HPV testing of self-samples: Influence of collection and sample handling procedures on clinical accuracy to detect cervical precancer

Findings and Challenges in Replacing Traditional Uterine Cervical Cancer Diagnosis with Molecular Tools in Private Gynecological Practice in Mexico

We have been encouraging practicing gynecologists to adopt molecular diagnostics tests, PCR, and cancer biomarkers, as alternatives enabled by these platforms, to traditional Papanicolaou and colposcopy tests, respectively. An aliquot of liquid-based cytology was used for the molecular test [high-risk HPV types, (HR HPV)], another for the PAP test, and one more for p16/Ki67 dual-stain cytology. A total of 4499 laboratory samples were evaluated, and we found that 25.1% of low-grade samples and 47.9% of high-grade samples after PAP testing had a negative HR HPV-PCR result. In those cases, reported as Pap-negative, 22.1% had a positive HR HPV-PCR result. Dual staining with p16/Ki67 biomarkers in samples was positive for HR HPV, and 31.7% were also positive for these markers. Out of the PCR results that were positive for any of these HR HPV subtypes, n 68.3%, we did not find evidence for the presence of cancerous cells, highlighting the importance of performing dual staining with p16/Ki67 after PCR to avoid unnecessary colposcopies. The encountered challenges are a deep-rooted social reluctance in Mexico to abandon traditional Pap smears and the opinion of many specialists. Therefore, we still believe that colposcopy continues to be a preferred procedure over the dual-staining protocol.

Evaluation of two alternative non-alcohol-based media for the suspension of self-collected vaginal swabs for HPV testing in cervical cancer screening

The introduction of Human Papillomavirus (HPV) testing in cervical cancer screening enhanced the opportunity to introduce self-collection as an innovative approach to improve coverage rates. Validation and standardization of the pre-analytical and analytical procedures are crucial for the quality assurance of HPV tests on self-collected samples. This study evaluated the analytical performance and the stability of self-collected vaginal samples resuspended in 5 mL of two non-alcohol-based media, eNat® and MSwab® compared to a professionally collected cervical sample, resuspended in 20 mL ThinPrep®, for the detection of high-risk HPV (hrHPV). The impact of the suspension volumes on analytical performance was also evaluated (2 and 5 ml). A good analytical concordance in hrHPV detection in cervical and vaginal self-collected swabs suspended in 5 ml of both non-alcohol-based media was demonstrated (eNat®: 91.2 %, k = 0.821; MSwab®: 91.4 %; k = 0.798). A similar analytical performance was found for samples resuspended in 2 mL (eNat®: 92.9 %, k = 0.811; MSwab®: 92.9 %, k = 0.811) compared to cervical samples. Good nucleic acid stability was demonstrated for vaginal samples stored at 20-25 °C and 37 °C for up to 4 weeks. Results of this preliminary study support the introduction of these media for vaginal self-sampling-based prevention programs. Nevertheless, further research is necessary to evaluate clinical accuracy in larger settings.

Performance of BD Onclarity HPV assay on FLOQSwabs vaginal self-samples

This study assessed the accuracy of high-risk human papillomavirus testing of BD Onclarity HPV (Onclarity) assay on vaginal self-collected FLOQSwab versus cervical samples to ensure similar accuracy to detect cervical intraepithelial neoplasia. Testing was performed on two automated platforms, BD Viper LT and BD COR, to evaluate the effect of machine and using two vaginal self-samples to analyze the influence of collection, transport, and freezing-unfreezing on the results. A cervical sample and two self-samples were collected from 300 women. The first collected vaginal and the cervical sample were tested on BD Viper LT, and the second swab was frozen and subsequently tested on both automated systems. Test results on vaginal and cervical specimens were considered the index and comparator, respectively; colposcopy and histology were reference standards. Relative sensitivity for ≥CIN2 on vaginal samples analyzed versus the cervical sample was 1.01 (0.97-1.06), 1.01 (0.97-1.06), and 1.00 (0.95-1.05), for the first, second self-collected sample tested on BD VIPER LT, and second self-collected sample tested on BD COR, respectively. Relative specificity was 0.83 (0.73-0.94), 0.76 (0.67-0.87), and 0.82 (0.73-0.92) using the three different workflows. Cut-off optimization for human papillomavirus (HPV) positivity defined at Ct ≤38.3 for HPV16, ≤ 34.2 for HPV18, and ≤31.5 for all other types showed an increased relative specificity with similar sensitivity. No significant difference was observed between self-samples tested with the two platforms and between first- and second-collected swabs. Onclarity assay on FLOQSwab using both platforms showed similar sensitivity but lower specificity to detect ≥CIN2 compared to cervical samples. By cut-off optimization, non-inferior specificity could be reached.

IMPORTANCE

Human papillomavirus (HPV) testing on self-collected vaginal samples has been shown to improve women's participation to cervical cancer screening programs, particularly in regions with limited access to health care. Nevertheless, the introduction of self-sampling in cervical cancer screening programs requires prior clinical validation of the HPV assay in combination with a self-sample collection device, including also the laboratory workflow and automation required for high-throughput testing in screening. In this study, the performance of BD Onclarity HPV on FLOQSwab-collected vaginal self-samples has been compared to clinician-taken liquid-based cytology samples, to detect high-grade cervical intraepithelial neoplasia using two high-throughput platforms, BD Viper LT and BD COR. The study findings have shown a similar performance of BD Onclarity on testing self-collected samples, confirming the validation of the proposed pre-analytical and analytical protocols for their use in cervical cancer screening programs based on self-collected vaginal samples.

Evaluation of self-sampling-based cervical cancer screening strategy using HPV Selfy CE-IVD test coupled with home-collection kit: a clinical study in Italy

BACKGROUND

Primary human papillomaviruses (HPV) cervical cancer screening can be strengthened by offering home-collection of biological specimen as a valuable option to increase screening coverage. As recommended by World Health Organization (WHO), screening programs should consider whether the inclusion of HPV self-sampling as a complementary option within their existing screening algorithms could address the gaps in current coverage. However, few HPV screening tests are validated for self-sampling according to international guidelines. This study aimed to test a self-sampling-based screening strategy, complementary to the main screening program based on clinician-collected cervical samples. The study took place in Trieste, Italy, and it aimed to evaluate the feasibility of self-testing at home under an opt-in system during COVID-19 pandemic in order to exploit self-sampling to reduce the screening delay generated by the lockdown.

METHODS

500 women, who should have received the screening call in 2020, were asked, via phone call, to participate in the study. To whom agreed, a home-collection kit, including a vaginal dry swab for specimen collection, was sent. The recipients performed the sample self-collection and sent back the swab through traditional mail using a prepaid envelope. Once received by the hospital, the samples were analyzed with HPV Selfy (Ulisse BioMed, Italy), a CE-IVD HPV screening test specifically validated for self-collection. Results were further compared using cobas® 4800 HPV (Roche, Switzerland).

RESULTS

80% women sent back their swab, showing one of the highest return rate obtained in comparable studies. 34 HPV-positive women were followed up and underwent the Pap test, that revealed 8 low squamous intraepithelial lesions (LSIL) cases, later triaged to colposcopy. HPV Selfy was confirmed to be an adequate test for self-sampling-based screening.

CONCLUSIONS

This study further confirmed the feasibility of self-test at home screening strategy based on self-sampling with an opt-in system as a support method to enhance cervical cancer screening coverage in Italy. Enrolled women showed a high appreciation for this approach. HPV Selfy test demonstrated to be a valuable assay for cervical cancer screening based on home self-collection.

TRIAL REGISTRATION

ASUGI Trieste n. 16008/2018 and amendment 02-11/09/2020.

Cost-utility and budget impact analyses of cervical cancer screening using self-collected samples for HPV DNA testing in Thailand

INTRODUCTION

Cervical cancer ranks as the third most prevalent cancer among women in Thailand. However, the effectiveness of cervical cancer screening programs is limited by several factors that impede the screening rate. The utilization of self-collected samples for screening purposes has the potential to alleviate barriers to screening in Thai women. This study assessed the cost-utility and budget impact of implementing cervical cancer screening using self-collected samples for human papillomavirus (HPV) deoxyribonucleic acid (DNA) testing in Thailand.

MATERIALS AND METHODS

We employed a decision tree integrated with a Markov model to estimate the lifetime costs and health benefits associated with the cervical cancer screening program for women aged 25-65. The analysis was conducted from a societal perspective. Four screening policy options were compared: (1) additional self-collected samples for HPV DNA testing, (2) clinician-collected samples for HPV DNA testing only, (3) clinician-collected samples for cytology test (i.e., status quo), and (4) no screening. The model inputs were based on unvaccinated women. The screening strategies and management in those with positive results were assumed followed to the Thai clinical practice guideline. Costs were reported in 2022 Thai baht. Sensitivity analyses were conducted. The ten-year budget impacts of the additional self-collected samples for HPV DNA testing were calculated from a payer perspective.

RESULTS

All screening policies were cost-saving compared to no screening. When comparing the additional self-collected samples for HPV DNA testing with the clinician-collected samples policy, it emerged as the dominant strategy. The incremental benefit in cervical cancer prevention achieved by incorporating self-collected samples for screening was observed at any additional screening rate that could be achieved through their use. Sensitivity analyses yielded consistently favorable results for the screening policies. The average annual budget impact of the additional self-collected samples for screening policy amounted to 681 million Thai baht. This budget allocation could facilitate cervical cancer screening for over 10 million women.

CONCLUSIONS

An addition of self-collected samples for HPV DNA testing into the cervical cancer screening program is cost-saving. The benefits of this screening policy outweigh the associated incremental costs. Policymakers should consider this evidence during the policy optimization process.

Human papillomavirus testing using HPV APTIMA® assay and an external cellularity control in self-collected samples

In cervical cancer screening programs, the detection of high-risk human papillomavirus (HR-HPV) is now widely implemented on physician-collected samples and has expanded to include self-collected samples. The use of a cellularity control (CC) is needed to reduce false-negative HPV results. An external mRNA CC for the HPV APTIMA® assay was assessed for its analytical performance and the results were compared with both cervix cytobrush samples taken by physicians and self-collected vaginal samples from 148 women. The performance of the CC was adjusted to control for the presence of cellular mRNA in the ThinPrep® and Multitest® transport media. This CC is user-friendly but implies to perform two independent assays on PANTHER® automate. Self-collected vaginal sampling gives a lower median CC results (13.2 vs. 16.9 min) but a higher risk of negative CC results (3.3 vs. 0%). The usefulness of the CC for the HR-HPV assay may be optimized by the definition of a threshold for a minimum cell number to be tested to increase confidence in HPV-negative results. The systematic use of an RNA CC increases confidence for HPV RNA assays on self-collected vaginal samples.

Toward 70% cervical cancer screening coverage: Technical challenges and opportunities to increase access to human papillomavirus (HPV) testing

The World Health Organization (WHO) has called for the elimination of cervical cancer as a public health problem. Cervical cancer screening through human papillomavirus (HPV) testing is a core component of the strategy for elimination, with a set target of screening 70% of women twice in their lifetimes. In this review, we discuss technical barriers and opportunities to increase HPV screening globally.

Widening the offer of human papillomavirus self-sampling to all women eligible for cervical screening: Make haste slowly

Self-collection of samples for human papillomavirus (HPV) testing has the potential to increase the uptake of cervical screening among underscreened women and will likely form a crucial part of the WHO's strategy to eliminate cervical cancer by 2030. In high-income countries with long-standing, organised cervical screening programmes, self-collection is increasingly becoming available as a routine offer for women regardless of their screening histories, including under- and well-screened women. For these contexts, a validated microsimulation model determined that adding self-collection to clinician collection is likely to be cost-effective on the condition that it meets specific thresholds relating to (1) uptake and (2) sensitivity for the detection of high-grade cervical intraepithelial neoplasia (CIN2+). We used these thresholds to review the 'early-adopter' programme-level evidence with a mind to determine how well and how consistently they were being met. The available evidence suggested some risk to overall programme performance in the situation where low uptake among underscreened women was accompanied by a high rate of substituting clinician sampling with self-collection among well-screened women. Risk was further compounded in a situation where the slightly reduced sensitivity of self-sampling vs clinician sampling for the detection of CIN2+ was accompanied with lack of adherence to a follow-up triage test that required a clinician sample. To support real-world programmes on their pathways toward implementation and to avoid HPV self-collection being introduced as a screening measure in good faith but with counterproductive consequences, we conclude by identifying a range of mitigations and areas worthy of research prioritisation.

HPV-based Cervical Cancer Screening on Self-samples in the Netherlands: Challenges to Reach Women and Test Performance Questions

In 2017, cervical cancer screening in the Netherlands switched from cytology to human papillomavirus (HPV) testing using the validated PCR-based cobas 4800. Women could order and subsequently received a free self-sampling kit (Evalyn Brush) at their home address instead of clinician sampling. In the laboratory, the shipped brush was placed into 20 mL of PreservCyt fluid, before testing. In the first 2 years of the new program, only 7% of screening tests were performed on a self-sample. Those who chose self-sampling versus clinician sampling were more likely to have never been screened previously and differed also with respect to sociodemographic factors. Subsequent more active promotion and increasing the ease to obtain kits increased the proportion opting for self-sampling (16% in 2020). HPV positivity and detection rate of precancer (CIN3+) were lower in the self-sampling compared with the clinician-sampling group (adjusted ORs of 0.65 and 0.86, respectively). Although population differences may partially explain these results, self-samples may have been too dilute, thereby reducing the analytic and clinical sensitivity. The Dutch findings demonstrate the importance of optimizing outreach, specimen handling and testing protocols for self-samples to effectively screen the target population and reach in particular the women at highest risk for cervical cancer. See related article by Aitken et al., p. 183.

Clinical Performance of the RealTime High Risk HPV Assay on Self-Collected Vaginal Samples within the VALHUDES Framework

The VALHUDES framework (NCT03064087) was established to evaluate the clinical accuracy of HPV testing on self-samples compared with HPV testing on matched clinician-taken cervical samples. Women referred to colposcopy due to previous cervical abnormalities were recruited at five Belgian colposcopy centers. A total of 486 pairs of matched cervical samples and vaginal self-samples were included in the analysis (228 collected with Evalyn Brush and 258 with Qvintip). The dry vaginal brushes were transferred into 20 mL ThinPrep PreservCyt solution. All specimens were tested with the Abbott RealTime High Risk HPV assay (Abbott RT). Testing on vaginal and cervical specimens was considered the index and comparator tests, respectively, and colposcopy and histology as the reference standard. The clinical sensitivity for CIN2+ of Abbott RT (cutoff ≤32 cycle number [CN]) on vaginal self-samples (Evalyn Brush and Qvintip combined) was 8% lower than on the cervical clinician-collected samples (ratio = 0.92 [95% CI, 0.87 to 0.98]), while the specificity was similar (ratio = 1.04 [95% CI, 0.97 to 1.12]). Sensitivity (ratio = 0.95 [95% CI, 0.89 to 1.02]) and specificity (ratio = 1.11 [95% CI, 0.995 to 1.23]) on Evalyn Brush samples was similar to cervical, while on Qvintip samples, the sensitivity was 12% lower than cervical samples (ratio = 0.88 [95% CI, 0.78 to 0.998]) with similar specificity (0.99 [95% CI, 0.90 to 1.10]). Exploratory cutoff optimization (cutoff ≤35 CN) resulted in an improvement of the relative sensitivity (self-sampling versus clinician sampling: ratio = 0.96 [95% CI, 0.91 to 1.02]) but yielded a loss in relative specificity (ratio = 0.92 [0.85 to 1.00]). The clinical accuracy of Abbott RT differed from the self-sampling device. However, after cutoff optimization, the sensitivity on self-samples taken with either of two vaginal brushes became similar to clinician-collected samples. IMPORTANCE Self-samples are becoming a crucial part of HPV-based cervical cancer screening programs to reach nonattendee women and increase screening coverage. Therefore, the VALHUDES framework was established to validate and evaluate HPV tests and devices on self-samples. Here, in the present manuscript, we evaluated the accuracy of the RealTime High Risk HPV assay (Abbott RT) on two different vaginal devices to detect cervical intraepithelial neoplasia grade two or higher (CIN2+). The study results demonstrated that the Abbott RT assay is similarly accurate on vaginal self-samples as on matched clinician-taken cervical samples after adjusting cutoff values. Moreover, we observed that some vaginal devices perform better than others in CIN2+ detection. We also underline the necessity of standardization and validation of general workflow and sample handling procedures for vaginal self-samples.