Five-Year Risk of CIN3+ After CIN1 Biopsy in a Norwegian Screening Setting: Comparison of CIN1 Diagnosed in…

Cohort studyPathogens (Basel, Switzerland)· Jun 2026

Five-Year Risk of CIN3+ After CIN1 Biopsy in a Norwegian Screening Setting: Comparison of CIN1 Diagnosed in a Single Calendar Year and in Two Consecutive Calendar Years.

Sveinung Wergeland Sørbye, Mona Antonsen, Elin Richardsen

PathologyCohort studyPrognosisQ1IF 3.9

Repeated CIN1 diagnosis was not associated with higher subsequent CIN3+ risk than single CIN1

Five-Year Risk of CIN3+ After CIN1 Biopsy in a Norwegian Screening Setting: Comparison of CIN1 Diagnosed in a Single Calendar Year and in Two Consecutive Calendar Years.

Sveinung Wergeland Sørbye … Elin Richardsen

Pathogens (Basel, Switzerland) · Jun 2026

Background

Cervical intraepithelial neoplasia grade 1 (CIN1) is usually managed conservatively, but uncertainty remains about the subsequent risk of clinically significant high-grade disease, particularly after repeated CIN1.

Methods

We conducted a retrospective population-based cohort study using anonymized cervical cytology, HPV, and histopathology records from Northern Norway from 2011 to 2025.

n = 334,471 screening records

Results

repeat cases were not more likely to progress to high grade disease

Single calendar year

4.3%

Two consecutive years

3.4%

More results

We described temporal trends in screening-related outcomes and estimated the 5-year risk of CIN3+ after histologically confirmed CIN1 diagnosed in a single calendar year or in two consecutive calendar years.

More results

Across 2011-2025, the annual datasets comprised 334,471 screening records; 35,796 had ASC-US+ cytology (10.7%), 29,723 had a positive HPV test (8.9%), 35,416 underwent biopsy (10.6%), and 7870 were diagnosed with CIN2+ (2.4%).

HPV positivity increased from 0.9% in 2011 to 15.7% in 2025, whereas CIN2+ detection peaked at 3.1% in 2018 and declined to 1.8% in 2025.

“

Conclusion

Repeated CIN1 was not associated with higher subsequent CIN3+ risk, supporting conservative, risk-based follow-up after CIN1 biopsy.

Five-Year Risk of CIN3+ After CIN1 Biopsy in a Norwegian Screening Setting: Comparison of CIN1 Diagnosed in a Single Calendar Year and in Two Consecutive Calendar Years.

Five-Year Risk of CIN3+ After CIN1 Biopsy in a Norwegian Screening Setting: Comparison of CIN1 Diagnosed in a Single Calendar Year and in Two Consecutive Calendar Years.

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