Comparative sensitivities of ThinPrep and Papanicolaou smear for adenocarcinoma in situ (AIS) and combined AIS/high-grade squamous intraepithelial lesion (HSIL): comparison with HSIL.

BACKGROUND: Despite the historic belief that cytologic screening offers little protection against cervical adenocarcinoma (CAC), there is emerging evidence that, by detecting the precursor lesion, adenocarcinoma in situ (AIS), cervical screening may reduce the incidence of CAC as it has for cervical squamous carcinoma. Because liquid-based cytology is fast replacing the conventional Papanicolaou smear (PS), it is important to establish that it is at least as effective in detecting AIS.

METHODS: The authors calculated the sensitivities of PS and ThinPrep (TP) for 100 women with histologic AIS (from 160 PS slides and 60 TP slides), for 94 women with AIS+high-grade squamous intraepithelial lesion (HSIL) (from 151 PS slides and 50 TP slides), and for 558 women with HSIL (from 788 PS slides and 383 TP slides). All smears were taken up to 36 months before the histologic diagnosis.

RESULTS: In no category was there a significant difference between PS sensitivity and TP sensitivity. The HSIL category had a significantly higher overall sensitivity than the other categories. However, when sensitivity was defined as cytologic detection of high-grade disease, there was no difference between any of the categories. For the detection of a high-grade glandular lesion, the presence of a concurrent histologic HSIL was associated with reduced sensitivity for the detection of AIS.

CONCLUSIONS: The current results indicated that it may prove possible for cervical screening, with either PS or TP, to reduce the incidence of CAC.