[How far into the anal canal should the brush be introduced for more efficient cytological evaluation?]

In literature, sensitivity of Pap smears ranges widely from 45 to 98%. Possibly this is because there is no standard for how far the brush should be introduced into the anal canal. The aim was to evaluate whether the sampling site has an influence on the results of anal Pap smears.

This is a non-randomized, non-blinded, retrospective review carried out in the Proctology and Pathology Sectors, Emilio Ribas Infectious Diseases Institute.

We obtained specimens with brushes introduced 4 cm into the anal canal in 114 patients (Group A) and 2 cm in 94 patients (Group B), before anorectal examination. These brushes were rotated five or six times before being withdrawn and rubbed on a slide that underwent Pap testing using standard cytopathology laboratory equipment. All patients were HIV-infected. Statistical tests were used.

In Group A, 39 patients had anal canal condylomas and the cytology was positive in 29 of them (74.3%). We also observed cytological alterations in 30 of 75 patients (40%) without clinical lesions in the anal canal. In Group B, there were 54 patients with condylomas and 13 of them (24.1%) were confirmed by cytology. In 40 patients with no clinical lesions, we observed that nine (22.5%) had cytological abnormalities Statistical analysis revealed that examination in Group A was more efficient. CONCLUSION. Specimens collected by inserting the brush deeper into the anal canal improved the efficiency of anal Pap smears.