ABSTRACT
Identifying and reaching women at higher risk for cervical cancer is all-important for achieving the ambitious endpoints set in 2020 by the WHO for global cervical cancer control by 2030. HPV-based (vaginal) self-sampling (SS) represents a cost-effective screening strategy, which has been successfully implemented during the last decade both in affluent and constrained settings. Among other advantages, SS strategies offer convenience, diminished costs, flexibility to obtain a sample in the office or home, avoiding a pelvic exam and uncomfortable appointment with a healthcare professional, as well as social and cultural acceptability. SS implementation has been globally boosted during the COVID-19 pandemic. In pragmatic terms, social distancing, local lockdowns, discontinuation of clinics and reallocation of human and financial resources challenged established clinician-based screening; self-collection strategies apparently surpassed most obstacles, representing a viable and flexible alternative. With time, sufficient reassuring data has accumulated regarding specially designed SS devices, aspects of sample preparation, transport and storage and, importantly, optimization of validated PCR-based HPV testing platforms for self-collected specimens. Suboptimal rates of clinical follow-up post-SS screening, as well as overtreatment with reliance solely on molecular assays, have both been documented and remain concerning. Therefore, effective strategies are still required to ensure linkage to follow-up testing and management following positive SS results by trained health professionals with knowledge of HPV biology and management algorithms. Because of the prolonged SS screening intervals, implementation data are limited regarding subsequent screening rounds of SS-screened individuals; however, these are accumulating gradually. With further refinement of assays and validation of novel biomarkers in self-collected samples, there is a clear potential for increasing SS accuracy and PPV. The potential differentiation of self-collection protocols for vaccinated versus non-vaccinated individuals also represents an open issue. In conclusion, HPV-based self-collection techniques can effectively address limited uptake alongside other conventional cervical screening drawbacks; however, assays, logistics and infrastructures need further optimization to increase the efficacy, effectiveness and cost-effectiveness of SS approaches.
ABSTRACT
Within the previous decades, following the widespread implementation of HPV-related biomarkers and computerization in liquid-based cytology, screening for lower genital tract malignancies has been optimized in several parts of the world. Many organized anogenital cancer prevention systems have reached a point at which efficacy is more a matter of population coverage and less of available infrastructures. Meanwhile, self-sampling modalities in which biologic material (vaginal secretions, urine, etc.) is obtained by the individual and not the clinician and subsequently undergoes examination for HPV biomarkers enjoy appreciating acceptance. Bygone the initial skepticism that vaginal or urine HPV represents "passenger" transient infections, extensive scientific work has been conducted to optimize high-risk HPV (hrHPV) detection from this "novel" biologic material. Nowadays, several state-of-the-art meta-analyses have illustrated that self-sampling techniques involving urine self-sampling represent a feasible alternative strategy with potentially enhanced population coverage possessing excellent performance and sensitivity. Recently published scientific work focusing on urine HPV was reviewed, and after a critical appraisal, the following points should be considered in the clinical application of hrHPV urine measurements; (i) use of first-void urine (FVU) and purpose-designed collection devices; (ii) using a preservation medium to avoid human/HPV DNA degradation during extraction and storage; (iii) using polymerase chain reaction (PCR) based assays, ideally with genotyping capabilities; (iv) processing of a sufficient volume of whole urine; and (v) the use of an analytically sensitive HPV test/recovery of cell-free HPV DNA in addition to cell-associated DNA.