Background: Countries must decide whether or not to replace primary cytology-based screening with primary human papillomavirus (HPV)-based screening. We aimed to assess how primary screening for an HPV infection, a sexually transmitted infection (STI), and the type of information included in the invitation letter, will affect screening intention.
Methods: We randomized a representative sample of Norwegian women to one of three invitation letters: 1) Pap smear, 2) HPV testing or 3) HPV testing with additional information about the nature of the infection. Intention to participate, anxiety level and whether women intend to follow-up abnormal results were measured between groups using chi-squared and nonparametric Kruskal-Wallis tests. Determinants of intention were explored using logistic regression.
Results: Responses from 3540 women were representative of the Norwegian population with respect to age, civil status and geographic location. No significant difference across invitation letters was found in women's stated intention to participate (range: 91.8-92.3%), anxiety (39-42% were either quite or very worried) or to follow-up after an abnormal result (range: 97.1-97.6%). Strength of intention to participate was only marginally lower for HPV-based invitation letters, albeit significant (p-value = 0.008), when measured on a scale. Only 36-40% of respondents given the HPV invitations correctly understood that they likely had an STI.
Conclusions: We found that switching to primary HPV screening, independent of additional information about HPV infections, is not likely to reduce screening participation rates or increase anxiety; however, women lacked the ability to interpret the meaning of an HPV-test result.