New School Vs. Old School Paps

Cervical cancer test results are more accurate with newer liquid based cytology tests

(RxWiki News) What type of Pap smear do gynecologists use? If the sampling method is the same, a patient may not know what type of lab techniques are used to search for cervical cancers.

A recent study evaluated the accuracy in detecting cervical cancer of two types of Pap smears in women.

The newer testing method simply uses lab techniques to clean the sample and see the tissue better.

"Talk to your doctor about Pap smears."

Stefanie J. Klug, PhD, MPG, professor at the University Cancer Center at the University Hospital in Dresden, Germany, led a team of researchers to investigate two types of cervical cancer testing methods. There is more than one way to test for cervical cancer. Liquid-based cytology (LBC) is more modern and used more often than conventional cytology (CC).

LBC is collected similarly to CC by swabbing the cervix. With LBC, the sample is placed in liquid where the sample can be spun in a lab to separate the cervical tissue from any unnecessary matter like mucus. With CC, the sample is “smeared” directly onto a glass microscope slide. Both methods end up with a tissue sample on a microscope slide to be examined by a cytologist for cancer cells.

For the study, researchers used computer-assisted imaging technology (CAS) and human cytologists to evaluate LBC and CC pap smears from 20,627 women in Germany from 2007-2009. A total of 20 gynecological clinics participated in collecting the 20,627 samples.

The goal was to determine which test was more accurate at detecting cervical cancer.

Researchers found the use of  CAS did not change the results of either test. LBC prediction of cervical cancer was 48 percent, while CC was 38 percent.

While these results would indicate that LBC was more accurate at detecting cervical cancer, researchers did not indicate whether they did any re-testing for false positives.

It would stand to reason that the LBC testing method provided cleaner samples of cervical tissue that could be better identified as cancerous or health by cytologists.

The LBC testing method takes a few more steps and the use of more equipment than the CC method, but is not significantly more expensive to facilitate, as both are less than $100. While LBCs are most common in US gynecology clinics, patients can request LBC type tests in place of CC tests if preferred.

This study was published in November in the International Journal of Cancer. No funding information was provided and no conflicts of interest were reported.

Review Date: 
November 27, 2012