Recent increase in incidence of cervical precancerous lesions in Norway: Nationwide study from 1992 to 2016

Abstract

We analysed patterns in the incidence of cervical intraepithelial neoplasia grades 2 and 3 (CIN2, CIN3) and adenocarcinoma in situ (AIS) by age and histology in 1992–2016 in Norway and described changes in screening tests. Incident cases of CIN2, CIN3, AIS and cervical cancer were identified in the Cancer Registry of Norway, as were all women with at least one screening test. The annual percentage change statistic was used to assess point estimates and changes in age‐specific and age‐standardised incidence rates (IR). Women aged 25–29 years had the highest incidence of cervical precancerous lesions (CIN2: 192.9/10, CIN3: 737.2/10, AIS: 32.5/105 in 2016). The IR of CIN2 increased for all screening ages (25–69 years) from 3.6% to 6.7% per year. CIN3 incidence increased by 1.6% (95% confidence interval [CI] 0.6–2.6) annually. A steep increase in AIS incidence was observed in all age groups (7.1% per year, 95% CI 5.3–8.8). Changes in screening tests and the histological verification of cervical precancerous lesions alone cannot explain the steady increase in incidence we observed over the 25‐year study period, and increased exposure to human papillomavirus (HPV) likely plays a role. Age‐appropriate treatment of screening‐detected cervical precancerous lesions is needed for effective cervical cancer control while avoiding overtreatment and related health risks. In order to perform an appropriate harm‐benefit evaluation of cervical cancer control efforts, detailed information on screening technology and background risks, including HPV vaccination status, is needed to create optimal public health policy.

Potential Effects of Human Papillomavirus Type Substitution, Superinfection Exclusion and Latency on the Efficacy of the Current L1 Prophylactic Vaccines

“…However, that being said, this work clearly supports HPV type replacement in vaccinated and unvaccinated women which implies that direct or indirect (herd) effects of the vaccines on the prevalence of HPV types could still be a factor in the recent increase in the incidence of cervical cancer in Sweden and elsewhere. Norway started single cohort vaccination of 12-year-old girls with Gardasil in 2009 achieving a coverage of 89% but, unlike most other nations, did not start catch-up vaccinations until 2016 [81]. It is notable that Norway also observed an increase in the incidence of cervical cancer since vaccination started [82] which is consistent with an increase in the CIN2/3 observed over the same time period [81].…”

“…Norway started single cohort vaccination of 12-year-old girls with Gardasil in 2009 achieving a coverage of 89% but, unlike most other nations, did not start catch-up vaccinations until 2016 [81]. It is notable that Norway also observed an increase in the incidence of cervical cancer since vaccination started [82] which is consistent with an increase in the CIN2/3 observed over the same time period [81].…”

Long-term effectiveness of the nine-valent human papillomavirus vaccine in Scandinavian women: interim analysis after 8 years of follow-up

“…Note that we used conservative estimates of expected HPV incidence based on survey data from 2004 to 2005, and more recent data suggest that HPV exposure has increased since then, which further strengthens our observation of high vaccine effectiveness. 14 The following limitations of this study are noted. The LTFU study does not have a control arm since participants who received the qHPV vaccine in the base study were offered the 9vHPV vaccination at the end of the base study.…”

Effects of training based on the health belief model on Iranian women's performance about cervical screening: A systematic review and meta-analysis

“…[ 4 ] This method diagnoses 13,000 invasive cancer cases as well as one million precancerous lesions annually. [ 6 ] Although in the health system of Iran, the Pap test is performed on the age group of 20–65 years one to three times a year since 1991 and also it is an effective and nonexpensive test, several studies have indicated that the Iranian women have not greatly welcomed it. [ 7 ] In general, knowledge, attitude, and beliefs are considered the determinant factors for an individual's participation in screening programs.…”