Internal Validation of Automated Visual Evaluation (AVE) on Smartphone Images for Cervical Cancer Screening in a Prospective Study in Zambia

Objectives

Visual inspection with acetic acid (VIA) is a low-cost approach for cervical cancer screening used in most low- and middle-income countries (LMICs) but, similar to other visual tests like histopathology, is subjective and requires sustained training and quality assurance. We developed, trained, and validated an artificial-intelligence-based "Automated Visual Evaluation" (AVE) tool that can be adapted to run on smartphones to assess smartphone-captured images of the cervix and identify precancerous lesions, helping augment performance of VIA.

Design

Prospective study.

Setting

Eight public health facilities in Zambia.

Participants

8,204 women aged 25-55.

Interventions

Cervical images captured on commonly used low-cost smartphone models were matched with key clinical information including human immunodeficiency virus (HIV) and human papillomavirus (HPV) status, plus histopathology analysis (where applicable), to develop and train an AVE algorithm and evaluate its performance for use as a primary screen and triage test for women who are HPV positive.

Main outcome measures

Area under the receiver operating curve (AUC); sensitivity; specificity.

Results

As a general population screening for cervical precancerous lesions, AVE identified cases of cervical precancerous and cancerous (CIN2+) lesions with high performance (AUC = 0.91, 95% confidence interval [CI] = 0.89 to 0.93), which translates to a sensitivity of 85% (95% CI = 81% to 90%) and specificity of 86% (95% CI = 84% to 88%) based on maximizing the Youden's index. This represents a considerable improvement over VIA, which a meta-analysis by the World Health Organization (WHO) estimates to have sensitivity of 66% and specificity of 87%. For women living with HIV, the AUC of AVE was 0.91 (95% CI = 0.88 to 0.93), and among those testing positive for high-risk HPV types, the AUC was 0.87 (95% CI = 0.83 to 0.91).

Conclusions

These results demonstrate the feasibility of utilizing AVE on images captured using a commonly available smartphone by screening nurses and support our transition to clinical evaluation of AVE's sensitivity, specificity, feasibility, and acceptability across a broader range of settings. The performance of the algorithm as reported may be inflated, as biopsies were obtained only from study participants with visible aceto-white cervical lesions, which can lead to verification bias; and the images and data sets used for testing of the model, although "unseen" by the algorithm during training, were acquired from the same set of patients and devices, limiting the study to that of an internal validation of the AVE algorithm.

Validation in Zambia of a cervical screening strategy including HPV genotyping and artificial intelligence (AI)-based automated visual evaluation

BACKGROUND

WHO has recommended HPV testing for cervical screening where it is practical and affordable. If used, it is important to both clarify and implement the clinical management of positive results. We estimated the performance in Lusaka, Zambia of a novel screening/triage approach combining HPV typing with visual assessment assisted by a deep-learning approach called automated visual evaluation (AVE).

METHODS

In this well-established cervical cancer screening program nested inside public sector primary care health facilities, experienced nurses examined women with high-quality digital cameras; the magnified illuminated images permit inspection of the surface morphology of the cervix and expert telemedicine quality assurance. Emphasizing sensitive criteria to avoid missing precancer/cancer, ~ 25% of women screen positive, reflecting partly the high HIV prevalence. Visual screen-positive women are treated in the same visit by trained nurses using either ablation (~ 60%) or LLETZ excision, or referred for LLETZ or more extensive surgery as needed. We added research elements (which did not influence clinical care) including collection of HPV specimens for testing and typing with BD Onclarity™ with a five channel output (HPV16, HPV18/45, HPV31/33/52/58, HPV35/39/51/56/59/66/68, human DNA control), and collection of triplicate cervical images with a Samsung Galaxy J8 smartphone camera™ that were analyzed using AVE, an AI-based algorithm pre-trained on a large NCI cervical image archive. The four HPV groups and three AVE classes were crossed to create a 12-level risk scale, ranking participants in order of predicted risk of precancer. We evaluated the risk scale and assessed how well it predicted the observed diagnosis of precancer/cancer.

RESULTS

HPV type, AVE classification, and the 12-level risk scale all were strongly associated with degree of histologic outcome. The AVE classification showed good reproducibility between replicates, and added finer predictive accuracy to each HPV type group. Women living with HIV had higher prevalence of precancer/cancer; the HPV-AVE risk categories strongly predicted diagnostic findings in these women as well.

CONCLUSIONS

These results support the theoretical efficacy of HPV-AVE-based risk estimation for cervical screening. If HPV testing can be made affordable, cost-effective and point of care, this risk-based approach could be one management option for HPV-positive women.

Thermal ablation versus cryotherapy or loop excision to treat women positive for cervical precancer on visual inspection with acetic acid test: pilot phase of a randomised controlled trial

BACKGROUND

Cryotherapy is standard practice for treating patients with cervical precancer in see-and-treat programmes in low-income and middle-income countries (LMICs). Because of logistical difficulties with cryotherapy (eg, the necessity, costs, and supply chain difficulties of refrigerant gas; equipment failure; and treatment duration >10 min), a battery-operated thermal ablator that is lightweight and portable has been developed. We aimed to compare thermal ablation using the new device with cryotherapy.

METHODS

We report the pilot phase of a randomised controlled trial in routine screen-and-treat clinics providing cervical screening using visual inspection with acetic acid (VIA) in Lusaka, Zambia. We recruited non-pregnant women, aged 25 years or older, who were eligible for ablative therapy. We randomly assigned participants (1:1:1) to thermal ablation, cryotherapy, or large loop excision of the transformation zone (LLETZ), using computer-generated allocation. The randomisation was concealed but the nurses providing treatment and the participants were unmasked. Thermal ablation was achieved using the Liger thermal ablator (using 1-5 overlapping applications of the probe heated to 100°C, each application lasting for 40 s), cryotherapy was carried out using the double-freeze technique (freeze for 3 min, thaw for 5 min, and freeze again for 3 min), and LLETZ (using a large loop driven by an electro-surgical unit to excise the transformation zone) was done under local anaesthesia. The primary endpoint was treatment success, defined as either human papillomavirus (HPV) type-specific clearance among participants who were positive for the same HPV type at baseline, or a negative VIA test at 6-month follow-up, if the baseline HPV test was negative. Per protocol analyses were done. Enrolment for the full trial is ongoing. Here, we present findings from a prespecified pilot phase of the full trial. The final analysis of the full trial will assess non-inferiority of the groups for the primary efficacy endpoint. The study is registered with ClinicalTrials.gov, number NCT02956239.

FINDINGS

Between Aug 2, 2017, and Jan 15, 2019, 750 participants were randomly assigned (250 per group). 206 (84%) participants in the cryotherapy group, 197 (81%) in the thermal ablation group, and 204 (84%) in the LLETZ group attended the 6-month follow-up examination. Treatment success was reported in 120 (60%) of 200 participants in the cryotherapy group, 123 (64%) of 192 in the thermal ablation group, and 134 (67%) of 199 in the LLETZ group (p=0·31). Few participants complained of moderate to severe pain in any group immediately after the procedure (six [2%] of 250 in the cryotherapy group, four [2%] of 250 in the thermal ablation group, and five [2%] of 250 in the LLETZ group) and 2 weeks after the procedure (one [<1%] of 241 in the cryotherapy group, none of 242 in the thermal ablation group, and two [<1%] of 237 in the LLETZ group). None of the participants reported any complication requiring medical consultation or admission to hospital.

INTERPRETATION

Results from this pilot study preliminarily suggest that thermal ablation has similar treatment success to cryotherapy, without the practical disadvantages of providing cryotherapy in an LMIC. However, the study was not powered to establish the similarity between the techniques, and results from the ongoing randomised controlled trial are need to confirm these results.

FUNDING

US National Institutes of Health.

The burden of cervical pre-cancer and cancer in HIV positive women in Zambia: a modeling study

Background

HIV infection is associated with a higher incidence of precancerous cervical lesions and their progression to invasive cervical cancer (ICC). Zambia is a global epicenter of HIV and ICC, yet the overall burden of cervical pre-cancer [cervical intraepithelial neoplasia 3 (CIN3)] and ICC among its HIV positive adult female population is unknown. The objective of this study was to determine the burden of cervical disease among HIV positive women in Zambia by estimating the number with CIN3 and ICC.

Methods

We conducted a cross-sectional study among 309 HIV positive women attending screening in Lusaka (Zambia’s most populated province) to measure the cervical disease burden by visual inspection with acetic acid enhanced by digital cervicography (DC), cytology, and histology. We then used estimates of the prevalence of CIN3 and ICC from the cross-sectional study and Spectrum model-based estimates for HIV infection among Zambian women to estimate the burden of CIN3 and ICC among HIV positive women nationally.

Results

Over half (52 %) of the study participants screened positive by DC, while 45 % had cytologic evidence of high grade squamous intraepithelial lesions (SIL) or worse. Histopathologic evaluation revealed that 20 % of women had evidence of CIN2 or worse, 11 % had CIN3 or worse, and 2 % had ICC. Using the Spectrum model, we therefore estimate that 34,051 HIV positive women in Zambia have CIN3 and 7,297 have ICC.

Conclusions

The DC, cytology, and histology results revealed a large cervical disease burden in this previously unscreened HIV positive population. This very large burden indicates that continued scale-up of cervical cancer screening and treatment is urgently needed.

Population-level scale-up of cervical cancer prevention services in a low-resource setting: development, implementation, and evaluation of the cervical cancer prevention program in Zambia

BACKGROUND

Very few efforts have been undertaken to scale-up low-cost approaches to cervical cancer prevention in low-resource countries.

METHODS

In a public sector cervical cancer prevention program in Zambia, nurses provided visual-inspection with acetic acid (VIA) and cryotherapy in clinics co-housed with HIV/AIDS programs, and referred women with complex lesions for histopathologic evaluation. Low-cost technological adaptations were deployed for improving VIA detection, facilitating expert physician opinion, and ensuring quality assurance. Key process and outcome indicators were derived by analyzing electronic medical records to evaluate program expansion efforts.

FINDINGS

Between 2006-2013, screening services were expanded from 2 to 12 clinics in Lusaka, the most-populous province in Zambia, through which 102,942 women were screened. The majority (71.7%) were in the target age-range of 25-49 years; 28% were HIV-positive. Out of 101,867 with evaluable data, 20,419 (20%) were VIA positive, of whom 11,508 (56.4%) were treated with cryotherapy, and 8,911 (43.6%) were referred for histopathologic evaluation. Most women (87%, 86,301 of 98,961 evaluable) received same-day services (including 5% undergoing same-visit cryotherapy and 82% screening VIA-negative). The proportion of women with cervical intraepithelial neoplasia grade 2 and worse (CIN2+) among those referred for histopathologic evaluation was 44.1% (1,735/3,938 with histopathology results). Detection rates for CIN2+ and invasive cervical cancer were 17 and 7 per 1,000 women screened, respectively. Women with HIV were more likely to screen positive, to be referred for histopathologic evaluation, and to have cervical precancer and cancer than HIV-negative women.

INTERPRETATION

We creatively disrupted the 'no screening' status quo prevailing in Zambia and addressed the heavy burden of cervical disease among previously unscreened women by establishing and scaling-up public-sector screening and treatment services at a population level. Key determinants for successful expansion included leveraging HIV/AIDS program investments, and context-specific information technology applications for quality assurance and filling human resource gaps.

Utilization of cervical cancer screening services and trends in screening positivity rates in a 'screen-and-treat' program integrated with HIV/AIDS care in Zambia

Background

In the absence of stand-alone infrastructures for delivering cervical cancer screening services, efforts are underway in sub-Saharan Africa to dovetail screening with ongoing vertical health initiatives like HIV/AIDS care programs. Yet, evidence demonstrating the utilization of cervical cancer prevention services in such integrated programs by women of the general population is lacking.

Methods

We analyzed program operations data from the Cervical Cancer Prevention Program in Zambia (CCPPZ), the largest public sector programs of its kind in sub-Saharan Africa. We evaluated patterns of utilization of screening services by HIV serostatus, examined contemporaneous trends in screening outcomes, and used multivariable modeling to identify factors associated with screening test positivity.

Results

Between January 2006 and April 2011, CCPPZ services were utilized by 56,247 women who underwent cervical cancer screening with visual inspection with acetic acid (VIA), aided by digital cervicography. The proportion of women accessing these services who were HIV-seropositive declined from 54% to 23% between 2006–2010, which coincided with increasing proportions of HIV-seronegative women (from 22% to 38%) and women whose HIV serostatus was unknown (from 24% to 39%) (all p-for trend<0.001). The rates of VIA screening positivity declined from 47% to 17% during the same period (p-for trend <0.001), and this decline was consistent across all HIV serostatus categories. After adjusting for demographic and sexual/reproductive factors, HIV-seropositive women were more than twice as likely (Odds ratio 2.62, 95% CI 2.49, 2.76) to screen VIA-positive than HIV-seronegative women.

Conclusions

This is the first ‘real world’ demonstration in a public sector implementation program in a sub-Saharan African setting that with successful program scale-up efforts, nurse-led cervical cancer screening programs targeting women with HIV can expand and serve all women, regardless of HIV serostatus. Screening program performance can improve with adequate emphasis on training, quality control, and telemedicine-support for nurse-providers in clinical decision making.

Motivations and experiences of women who accessed "see and treat" cervical cancer prevention services in Zambia

BACKGROUND

In Zambia, a country with a generalized HIV epidemic, age-adjusted cervical cancer incidence is among the highest worldwide. In 2006, the University of Alabama at Birmingham-Center for Infectious Disease Research in Zambia and the Zambian Ministry of Health launched a visual inspection with acetic acid (VIA) -based "see and treat" cervical cancer prevention program in Lusaka. All services were integrated within existing government-operated primary health care facilities.

OBJECTIVE

Study aims were to (i) identify women's motivations for cervical screening, (ii) document women's experiences with screening and (iii) describe the potentially reciprocal influences between women undergoing cervical screening and their social networks.

DESIGN AND METHODS

Focus group discussions (FGD) and in-depth interviews (IDI) were conducted with women who accepted screening and with care providers. Low-level content analysis was performed to identify themes evoked by participants. Between September 2009 and July 2010, 60 women and 21 care providers participated in 8 FGD and 10 IDI.

RESULTS

Women presented for screening with varying needs and expectations. A majority discussed their screening decisions and experiences with members of their social networks. Key reinforcing factors and obstacles to VIA screening were identified.

CONCLUSIONS

Interventions are needed to gain support for the screening process from influential family members and peers.

'Worse than HIV' or 'not as serious as other diseases'? Conceptualization of cervical cancer among newly screened women in Zambia

Invasive cervical cancer is the second most common cancer among women worldwide, with approximately 85% of the disease burden occurring in developing countries. To date, there have been few systematic efforts to document African women's conceptualization of cervical cancer after participation in a visual inspection with acetic acid (VIA)-based "see and treat" cervical cancer prevention program. In this study, conducted between September, 2009-July, 2010, focus groups and in-depth interviews were conducted with 60 women who had recently undergone cervical cancer screening at a government-operated primary health care clinic in Lusaka, Zambia. Interviewers elicited participants' causal representations of cervical cancer, associated physical signs and symptoms, perceived physical and psychological effects, and social norms regarding the disease. The lay model of illness causation portrayed by participants after recent exposure to program promotion messages departed in several ways from causal models described in other parts of the world. However, causal conceptualizations included both lay and biomedical elements, suggesting a possible shift from a purely traditional causal model to one that incorporates both traditional concepts and recently promoted biomedical concepts. Most, but not all, women still equated cervical cancer with death, and perceived it to be a highly stigmatized disease in Zambia because of its anatomic location, dire natural course, connections to socially-condemned behaviors, and association with HIV/AIDS. No substantive differences of disease conceptualization existed according to HIV serostatus, though HIV positive women acknowledged that their immune status makes them more aware of their health and more likely to seek medical attention. Further attention should be dedicated to the processes by which women incorporate new knowledge into their representations of cervical cancer.

Cervical cancer prevention in low- and middle-income countries: feasible, affordable, essential

The annual worldwide burden of the preventable disease cervical cancer is more than 530,000 new cases and 275,000 deaths, with the majority occurring in low- and middle-income countries (LMIC), where cervical cancer screening and early treatment are uncommon. Widely used in high-income countries, Pap smear (cytology based) screening is expensive and challenging for implementation in LMICs, where lower-cost, effective alternatives such as visual inspection with acetic acid (VIA) and rapid human papillomavirus (HPV)-based screening tests offer promise for scaling up prevention services. Integrating HPV screening with VIA in "screen-and-treat-or-refer" programs offers the dual benefits of HPV screening to maximize detection and using VIA to triage for advanced lesions/cancer, as well as a pelvic exam to address other gynecologic issues. A major issue in LMICs is coinfection with human immunodeficiency virus (HIV) and HPV, which further increases the risk for cervical cancer and marks a population with perhaps the greatest need of cervical cancer prevention. Public-private partnerships to enhance the availability of cervical cancer prevention services within HIV/AIDS care delivery platforms through initiatives such as Pink Ribbon Red Ribbon present an historic opportunity to expand cervical cancer screening in LMICs.

Cervical cancer prevention in low- and middle-income countries: feasible, affordable, essential

The annual worldwide burden of the preventable disease cervical cancer is more than 530,000 new cases and 275,000 deaths, with the majority occurring in low- and middle-income countries (LMIC), where cervical cancer screening and early treatment are uncommon. Widely used in high-income countries, Pap smear (cytology based) screening is expensive and challenging for implementation in LMICs, where lower-cost, effective alternatives such as visual inspection with acetic acid (VIA) and rapid human papillomavirus (HPV)-based screening tests offer promise for scaling up prevention services. Integrating HPV screening with VIA in "screen-and-treat-or-refer" programs offers the dual benefits of HPV screening to maximize detection and using VIA to triage for advanced lesions/cancer, as well as a pelvic exam to address other gynecologic issues. A major issue in LMICs is coinfection with human immunodeficiency virus (HIV) and HPV, which further increases the risk for cervical cancer and marks a population with perhaps the greatest need of cervical cancer prevention. Public-private partnerships to enhance the availability of cervical cancer prevention services within HIV/AIDS care delivery platforms through initiatives such as Pink Ribbon Red Ribbon present an historic opportunity to expand cervical cancer screening in LMICs.

Advancing cervical cancer prevention initiatives in resource-constrained settings: insights from the Cervical Cancer Prevention Program in Zambia

Groesbeck Parham and colleagues describe their Cervical Cancer Prevention Program in Zambia, which has provided services to over 58,000 women over the past five years, and share lessons learned from the program's implementation and integration with existing HIV/AIDS programs.

Implementation of cervical cancer prevention services for HIV-infected women in Zambia: measuring program effectiveness

BACKGROUND

Cervical cancer kills more women in low-income nations than any other malignancy. A variety of research and demonstration efforts have proven the efficacy and effectiveness of low-cost cervical cancer prevention methods but none in routine program implementation settings of the developing world, particularly in HIV-infected women.

METHODS

In our public sector cervical cancer prevention program in Zambia, nurses conduct screening using visual inspection with acetic acid aided by digital cervicography. Women with visible lesions are offered same-visit cryotherapy or referred for histologic evaluation and clinical management. We analyzed clinical outcomes and modeled program effectiveness among HIV-infected women by estimating the total number of cervical cancer deaths prevented through screening and treatment.

RESULTS

Between 2006 and 2008, 6572 HIV-infected women were screened, 53.6% (3523) had visible lesions, 58.5% (2062) were eligible for cryotherapy and 41.5% (1461) were referred for histologic evaluation. A total of 75% (1095 out of 1462) of patients who were referred for evaluation complied. Pathology results from 65% (715 out of 1095) of women revealed benign abnormalities in 21% (151), cervical intraepithelial neoplasia (CIN) I in 30% (214), CIN 2/3 in 33% (235) and invasive cervical cancer in 16.1% (115, of which 69% were early stage). Using a conditional probability model, we estimated that our program prevented 142 cervical cancer deaths (high/low range: 238-96) among the 6572 HIV-infected women screened, or one cervical cancer death prevented per 46 (corresponding range: 28-68) HIV-infected women screened.

CONCLUSION

Our prevention efforts using setting-appropriate human resources and technology have reduced morbidity and mortality from cervical cancer among HIV-infected women in Zambia. Financial support for implementing cervical cancer prevention programs integrated within HIV/AIDS care programs is warranted. Our prevention model can serve as the implementation platform for future low-cost HPV-based screening methods, and our results may provide the basis for comparison of programmatic effectiveness of future prevention efforts.

Are treatments for cervical precancerous lesions in less-developed countries safe enough to promote scaling-up of cervical screening programs? A systematic review

Background

Since the mid-1990s, there have been growing efforts to prevent cervical cancer in less-developed countries through the development of innovative screening approaches such as visual inspection of the cervix associated with same day management of cervical lesions with cryotherapy or loop electrosurgical excision procedure (LEEP). In the past, promising cancer screening interventions have been widely promoted despite incomplete evidence, only to become the subject of intense controversies about ensuing net health benefit. Because the efficacy and effectiveness of the new protocols for global cervical cancer screening have not been well characterized yet, and as a contribution to the evaluation of the balance between the benefits and risks of these protocols, we reviewed the literature on the safety of cryotherapy and LEEP for cervical intraepithelial neoplasia (CIN) in low- and middle-income countries.

Methods

We searched 12 databases (Medline, Google Scholar, Scopus, Cochrane Library, Web of Science, OCLC, PAIS International Database, WHO Global Health Library, CINAHL, Science.gov, NYAM Grey Literature Report, and POPLINE) for original research published between January 1995 and April 2009. Both peer-reviewed publications and items of "grey" literature were retrieved; no language restriction was applied. We calculated the median (minimum, maximum) reported rate for each harm considered. Because of limitations and heterogeneity in the data, no formal meta-analysis was performed.

Results

The search identified 32 articles that reported safety data from 24 cryotherapy and LEEP studies. The combined sample consisted of 6,902 women treated by cryotherapy and 4,524 women treated by LEEP. Most studies were conducted in reference or research settings in Asia and Africa. Short-term harms of cryotherapy and LEEP appeared to be similar to those described in the literature from high-income countries. Information was sparse on HIV-related harms and long-term reproductive outcomes of treatment.

Conclusions

When performed in resource-limited settings by qualified providers, cryotherapy and LEEP are not associated with excess harm. However, available data are insufficient to propose fully evidence-based protocols for routine screening of HIV-infected women and women of reproductive age.

Management of cryotherapy-ineligible women in a "screen-and-treat" cervical cancer prevention program targeting HIV-infected women in Zambia: lessons from the field

OBJECTIVE

We demonstrate the feasibility of implementing a referral and management system for cryotherapy-ineligible women in a "screen-and-treat" cervical cancer prevention program targeting HIV-infected women in Zambia.

METHODS

We established criteria for patient referral, developed a training program for loop electrosurgical excision procedure (LEEP) providers, and adapted LEEP to a resource-constrained setting.

RESULTS

We successfully trained 15 nurses to perform visual inspection with acetic acid (VIA) followed by immediate cryotherapy. Women with positive tests but ineligible for cryotherapy were referred for further evaluation. We trained four Zambian physicians to evaluate referrals, perform punch biopsy, LEEP, and manage intra-operative and post-operative complications. From January 2006 through October 2007, a total of 8823 women (41.5% HIV seropositive) were evaluated by nurses in outlying prevention clinics; of these, 1477 (16.7%) were referred for physician evaluation based on established criteria. Of the 875 (59.2% of 1147 referred) that presented for evaluation, 748 (8.4% of total screened) underwent histologic evaluation in the form of punch biopsy or LEEP. Complications associated with LEEP included anesthesia reaction (n=2) which spontaneously resolved, intra-operative (n=12) and post-operative (n=2) bleeding managed by local measures, and post-operative infection (n=12) managed with antibiotics.

CONCLUSION

With adaptations for a resource-constrained environment, we have demonstrated that performing LEEP is feasible and safe, with low rates of complications that can be managed locally. It is important to establish referral and management systems using LEEP-based excisional evaluation for women with cryotherapy-ineligible lesions in VIA-based "screen-and-treat" protocols nested within HIV-care programs in resource-constrained settings.

Prevalence and distribution of HPV genotypes among HIV-infected women in Zambia

We screened 145 HIV-infected non-pregnant women at a tertiary care centre in Lusaka, Zambia. Liquid-based cytology and human papillomavirus (HPV) genotyping with PGMY09/11 biotinylated primers (Roche Linear Array® HPV genotyping test) maximised sensitivity of cytology and HPV assessments. Among high-risk (HR) types, HPV 52 (37.2%), 58 (24.1%) and 53 (20.7%) were more common overall than HPV 16 (17.2%) and 18 (13.1%) in women with high-grade squamous intraepithelial lesions or squamous cell carcinoma (SCC) on cytology. High-risk HPV types were more likely to be present in women with CD4⁺ cell counts <200 μ l⁻¹ (odds ratios (OR): 4.9, 95% confidence intervals (CI): 1.4–16.7, P=0.01) and in women with high-grade or severe cervical cytological abnormalities (OR: 8.0, 95% CI: 1.7–37.4, P=0.008). Human papillomavirus diversity in high-grade lesions and SCC on cytology suggests that HPV 16- and 18-based vaccines may not be adequately polyvalent to induce protective immunity in this population.

Prevalence and predictors of squamous intraepithelial lesions of the cervix in HIV-infected women in Lusaka, Zambia

OBJECTIVES

HIV-infected women living in resource-constrained nations like Zambia are now accessing antiretroviral therapy and thus may live long enough for HPV-induced cervical cancer to manifest and progress. We evaluated the prevalence and predictors of cervical squamous intraepithelial lesions (SIL) among HIV-infected women in Zambia.

METHODS

We screened 150 consecutive, non-pregnant HIV-infected women accessing HIV/AIDS care services in Lusaka, Zambia. We collected cervical specimens for cytological analysis by liquid-based monolayer cytology (ThinPrep Pap Test) and HPV typing using the Roche Linear Array PCR assay.

RESULTS

The median age of study participants was 36 years (range 23-49 years) and their median CD4+ count was 165/microL (range 7-942). The prevalence of SIL on cytology was 76% (114/150), of which 23.3% (35/150) women had low-grade SIL, 32.6% (49/150) had high-grade SIL, and 20% (30/150) had lesions suspicious for squamous cell carcinoma (SCC). High-risk HPV types were present in 85.3% (128/150) women. On univariate analyses, age of the participant, CD4+ cell count, and presence of any high-risk HPV type were significantly associated with the presence of severely abnormal cytological lesions (i.e., high-grade SIL and lesions suspicious for SCC). Multivariable logistic regression modeling suggested the presence of any high-risk HPV type as an independent predictor of severely abnormal cytology (adjusted OR: 12.4, 95% CI 2.62-58.1, p=0.02).

CONCLUSIONS

The high prevalence of abnormal squamous cytology in our study is one of the highest reported in any population worldwide. Screening of HIV-infected women in resource-constrained settings like Zambia should be implemented to prevent development of HPV-induced SCC.