Cervical intraepithelial neoplasia grade 1 and long-term risk of progression and treatment.

<h4>Background</h4>Cervical intraepithelial neoplasia grade 1 (CIN1) is often managed by active surveillance, as the risk of progression to high grade lesions is reported to be low, but long-term data is sparse. To inform management of CIN1, we estimated risk of progression and occurrenc...

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Main Authors: Ingrid Baasland, Tone Bjørge, Birgit Engesæter, Ameli Tropé, Signe Opdahl
Format: Article
Language:English
Published: Public Library of Science (PLoS) 2025-01-01
Series:PLoS ONE
Online Access:https://doi.org/10.1371/journal.pone.0320739
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author Ingrid Baasland
Tone Bjørge
Birgit Engesæter
Ameli Tropé
Signe Opdahl
author_facet Ingrid Baasland
Tone Bjørge
Birgit Engesæter
Ameli Tropé
Signe Opdahl
author_sort Ingrid Baasland
collection DOAJ
description <h4>Background</h4>Cervical intraepithelial neoplasia grade 1 (CIN1) is often managed by active surveillance, as the risk of progression to high grade lesions is reported to be low, but long-term data is sparse. To inform management of CIN1, we estimated risk of progression and occurrence of treatment in women attending a cervical cancer screening program.<h4>Methods</h4>We used nationwide, registry data on all women aged 25-69 years attending the Norwegian Cervical Cancer Screening Program in 2002-2019. The eligible source population was women with at least one cytology registration (n = 1,771,876). Women with a histologically confirmed, first CIN1 diagnosis were included (n = 26,130) and followed for detection of CIN2+, defined as histologically confirmed CIN2, CIN3, adenocarcinoma in situ (AIS), or cervical cancer. CIN3+ was defined as CIN3, AIS, or cervical cancer. Treatment included both excision and ablation.<h4>Results</h4>Overall, the cumulative incidence of CIN2+ increased to 9.5% (95% confidence interval (CI), 8.8 to 9.5) during the first year and to 19.0% (95% CI, 18.4-19.5) during the first five years. For women with high-grade cytology, 5-year cumulative incidence reached 26.0% (95% CI, 25.0-27.0), whereas for women with normal or low-grade cytology, but HPV16 and/or HPV18 positive status, the corresponding estimate was 25.0% (95% CI, 23.3-26.8). Other high-risk HPV genotypes and HPV negative status were associated with lower risks (5-year cumulative incidence 15.5% (95% CI, 14.5-16.6) and 8.2% (95% CI, 7.1-9.5), respectively). Detection of CIN3+ was substantial (cumulative incidence 5.7% (95% CI, 5.4-6.0) and 12.7% (95% CI, 12.2-13.1) after 1 and 5 years, respectively), and overall, cumulative incidence of treatment was 15.2% (95% CI, 14.7-15.7) after 5 years, following similar patterns as observed for CIN2+.<h4>Conclusions</h4>A differentiation of follow-up guidelines by index cytology and HPV16/18 status for women diagnosed with CIN1, might be warranted.
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spelling doaj-art-1706d8c7893f4f53b2d31d0b4b85cfbd2025-08-20T02:18:50ZengPublic Library of Science (PLoS)PLoS ONE1932-62032025-01-01204e032073910.1371/journal.pone.0320739Cervical intraepithelial neoplasia grade 1 and long-term risk of progression and treatment.Ingrid BaaslandTone BjørgeBirgit EngesæterAmeli TropéSigne Opdahl<h4>Background</h4>Cervical intraepithelial neoplasia grade 1 (CIN1) is often managed by active surveillance, as the risk of progression to high grade lesions is reported to be low, but long-term data is sparse. To inform management of CIN1, we estimated risk of progression and occurrence of treatment in women attending a cervical cancer screening program.<h4>Methods</h4>We used nationwide, registry data on all women aged 25-69 years attending the Norwegian Cervical Cancer Screening Program in 2002-2019. The eligible source population was women with at least one cytology registration (n = 1,771,876). Women with a histologically confirmed, first CIN1 diagnosis were included (n = 26,130) and followed for detection of CIN2+, defined as histologically confirmed CIN2, CIN3, adenocarcinoma in situ (AIS), or cervical cancer. CIN3+ was defined as CIN3, AIS, or cervical cancer. Treatment included both excision and ablation.<h4>Results</h4>Overall, the cumulative incidence of CIN2+ increased to 9.5% (95% confidence interval (CI), 8.8 to 9.5) during the first year and to 19.0% (95% CI, 18.4-19.5) during the first five years. For women with high-grade cytology, 5-year cumulative incidence reached 26.0% (95% CI, 25.0-27.0), whereas for women with normal or low-grade cytology, but HPV16 and/or HPV18 positive status, the corresponding estimate was 25.0% (95% CI, 23.3-26.8). Other high-risk HPV genotypes and HPV negative status were associated with lower risks (5-year cumulative incidence 15.5% (95% CI, 14.5-16.6) and 8.2% (95% CI, 7.1-9.5), respectively). Detection of CIN3+ was substantial (cumulative incidence 5.7% (95% CI, 5.4-6.0) and 12.7% (95% CI, 12.2-13.1) after 1 and 5 years, respectively), and overall, cumulative incidence of treatment was 15.2% (95% CI, 14.7-15.7) after 5 years, following similar patterns as observed for CIN2+.<h4>Conclusions</h4>A differentiation of follow-up guidelines by index cytology and HPV16/18 status for women diagnosed with CIN1, might be warranted.https://doi.org/10.1371/journal.pone.0320739
spellingShingle Ingrid Baasland
Tone Bjørge
Birgit Engesæter
Ameli Tropé
Signe Opdahl
Cervical intraepithelial neoplasia grade 1 and long-term risk of progression and treatment.
PLoS ONE
title Cervical intraepithelial neoplasia grade 1 and long-term risk of progression and treatment.
title_full Cervical intraepithelial neoplasia grade 1 and long-term risk of progression and treatment.
title_fullStr Cervical intraepithelial neoplasia grade 1 and long-term risk of progression and treatment.
title_full_unstemmed Cervical intraepithelial neoplasia grade 1 and long-term risk of progression and treatment.
title_short Cervical intraepithelial neoplasia grade 1 and long-term risk of progression and treatment.
title_sort cervical intraepithelial neoplasia grade 1 and long term risk of progression and treatment
url https://doi.org/10.1371/journal.pone.0320739
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