The aim of this study is to assess the extent of histopathological regression of severe cervical precancerous lesions (CIN 2 and CIN 3); evaluate the proportion of patients who experience the normalization of HPV test and cytology finding among those who were treated conservatively and those who underwent conization; and identify predictive parameters associated with regression. Based on this analysis, a model will be proposed to predict the likelihood of lesion regression.

Introduction There are three grades of dysplasia of the cervix based on their severity (CIN 1-3). Most women with CIN 2 or CIN 3 (high-grade - HG lesions) are referred for conization due to the presumed risk of developing invasive cervical cancer. However, this surgical intervention is associated with an increased risk of preterm labor in the future.

From the literature, it is evident that 30% - 60% of CIN 2 and CIN 3 lesions spontaneously regress. Colposcopic examination is a tool that can accurately assess the severity of the lesion and safely evaluate the dynamics of its development. It can be used to exclude the presence of invasive cervical cancer.

The aim of the study is to determine the absolute rate of spontaneous regression of HG lesions, considering stratification factors.

Methods Patients meeting all inclusion criteria and none of the exclusion criteria are included (see below). Colposcopic evaluations occur at four-month intervals during the study. In case of progression, the patient is indicated for conization; in case of persistence, the patient is consulted and can choose further observation or conization; in case of regression, punch biopsy is performed to acquire a histopathologic sample for primary endpoint evaluation. The biopsy/conization result is subsequently compared with the initial sample to declare regression or persistence of the HG lesion.

The HPV status and cytological findings are evaluated similarly. Stratification criteria such as age, colposcopic characteristics, HPV genotype (Cobas 4800, Roche Molecular Systems, Pleasanton, USA), methylation markers (GynTect®, Oncgnostics GmbH, Löbstedter Str. 41, 07749 Jena, Germany), semiquantitative microscopic assessment of the vaginal swab, and personal history are assessed during monitoring.

Inclusion Criteria:

1. squamocolumnar junction fully visualized
2. bioptically verified CIN 2 or CIN 3
3. age ≥ 18 years
4. age ≤ 40 years
5. informed consent

Exclusion Criteria:

1. squamocolumnar junction not fully visualized
2. suspicion on glandular lesion
3. suspicion on invasive cancer
4. personal history of CIN 2, 3 or cerv. cancer
5. gravidity
6. HIV positivity
7. immunosuppression
8. impossible photographic documentation

Consecutive participant sampling of patients with bioptically-verified CIN 2 or CIN 3 and fully visualised squamocolumnar junction with no suspiction on invasive cancer or glandular lesion.