the observed data. Semi-parametric estimation methods provided flexibility and reduced reliance on correct model form. Although selected results suggest an increased prevalence of CIN2+ associated with COC, evidence is insufficient to conclude causality. Priority areas for future studies to better satisfy causal criteria are identified.

A comparison of two visual inspection methods for cervical cancer screening among HIV-infected women in Kenya

OBJECTIVE

To determine the optimal strategy for cervical cancer screening in women with human immunodeficiency virus (HIV) infection by comparing two strategies: visual inspection of the cervix with acetic acid (VIA) and VIA followed immediately by visual inspection with Lugol's iodine (VIA/VILI) in women with a positive VIA result.

METHODS

Data from a cervical cancer screening programme embedded in two HIV clinic sites in western Kenya were evaluated. Women at a central site underwent VIA, while women at a peripheral site underwent VIA/VILI. All women positive for cervical intraepithelial neoplasia grade 2 or worse (CIN 2+) on VIA and/or VILI had a confirmatory colposcopy, with a biopsy if necessary. Overall test positivity, positive predictive value (PPV) and the CIN 2+ detection rate were calculated for the two screening methods, with biopsy being the gold standard.

FINDINGS

Between October 2007 and October 2010, 2338 women were screened with VIA and 1124 with VIA/VILI. In the VIA group, 26.4% of the women tested positive for CIN 2+; in the VIA/VILI group, 21.7% tested positive (P < 0.01). Histologically confirmed CIN 2+ was detected in 8.9% and 7.8% (P = 0.27) of women in the VIA and VIA/VILI groups, respectively. The PPV of VIA for biopsy-confirmed CIN 2+ in a single round of screening was 35.2%, compared with 38.2% for VIA/VILI (P = 0.41).

CONCLUSION

The absence of any differences between VIA and VIA/VILI in detection rates or PPV for CIN 2+ suggests that VIA, an easy testing procedure, can be used alone as a cervical cancer screening strategy in low-income settings.

Risk factors for cervical precancer detection among previously unscreened HIV-infected women in Western Kenya

HIV and cervical cancer are intersecting epidemics in many low-resource settings, yet there are few accurate estimates of the scope of this public health challenge. To understand disease prevalence and risk factors for cervical intraepithelial neoplasia 2 or greater (CIN2+), we conducted a cross-sectional study of women undergoing cervical cancer screening as part of routine HIV care in Kisumu, Kenya. Women were offered screening with visual inspection with acetic acid, followed by confirmation with colposcopy and biopsy as needed. Univariable and multivariable analyses were carried out to determine clinical and demographic predictors of prevalent CIN2+. Among 3,241 women screened, 287 (9%) had an initial diagnosis of biopsy-confirmed CIN2+. On multivariable analysis, combined oral contraceptives remained significantly associated with detection of CIN2+ among women on HAART (AOR 1.84, CI 1.20-2.82), and not on HAART (AOR 1.72, 95% CI 1.08-2.73), while use of a progesterone implant was associated with increased detection of CIN2+ (AOR 9.43, 95% CI 2.85-31.20) only among women not on HAART. CD4+ nadir over 500 cells/mm(3) was associated with reduced detection of CIN2+ (AOR 0.61, CI 0.38, 0.97) in the overall group, but current CD4+ was only associated with reduced detection of CIN2+ among women not on HAART (AOR 0.42, CI 0.22, 0.80). In conclusion, a history of less severe immunosuppression appeared to reduce the risk of CIN2+ detection, but current CD4+ count was significant only in non-HAART users. The association of CIN2+ with hormonal contraception should be explored more in prospective studies designed to better control for confounding factors.

Screening for Cervical Cancer in Low-Resource Settings in 2011

Context.—Cervical cancer remains the most common malignancy in women living in low- and middle-income countries, despite the decline of the disease in countries where cervical cytology screening programs have been implemented.

Objectives.—To review the current incidence of cervical cancer in low-resource countries, the availability and types of screening programs, and the treatment options.

Data Sources.—Literature review through PubMed, Internet search, and personal communication.

Conclusions.—Although data are incomplete, available figures confirm that the rate of cervical cancer deaths and the availability of cervical cancer screening programs are inversely proportional and vary, in general, by the wealth of the nation. Despite the success of cervical cytology screening, many major health care organizations have abandoned screening by cytology in favor of direct visualization methods with immediate treatment of lesions by cryotherapy provided by trained, nonmedical personnel.

Visual inspection with acetic acid for detection of high grade lesion in atypical squamous cells and low grade squamous intraepithelial lesions from cervical Pap smear

Objective

To evaluate the value of visual inspection with acetic acid (VIA) test to detect high grade lesion in women with atypical squamous cells or low grade squamous intraepithelial lesions cervical cytology.

Methods

Women with atypical squamous cells or low grade squamous intraepithelial lesions who were scheduled to undergo colposcopy at Vajira Hospital and met inclusion criteria were included. All participants underwent VIA test prior to usual steps of colposcopy. The VIA results were interpreted as positive or negative using the criteria by the International Agency for Cancer Research. The standard colposcopic examination and appropriate investigations for cervical pathology were then continued. The diagnostic values of VIA test including sensitivity, specificity, positive predictive value, and negative predictive value were determined using high grade lesion including cervical intraepithelial neoplasia 2-3 and squamous cell carcinoma as a threshold.

Results

Total of 106 women was included. The VIA test was positive in 33 women (31.1%) and negative in 73 women (68.9%). Among the women with VIA test positive, 14 had high grade lesion (42.4%) while 19 had no significant lesions. Only 2/73 (2.7%) cases with negative VIA test had high grade lesion (both had cervical intraepithelial neoplasia 2). The sensitivity, specificity, positive predictive value and negative predictive value with 95% confidence interval were 87.5% (81.2 to 93.8%), 78.8% (71.1 to 86.7%), 42.4% (33.0 to 51.8%), and 97.2% (94.2 to 1.0%) respectively.

Conclusion

VIA as the intermediate test in atypical squamous cells and low grade squamous intraepithelial lesions cytology may reduce the necessity to refer some women for colposcopy.

See-and-treat approaches to cervical cancer prevention for HIV-infected women

Cervical cancer remains the second commonest cancer among women worldwide, and more than 85% of the global burden of this disease occurs in the developing world. HIV-infected women have a higher likelihood of developing persistent high-risk human papillomavirus (HPV) infection, precancer, and invasive cervical cancer than seronegative women. Although highly effective primary and secondary prevention strategies are currently available, they remain inaccessible to the vast majority of women. Because of their simplicity and affordability, see-and-treat cervical cancer screening modalities have the potential to substantially improve women's access to cancer prevention, as well as to create much needed infrastructure for future molecular-based cervical screening and HPV vaccination programs. Additional data addressing the effectiveness of see-and-treat approaches for HIV-infected women are urgently needed. Studies informing best practice guidelines on when to start, when to stop, and how frequently to screen HIV-infected women within the see-and-treat paradigm would be of great value.