CERVICAL DISEASE
The HPV vaccine is a boon to prevention efforts, but other aspects of cervical cancer screening and treatment still require our attention
IN THIS ARTICLE
Similarly, in a large trial from Italy, Ronco and colleagues also failed to find LBC to be more sensitive than conventional cytology. Their trial randomized 33,364 women to LBC or conventional cytology. The use of LBC did not increase the detection of CIN 2,3 or cancer, compared with conventional cytology, but did lead to a dramatic reduction (43%) in positive predictive value due to an increase in the number of abnormal samples.
A similar increase in minor cytologic abnormalities with the use of LBC is now well documented in the United States. According to surveys from the College of American Pathologists, the median percentile reporting rate of LSIL in US laboratories in 2003 was 1.4% for conventional cytology specimens and 2.4% for liquid-based specimens.1
Taken together (TABLE 3), these studies suggest that LBC has no greater sensitivity than conventional cytology and therefore does not solve the problems associated with the poor sensitivity of cervical cytology. However, LBC does have other advantages, the greatest being the availability of residual fluid for “reflex” HPV testing in women with ASC-US and for testing for other pathogens, such as Chlamydia.
TABLE 3
When conventional and liquid-based cytology are compared, the latter isn’t more sensitive
| STUDY | NO. WOMEN | CONVENTIONAL CYTOLOGY | LIQUID-BASED CYTOLOGY | ||
|---|---|---|---|---|---|
| SENSITIVITY* | PPV* | SENSITIVITY* | PPV* | ||
| Taylor et al | 5,652 | 84%† | 11.4 | 71% | 9.4 |
| Ronco et al | 33,364 | 70% | 11.4 | 74%† | 6.5 |
| PPV=positive predictive value | |||||
| *for detection of CIN 2,3 or cancer | |||||
| †Nonsignificant | |||||
Most cytologists find it easier to evaluate LBC specimens than conventional cytology specimens. Nor is it likely that cytology laboratories will want to switch back to conventional cytology now that the conversion to LBC has taken place.
Dr. Wright reports no financial relationships with any company whose products are mentioned in this article.
