Findings from a review of published studies suggest that the newer liquid-based cervical cancer tests are no better than the conventional Pap test for checking for signs of cervical cancer. However, definitive research in this area is lacking, so the authors are calling for large randomized controlled trials.

Developed as an alternative to the traditional Pap smear, liquid-based “cytology” uses a thin layer of cells that yields results faster than the Pap test and is thought to be more sensitive than the Pap smear. The newer tests are also believed to generate fewer unsatisfactory slide results. While some countries have adopted liquid-based cytology as a screening method, controversy regarding its benefits persists.

In a review of 56 studies, including more than one million slides, that looked at liquid-based and conventional cytology, Dr. Elizabeth Davey, from the University of Sydney in Australia, and colleagues found little differences in the two approaches.

They report in the Lancet this week that the liquid-based tests did not detect any more serious cervical lesions, which could lead to cancer, than the conventional tests. Liquid-based and conventional cytology also produced a similar number of unsatisfactory slides.

However, only four studies had sufficient data to determine the sensitivity and specificity of both types of cytology, suggesting, the researchers conclude, that much more study is needed before firm conclusions can be drawn.

SOURCE: The Lancet January 14, 2006.