Marcelo Flávio Gomes Jardim Filho
Background: Recent registry and cohort data suggest that new onset atrial fibrillation (AF) is temporally associated with an increased risk of occult malignancy, but contemporary estimates derived from large populations remain limited. Objective: To quantify the short and medium term cancer risk following a first AF diagnosis using evidence published from 2020 to 2024, to characterise the spectrum of tumours detected, and to identify clinical features that may support risk adapted surveillance. Methods: An integrative review was conducted in accordance with PRISMA 2020, searching PubMed, Embase and Web of Science for January 2020 – July 2025. Seven observational studies met eligibility criteria: five nationwide registry based cohorts (Netherlands, Norway, China, Austria, Netherlands BLITZ) comprising > 26 million AF patients, one hospital cohort (South Korea), and one meta analysis of 24 studies involving ≈ 1.1 million cancer survivors. Data extraction was performed independently by two reviewers; outcomes were narratively synthesised because of methodological heterogeneity. Results: One year cancer incidence after AF ranged from 2.5 % to 2.8 % in European cohorts and 12.6 % in a large Chinese insurance database. Short term adjusted hazard ratios or risk ratios for incident malignancy lay between 1.28 and 1.52, with the greatest excess observed during the first 90 days following AF onset. Lung, gastrointestinal, pancreatic and haematologic cancers predominated, and two studies demonstrated bidirectional associations (cancer → AF and AF → cancer). A meta analysis of cancer survivors reported a pooled relative risk of 1.29 for developing AF. Age ≥ 65 years, male sex, metabolic comorbidity and systemic inflammation were consistent modifiers of risk across studies. Conclusions: Contemporary data confirm that new onset AF is linked to a clinically relevant, short term increase in cancer detection, supporting the concept of AF as an early systemic signal rather than an isolated cardiac finding. Prospective research should determine the cost effectiveness and optimal scope of targeted malignancy screening in selected high risk AF populations.