Distribution of cervical intraepithelial neoplasia is closely associated with HPV status and uterine position.

Although cervical intraepithelial neoplasia (CIN) lesions are considered to be not randomly distributed across the cervix, but predominantly in the anterior wall, the clinicopathological etiology remains unknown. Herein, we aimed to elucidate the relationship between quantitatively measured area of CIN2/3 and cervical cancer associated factors by retrospective cohort study. We analyzed 235 consecutive therapeutic conization specimens dissected as a single intact section to determine CIN2/3 area and its correlation with both clinical risk factors including human papillomavirus (HPV) status (single or multiple infection) and uterine position defined by transvaginal ultrasound. Cervical wall was classified into three groups: anterior: (11, 12, 1, and 2 o'clock), posterior (5, 6, 7, and 8 o'clock) and lateral (3, 4, 9, and 10 o'clock). Multiple regression revealed that younger age and HPV16 status were significantly correlated with CIN2/3 area (p = 0.0224 and p = 0.0075, respectively). The Jonckheere-Terpstra test showed a significant trend: CIN2/3 area was highest in the single HPV16 group, followed by the multiple HPV16 group and the non-HPV16 group (p < 0.0001). CIN2/3 area in the anterior wall was statistically significantly larger than the posterior and lateral wall (p = 0.0059 and p = 0.0107, respectively). CIN2/3 area in the anterior wall was significantly greater with anteversion-anteflexion than retroversion-retroflexion (p = 0.0485), whereas CIN2/3 area in the posterior wall was significantly larger with retroversion-retroflexion than anteversion-anteflexion (p = 0.0394). In conclusion, the topographical distribution of CIN2/3 area is closely associated with patient age, high-risk HPV status, especially single HPV16 infection and uterine position.