Dr. Peter Snijders noted that, in high income countries, approximately 75% of women are covered by organised or opportunistic screening. In The Netherlands, these coverage estimates are 65% and 10%, respectively. Correspondingly, 55% of cervical cancers are diagnosed in the 25% of women not attending screening.

According to a systematic review [1], offering the possibility for self-sampling significantly increases attendance to screening in women, possibly increasing coverage in the non-responder social groups that represent the source of advanced cervical cancer cases.

In a sizeable cross-sectional study of 230.000 women, the possibility for HPV-testing of self-samples obtained from non-attendees yielded equal proportions of CIN2 findings and 2-3 times higher rates of CIN3 and cervical cancer diagnoses as organized screening (figure 1)

Certain PCR-based assays can be considered for self-sampling in organised population-based primary screening programmes [2]. Since the beginning of 2017, screening of Dutch women is based on HPV testing and women not responding to the screening invitation are offered HPV self-sampling. Two remaining questions are of relevance to the program: 1) Is the clinical performance of HPV self-sampling comparable to HPV physician sampling? and 2) How to triage HPV self-sample positive women for colposcopy?

Due to the lower specificity of a single HPV test compared to cytology (difference in specificity in the 2-4% range), referral to colposcopy of all HPV positive women would result in over 3 times more colposcopies and related diagnostic tests.The purpose of a triage test is to limit the number of HPV positive women to be referred for colposcopy without compromising safety. The currently preferred triage options in The Netherlands: repeat cytology or cytology combined with HPV16/18 genotyping, is not applicable since self-sample based cytology is not reliable. The possibility that alternative biomarkers can be applied to self-samples is being studied in trials which will reveal to what extent HPV self-sampling is clinically non-inferior to HPV physician sampling, and if DNA methylation analysis of selfsamples is an alternative to cytology triage testing based on physician-collected cervical scrape combined with HPV typing.

Offering the possibility for self-sampling significantly increases at tendance to screening in women, possibly increasing coverage in the non-responder social groups

Figure 1. Comparison of ordinary screening and HPV tests based on self-sampling specimens.

References
1. Verdoodt F, Jentschke M, Hillemanns P, et al. Reaching women who do not participate in the regular cervical cancer screening programme by offering self-sampling kits: a systematic review and meta-analysis of randomised trials. Eur J Cancer, 2015. 51:p.2375-2385.
2. Arbyn M, Verdoodt F, Snijders PJF, et al. Accuracy of human papillomavirus testing on self-collected versus clinician-collected samples: a meta-analysis. Lancet Oncol, 2014. 15: p.172-183.