Introduction/Background Human papilloma virus infection is the most common venereal disease and is behind 95% of cervical cancer cases and its precursor lesions. According to the American Society of Colposcopy and Cervical Pathology (ASCCP), 50% of CIN II cases managed conservatively spontaneously regress. The aim of this study was to evaluate the effect of a Coriolus versicolor-based vaginal gel in the conservative management of CIN II lesions.

Methodology A one-cohort, prospective, single-centre, observational study including women ≥ 18 years old, with a CIN II diagnosis who were treated with 1 cannula/day for 1 month + 1 cannula/alternate days for 5 months of Coriolus versicolor-based vaginal gel, was performed. Inclusion criteria was based on the Spanish Society of Colposcopy and Cervical Pathology (AEPCC) guidelines for CIN II conservative treatment: adequate colposcopy image with visible transition zone, completely visible lesion affecting less than 2 quadrants, non-affected endocervix and accepting cytology/colposcopy after 6 months. Baseline and 6-month biopsies were performed.

Results A total of 44 women with an average age of 35.5 years were included. After 6 months, 68.2% of them shown a regression by biopsy. From the rest of the patients 11.4% persisted on CIN II and 18.2% progressed to CIN III. Three patients were considered null and not included in the data analysis because they did not have a biopsy taken after 6 months.

Conclusion The application of Coriolus versicolor-based vaginal gel seems to increase regression of the lesions compared to spontaneous resolution and could represent a clinical advantage compared to the ‘wait and see’ approach in patients meeting the conservative treatment criteria for CIN II lesions.