Self-Sampling for High-Risk Human Papillomavirus Detection: Future Cervical Cancer Screening?

Abstract

ISSN 1745-5057 10.2217/WHE.14.8 © Alexandros Daponte, Spyros Pournaras, Athanassios Tsakris Women's Health (2014) 10 (2), 115–118 with cytology, but exhibits lower specificity. The specificity can be increased by screening women over 30 or 35 years of age and by adjusting the threshold for HPV positivity (e.g., 2 pg/ml instead of 1 pg/ml on the Hybrid Capture 2 assay [Qiagen, MD, USA]) [3]. Furthermore, it is the high-negative predictive value of HPV testing that allows the safe increase of screening intervals to at least 3–5 years for women who test negative. Still, the enhanced sensitivity of HPV testing and the potential for application of high-throughput automated methods, makes it an attractive alternative to cytology. Further to its role in cervical cancer screening, hr-HPV testing is valuable in the triage of women with borderline cytology, aiming to reduce those who are referred to colposcopy, in addition to monitoring women following treatment of high-grade CIN, as it is better at predicting recurrent disease than cytology and colposcopy [4]. At present, all the above applies mainly to cervical sampling, which is the standard choice in hr-HPV DNA detection. However, it requires a gynecological examination to enable the physician-obtained cervical sampling. It should be noted that, as recently highlighted in a European population, the most common reason claimed by women for not attending screening was that they felt “uncomfortable with vaginal examination.” This evidence suggests that self-sampling, which bypasses this internal examination, should be further explored as a strategy to increase the coverage of cervical screening and follow-up programs [5]. In that respect, self-collected urine, vaginal, rectal and pharyngeal samples provide a different, cost-effective option and have been extensively investigated for screening outside the traditional clinical setting [5–13]. The majority of those studies aimed to: explore the specificity and sensitivity of selfcompared with clinician-collected samples; to investigate their potential to increase population coverage, including those unwilling to provide samples The widespread application of the Papanicolaou smear for the prevention of cervical cancer has led to a substantial decrease in the prevalence of the disease. However, the majority of cervical cancer cases (60%) are still occurring in women who experience an absence or deficiency of screening [1]. Therefore, an important immediate gain in cervical cancer prevention could be attained by increasing screening participation among women who are currently either unscreened or screened infrequently, regardless of the test used [1–7]. High-risk human papillomavirus (HPV; hrHPV) types are associated with over 99% of invasive cervical cancers and, nowadays, detection of hr-HPV DNA is considered the primary screening method [2]. Several methods considered to be clinically validated for use in primary screening have been applied for the detection of hr-HPV DNA, involving either nonamplification, hybridization-based or PCR-based assays [2,3]. Comparative studies have demonstrated that molecular techniques for hr-HPV DNA detection exhibit higher diagnostic sensitivity and reproducibility compared with cervical cytology for detecting cervical intraepithelial neoplasia (CIN) grade 2 (CIN2) or grade 3 (CIN3), which are the high-grade lesion precursors of invasive cervical cancer [3,4]. In addition, a pooled analysis of four randomized controlled trials, SwEDESCREEN, POBASCAM, ARTISTIC and NTCC demonstrated that a lower CIN3 incidence was recorded when HPV DNA testing was applied instead of cytology [2]. Furthermore, in this analysis HPV-based cervical screening versus conventional cytology provided 60–70% greater protection against invasive cervical carcinomas, prompting the authors to recommend the implementation of HPVbased cervical screening with triage from the age of 30 years at intervals of 5 or more years [2]. This age restriction could be anticipated, since hr-HPV testing has higher sensitivity compared Editorial