Abstract Background: Early-stage lung adenocarcinoma (LUAD) patients have substantial risk for recurrence and disease-related death. Cisplatin-based adjuvant chemotherapy remains the standard for care of LUAD patients who have undergone surgical resection with a high risk of recurrence. However, adjuvant chemotherapy is associated with increased risk of toxicity including chemotherapy-related death, with only a modest survival benefit. Therefore, there is an unmet need of biomarkers for assessment and identification of those in an early stage who would likely benefit from adjuvant chemotherapy. Circulating miRNAs are stably present in blood and potentially reflect different expressions in cancerous and non-cancerous tissues, making them attractive biomarkers. The purpose of this study was to identify circulating miRNAs useful for predicting recurrence in early-stage LUAD. Materials and Methods: miRNA microarray analysis was performed with pooled pretreatment plasma samples from stage I LUAD patients who developed recurrence within two years after curative surgery or remained recurrence free over a six-year follow-up period, as well as from healthy controls. miRNA biomarker candidates were assayed in two independent plasma sample sets from 85 stage I LUAD (validation set) and from 57 stage I and II LUAD (test set) patients. Results: Based on miRNA microarray data and previous reports, predictive performance of miR-23a-3p, miR-23b-3p, miR-191-5p, miR-185-5p, miR-151a-3p, miR-320c, miR-21-5p, miR-125b-5p, miR-30d-5p, and miR-197-3p was evaluated in the validation set. Plasma levels of miR-23a-3p, miR-185-5p, miR-320c, miR-21-5p, miR-125b-5p, miR-30d-5p, and miR-197-3p were significantly higher in those with recurrence as compared to those without. A miRNA panel comprised of miR-23a-3p, miR-320c, and miR-125b-5p was developed based on a logistic regression, with yielding an AUC of 0.776 (95% confidence interval [CI] = 0.660 to 0.893). The three-miRNA panel with fixed coefficients yielded an AUC of 0.804 (95% CI = 0.688 to 0.920) with a sensitivity of 45.8% at 95% specificity in the test set. The miRNA panel score was a significant and independent factor for predicting disease-free survival (DFS; P < 0.001, HR = 1.64, 95% CI = 1.51-4.22) and overall survival (OS; P = 0.001, HR = 1.51, 95% CI = 1.17-1.94). Conclusion: This circulating miRNA panel may serve as a noninvasive blood test for predicting DFS and OS in early-stage LUAD patients. Our findings provide rationale for further investigation to stratify early-stage LUAD patients using blood-based biomarkers to increase the ability to provide more personalized care. Citation Format: Mei-Chee Tai, Leonidas E. Bantis, Gargy Parhy, Taketo Kato, Ichidai Tanaka, Chi-Wan Chow, Junya Fujimoto, Carmen Behrens, Tetsunari Hase, Koji Kawaguchi, Johannes F. Fahrmann, Edwin Ostrin, Kohei Yokoi, Toyofumi F. Chen-Yoshikawa, Yoshinori Hasegawa, Samir M. Hanash, Ignacio I. Wistuba, Ayumu Taguchi. A circulating microRNA panel predicts recurrence and survival in early-stage lung adenocarcinoma. [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 3744.