Abstract 7411: Screening of nasopharyngeal cancer in a multi-ethnic healthy Singaporean cohort

Abstract Background: Epstein-Barr Virus (EBV)-positive Nasopharyngeal Cancer (EBV-NPC) is highly prevalent in Asia, with annual incidences of 20-100 per 100, 000. In Singapore's multi-ethnic population, EBV IgA serologies targeting viral capsid antigen (VCA) and early antigen (EA) are commonly performed for NPC screening. However, the longitudinal variability of EBV IgA serologies and its relationship with NPC risk remains unclear. This study evaluates the longitudinal patterns of EBV IgA serologies and NPC development in a tertiary medical center. Methods: Retrospective analysis of asymptomatic individuals referred for NPC screening at Singapore General Hospital between 2008-2021 was performed. Demographics, EBV IgA serologies titers, plasma DNA PCR, nasoendoscopy, biopsy, and MRI post-nasal space (PNS) findings were collected. A positive family history was defined as any first-degree relative with a prior history of NPC. Patients with only one serology test and screening of less than 1 year were excluded. Results: 4586 patients had EBV IgA serologies performed and 1977 met our inclusion criteria. Patients (45.6% male, 54.4% female; aged 12-90) had a median follow-up of 207.1 months (range: 12-5125 months) and were predominantly Chinese (95%), with 1.16% Indian, 1.66% Malay, and 2.17% from other ethnicities. All were screened using nasal endoscopy examination (n=11, 423) and 725 biopsies were performed. Adjunctive tests including MRI PNS (n=876) and EBV DNA-PCR (n=392) were also performed as per physician’s discretion. EBV serologies were repeated in 2-5 times (61%), 6-10 (21.3%), or >10 (18.1%) over the screening period. Titre fluctuations showed no clear pattern: 61.96% were positive for only one serology type, 12.13% were persistently positive for both, 23.4% had decreasing titers, and 2.42% had increasing titers. Six patients (0.3%) developed NPC, all ethnic Chinese, asymptomatic, and aged 50 on average. Among these, 3/6, 1/6, and 2/6 had Stage I, III, and IV NPC at diagnosis, respectively. Two had a family history of NPC. The mean detection time was 61 months, and follow-up averaged 12.7 years. Serology titer patterns were persistently positive or increasing. Increased EBV EA-IgA (2/6) or VCA-IgA (2/6) titers were observed 1-2 years before diagnosis. One patient had a normal biopsy but suspicious MRI, leading to repeat biopsy and NPC diagnosis. Conclusion: In this longitudinal heterogeneous healthy multi-ethnic NPC screening cohort, the NPC detection rate was 0.3%. Fluctuation of EBV IgA serologies was variable, and increasing titers of both Ea and VCA serologies were identified in 33.3% of NPC. Future evaluation of high risk cohorts and cost-effectiveness of NPC screening are warranted. Citation Format: Ashlynn Chen, Arthur Tan, Jia Hui Isabelle Jang, Song Tar Toh, Wei Yee Wan, Chwee Ming Lim. Screening of nasopharyngeal cancer in a multi-ethnic healthy Singaporean cohort [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2025; Part 1 (Regular Abstracts); 2025 Apr 25-30; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2025;85(8_Suppl_1):Abstract nr 7411.