Are fluid-based cytologies superior to the conventional Papanicolaou test? A systematic review.

OBJECTIVE: We compared fluid-based cytologies (FBC) with conventional Papanicolaou (Pap) tests (CT) to determine if either is superior.

STUDY DESIGN: This was a systematic review of original research reports evaluating both CT and FBC with respect to specimen adequacy, comparison with a reference standard, or both. Two reviewers independently reviewed the titles, abstracts, and full articles to determine inclusion status, with differences resolved by consensus with a third author. Risk differences (RD) between occurrence rates for FBC and CT were used for the specimen adequacy data. Sensitivity and specificity were pooled independently and weighted by the inverse of the variance using a random effects model.

DATA SOURCES: Studies published between 1985 and November 1999 were identified from MEDLINE, Best Evidence, EMBASE, Biological Abstracts/RRM, and The Cochrane Library.

OUTCOMES MEASURED: Sensitivity, specificity, area under the receiver operating characteristic curve (AuROC), and the proportion of satisfactory, unsatisfactory, and "satisfactory but limited by" test results were measured.

RESULTS: There was no significant difference in AuROC (P = .37). FBC specimens were more likely to be satisfactory (RD=0.06; 95% confidence interval [CI], 0.03-0.09) or to have absent endocervical cells (RD=0.06; 95% CI, 0.02-0.10) but had 10% fewer "satisfactory but limited by - other" reports (RD = -0.10; 95% CI, -0.14 to -0.06). There was no difference in unsatisfactory Pap test results.

CONCLUSIONS: For most women there is no reason to replace CT with FBC. For women at high risk of cervical cancer or who are screened infrequently, the possible increase in FBC sensitivity may outweigh the potential harms from additional false positives.