Right-sided ectocervical lesions may be associated with false-negative cytology among women with histologic cervical intraepithelial neoplasia 2 or 3

Background. The association between the location of an ectocervical lesion and the sensibility of cytologic screening has not been adequately evaluated. Methods. We evaluated the proportion of false-negative cytologic interpretations using three independent cytologic interpretations (conventional, PapNet, and ThinPrep) according to lesion location in 111 women with histologic cervical intraepithelial neoplasia 2 or 3 of a population-based study of cervical neoplasia conducted in Guanacaste, Costa Rica. Semiquantitative measures of human papillomavirus viral load were also considered. Results. Lesions on a women's right ectocervix were associated with more frequent false-negative results than lesions on left ectocervix for each of the cytologic methods or when the most severe interpretation was considered (p = .004). Right-sided lesions had nonsignificantly lower viral loads than left-sided lesions (p = .2). Conclusions. Cervical intraepithelial neoplasia 2 or 3 located on the right side of the cervix may be poorly sampled with broom samplers in some settings, resulting in false-negative cytologic results.