Factors predicting the spontaneous regression of cervical high-grade squamous intraepithelial lesions (HSIL/CIN2).

Purpose: To determine clinical, pathological and virological factors predicting the spontaneous regression of HSIL/CIN2.

Methods: This retrospective study included 73 patients with HSIL/CIN2 diagnosed by biopsy between 2012 and 2016 and followed-up without treatment in the department of gynecology at Bordeaux University Hospital. All biopsies sampled inside or outside our department were reviewed and immunolabelled for p16 and Ki67. The response rate was the regression or the disappearance of HSIL/CIN2 as defined by the regression or the disappearance of initial colposcopic findings, cytological and/or histological results.

Results: The diagnosis of CIN2 was confirmed in 63 of 70 biopsies available for review. The Cohen's kappa coefficient was κ = 90%, indicating almost perfect inter-observer agreement. The lesion spontaneously regressed or disappeared in 36 of 60 patients (60%) with confirmed CIN2 during a median follow-up of 20 months (range 6-55). Baseline factors influencing the response rate were colposcopic findings (69% with minor change vs 31% with major change, p = 0.033), cytological results (72% with ASCUS/LSIL vs 28% with ASC-H/HSIL, p = 0.018), and HPV genotyping (71% with HPV not 16 vs 42% with HPV-16, p = 0.027). The other factors (age, smoking, surface area of the lesion, p16 and Ki67 expressions) did not significantly influence the outcome.

Conclusion: Colposcopic findings, cytological results, and HPV genotyping were baseline factors predicting spontaneous regression of HSIL/CIN2.