Discrepancy between Cytology and Histology in Cervical Cancer Screening: a Multicenter Retrospective Study (KGOG 1040).

Background: Cervical cancer is the fourth common cancer in women worldwide. The Papanicolau test is the primary screening procedure to detect abnormal cervical cells. Colposcopy is the main procedure for discriminating high-grade cervical lesions. The study aimed at clarifying the discrepancy between cervical cytology and colposcopic biopsy histology as well as confounding factors.

Methods: Eligible patients visited thirteen tertiary hospitals for colposcopic biopsy following cervical cytology and human papillomavirus (HPV) genotypes between January and December 2018. Baseline characteristics including age, body mass index (BMI), and parity were collected.

Results: In our study, 3,798 eligible patients were included. Mean age of patients was 42.7 (19-88) years and mean BMI was 22.5 (16.9-34.1) kg/m². The referred cervical cytologic findings consisted of 495 normal, 1,390 atypical squamous cells of undetermined significance, 380 atypical squamous cells cannot exclude high-grade squamous intraepithelial lesion, 792 low-grade squamous intraepithelial lesion, 593 high-grade squamous intraepithelial lesion, 79 atypical glandular cells, 46 squamous cell carcinoma, and 23 adenocarcinoma. HPV-positive findings were found in 3,008 (79.2%) patients and were not detected in 914 (24.1%) cases. The risk of unexpected low-grade lesions from histology was higher in patients > 45 years (odds ratio [OR], 2.137; 95% confidence intervals [CIs], 1.475-3.096). In contrast, the risk of unexpected high-grade lesions from colposcopic biopsy was lower in patients ≥ 45 years (OR, 0.530; 95% CI, 0.367-0.747) and HPV 16/18 infection was higher than other HPV (OR, 1.848; 95% CI, 1.385-2.469).

Conclusion: Age and HPV genotypes were responsible for the discrepancies between cytology and histology. Precautions should be taken for women over the age of 45 in triage for colposcopy in order to avoid unnecessary testing.