Elucidating the Contexts That Enable or Constrain Normalization of Guideline-Based LDCT Lung Cancer Screening Processes in U.S. Primary Care.

Routine primary care encounters offer a major opportunity to reach a large population of individuals eligible for lung cancer screening (LCS) in the U.S., potentially representing up to one-third of all primary care visits each year. This article, the first in a two-part integrative review, synthesizes evidence on the contextual factors that enable or constrain the normalization of guideline-based LCS processes in U.S. primary care. Seven electronic databases were searched in February 2025 (updated in December 2025) to identify relevant studies. The findings reported here draw on 146 studies integrated using thematic synthesis. Four main themes emerged: (1) leadership and policy decisions shaping LCS priorities; (2) alignment of guideline-concordant LCS processes with primary care capacity; (3) frontline adaptations and workarounds sustaining routine LCS delivery; and (4) reframing organizational norms to institutionalize guideline-concordant LCS in primary care. Our review revealed limited health system-level investment in formal screening governance and integrated clinical informatics infrastructure. Normalization required continuous negotiation among providers to reconcile persistent misalignments between guideline demands and primary care capacity. Notably, frontline providers and staff relied heavily on pragmatic adjustments and workarounds, enabling screening to continue through labor-intensive and often fragile processes. Providers operated within and sometimes perpetuated entrenched clinical heuristics and paternalistic traditions while navigating heavy documentation burdens and structural inequities that continued to position LCS as optional, controversial, or administratively burdensome. LCS implementation remains largely provider-driven in contemporary U.S. primary care. Normalization will require deliberate and sustained leadership and policy reform, alongside investments in workforce capacity and data infrastructure.