Comparative performance evaluation of different HPV tests and triaging strategies using self-samples and feasibility assessment of thermal ablation in 'colposcopy and treat' approach: A population-based study in rural China

Human papillomavirus (HPV) test, self-sampling and thermal ablation for cervical intraepithelial neoplasia (CIN) have been developed separately to increase screening coverage and treatment compliance of cervical cancer screening programmes. A large-scale study in rural China screened 9,526 women with their combinations to explore the optimal cervical cancer-screening cascade in the real-world. Participants received careHPV and polymerase chain reaction (PCR) HPV tests on self-collected samples. Women positive on either HPV test underwent colposcopy, biopsy and thermal ablation in a single visit. Samples positive on either HPV test were retested for genotyping. Absolute and relative performance of HPV tests, triage strategies, 'colposcopy and thermal ablation' approach were statistically evaluated. PCR HPV test detected 33.3% more CIN grade two or worse (CIN2+) at a cost of 28.1% more colposcopies compared to careHPV. Sensitivities of PCR HPV and careHPV tests to detect CIN2+ were 96.7 and 72.5%. Specificities for the same disease outcome were 82.1 and 86.0%. Triaging HPV-positive women with HPV16/18 genotyping considerably improved the positive predictive value for CIN2+ (4.8-5.0 to 18.2-19.2%). Ninety-six women positive on HPV and having abnormal colposcopy were eligible for thermal ablation and all accepted same-day treatment, contributing to 64.6% being treated appropriately (CIN1+ on histopathology), which reached up to 84.8% among women positive on HPV 16/18 triage. No serious side-effects/complications were reported. The combination of PCR HPV test followed by HPV 16/18 triaging on self-collected samples and colposcopy of triage positive women followed by immediate thermal ablation might be the appropriate screening cascade for rural China.

Detecting cervical precancer and reaching underscreened women by using HPV testing on self samples: updated meta-analyses

OBJECTIVE

To evaluate the diagnostic accuracy of high-risk human papillomavirus (hrHPV) assays on self samples and the efficacy of self sampling strategies to reach underscreened women.

DESIGN

Updated meta-analysis.

DATA SOURCES

Medline (PubMed), Embase, and CENTRAL from 1 January 2013 to 15 April 2018 (accuracy review), and 1 January 2014 to 15 April 2018 (participation review).

REVIEW METHODS

Accuracy review: hrHPV assay on a vaginal self sample and a clinician sample; and verification of the presence of cervical intraepithelial neoplasia grade 2 or worse (CIN2+) by colposcopy and biopsy in all enrolled women or in women with positive tests. Participation review: study population included women who were irregularly or never screened; women in the self sampling arm (intervention arm) were invited to collect a self sample for hrHPV testing; women in the control arm were invited or reminded to undergo a screening test on a clinician sample; participation in both arms was documented; and a population minimum of 400 women.

RESULTS

56 accuracy studies and 25 participation trials were included. hrHPV assays based on polymerase chain reaction were as sensitive on self samples as on clinician samples to detect CIN2+ or CIN3+ (pooled ratio 0.99, 95% confidence interval 0.97 to 1.02). However, hrHPV assays based on signal amplification were less sensitive on self samples (pooled ratio 0.85, 95% confidence interval 0.80 to 0.89). The specificity to exclude CIN2+ was 2% or 4% lower on self samples than on clinician samples, for hrHPV assays based on polymerase chain reaction or signal amplification, respectively. Mailing self sample kits to the woman's home address generated higher response rates to have a sample taken by a clinician than invitation or reminder letters (pooled relative participation in intention-to-treat-analysis of 2.33, 95% confidence interval 1.86 to 2.91). Opt-in strategies where women had to request a self sampling kit were generally not more effective than invitation letters (relative participation of 1.22, 95% confidence interval 0.93 to 1.61). Direct offer of self sampling devices to women in communities that were underscreened generated high participation rates (>75%). Substantial interstudy heterogeneity was noted (I²>95%).

CONCLUSIONS

When used with hrHPV assays based on polymerase chain reaction, testing on self samples was similarly accurate as on clinician samples. Offering self sampling kits generally is more effective in reaching underscreened women than sending invitations. However, since response rates are highly variable among settings, pilots should be set up before regional or national roll out of self sampling strategies.

Evaluation of a specialized filter-paper matrix for transportation of extended bovine semen to screen for bovine herpesvirus-1 by real-time PCR

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Retrieval of BoHV-1 DNA from extended semen spotted paper matrix was optimized.

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The method was repeatable in inter-assay and intra-assay precision testing.

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Viral DNA was stable in the matrix for at least 28 days when stored at 4°–37 °C.

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The analytical sensitivity was equivalent to the OIE approved Chelex based method.

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The dsn and dsp was 83% and 93% respectively in comparison to Chelex based method.

The extended frozen semen (EFS) batches produced from infectious bovine rhinotracheitis (IBR) sero-positive cattle and buffalo bulls housed in various semen stations in India are transported to the testing laboratory in liquid nitrogen (LN₂) for screening bovine herpesvirus-1 (BoHV-1). This procedure is laborious and poses LN₂ related hazards. An alternative logistics for transportation of samples was investigated. Use of Flinders Technology Associates (FTA^®) elute card was evaluated for transportation of extended bovine semen to screen BoHV-1 DNA by real-time PCR targeting gB gene and the method was compared with the OIE approved Chelex resin based method. A protocol for extraction of BoHV-1 DNA from FTA^® card spotted with extended semen was optimized. The viral DNA was found to be stable on FTA^® card for at least 28 days when the cards are stored at 4°–37 °C. The analytical sensitivity for the assay was determined using variable dilutions of BoHV-1 spiked semen and positive plasmid harbouring gB gene (97bp) spotted onto FTA^® card and it was found to be 10^0.8 TCID₅₀/ml or 100 copies respectively in real-time PCR. The test could detect as low as 10^0.008 TCID₅₀/ml or 1 copy of positive plasmid when more number of replicates (n = 6) of the same sample were tested. This sensitivity was found to be comparable to Chelex method and both the methods demonstrated a very strong correlation (r = 0.9774; 95% CI: 0.9620–0.9860) in terms of Ct value (p < 0.0001). The diagnostic sensitivity and specificity of the FTA method in comparison to the Chelex method was 83.08% (95% CI: 71.73%–91.24%) and 93.23% (95% CI: 89.38%–96.01%) respectively when 316 samples were screened by both the methods. The degree of agreement between these two tests was good (Kappa value: 0.738; 95% CI: 0.646–0.829). The method was found to be robust and highly repeatable in inter-assay and intra-assay precision testing. The result suggests that the FTA^® card holds promise as an alternative system for transportation of EFS for downstream screening of BoHV-1 DNA.

Vaginal self-sampling as a diagnosis tool in low-income countries and potential applications for exploring the infectious causes of miscarriage

Gynecological health is a challenge in low-income countries. Personal opposition to perineal examination has been overcome by the use of vaginal self-sampling. Here, we review the use of this procedure notably in low-income countries and the main infectious causes of miscarriage. Vaginal self-sampling was mainly used for human papillomavirus detection but also to detect microorganisms causing sexually transmitted infections or bacterial vaginosis. 58 studies have been performed in low-resource countries, mainly studies performed to detect human papillomavirus in urban and peri-urban areas and demonstrating excellent acceptability. Several infectious causes of miscarriage could be tested using self-vaginal samples. In the future, such strategies coupled with a rapid-identification point-of-care method could allow the development of screening and treatment programs in rural areas in low-resource countries.

Evaluation of human papillomavirus detection by Abbott m2000 system on samples collected by FTA Elute™ Card in a Chinese HIV-1 positive population

BACKGROUND

HIV+/AIDS women have an increased risk of developing into CIN and cervical cancer compared to the general population. Limited medical resource and the lack of AIDS relevant knowledge impair the coverage and efficiency of cervical cancer screening.

OBJECTIVES

To compare the clinical performance of self-collected dry storage medium (FTA Elute card) and physician-collected PreservCyt medium in detection of high risk human papillomavirus (HR HPV) among HIV-1 positive population.

METHODS

Three hundred HIV-1 positive women (aged 25-65) were recruited from Yunnan infectious hospital. Two cervicovaginal samples were collected from each participant: one was collected by the women themselves and applied on a FTA Elute card; the other one was collected by a physician and stored in PreservCyt solution. All the samples were tested for 14 HR HPV using Abbott RealTime High Risk HPV assay. Biopsies were taken for histological diagnosis if any abnormal impression was noticed under colposcopy.

RESULTS

291 (97.0%) of participants were eligible for this study. 101 (34.70%) participants were found HR HPV positive in both FTA card and PreservCyt samples, and 19 (6.53%) women were diagnosed as CIN2+. The HR HPV positive rate on samples collected by FTA Elute card and PreservCyt solution was 42.61% and 39.86%, respectively. The overall agreement was 87% (kappa=0.731) between FTA card and PreservCyt. The clinical sensitivity and specificity of FTA card and PreservCyt were 100%, 61.39% and 100%, 64.33%, respectively.

CONCLUSIONS

In this study, FTA Elute card demonstrated a good performance on self-collected sample for HR HPV detection in HIV-1 positive population. For the women from low-resource area with HIV-1 infection, FTA Elute card could be an attractive sample collection method for cervical cancer screening.

An Evaluation of the Cobas4800 HPV Test on Cervico-Vaginal Specimens in Liquid versus Solid Transport Media

Objectives

Determine the ability of the Cobas 4800 assay to detect high-risk human papillomavirus (HrHPV) and high-grade cervical lesions when using cervico-vaginal samples applied to liquid medium and solid media cards compared to a direct cervical sample.

Methods

Two cervico-vaginal specimens (pseudo self-collected) were obtained from 319 women. One was applied to an iFTA Card (FTA) then the brush placed in liquid-based medium (LSELF); the other was applied to a new solid media: POI card (POI). The clinical performance of Cobas4800 assay using the three aforementioned specimens was compared to direct collected endocervical specimens in liquid media (LDOC).

Results

The overall agreements of HrHPV detection were 84.2% (LSELF vs. LDOC), 81.0% (FTA vs. LDOC), and 82.3% (POI vs. LDOC). LSELF, FTA and POI identified 98.0%, 79.6%, and 97.5% positive cases of LDOC. Sensitivity to identify CIN2+ were 98.4% (LSELF), 73.8% (FTA), 95.1% (POI), and 93.4% (LDOC) respectively. FTA had 78.1% and 90.4% agreement with the LSELF samples for all HrHPV and HPV16/18 detection respectively, while POI had 91.6% for both.

Conclusions

Cobas4800 HPV test combined with cervico-vaginal specimens applied to both liquid media and POI solid card are accurate to detect HrHPV infection and high-grade cervical lesions as compared with direct endocervical samples in liquid media.

Evaluation of a new solid media specimen transport card for high risk HPV detection and cervical cancer prevention

BACKGROUND

Solid media transport can be used to design adaptable cervical cancer screening programs but currently is limited by one card with published data.

OBJECTIVE

To develop and evaluate a solid media transport card for use in high-risk human papillomavirus detection (HR-HPV).

STUDY DESIGN

The Preventative Oncology International (POI) card was constructed using PK 226 paper(®) treated with cell-lysing solution and indicating dye. Vaginal samples were applied to the POI card and the indicating FTA (iFTA) elute card. A cervical sample was placed in liquid media. All specimens were tested for HR-HPV. Color change was assessed at sample application and at card processing. Stability of the POI card and iFTA elute card was tested at humidity.

RESULTS

319 women were enrolled. Twelve women had at least one insufficient sample with no difference between media (p=0.36). Compared to liquid samples, there was good agreement for HR-HPV detection with kappa of 0.81 (95% CI 0.74-0.88) and 0.71 (95% CI 0.62-0.79) for the POI and iFTA elute card respectively. Sensitivity for ≥CIN2 was 100% (CI 100-100%), 95.1% (CI 92.7-97.6%), and 93.5% (CI 90.7-96.3%) for the HR-HPV test from the liquid media, POI card, and iFTA elute card respectively. There was no color change of the POI card noted in humidity but the iFTA elute card changed color at 90% humidity.

CONCLUSIONS

The POI card is suitable for DNA transport and HR-HPV testing. This card has the potential to make cervical cancer screening programs more affordable worldwide.

Protein Detection Using the Multiplexed Proximity Extension Assay (PEA) from Plasma and Vaginal Fluid Applied to the Indicating FTA Elute Micro Card™

The indicating FTA elute micro card™ has been developed to collect and stabilize the nucleic acid in biological samples and is widely used in human and veterinary medicine and other disciplines. This card is not recommended for protein analyses, since surface treatment may denature proteins. We studied the ability to analyse proteins in human plasma and vaginal fluid as applied to the indicating FTA elute micro card™ using the sensitive proximity extension assay (PEA). Among 92 proteins in the Proseek Multiplex Oncology Iv2 panel, 87 were above the limit of detection (LOD) in liquid plasma and 56 among 92 above LOD in plasma applied to FTA cards. Washing and protein elution protocols were compared to identify an optimal method. Liquid-based cytology samples showed a lower number of proteins above LOD than FTA cards with vaginal fluid samples applied. Our results demonstrate that samples applied to the indicating FTA elute micro card™ are amendable to protein analyses, given that a sensitive protein detection assay is used. The results imply that biological samples applied to FTA cards can be used for DNA, RNA and protein detection.

Paper-based sample-to-answer molecular diagnostic platform for point-of-care diagnostics

Nucleic acid testing (NAT), as a molecular diagnostic technique, including nucleic acid extraction, amplification and detection, plays a fundamental role in medical diagnosis for timely medical treatment. However, current NAT technologies require relatively high-end instrumentation, skilled personnel, and are time-consuming. These drawbacks mean conventional NAT becomes impractical in many resource-limited disease-endemic settings, leading to an urgent need to develop a fast and portable NAT diagnostic tool. Paper-based devices are typically robust, cost-effective and user-friendly, holding a great potential for NAT at the point of care. In view of the escalating demand for the low cost diagnostic devices, we highlight the beneficial use of paper as a platform for NAT, the current state of its development, and the existing challenges preventing its widespread use. We suggest a strategy involving integrating all three steps of NAT into one single paper-based sample-to-answer diagnostic device for rapid medical diagnostics in the near future.

Implementation of cervical cancer screening and prevention in China--challenges and reality

This article summarizes great efforts that Chinese scholars had made in fighting against cervical cancer from aspects of the epidemiology, etiology, population-based screening studies, novel screening technology development, guideline, strategy and policy making and population delivery. After decades of continuous efforts, Chinese scientists successfully translated their scientific discovery to appropriate screening product development and eventually, delivered it to the whole population. We hope our experience could serve as a 'case-story' for cancer prevention in other low- and middle-income countries. Moreover, challenges confronted in the prevention and control of cervical cancer in China are reviewed as well to appeal for future multi-collaborations and potential solutions to acquire the final success of the campaign.