Association of atrial fibrillation and cancer: Analysis from two large population-based case-control studies

Abstract

BackgroundAn association between atrial fibrillation (AF) and risk of cancer has been suggested in several studies, including prospective cohort studies. However, the magnitude and the temporal nature of this association remain unclear.MethodsData from two large prospective population-based case-control studies, the Molecular Epidemiology of Colorectal Cancer (MECC, n = 8,383) and the Breast Cancer in Northern Israel Study (BCINIS, n = 11,608), were used to better understand the nature and temporality of a possible association between cancer diagnosis and AF events before and after cancer diagnosis. A case-control study approach was employed to study prior AF as a risk factor for cancer, and a cohort study approach was employed to study incident cancer as a risk factor for AF.ResultsAF was associated with a significant reduced odds of cancer as reflected in the case-control approach, with an adjusted OR = 0.77 (95% CI, 0.65–0.91), while cancer was not found to be significantly associated with elevated risk of AF in the cohort approach, with an adjusted HR = 1.10 (0.98–1.23). The immediate period (90 days) after an AF event was associated with a 1.85 times increased risk of cancer, and the immediate period after the diagnosis of cancer was associated with a 3.4 fold increased risk of AF. These findings probably reflect both the effect of acute transient conditions associated with new cancer diagnosis and detection bias. Similar results were identified with colorectal and breast cancer cases.ConclusionsAtrial fibrillation of longer than 90 days duration is associated with reduced odds of new cancer diagnosis. The results of this study suggest that an association observed in prior research may be due to instances related to cancer diagnosis and detection bias rather than a causal relationship. However, there may be bias in the sampling and residual confounding that distort the associations.

The association of new-onset atrial fibrillation and risk of cancer: A systematic review and meta-analysis

“…Six published observational articles were incorporated into the present analysis. [9][10][11][12][13][14] The integrated result demonstrated that patients with NOAF have a 24% increased risk of developing cancer. The subgroup analysis stratified by time interval, gender and type of cancer revealed the following: (1) the incident cancer significantly increased within 90 days after NOAF diagnosis, but not after that; (2) males appeared to have a higher risk, when compared to females; (3) the risk of lung cancer, but not colorectal cancer or breast cancer, was higher in patients with NOAF, when compared to non-AF patients.…”

“…The funnel plot (Figure 4) presents the limited symmetry distribution of all the researches, with only one research randomly beyond 95% CI, which need to be examined. That is, the study conducted by Salibaet al 9 was the only case-control report, and was influenced by potential selection bias. The integrated result was optimized (RR: 1.35, 95% CI: 1.28-1.42, P<0.00001, I 2 =46%) after discarding the study conducted by Saliba et al 9…”

“…First, a small number of studies was included for the meta-analysis, and there was high heterogeneity was among these studies. The study conducted by Saliba et al 9 was as case-control study, which was prone to representative crowd bias. Second, eligible studies in the English language were included, while studies in non-English languages were missed.…”

Atrial fibrillation and cancer; understanding the mysterious relationship through a systematic review

“…A total of nine cohort studies (N = 670, 733) were included [8][9][10][11]. Summary of this selection process is given in PRISMA flow chart ( Figure 1).…”

“…Alternatively, studies also suggest that AFib could promote the development of cancer; as both Women's Health Study (WHS) and Danish National Registry study detected a significant increased risk of cancer after AFib diagnosis [9,10]. However, recent studies by Saliba et al, and Wassertheil-Smoller et al, paradoxically did not support the notion of AFib being a risk marker for cancer [11,12]. An increased risk of malignancy among patients with AFib would be of substantial public health importance, given the high prevalence and associated economic burden of both disorders.…”