Atypical squamous cells of undetermined significance cervical cytology in Bahrain: Reporting rates, high-risk HPV testing, and cytologic and histopathologic follow-up findings

Atypical squamous cells of undetermined significance cytology (ASC-US) is a challenging and equivocal diagnosis for pathologists in cervical Pap smears. The data on ASC-US cervical cytology in Bahrain are deficient. This study reviewed and identified the reporting rates, high-risk human papillomavirus (HPV) testing results, histopathologic follow-up findings, and the cytologic progression of patients diagnosed with ASC-US in Bahrain. A retrospective chart review was conducted on the medical records of 23,888 women who had Pap smear test results between January 2019 and March 2022 at the main referral tertiary hospital in Bahrain to identify the ASC-US cases. High-risk HPV (hrHPV) genotype was identified, and the histopathological results of the cervical biopsy was recorded. In addition, cytologic follow-up Pap smear tests conducted within 1 year of ASC-US diagnosis were tracked to monitor the progression or regression of ASC-US. In this study, 259 out of 23,888 women reported to have ASC-UC cytology results with a reporting rate of 1.1%. The mean age of the ASC-US cases was 43 ± 11.6. Thirty percent of the ASC-US cases tested positive for hrHPV, and they were predominantly infected with the other hrHPV genotype (75%). When the histopathological changes of the cervix were analyzed, 82.1% had normal histopathologic findings. However, low-grade cervical intraepithelial neoplasia-1 was reported in 2 cases (7.1%), and high-grade cervical lesions (cervical intraepithelial neoplasia-2 and higher) were reported in 3 cases (10.7%). Regarding the cytologic follow-up, most of the ASC-US cases were negative for intraepithelial lesion or malignancy (NILM) (73.8%) or had persistent ASC-US (17.9%). The remaining minority of cases progressed into either low-grade squamous intraepithelial lesions (6%) or high-grade squamous intraepithelial lesions (2.4%). There was a statistically significant and relatively strong association between the cytology follow-up findings and the hrHPV test results (χ2 [2] = 8.869, P < 0.012, Cramer’s V = 0.417). This is the first and largest study to characterize the ASC-US cytology cases in Bahrain. The reporting rates of ASC-US fell within the worldwide reported range. Although most of the ASC-US cases regressed into NILM, ASC-US showed progression into more advanced cervical cytologic diagnoses or contributed to the malignant transformation of cervical tissue, especially in the presence of hrHPV infection which was positive in 30% of the ASC-US cases. This emphasizes the role of cotesting (combination of hrHPV genotyping and Pap smear test) and the importance of colposcopic evaluation of those women with cytologic follow-up tests at 1 year of diagnosis. Implementing these recommendations in the cervical cancer screening practice in Bahrain will help in having a better management plan for women diagnosed with ASC-US cervical cytology.