Atrial Fibrillation as a Marker of Occult Cancer

Abstract

BackgroundRecent studies suggest that cancer increases risk of atrial fibrillation. Whether atrial fibrillation is a marker for underlying occult cancer is unknown.MethodsWe conducted a cohort study (1980–2011) of all Danish patients with new-onset atrial fibrillation. To examine cancer risk, we computed absolute risk at 3 months and standardized incidence ratios (SIRs) by comparing observed cancer incidence among patients newly diagnosed with atrial fibrillation with that expected based on national cancer incidence during the period.ResultsMedian follow-up time was 3.4 years among 269 742 atrial fibrillation patients. Within 3 months of follow-up, 6656 cancers occurred (absolute risk, 2.5%; 95% confidence intervals [CI], 2.4%–2.5%) versus 1302 expected, yielding a SIR of 5.11; 95% CI, 4.99–5.24. Associations were particularly strong for cancers of the lung, kidney, colon, ovary, and for non-Hodgkin's lymphoma. The SIR within 3 months of follow-up was 7.02; 95% CI, 6.76–7.28 for metastatic and 3.53; 95% CI, 3.38–3.68 for localized cancer. Beyond 3 months of follow-up, overall cancer risk was modestly increased (SIR, 1.13; 95% CI, 1.12–1.15).ConclusionPatients with new-onset atrial fibrillation had a markedly increased relative risk of a cancer diagnosis within the next three months, however, corresponding absolute risk was small.

Atrial Fibrillation and Risk of Cancer: A Danish Population‐Based Cohort Study

“…A Danish nationwide cohort study by Ostenfeld et al that involved both sexes supported an increased risk of cancer following the diagnosis of AF. This association was particularly strong within the initial 90 days after the diagnosis of AF 12. However, the study lacked information on lifestyle markers, such as smoking and dietary habits, which may have caused residual confounding.…”

“…Only 2 studies have examined the association between AF and cancer thus far 12, 13. In these studies, restricted time intervals from AF were explored, which is a methodology different from the methods used in our study, as we explored extended time intervals from the time of AF.…”

“…However, only 2 cohort studies have so far examined the association between AF and the risk of subsequent cancer. A Danish nationwide registry‐based cohort study by Ostenfeld et al suggested that occult cancer was likely to be present at the time of the diagnosis of AF 12. Recently, Conen et al reported an association in a population‐based cohort study of female Americans from the Women's Health Study 13.…”

Efficacy and Safety of Edoxaban in Patients With Active Malignancy and Atrial Fibrillation: Analysis of the ENGAGE AF‐TIMI 48 Trial

“…Use of DOACs in patients with AF is increasing in clinical practice and the aging population 36, 37. Older patients receiving DOACs may develop a new or recurrent malignancy because of shared risk factors with aging 3, 4, 5, 6. We anticipate, therefore, an increase in use of DOACs in patients with cancer and a need for efficacy and safety data.…”

“…Although data on patients with AF with malignancy are limited, observational studies suggest an association between AF and cancer,2, 3, 4, 5 likely because of systemic inflammation, shared risk factors, and common disease states underlying both conditions in aging populations 4, 6. Although 20‐year incident malignancy in patients with new‐onset AF has been reportedly low at 10%,4 incident AF may occur in up to 30% of patients with certain types of malignancy (eg, thoracic) 6.…”