Performance of cervical cytology and HPV testing for primary cervical cancer screening in Latin America: an analysis within the ESTAMPA study

Background

Cervical cytology remains widely used as the initial tool in cervical cancer screening worldwide. WHO guidelines recommend replacing cytology with primary HPV testing to reach cervical cancer elimination goals. We assessed the performance of cytology and high-risk HPV testing to detect cervical precancer, cervical intraepithelial neoplasia (CIN) grade 3 or worse (CIN3+) among women aged 30-64 years participating in the ESTAMPA study.

Methods

Women were screened with cytology and HPV across ESTAMPA study centres in Latin America. Screen-positives were referred to colposcopy with biopsy collection and treatment as needed. Those with no evident precancer were recalled at 18-months for a second HPV test to complete disease ascertainment. Performance indicators for cytology and HPV to detect CIN3+ were estimated.

Findings

30,606 participants with available cytology and HPV results were included in the analysis. A total of 440 histologically confirmed CIN3s and 30 cancers were diagnosed. Cytology sensitivity for CIN3+ was 48.5% (95% CI: 44.0-53.0), whereas HPV testing had a sensitivity of 98.1% (95% CI: 96.3-96.7). Specificity was 96.5% (95% CI: 96.3-96.7) using cytology and 88.7% (95% CI: 88.3-89.0) with HPV. Performance estimates varied substantially by study centre for cytology (ranging from 32.1% to 87.5% for sensitivity and from 89.2% to 99.5% for specificity) while for HPV results were more consistent across sites (96.7%-100% and 83.6-90.8%, respectively).

Interpretation

The limited and highly variable sensitivity of cytology strongly supports transition to the more robust and reproducible HPV-based cervical screening to ensure progress towards global cervical cancer elimination targets in Latin America.

Funding

IARC/WHO, UNDP, HRP/WHO, NCI and local funders.

Performance of visual inspection of the cervix with acetic acid (VIA) for triage of HPV screen-positive women: results from the ESTAMPA study

VIA is recommended for triage of HPV-positive women attending cervical screening. In the multicentric ESTAMPA study, VIA performance for detection of cervical intraepithelial neoplasia grade 3 or worse (CIN3+) among HPV-positive women was evaluated. Women aged 30-64 years were screened with HPV testing and cytology and referred to colposcopy if either test was positive. At colposcopy visit, study-trained midwives/nurses/GPs performed VIA ahead of colposcopy. VIA was considered positive if acetowhite lesions were observed in or close to the transformation zone. Ablative treatment eligibility was assessed for VIA positives. Performance indicators were estimated. Three thousand one hundred and forty-two HPV-positive women were included. Sensitivity for CIN3+ was 85.9% (95% CI 81.2-89.5) among women <50 years and, although not significant, slightly lower in women 50+ (78.0%, 95% CI 65.9-86.6). Overall specificity was 58.6% (95% CI 56.7-60.5) and was significantly higher among women 50+ (70.3%, 95% CI 66.8-73.5) compared to women <50 (54.3%, 95% CI 52.1-56.5). VIA positivity was lower among women 50+ (35.2%, 95% CI 31.9-38.6) compared to women <50 (53.2, 95% CI 51.1-55.2). Overall eligibility for ablative treatment was 74.5% and did not differ by age. VIA sensitivity, specificity, and positivity, and ablative treatment eligibility varied highly by provider (ranges: 25%-95.4%, 44.9%-94.4%, 8.2%-65.3%, 0%-98.7%, respectively). VIA sensitivity for cervical precancer detection among HPV-positive women performed by trained providers was high with an important reduction in referral rates. However, scaling-up HPV screening triaged by VIA will be challenging due to the high variability of VIA performance and providers' need for training and supervision.

Performance of standardised colposcopy to detect cervical precancer and cancer for triage of women testing positive for human papillomavirus: results from the ESTAMPA multicentric screening study

BACKGROUND

Colposcopy, currently included in WHO recommendations as an option to triage human papillomavirus (HPV)-positive women, remains as the reference standard to guide both biopsy for confirmation of cervical precancer and cancer and treatment approaches. We aim to evaluate the performance of colposcopy to detect cervical precancer and cancer for triage in HPV-positive women.

METHODS

This cross-sectional, multicentric screening study was conducted at 12 centres (including primary and secondary care centres, hospitals, laboratories, and universities) in Latin America (Argentina, Bolivia, Colombia, Costa Rica, Honduras, Mexico, Paraguay, Peru, and Uruguay). Eligible women were aged 30-64 years, sexually active, did not have a history of cervical cancer or treatment for cervical precancer or a hysterectomy, and were not planning to move outside of the study area. Women were screened with HPV DNA testing and cytology. HPV-positive women were referred to colposcopy using a standardised protocol, including biopsy collection of observed lesions, endocervical sampling for transformation zone (TZ) type 3, and treatment as needed. Women with initial normal colposcopy or no high-grade cervical lesions on histology (less than cervical intraepithelial neoplasia [CIN] grade 2) were recalled after 18 months for another HPV test to complete disease ascertainment; HPV-positive women were referred for a second colposcopy with biopsy and treatment as needed. Diagnostic accuracy of colposcopy was assessed by considering a positive test result when the colposcopic impression at the initial colposcopy was positive minor, positive major, or suspected cancer, and was considered negative otherwise. The main study outcome was histologically confirmed CIN3+ (defined as grade 3 or worse) detected at the initial visit or 18-month visit.

FINDINGS

Between Dec 12, 2012, and Dec 3, 2021, 42 502 women were recruited, and 5985 (14·1%) tested positive for HPV. 4499 participants with complete disease ascertainment and follow-up were included in the analysis, with a median age of 40·6 years (IQR 34·7-49·9). CIN3+ was detected in 669 (14·9%) of 4499 women at the initial visit or 18-month visit (3530 [78·5%] negative or CIN1, 300 [6·7%] CIN2, 616 [13·7%] CIN3, and 53 [1·2%] cancers). Sensitivity was 91·2% (95% CI 88·9-93·2) for CIN3+, whereas specificity was 50·1% (48·5-51·8) for less than CIN2 and 47·1% (45·5-48·7) for less than CIN3. Sensitivity for CIN3+ significantly decreased in older women (93·5% [95% CI 91·3-95·3] in those aged 30-49 years vs 77·6% [68·6-85·0] in those aged 50-65 years; p<0·0001), whereas specificity for less than CIN2 significantly increased (45·7% [43·8-47·6] vs 61·8% [58·7-64·8]; p<0·0001). Sensitivity for CIN3+ was also significantly lower in women with negative cytology than in those with abnormal cytology (p<0·0001).

INTERPRETATION

Colposcopy is accurate for CIN3+ detection in HPV-positive women. These results reflect ESTAMPA efforts in an 18-month follow-up strategy to maximise disease detection with an internationally validated clinical management protocol and regular training, including quality improvement practices. We showed that colposcopy can be optimised with proper standardisation to be used as triage in HPV-positive women.

FUNDING

WHO; Pan American Health Organization; Union for International Cancer Control; National Cancer Institute (NCI); NCI Center for Global Health; National Agency for the Promotion of Research, Technological Development, and Innovation; NCI of Argentina and Colombia; Caja Costarricense de Seguro Social; National Council for Science and Technology of Paraguay; International Agency for Research on Cancer; and all local collaborative institutions.

Daily tenofovir disoproxil fumarate/emtricitabine and hydroxychloroquine for pre-exposure prophylaxis of COVID-19: a double-blind placebo-controlled randomized trial in healthcare workers

OBJECTIVES

To assess the effect of hydroxychloroquine (HCQ) and Tenofovir disoproxil fumarate/emtricitabine (TDF/FTC) as pre-exposure prophylaxis on COVID-19 risk.

METHODS

EPICOS is a double-blind, placebo-controlled randomized trial conducted in Spain, Bolivia, and Venezuela. Healthcare workers with negative SARS-CoV-2 IgM/IgG test were randomly assigned to the following: daily TDF/FTC plus HCQ for 12 weeks, TDF/FTC plus HCQ placebo, HCQ plus TDF/FTC placebo, and TDF/FTC placebo plus HCQ placebo. Randomization was performed in groups of four. Primary outcome was laboratory-confirmed, symptomatic COVID-19. We also studied any (symptomatic or asymptomatic) COVID-19. We compared group-specific 14-week risks via differences and ratios with 95% CIs.

RESULTS

Of 1002 individuals screened, 926 (92.4%) were eligible and there were 14 cases of symptomatic COVID-19: 220 were assigned to the TDF/FTC plus HCQ group (3 cases), 231 to the TDF/FTC placebo plus HCQ group (3 cases), 233 to the TDF/FTC plus HCQ placebo group (3 cases), and 223 to the double placebo group (5 cases). Compared with the double placebo group, 14-week risk ratios (95% CI) of symptomatic COVID-19 were 0.39 (0.00-1.98) for TDF + HCQ, 0.34 (0.00-2.06) for TDF, and 0.49 (0.00-2.29) for HCQ. Corresponding risk ratios of any COVID-19 were 0.51 (0.21-1.00) for TDF + HCQ, 0.81 (0.44-1.49) for TDF, and 0.73 (0.41-1.38) for HCQ. Adverse events were generally mild.

DISCUSSION

The target sample size was not met. Our findings are compatible with both benefit and harm of pre-exposure prophylaxis with TDF/FTC and HCQ, alone or in combination, compared with placebo.

Implementing HPV testing in 9 Latin American countries: The laboratory perspective as observed in the ESTAMPA study

Background

Replacement of cytology screening with HPV testing is recommended and essential for cervical cancer elimination. HPV testing for primary screening was implemented in 12 laboratories within 9 Latin American countries, as part of the ESTAMPA cervical cancer screening study. Our observations provide information on critical operational aspects for HPV testing implementation in diverse resource settings.

Methods

We describe the implementation process of HPV testing in ESTAMPA, focusing on laboratory aspects. We assess the readiness of 12 laboratories to start HPV testing and their continuity capacity to maintain good quality HPV testing until end of recruitment or up to December 2021. Readiness was based on a checklist. Information from the study database; regular meetings and monitoring visits; and a questionnaire on laboratory operational aspects sent in May 2020 were used to assess continuity capacity. Compliance with seven basic requirements (readiness) and eight continuity requirements (continuity capacity) was scored (1 = compliant, 0 = not compliant) and totaled to classify readiness and continuity capacity as very limited, limited, moderate or high. Experiences, challenges, and enablers of the implementation process are also described.

Results

Seven of 12 laboratories had high readiness, three moderate readiness, and of two laboratories new to HPV testing, one had limited readiness and the other very limited readiness. Two of seven laboratories with high readiness also showed high continuity capacity, one moderate continuity capacity, and the other four showed limited continuity capacity since they could not maintain good quality HPV testing over time. Among three laboratories with moderate readiness, one kept moderate continuity capacity and two reached high continuity capacity. The two laboratories new to HPV testing achieved high continuity capacity. Based on gained expertise, five laboratories have become part of national screening programs.

Conclusion

High readiness of laboratories is an essential part of effective implementation of HPV testing. However, high readiness is insufficient to guarantee HPV testing high continuity capacity, for which a "culture of quality" should be established with regular training, robust monitoring and quality assurance systems tailored to local context. All efforts to strengthen HPV laboratories are valuable and crucial to guarantee effective implementation of HPV-based cervical screening.

"We have already heard that the treatment doesn't do anything, so why should we take it?": A mixed method perspective on Chagas disease knowledge, attitudes, prevention, and treatment behaviour in the Bolivian Chaco

BACKGROUND

Chagas disease (CD) is highly endemic in the Bolivian Chaco. The municipality of Monteagudo has been targeted by national interventions as well as by Médecins Sans Frontières to reduce infection rates, and to decentralize early diagnosis and treatment. This study seeks to determine the knowledge and attitudes of a population with increased awareness and to identify remaining factors and barriers for sustained vector control, health care seeking behaviour, and access, in order to improve future interventions.

METHODOLOGY/PRINCIPAL FINDINGS

A cross-sectional survey was conducted among approximately 10% (n = 669) of the municipality of Monteagudo's households that were randomly selected. Additionally, a total of 14 in-depth interviews and 2 focus group discussions were conducted with patients and key informants. Several attitudes and practices were identified that could undermine effective control against (re-)infection. Knowledge of clinical symptoms and secondary prevention was limited, and revealed specific misconceptions. Although 76% of the participants had been tested for CD, only 18% of those who tested positive concluded treatment with benznidazole (BNZ). Sustained positive serologies after treatment led to perceived ineffectiveness of BNZ. Moreover, access barriers such as direct as well as indirect costs, BNZ stock-outs and a fear of adverse reactions triggered by other community members made patients opt for alternative treatments against CD such as veterinary ivermectin, used by 28% of infected participants in our study. The lack of accessible care for chronic complications as well as socioeconomic consequences, such as the exclusion from both job opportunities and bank loans contributed to the ongoing burden of CD.

CONCLUSIONS/SIGNIFICANCE

Large scale interventions should be accompanied by operational research in order to identify misconceptions and unintended consequences early on, to generate accessible data for future interventions, and for rigorous evaluation. An integrated, community-based approach tackling social determinants and including both traditional and animal health sectors might help to overcome current barriers and advocate for patients' rights.

Multicentric study of cervical cancer screening with human papillomavirus testing and assessment of triage methods in Latin America: the ESTAMPA screening study protocol

INTRODUCTION

Human papillomavirus (HPV) testing is replacing cytology in primary screening. Its limited specificity demands using a second (triage) test to better identify women at high-risk of cervical disease. Cytology represents the immediate triage but its low sensitivity might hamper HPV testing sensitivity, particularly in low-income and middle-income countries (LMICs), where cytology performance has been suboptimal. The ESTAMPA (EStudio multicéntrico de TAMizaje y triaje de cáncer de cuello uterino con pruebas del virus del PApiloma humano; Spanish acronym) study will: (1) evaluate the performance of different triage techniques to detect cervical precancer and (2) inform on how to implement HPV-based screening programmes in LMIC.

METHODS AND ANALYSIS

Women aged 30-64 years are screened with HPV testing and Pap across 12 study centres in Latin America. Screened positives have colposcopy with biopsy and treatment of lesions. Women with no evident disease are recalled 18 months later for another HPV test; those HPV-positive undergo colposcopy with biopsy and treatment as needed. Biological specimens are collected in different visits for triage testing, which is not used for clinical management. The study outcome is histological high-grade squamous intraepithelial or worse lesions (HSIL+) under the lower anogenital squamous terminology. About 50 000 women will be screened and 500 HSIL+ cases detected (at initial and 18 months screening). Performance measures (sensitivity, specificity and predictive values) of triage techniques to detect HSIL+ will be estimated and compared with adjustment by age and study centre.

ETHICS AND DISSEMINATION

The study protocol has been approved by the Ethics Committee of the International Agency for Research on Cancer (IARC), of the Pan American Health Organisation (PAHO) and by those in each participating centre. A Data and Safety Monitoring Board (DSMB) has been established to monitor progress of the study, assure participant safety, advice on scientific conduct and analysis and suggest protocol improvements. Study findings will be published in peer-reviewed journals and presented at scientific meetings.

TRIAL REGISTRATION NUMBER

NCT01881659.

Rapid diagnostic tests duo as alternative to conventional serological assays for conclusive Chagas disease diagnosis

Chagas disease is caused by the parasite Trypanosoma cruzi. It affects several million people, mainly in Latin America, and severe cardiac and/or digestive complications occur in ~30% of the chronically infected patients. Disease acute stage is mostly asymptomatic and infection goes undiagnosed. In the chronic phase direct parasite detection is hampered due to its concealed presence and diagnosis is achieved by serological methods, like ELISA or indirect hemagglutination assays. Agreement in at least two tests must be obtained due to parasite wide antigenic variability. These techniques require equipped labs and trained personnel and are not available in distant regions. As a result, many infected people often remain undiagnosed until it is too late, as the two available chemotherapies show diminished efficacy in the advanced chronic stage. Easy-to-use rapid diagnostic tests have been developed to be implemented in remote areas as an alternative to conventional tests. They do not need electricity, nor cold chain, they can return results within an hour and some even work with whole blood as sample, like Chagas Stat-Pak (ChemBio Inc.) and Chagas Detect Plus (InBIOS Inc.). Nonetheless, in order to qualify a rapidly diagnosed positive patient for treatment, conventional serological confirmation is obligatory, which might risk its start. In this study two rapid tests based on distinct antigen sets were used in parallel as a way to obtain a fast and conclusive Chagas disease diagnosis using whole blood samples. Chagas Stat-Pak and Chagas Detect Plus were validated by comparison with three conventional tests yielding 100% sensitivity and 99.3% specificity over 342 patients seeking Chagas disease diagnosis in a reference centre in Sucre (Bolivia). Combined used of RDTs in distant regions could substitute laborious conventional serology, allowing immediate treatment and favouring better adhesion to it.

Chagas disease is a neglected tropical disease caused by the parasite Trypanosoma cruzi. It affects 6–7 million people, mainly in Latin America. An initial asymptomatic phase make the infection go undiagnosed and untreated, silently progressing into its chronic stage. About 30% of the chronically infected patients end up developing life-threatening disruption of the heart and/or gut tissues. Two drugs are available but their efficacy diminishes the longer a person has been infected. Therefore, it is of paramount importance to achieve an early diagnosis to start treatment before symptoms advance. In the chronic stage parasite presence is intermittent and diagnosis is made by serological assays that detect parasite-specific immunoglobulins. Problem is that conventional serological techniques are laborious and require equipment and trained personnel unavailable in remote regions with high disease prevalence. To circumvent those inconveniences easy-to-use rapid diagnostic tests were developed. They return results within an hour and some work with whole blood as sample allowing diagnosis out of digital puncture. We propose that conventional assays could be substituted by whole blood-friendly rapid tests in order to achieve a conclusive Chagas disease diagnosis in remote regions. This would ease access to treatment increasing adherence rates to it.

GETAWAY descriptors to predicting A2A adenosine receptors agonists

The GEometry, Topology and Atom-Weights AssemblY approach has been applied to the study of the A(2A) adenosine receptors agonist effect of 29 adenosine analogues: N(6)-arylcarbamoyl, 2-arylalkynyl-N(6)-arylcarbamoyl, and N(6)-carboxamido derivatives. A model able to describe more than 77% of the variance in the experimental activity was developed with the use of the mentioned approach. In contrast, no one of four different approaches, including the use of Topological, Galvez Topological Charges indexes, Geometrical and WHIM descriptors were able to explain more than 70% of the variance in the mentioned property with the same number of variables in the equation.

Synthesis of carbocyclic analogues of MECA and NECA 1,2-disubstituted as potential adenosine receptor agonists

A new class of 1,2-disubstituted carbocyclic nucleosides of MECA and NECA analogues was synthesized in good yield starting from (+/-) 6-azabicyclo[3.2.0]heptan-7-one.

Purine derivatives of 1,2-disubstituted cyclohexane analogues of nucleosides

Starting from (+/-)-cis-2-hydroxymethylcyclohexylamine, a series of cyclohexane-derived cis-1,2-disubstituted carbonucleoside analogues with a 6- or 2,6-purine or 8-azapurine base were synthesized. The antiviral and antitumoral in vitro effects of the new compounds were evaluated.

Synthesis and structural study of pyrimidyl carbocyclic analogues of nucleosides based on cyclopentene rings

A series of 1,2-disubstituted carbonucleoside analogues of pyrimidine and 5-halopyrimidines with the unsaturated carbocycle cyclopentene was synthesized. AIM theory was applied to analyse the conformational and electronic effects of 5-halogenation.

Resolution of racemic mixtures of carbocyclic analogues of nucleosides and assignment of their absolute configuration

Racemic trans-6-chloro-9-[2-(hydroxymethyl)cyclopentyl]purine was resolved using HPLC with a chiral column. The absolute configurations of the enantiomers were determined by NMR studies of their (R)- and (S)-methoxyphenylacetates.

A model of suture-induced urolithiasis with urographic control in the bladder of the rat

The characteristics of a model of urolithiasis in the bladder of male Wistar rats were evaluated. Two techniques were compared: one knot of suture material through the bladder wall, or 15-throw knots inside the bladder. Rats were randomly assigned to one of six groups, according to the technique and suture material used (polyester, silk, or chromic catgut). An excretory urogram was performed at days 30, 60, and 90. At the moment of positive radiographic diagnosis, animals were sacrificed and stones were obtained. All rats were sacrificed at day 90 regardless of the x-ray results. Variables evaluated were average days to a positive urogram, average weight of all uroliths, and percentage of animals developing urolithiasis throughout the study. There were no statistical differences between groups for the average weight of stones, which ranged from 0.008 to 1.502 g for individual cases. All three materials were more lithogenic with the 15-throw knot inside technique. No significant differences were detected for lithogenesis criteria between suture materials. X-ray dispersion spectroscopy evidenced calcium phosphate composition of two stones from chromic catgut, and magnesium phosphate composition of two stones from chromic catgut, two from silk, and two from polyester. Neo-epithelization over the suture was confirmed microscopically in bladders with the one-throw technique. We conclude that (1) this is an effective model of urolithiasis, with predictability in time, composition, and amount of stone formation; (2) the presence of more suture material inside the bladder is more lithogenic; and (3) excretory urograms are highly sensitive and specific for the noninvasive diagnosis of bladder urolithiasis.

Synthesis and biological evaluation of 1,2-disubstituted carbonucleosides of 6-substituted purine and 8-azapurine

A series of new one two substituted carbonucleoside analogues (OTC), with the purine and 8-azapurine base linked through a methylene group at the cyclopentane ring, were synthesized and evaluated for their activity against a number of viruses and tumor cells in vitro.

Phenylpiperazine derivatives with strong affinity for 5HT1A, D2A and D3 receptors

Four 7-[3-(4-phenyl-1-piperazinyl)propoxy]coumarins were synthesized. The affinities of these compounds for DA (D2A, D3) and 5HT1A receptors were evaluated for their ability to displace [3H]-raclopride and [3H]-8-OH-DPAT respectively from their specific binding sites. The affinities of the target compounds were all in the nanomolar range and followed the order 5-HT1A > D2 > D3.

[Typhoid fever in children: association with blood phenotypes ABO, Rh and MNSs]

The hypothesis that blood phenotype B is associated to typhoid fever either directly or interacting with other phenotypes of the Rh or MNSs blood systems was tested. 256 children from the Northern Area of Santiago (Chile) with bacteriologically confirmed typhoid fever and 329 afebrile controls matched by age and gender from the same population, were studied. Association was found between phenotype RH3 and protection against disease for the whole group (OR = 0.67; p < 0.042) and for males (OR = 0.05; p = 0.014) although the gender-RH3 interaction was at the limit of significance. RH8 and Ss phenotypes were associated to increased susceptibility (OR = 1.83; p < 0.034 and OR = 1.56; p = 0.01, respectively). Controlling RH3 and Ss phenotypes by B, increased their effects (OR = 0.26; p = 0.04 and OR = 3.42; p = 0.026, respectively), but interactions did not reach statistical significance. These results show a susceptibility cline whose implications and applicability deserve further studies. A high proportion of S. paratyphi B (23.8%) appeared in this series, which may imply sample heterogeneity. The meaning of these findings need further epidemiological and genetic studies.

Pyridazine derivatives, VII. Synthesis and hypotensive activity of 3-hydrazinocycloalkyl[1,2-c]pyridazines and their derivatives

The preparation of a series of 3-hydrazinocycloalkyl[1,2-c]pyridazines 7 and some derivatives as hydrazones 8, 9, triazoles 10 and pyrroles 11 are described together with their hypotensive activity in normotensive rats.