ASPO Abstracts

Authors: Gottschlich A, Gondara L, Smith LW, Cook D, Martin R, Stuart G, Lee M, Peacock S, Franco EL, Krajden M, van Niekerk D, Ogilvie G

Category: Early Detection & Risk Prediction
Conference Year: 2022

Abstract Body:
Purpose: While cervix screening using cytology is generally recommended at 2-3 year intervals, given the increased sensitivity of HPV-based screening to detect precancerous lesions, HPV-based screening is often recommended at 5-year intervals. As organized cervix screening programs begin to transition from cytology to HPV-based screening at extended intervals, there is some concern that cervical cancers will be missed between screens. Methods: Participants in HPV FOr CervicAL Cancer (FOCAL) trial received either cytology (Cyto Arm) at 24-month intervals or HPV-based screening (HPV Arm) at 48-month intervals, and one round of co-testing with both cytology and HPV testing at exit. We investigated the results of the exit co-tests to determine which participants with cervical intraepithelial neoplasia grade 2 or higher (CIN2+) or grade 3 or higher (CIN3+) would not have had their precancer detected if they had only had the primary screen at exit that they received at baseline (henceforth called a "missed detection"¬ù).Results: There were 62 and 49 total participants with CIN2+ detection at trial exit in the Cyto Arm and HPV Arm, respectively. In the Cyto Arm, 25 (40.3%) were missed detections (i.e., normal cytology/ positive HPV test) (CIN2 N = 17, CIN3+ N = 8). In the HPV arm, three participants (6.1%) were missed detections (negative HPV test/abnormal cytology) (CIN2 = 2, CIN3+ = 1). One of the three HPV Arm missed detections had low-grade cytology findings and would not have been referred to colposcopy even outside of the trial. In the Cyto Arm, all women had normal cytology 24-months prior to exit and had an average of nearly six screens prior to entry into the study, with over 75% of participants never having an abnormal screen prior to FOCAL. The highest burden of missed detections was in the youngest age group (25-29 at baseline), where there were three missed CIN2s and three missed CIN3+s.Conclusions: Multiple rounds of cytology missed precancerous lesions that were detected with one round of HPV-based screening. It appears that cytology misses more CIN2+, even at shorter screening intervals than HPV-based screening. This assuages concerns about missed detection post-implementation of an extended interval HPV-based screening program.

Keywords: cervical cancer HPV-based screening extended screening intervals

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