TZ Representation Impact on HSIL Detection and Cervical Cancer Screening Outcomes

Purpose: Cervical cancer is a major cause of morbidity and mortality among women, particularly in regions with limited access to screening. High-grade squamous intraepithelial lesions (HSIL), the main precursors to invasive cancer, are predominantly detected in the Transformation Zone (TZ) during cytopathological exams. This study evaluated the adequacy of TZ representation in screening and detecting HSIL in women aged 25 to 64 years in Southern Brazil between 2022 and 2024. Methods: Data from the Cancer Information System (SISCAN) were analyzed for cytopathological exams conducted in the Brazilian states of Paraná, Santa Catarina, and Rio Grande do Sul. The adequacy of TZ representation was assessed in terms of total exams performed and HSIL detection rates. Results: Among 5,885,630 cytopathological exams, 37.5% lacked TZ representation. Paraná conducted the highest number of exams (38.9%), followed by Rio Grande do Sul (33.9%) and Santa Catarina (27%), which showed the highest proportion of exams with TZ representation (68.6%). For HSIL detection, Paraná reported 9,878 exams with TZ representation and 942 without. Santa Catarina recorded 6,619 exams with TZ representation and 478 without, while Rio Grande do Sul had 6,441 exams with and 517 without TZ representation. Conclusion: Although most exams included TZ representation, a significant proportion lacked it, particularly in Paraná. This gap compromises diagnostic accuracy and highlights the need for improved sample collection, professional training, quality control measures, and the adoption of advanced technologies such as liquid-based cytology to enhance cervical cancer screening outcomes. Citation Format: João P. Farezin Fortti, Gabriela Pereira Macelaro. Representation of the Transformation Zone in Screening and Detection of High-Grade Squamous Intraepithelial Lesions in Cytopathological Exams Among Women in Southern Brazil (2022–2024) [abstract]. In: Proceedings of the 13th Annual Symposium on Global Cancer Research; 2025 Sep 16. Philadelphia (PA): AACR; Cancer Epidemiol Biomarkers Prev 2025;34(12_Suppl):Abstract nr 71.