Timothy Palmer

Human Papillomavirus Immunization and the Elimination of Cervical Carcinoma

Cervical screening with human papillomavirus primary testing: the way forward

The challenges of defining sample adequacy in an era of HPV based cervical screening

The implementation of Human Papillomavirus based cervical screening continues apace on a global scale. Understanding the basis and burden of inadequate or invalid samples is important to ensure confidence in high quality laboratory results and inform the development of new technologies. Here we present population based data from Scotland and Denmark which detail the extent of invalid samples for HPV detection in both clinician-taken and self-taken samples. As a comparator we report on the rate of inadequate cytology preparations in both countries. The proportion of samples with an invalid HPV test result was calculated by retrospective analysis of routine laboratory data associated with cervical screening programmes in the two countries. Two assays were in use for the programmes at the time (the Abbott RealTime High Risk HPV assay and the BD Onclarity); both have internal endogenous controls for human genes. In addition, acellular cytology samples were reported through a prospective audit (Scotland) and National quality reporting (Denmark). In total, 89,418 clinician samples and 14,677 self-taken samples were assessed. We observed low rates of invalid HPV tests in clinician taken samples (0.05-0.10 %), irrespective of sample collection media (ThinPrep or SurePath), HPV test system/endogenous control type or clinical indication for testing (primary screening, triage or test of cure). For self-taken samples, the number of invalid samples was 0.18 %. Complete absence of sample material (acellular) in clinician taken samples were observed at a level of 1 in approximately 16.5 thousand. Clinician and self-taken samples appear robust specimens for HPV testing and acellular samples are very rare. Efforts to develop endogenous controls for HPV assays that provide greater insight into true sample adequacy for cervical disease detection, beyond measuring the presence of human cells, will be welcome.

Clinical Performance of Triage Strategies for Hr-HPV–Positive Women; A Longitudinal Evaluation of Cytology, p16/K-67 Dual Stain Cytology, and HPV16/18 Genotyping

Abstract Background: We evaluated the longitudinal performance of three options: HPV16/18 genotyping (HPV16/18), cytology (LBC), and p16/Ki-67 dual stain cytology (DS) for the triage of high-risk Human Papillomavirus–positive (Hr-HPV+) women within the cervical screening program in Scotland. Methods: Data were derived from a cohort of Hr-HPV+ women (n = 385) who participated in PaVDaG (Papillomavirus Dumfries and Galloway) study. Performance of triage strategies for detecting high-grade disease was assessed at 3 (in women <50 years) or 5 years (in women >50 years). Sensitivity, specificity, PPV, and cNPV of each triage test were calculated for CIN2+ and CIN3+ when used singly or sequentially. Results: The sensitivity of LBC (≥ borderline), DS, and HPV 16/18 genotyping for the detection of CIN2+ was 62.7% (50.7–73.3), 77.7% (63.1–83.7), and 62.7% (50.7–73.3) with corresponding cNPVs of 10.9%, 8.4%, and 11.9%. The option with the highest sensitivity and lowest cNPV was HPV 16/18 genotyping followed by LBC of Hr-HPV other+ and then DS of the LBC negatives. This yielded sensitivity of 94.7% (86.2–98.3) and cNPV 2.7% for CIN2+. Triage performance was similar if women had tested Hr-HPV+ positive by vaginal self-sampling. Conclusions: Two-step triage with HPV 16/18 genotyping before LBC (or DS) for Hr-HPV other+ women was associated with a lower risk of significant disease at follow-up compared with single triage approaches. Impact: This study provides longitudinal performance data on triage strategies in Hr-HPV+ women and will be informative for the evolution of cervical screening programs that increasingly rely on molecular technologies.

Invasive cervical cancer incidence following bivalent human papillomavirus vaccination: a population-based observational study of age at immunization, dose, and deprivation

Abstract Background High-risk human papillomavirus causes cervical cancer. Vaccines have been developed that significantly reduce the incidence of preinvasive and invasive disease. This population-based observational study used linked screening, immunization, and cancer registry data from Scotland to assess the influence of age, number of doses, and deprivation on the incidence of invasive disease following administration of the bivalent vaccine. Methods Data for women born between January 1, 1988, and June 5, 1996, were extracted from the Scottish cervical cancer screening system in July 2020 and linked to cancer registry, immunization, and deprivation data. Incidence of invasive cervical cancer per 100 000 person-years and vaccine effectiveness were correlated with vaccination status, age at vaccination, and deprivation; Kaplan Meier curves were calculated. Results No cases of invasive cancer were recorded in women immunized at 12 or 13 years of age irrespective of the number of doses. Women vaccinated at 14 to 22 years of age and given 3 doses of the bivalent vaccine showed a significant reduction in incidence compared with all unvaccinated women (3.2/100 000 [95% confidence interval (CI) = 2.1 to 4.6] vs 8.4 [95% CI = 7.2 to 9.6]). Unadjusted incidence was significantly higher in women from most deprived (Scottish Index of Multiple Deprivation 1) than least deprived (Scottish Index of Multiple Deprivation 5) areas (10.1/100 000 [95% CI = 7.8 to 12.8] vs 3.9 [95% CI = 2.6 to 5.7]). Women from the most deprived areas showed a significant reduction in incidence following 3 doses of vaccine (13.1/100 000 [95% CI = 9.95 to 16.9] vs 2.29 [95% CI = 0.62 to 5.86]). Conclusion Our findings confirm that the bivalent vaccine prevents the development of invasive cervical cancer and that even 1 or 2 doses 1 month apart confer benefit if given at 12-13 years of age. At older ages, 3 doses are required for statistically significant vaccine effectiveness. Women from more deprived areas benefit more from vaccination than those from less deprived areas.