We previously reported PaVDaG study, which demonstrated that cobas 4800 hrHPV testing on self-collected vaginal samples have similar sensitivitity and specificity for detection of CIN2+ as on clinician-collected cervical samples. The relative sensitivity of cobas testing on random urine versus clinician samples was 0.67 hence could not be considered for primary cervical screening before further analytical optimisation. Here we are presenting the age-specific hrHPV detection in clinician-collected cervical and two self-collected samples.
A total of 5318 women aged 20-60 attending for routine cervical screening provided clinician-collected cervical, self-collected urine and vaginal samples for hrHPV testing. HrHPV testing of all samples was performed using the cobas 4800. We analysed hrHPV detection in urine and vaginal samples vs. cervical samples in increasing age groups of participates.
The proportion of hrHPV positive results was similar in cervical and vaginal samples in women ≤29 years old. Comparatively, hrHPV positivity was 38% higher in vaginal compared to cervical samples in women ≥50 years. This was also reflected in HPV16/18 positivity, which was 26% higher in vaginal samples compared with cervical samples in women ≥50 years old. The increase of HPV positivity ratio from 1.01 to 1.38 with increasing age was significant (p=0.03). Similarly the ratios of hrHPV positivity in urine vs. cervical samples increased from 0.66 to 0.95, with significant linear trend p=0.02. The significant differences in hrHPV detection between vaginal vs. cervical samples was already observed in women 45 years and older.
We hypothesise that the quality of cervical sampling deteriorates around the menopause and that menopausal atrophic changes in urogenital mucosa contribute to an increase of unsatisfactory cytology and a lower content of HPV DNA in cervical samples. These changes appear to be less influential of self-collected samples. Given clinical performance of vaginal samples we cannot rule out the possibility that, in follow-up, relatively more CIN2+ may be detected in older women who were hrHPV+ on the self-sample alone. Another hypothesis is that specificity of HPV testing on self-samples deteriorates with increasing age. Future longitudinal analysis of the PaVDaG cohort will provide some answers.