Silent High Grade Cervical Intraepithelial Neoplasia in Atypical Smears from Liquid Based Cervical Cytology - Three Years Experience in Thammasat University Hospital.

Purpose: To study the prevalence of CIN2+ diagnosis in women with atypical Papaniculoau (Pap) smears to suggest appropriate management option for Thai health care.

Materials And Methods: Data from all patients with liquid based cytology with human papillomavirus (HPV) testing between May 2013 - May 2016 were collected from medical records. Women with atypical cervical Pap smears were recruited. Results for age, HPV testing, HPV 16, 18, 45 and other genotypes tested, colposcopic examination and histopathological assessment were all collected. Atypical smears were defined as atypical squamous cells of undetermined significance (ASC-US) and atypical squamous cells cannot be exclude high grade squamous intraepithelial lesion (ASC-H).

Results: A total of 2,144 cases were recruited. Twenty six women with ASC-US on cytology had high risk (HR) HPV detection while eight cases with ASC-H had HR-HPV (40.0% VS 72.7%, p=0.005). Among the 26 women with ASC-US cytology and positive HR-HPV, HPV type 16 (n=8, 30.8%), type 18 (n=1, 3.8%), type 45 (n=1, 3.8%) and other HPV types (n=17, 65.4%) were found. Eight women with ASC-H and positive HR-HPV demonstrated type 16 (n=6, 75%) and other HPV types (n=2, 25%). Fifty seven women with ASC-US had normal colposcopy, CIN1 and CIN2+ at percentages of 80.7 (46/57), 14.0 (8/57) and 5.3 (3/57), respectively. In the ASC-H group, 7 out of 10 women had normal colposcopy and three (30%) had CIN2+ results.

Conclusions: In women with ASC-US cytology, immediate colposcopy is highly recommended. HPV testing can be performed if colposcopy is not an available option because there was high prevalence (5.3%) of CIN2+ in our findings. ASCCP recommendations for ASC-H that colposcopy should be performed on all ASC-H cases regardless of HPV result are thereby supported by the findings of this investigation.