Background: Lung cancer is the leading cause of cancer death in the US. Adherence to guideline- recommended low-dose computed tomography screening is poor and late-stage diagnosis is common. MCED tests may improve early cancer detection if adherence to guideline- recommended single cancer screening is maintained. The DETECT-A study evaluated an MCED test in 9,911 women in Geisinger Health System (GHS), age 65-75, without personal cancer history. This analysis evaluates lung cancer screening adherence among DETECT-A participants to determine if adherence changed significantly following receipt of an MCED test. Methods: Monthly screening eligibility and adherence data (2013 USPSTF criteria) were available from September 2016 - May 2020 for DETECT-A participants and screening-eligible women in GHS who met DETECT-A eligibility criteria but did not participate in DETECT-A. A control group was constructed by randomly selecting GHS non-participants at a 7:1 ratio and assigning index months that matched the distribution of consent months for DETECT-A participants. All analyzed participants had ≥24 consecutive months of adherence data centered around the consent/index month. The proportion adherent at consent/index month and the end of active study participation at 12 months were calculated descriptively. Changes in adherence over time, as well as group comparisons, were assessed using a mixed effects logistic regression model. Results: DETECT-A participants (n=364) and controls (n=2,548) had similar age, race, and ethnicity distributions. The population was predominantly white (>98%) and non-Hispanic (>90%). The odds of adherence at 12 months were significantly higher than at consent/index for both DETECT-A participants (OR: 3.20 [1.04 -9.80], p=0.042) and controls (OR: 2.02 [1.23- 3.33], p=0.006). The increase in odds of adherence between consent/index and 12 months was not significantly different between the groups (OR: 1.58 [0.47-5.31], p=0.461). DETECT-A participant adherence was 28.0% (23.4%-32.6%) in the consent month and increased to 38.5% (33.5-43.5%) at 12 months. Among the 102 DETECT-A participants adherent in the consent month, 70 (68.6%) were also adherent at 12 months. Control adherence was 16.0% (14.6%-17.4%) in the index month and increased to 20.2% (18.7%-21.8%) at 12 months. Among 408 controls adherent in the index month, 257 (63.0%) were also adherent at 12 months. Conclusions: DETECT-A participation did not negatively affect lung cancer screening adherence among this subset of participants. Screening adherence increased over time in both DETECT-A participants and controls; most DETECT-A participants adherent in the study consent month were also adherent 12 months later. Effectiveness of GHS screening programs, DETECT-A participant self-selection, and DETECT-A educational efforts promoting screening may have contributed to these observations.

Citation Format: Adam H. Buchanan, Anne Marie Lennon, Paul Z. Elias, Amy M. Lehman, Yongqiang Zhang, Darl D. Flake II, Eric S. Wagner, Seema P. Rego, Omair A. Choudhry, Nickolas Papadopoulos, Tomasz M. Beer. Lung cancer screening adherence among participants in DETECT-A, the first prospective interventional trial of a multi-cancer early detection (MCED) blood test [abstract]. In: Proceedings of the AACR Special Conference: Liquid Biopsy: From Discovery to Clinical Implementation; 2024 Nov 13-16; San Diego, CA. Philadelphia (PA): AACR; Clin Cancer Res 2024;30(21_Suppl):Abstract nr A064.