The impact of LSIL-H terminology on patient follow-up patterns: a comparison with LSIL and ASC-H

The Papanicolaou (Pap) test category of "low grade squamous intraepithelial lesion, cannot exclude high grade squamous intraepithelial lesion" (LSIL-H) is not recognized by The Bethesda System but is commonly used. It is essentially an amalgamation of the official LSIL and ASC-H categories. Since these two categories have similar follow-up algorithms, the clinical utility of the combined LSIL-H category is unclear. We have therefore studied follow-up patterns for these three entities in our laboratory to determine the real-world impact of each in our patient population. We searched our pathology database over an 18-month period to find Pap tests (predominantly ThinPrep) interpreted as LSIL-H (137), LSIL (2,189), and ASC-H (101). Like other studies, we found that the discovery rate of high grade dysplasia in biopsies after LSIL-H (31.9%) was similar to ASC-H (35.3%) and was higher than LSIL (7.6%; P < 0.0001). In women with no previous history of dysplasia, the frequency of biopsy follow-up after the initial Pap test was significantly higher for LSIL-H (68.3%) than for LSIL (49.6%; P = 0.0038) and similar to ASC-H (62.3%). We also found that women with an initial negative biopsy or a biopsy positive for low grade dysplasia were more likely to undergo an additional biopsy if the initial Pap test was LSIL-H (36.2%) than if it was LSIL (18.2%; P = 0.0023). ASC-H (26.9%) had an intermediate rate. In our patient population, the use of the terminology LSIL-H is associated with follow-up biopsy patterns much more similar to ASC-H than to LSIL.