Introduction/Background In general patients with ASC-US/LSIL cytology will be followed periodically with three or six month interval. We performed liquid nitrogen cryotherapy (N₂Cryo) of less than thirty second duration for the purpose of clearance of abnormal cytology and persistent HPV infection.

Methodology Between April 2015 to May 2019, retrospectively we analyzed patients with abnormal cytology of ASC-US/LSIL into the groups: A group of 37 cases with just follow-up without any treatment, B group of 39 cases with N₂Cryo according to colposcopic and/or cytological abnormality and HPV infection. Furthermore, 26 patients with HSIL undergone N₂Cryo were also compared to the effectiveness of clearance of abnormal cytology and HPV infection. Patients performed N₂Cryo three times every four weeks with written informed consent.

Results Among 37 patients with ASC-US/LSIL followed by no treatment, 2 cases recovered spontaneously with normal cytology (NILM) and HPV negative (complete regression: CR), 15 cases with partial regression (PR) (CR+PR Regression Rate (RR): 45.9%) including NILM or HPV negative, 6 cases with persistence, 2 cases with progressed to HSIL. However, 12 cases were missed with no visit during follow-up.

Among 39 patients with ASC-US/LSIL treated by N₂Cryo, 14 cases showed CR, 10 cases showed PR, with RR: 61.5%, including 8 cases with persistence.

Furthermore, 26 cases with HSIL treated by N₂Cryo, 8 cases showed CR, 12 cases showed PR with RR: 76.9%, and 4 cases with persistence.

Conclusion Liquid nitrogen cryotherapy (N₂Cryo) might be useful for the CIN regression, especially with avoidance of cone biopsy for cases with HSIL.

Disclosure Nothing to disclose.