Effect of Lower Anogenital Squamous Terminology Recommendations on the Use of p16 Immunohistochemistry and the Proportion of High-Grade Diagnoses in Cervical Biopsy Specimens.

OBJECTIVES: The Lower Anogenital Squamous Terminology (LAST) group has recommended that cervical intraepithelial neoplasia (CIN) terminology be replaced by squamous intraepithelial lesion (SIL) terminology, with p16 immunohistochemistry used to separate lesions formerly diagnosed as CIN grade 2 into high-grade SILs (HSILs) and low-grade SILs. This study investigated the impact of these changes on the frequency of p16 testing and the diagnosis of high-grade lesions. METHODS: Pathology reports for all cervical biopsy specimens in the 1 year before and after the introduction of LAST recommendations (July 2011 to June 2013) were examined. RESULTS: Before and after the implementation of LAST, 365 (15.4%) of 2,376 cases were diagnosed as high grade (CIN 2/3) vs 486 (17.6%) of 2,761 cases diagnosed as HSILs (P = .0343), and p16 was performed 79 (3.3%) times vs 383 (13.9%) times (P < .0001). CONCLUSIONS: Immunohistochemistry for p16 increased dramatically as a result of LAST recommendations, and high-grade diagnoses increased.