High-risk human papilloma virus (HR-HPV) testing as primary screening for cervical cancer, is currently implemented among women 34-69 years old in four Norwegian counties, counting approximately 285 000 women. Based on available international literature, we predicted an overall HR-HPV prevalence of 8% in this population. Our aim was to study the actual prevalence of HR-HPV prevalence in target age group for the first time in Norway.
A randomized implementation of HR-HPV testing in primary screening was started February 1st 2015. All three participating laboratories use HPV COBAS 4800 HPV Test (Roche Diagnostics) testing for 14 HR-HPV genotypes (16, 18 and 31, 33, 35, 39, 45, 51, 52, 56, 58, 59, 66 and 68), the same biobank solutions, and similar quality assurance protocols. All test results (HR-HPV, cytology and histology) are reported to the Cancer Registry of Norway for administration and surveillance. So far 23 851 women have been tested.
During the first year of primary HPV screening, the overall HR-HPV positivity rate was 6.7%. There were only minor differences in the HPV positivity rates between laboratories. The HR-HPV positivity rate declined as a function of age, with a weak increase in prevalence after 58 years of age. Genotypes 16 and 18 contributed 24% and 16%, respectively, to total HR-HPV prevalence.
HR-HPV prevalence in the age group 34-69 was slightly lower than predicted. There was a big proportion of non 16 and 18 HR-HPV positive women in this population. The slight increase in HR-HPV positivity among older women and the reasons for this should be explored further.