The Associations of Atrial Fibrillation With the Risks of Incident Invasive Breast and Colorectal Cancer

Coexisting atrial fibrillation and cancer: time trends and associations with mortality in a nationwide Dutch study

BACKGROUND AND AIMS

Coexisting atrial fibrillation (AF) and cancer challenge the management of both. The aim of the study is to comprehensively provide the epidemiology of coexisting AF and cancer.

METHODS

Using Dutch nationwide statistics, individuals with incident AF (n = 320 139) or cancer (n = 472 745) were identified during the period 2015-19. Dutch inhabitants without a history of AF (n = 320 135) or cancer (n = 472 741) were matched as control cohorts by demographic characteristics. Prevalence of cancer/AF at baseline, 1-year risk of cancer/AF diagnosis, and their time trends were determined. The association of cancer/AF diagnosis with all-cause mortality among those with AF/cancer was estimated by using time-dependent Cox regression.

RESULTS

The rate of prevalence of cancer in the AF cohort was 12.6% (increasing from 11.9% to 13.2%) compared with 5.6% in the controls; 1-year cancer risk was 2.5% (stable over years) compared with 1.8% in the controls [adjusted hazard ratio (aHR) 1.52, 95% confidence interval (CI) 1.46-1.58], which was similar by cancer type. The rate of prevalence of AF in the cancer cohort was 7.5% (increasing from 6.9% to 8.2%) compared with 4.3% in the controls; 1-year AF risk was 2.8% (stable over years) compared with 1.2% in the controls (aHR 2.78, 95% CI 2.69-2.87), but cancers of the oesophagus, lung, stomach, myeloma, and lymphoma were associated with higher hazards of AF than other cancer types. Both cancer diagnosed after incident AF (aHR 7.77, 95% CI 7.45-8.11) and AF diagnosed after incident cancer (aHR 2.55, 95% CI 2.47-2.63) were associated with all-cause mortality, but the strength of the association varied by cancer type.

CONCLUSIONS

Atrial fibrillation and cancer were associated bidirectionally and were increasingly coexisting, but AF risk varied by cancer type. Coexisting AF and cancer were negatively associated with survival.

Causal associations between atrial fibrillation and breast cancer: A bidirectional Mendelian randomization analysis

BACKGROUND

Previous observational studies indicated that atrial fibrillation may increase the risk of breast cancer. Following a breast cancer diagnosis, the chance of developing atrial fibrillation may increase as well. However, it is uncertain whether the link is causal or just due to confounding factors.

OBJECTIVE

Using bidirectional Mendelian randomization (MR) analysis, we sought to assess the bidirectional causal relationship between atrial fibrillation and breast cancer from a genetic level.

METHODS

Large genome-wide association studies yielded summary-level data for atrial fibrillation and breast cancer. The preliminary estimate was inverse variance weighted (IVW) under a random model. MR-Egger, weighted median, simple mode, weighted mode, and multivariable MR (adjusting body mass index, smoking, and alcohol drinking) were performed as sensitivity analyses.

RESULTS

Genetically predicted atrial fibrillation presented no statistically significant association with overall breast cancer (odds ratio [OR] = 1.00; 95% confidence interval [CI]: 0.97-1.04; p = 0.79), estrogen receptor (ER) + (OR = 1.00; 95% CI: 0.96-1.03; p = 0.89) or ER- subtypes (OR = 1.00; 95% CI: 0.97-1.04; p = 0.89). Similarly, genetically predicted overall breast cancer (OR = 1.01; 95% CI: 0.98-1.04; p = 0.37), ER+ (OR = 1.02; 95% CI: 0.99-1.05; p = 0.16) or ER- (OR = 0.98; 95% CI: 0.93-1.02; p = 0.32) subtypes had no causal effect on atrial fibrillation. Sensitivity analyses yielded similar results. Individual single nucleotide polymorphism had little effect on the total estimate. We did not observe any evidence of horizontal pleiotropy.

CONCLUSIONS

Our bidirectional MR studies revealed that there may be no causal links between atrial fibrillation and breast cancer.

Prognostic impact of coexisting cardiovascular disease in patients with cancer: A multicenter retrospective cohort study

Background

The incidence of malignancy and cardiovascular disease (CVD) is increasing worldwide. However, it is not entirely clear how the coexistence of CVD at the time of cancer diagnosis affects the overall survival of patients with cancer.

Methods and results

We used the cancer registries and administrative claims data of patients diagnosed with cancer at 36 designated cancer care hospitals in Osaka, Japan, from 2010 to 2015. The Cox proportional hazard model was used to examine how coexisting CVD (heart failure [HF], ischemic heart disease, peripheral arterial disease, cerebrovascular accidents, and atrial fibrillation) affected overall survival and the impact of HF severity, as documented by the New York Heart Association (NYHA) classification. Of the 131,701 patients with cancer, 9704 had coexisting CVD. The 3-year survival rates for patients with and without coexisting CVD were 62.9 % and 77.6 %, respectively. The adjusted hazard ratio (aHR) for all-cause mortality for coexisting CVD was 1.47 (95 % confidence interval, 1.41-1.52). Among the CVD subtype, patients with coexisting HF had the poorest prognosis. The aHRs in patients with HF by NYHA classification, using the patients without HF as a reference, were as follows: Class I: 1.33 (p = 0.217); II: 1.68 (p < 0.001); III: 1.54 (p = 0.011); IV: 2.47 (p < 0.001).

Conclusion

Coexisting CVD and HF severity at cancer diagnosis is associated with survival in patients with cancer.

Atrial fibrillation: better symptom control with rate and rhythm management

Atrial fibrillation (AF) is often associated with limiting symptoms, and with significant impairment in quality of life. As such, treatment strategies aimed at symptom control form an important pillar of AF management. Such treatments include a wide variety of drugs and interventions, including, increasingly, catheter ablation. These strategies can be utilised either singly or in combination, to improve and restore quality of life for patients, and this review covers the current evidence base underpinning their use. In this Review, we discuss the pros and cons of rate vs. rhythm control, while offering practical tips to non-specialists on how to utilise various treatments and counsel patients about all relevant treatment options. These include antiarrhythmic and rate control medications, as well as interventions such as cardioversion, catheter ablation, and pace-and-ablate.

Reverse Onco-Cardiology: What Is the Evidence for Breast Cancer? A Systematic Review of the Literature

Breast cancer and cardiovascular diseases (CVD) represent significant global health challenges, with CVD being the leading cause of mortality and breast cancer, showing a complex pattern of incidence and mortality. We explore the intricate interplay between these two seemingly distinct medical conditions, shedding light on their shared risk factors and potential pathophysiological connections. A specific connection between hypertension (HTN), atrial fibrillation (AF), myocardial infarction (MI), and breast cancer was evaluated. HTN is explored in detail, emphasizing the role of aging, menopause, insulin resistance, and obesity as common factors linking HTN and breast cancer. Moreover, an attempt is made to identify the potential impact of antihypertensive medications and highlight the increased risk of breast cancer among those women, with a focus on potential mechanisms. A summary of key findings underscores the need for a multisystem approach to understanding the relationship between CVD and breast cancer is also explored with a highlight for all the gaps in current research, such as the lack of clinical observational data on MI and breast cancer in humans and the need for studies specifically designed for breast cancer. This paper concludes that there should be a focus on potential clinical applications of further investigation in this field, including personalized prevention and screening strategies for women at risk. Overall, the authors attempt to provide a comprehensive overview of the intricate connections between breast cancer and cardiovascular diseases, emphasizing the importance of further research in this evolving field of cardio-oncology.

Sex Differences in Atrial Fibrillation

PURPOSE OF REVIEW

Atrial fibrillation (AF) is the most common sustained cardiac arrhythmia. The estimated lifetime risk of developing AF is higher in men; however, due to differences in life expectancy, the overall prevalence is higher among women, particularly in the older age group. Sex differences play an important role in the pathophysiology, presentation, and clinical outcomes of AF. Awareness of these differences minimizes the potential for disparities in AF management. Our review summarizes the current literature on sex differences in AF, including the epidemiology, pathophysiology, risk factors, clinical symptomatology, mechanisms, treatment, and outcomes. We also explore the implications of these differences for clinical practice and future research.

RECENT FINDINGS

Women are more likely to present with atypical symptoms, have a higher stroke risk, and have a worse quality of life with AF when compared to men. Despite this, they are less likely to receive rhythm control strategies and anticoagulants. The sex-based differences in AF pathology and management might be a combination of inherent biological and hormonal differences, and implicit bias of the research entities and treating clinicians. Our review stresses the need for further sex-specific research in the pathophysiology of AF and opens a dialogue on personalized medicine, where management strategies can be tailored to individual patient characteristics, including sex.

Atrial fibrillation and breast cancer—Vicious twins? A systematic review and meta-analysis

Background

Epidemiological studies suggest a bidirectional association between atrial fibrillation and breast cancer. This study aimed to conduct a meta-analysis to elucidate the prevalence of atrial fibrillation among breast cancer patients, and the bidirectional association between atrial fibrillation and breast cancer.

Methods

PubMed, the Cochrane Library, and Embase were searched to identify studies reporting the prevalence, incidence, and bidirectional association between atrial fibrillation and breast cancer. The study was registered with PROSPERO (CRD42022313251). Levels of evidence and recommendations were assessed by the Grading of Recommendations Assessment, Development and Evaluation (GRADE).

Results

Twenty-three studies (17 retrospective cohort studies, 5 case-control studies and 1 cross-sectional study) involving 8,537,551 participants were included. Among patients with breast cancer, the prevalence of atrial fibrillation was 3% (11 studies; 95% CI: 0.6 to 7.1%) and the incidence was 2.7% (6 studies; 95% CI: 1.1 to 4.9%). Breast cancer was associated with increased risk of atrial fibrillation (5 studies; hazard ratio [HR]: 1.43, 95% CI: 1.12 to 1.82, I2 = 98%). Atrial fibrillation was also significantly associated elevated risk of breast cancer (5 studies HR: 1.18, 95% CI: 1.14 to 1.22, I2 = 0%). Grade assessment shown low certainty of the evidence for the risk of atrial fibrillation and moderate certainty of the evidence for the risk of breast cancer.

Conclusion

Atrial fibrillation is not uncommon in patients with breast cancer and vice versa. There is a bidirectional association between atrial fibrillation (low certainty) and breast cancer (moderate certainty).

Mediastinal radiation therapy for breast cancer in female patients is an independent risk factor for atrial fibrillation recurrence post-catheter ablation

BACKGROUND

The aim of this study was to assess the safety, efficacy, and predictors of outcomes for atrial fibrillation (AF) ablation in patients with a history of breast cancer.

METHODS

Consecutive patients with a history of breast cancer undergoing AF ablation from January 2010 to December 2021 were propensity matched in a 1:1 ratio to patients without a history of any cancer. The primary outcome was procedural efficacy, defined by clinical AF recurrence and repeat catheter ablation. The secondary outcome was an assessment of safety looking at eight peri-procedural events.

RESULTS

Our cohort was comprised of 82 female patients, 41 patients with a history of breast cancer (mean age, 74.6 ± 7.4 years), and 41 patients with no history of cancer (76.7 ± 8.1 years). Both groups had similar echocardiographic, baseline, and arrhythmia characteristics. Breast cancer patients were at an increased risk of AF recurrence post-ablation compared to non-cancer patients (OR 2.68, 95% CI 1.05-6.86, p = 0.04). Multivariate analysis found prior mediastinal radiotherapy (OR 4.79, 95% CI 1.34-17.1) and AF diagnosis to ablation time (OR 1.2, 95% CI 1.03-1.29) were both independent predictors of AF recurrence post-ablation.

CONCLUSION

Our study suggests that female patients with a history of breast cancer are at a higher risk of developing AF recurrence after catheter ablation. Multivariate analysis showed that patients with a history of prior mediastinal radiation therapy and AF diagnosis to time to ablation were both independent risk factors.

Racial, ethnic, and sex disparities in atrial fibrillation management: rate and rhythm control

BACKGROUND

Atrial fibrillation (AF) affects around 6 million Americans. AF management involves pharmacologic therapy and/or interventional procedures to control rate and rhythm, as well as anticoagulation for stroke prevention. Different populations may respond differently to distinct management strategies. This review will describe disparities in rate and rhythm control and their impact on outcomes among women and historically underrepresented racial and/or ethnic groups.

METHODS

This is a narrative review exploring the topic of sex and racial and/or ethnic disparities in rate and rhythm management of AF. We describe basic terminology, summarize AF epidemiology, discuss diversity in clinical research, and review landmark clinical trials.

RESULTS

Despite having higher rates of traditional AF risk factors, Black and Hispanic adults have lower risk of AF than non-Hispanic White (NHW) patients, although those with AF experience more severe symptoms and report lower quality-of-life scores than NHW patients with AF. NHW patients receive antiarrhythmic drugs, cardioversions, and invasive therapies more frequently than Black and Hispanic patients. Women have lower rates of AF than men, but experience more severe symptoms, heart failure, stroke, and death after AF diagnosis. Women and people from diverse racial and ethnic backgrounds are inadequately represented in AF trials; prevalence findings may be a result of underdetection.

CONCLUSION

Race, ethnicity, and gender are social determinants of health that may impact the prevalence, evolution, and management of AF. This impact reflects differences in biology as well as disparities in treatment and representation in clinical trials.

A review of research on the intersection between breast cancer and cardiovascular research in the Women's Health Initiative (WHI)

Both obesity and metabolic syndrome are linked to increased incidence of type 2 diabetes, cardiovascular disease (CVD), and cancers of the breast (post-menopausal), and other obesity-related cancers. Over the past 50 years, the worldwide prevalence of obesity and metabolic syndrome has increased, with a concomitant higher incidence of associated co-morbidities and mortality. The precise mechanism linking metabolic syndrome to increased cancer incidence is incompletely understood, however, individual components of metabolic syndrome have been linked to increased breast cancer incidence and worse survival. There is a bidirectional relationship between the risk of CVD and cancer due to a high burden of shared risk factors and higher rates of CVD among cancer survivors, which may be impacted by the pro-inflammatory microenvironment associated with metabolic syndrome and cancer-directed therapies. The Women's Health Initiative (WHI) is an excellent resource to study a dual relationship between cancer and CVD (cardio-oncology) with extensive information on risk factors and long-term outcomes. The purpose of this review is to provide an overview of research on cardio-oncology conducted utilizing WHI data with focus on studies evaluating both breast cancer and CVD including shared risk factors and outcomes after cancer. The review also includes results on other obesity related cancers which were included in the analyses of breast cancer, articles looking at cancer after heart disease (reverse cardio-oncology) and the role of Clonal Hematopoiesis of Indeterminate Potential (CHIP) as a shared risk factor between CVD and cancer. A summary of pertinent WHI literature helps to delineate the direction of future research evaluating the relationship between CVD and other cancer sites, and provides information on the opportunity for other novel analyses within the WHI.

Association of atrial fibrillation and various cancer subtypes

BACKGROUND

Studies have shown that the incidence of atrial fibrillation (AF) in cancer is most likely due to the presence of inflammatory markers. The purpose of our study is to determine the association of AF with different cancer subtypes and its impact on in-hospital outcomes.

METHODS

Data were obtained from the National Inpatient Sample database between 2005 and 2015. Patients with various cancers and AF were studied. ICD-9-CM codes were utilized to verify variables. Patients were divided into three age groups: Group 1 (age < 65 years), Group 2 (age 65-80 years), and Group 3 (age > 80 years). Statistical analysis was performed using Pearson chi-square and binary logistic regression analysis to determine the association of individual cancers with AF.

RESULTS

The prevalence of AF was 14.6% among total study patients (n = 46 030 380). After adjusting for confounding variables through multivariate regression analysis, AF showed significant association in Group 1 with lung cancer (odds ratio, OR = 1.92), multiple myeloma (OR = 1.59), non-Hodgkin lymphoma (OR = 1.55), respiratory cancer (OR = 1.55), prostate cancer (OR = 1.20), leukemia (OR = 1.12), and Hodgkin's lymphoma (OR = 1.03). In Group 2, the association of AF with multiple myeloma (1.21), lung cancer (OR = 1.15), Hodgkin lymphoma (OR = 1.15), non-Hodgkin lymphoma (OR = 1.12), respiratory cancer (OR = 1.08), prostate cancer (OR = 1.06), leukemia (OR = 1.14), and colon cancer (OR = 1.01) were significant. In Group 3, AF showed significant association with non-Hodgkin lymphoma (OR = 1.06), prostate (OR = 1.03), leukemia (OR = 1.03), Hodgkin's lymphoma (OR = 1.02), multiple myeloma (OR = 1.01), colon cancer (OR = 1.01), and breast cancer (OR = 1.01). The highest mortality was found in lung cancer in age <80 and prostate cancer in age >80.

CONCLUSION

In patients age <80 years, AF has significant association with lung cancer and multiple myeloma, whereas in patients age >80 years, it has significant association with non-Hodgkin lymphoma and prostate cancer. In patients age <80 years, increased mortality was seen in AF with lung cancer and in patients age >80 years, increased mortality was seen in those with AF and prostate cancer.

TWITTER ABSTRACT

In age <80, lung cancer and multiple myeloma have a strong association with AF while thyroid and pancreatic cancers have no association with AF at any age. In age greater than 80, NHL and prostate cancer have a significant association with AF.

Atrial fibrillation in patients with systolic heart failure: pathophysiology mechanisms and management

Heart failure (HF) and atrial fibrillation (AF) demonstrate a constantly increasing prevalence during the 21^st century worldwide, as a result of the aging population and the successful interventions of the clinical practice in the deterioration of adverse cardiovascular outcomes. HF and AF share common risk factors and pathophysiological mechanisms, creating the base of a constant interrelation. AF impairs systolic and diastolic function, resulting in the increasing incidence of HF, whereas the structural and neurohormonal changes in HF with preserved or reduced ejection fraction increase the possibility of the AF development. The temporal relationship of the development of either condition affects the diagnostic algorithms, the prognosis and the ideal therapeutic strategy that leads to euvolaemia, management of non-cardiovascular comorbidities, control of heart rate or restoration of sinus rate, ventricular synchronization, prevention of sudden death, stroke, embolism, or major bleeding and maintenance of a sustainable quality of life. The indicated treatment for the concomitant HF and AF includes rate or/and rhythm control as well as thromboembolism prophylaxis, while the progress in the understanding of their pathophysiological interdependence and the introduction of the genetic profiling, create new paths in the diagnosis, the prognosis and the prevention of these diseases.

Atrial Cardiomyopathy and Atrial Fibrillation in Cancer

The number of patients with oncologic and cardiologic comorbidities is increasing. A growing number of evidence shows an inextricable link between cancer, atrial fibrillation, and atrial cardiomyopathy. Cancer itself and resultant inflammation, anticancer treatment, and other comorbidities lead to atrial remodeling and fibrosis, which increases the tendency to develop atrial cardiomyopathy and atrial fibrillation. The scarcity of current literature and ambiguous results make its relationship difficult to fully understand. In this review, we will summarize existing evidence of the relationships and interactions among cancer, atrial cardiomyopathy, and atrial fibrillation and discuss the underlying mechanisms, and provide better information for the management of these patients.

Women and atrial fibrillation

Atrial fibrillation (AF) remains a growing problem in the United States and worldwide, imposing a high individual and health system burden, including increased resource consumption due to repeated hospitalizations, stroke, dementia, heart failure, and death. This comprehensive review summarizes the most recent data on sex-related differences in risks associated with AF. Women with AF have increased risk of stroke and death compared to men, and possible reasons for this disparity are explored. Women also continue to have worse symptoms and quality of life, and poorer outcomes with stroke prevention, as well as with rate and rhythm control management strategies. Many current rhythm control treatment strategies for AF, including cardioversion and ablation, are used less frequently in women as compared to men, whereas women are more likely to be treated with rate control strategies or antiarrhythmic drugs. Sex differences should be considered in treating women with AF to improve outcomes and women and men should be offered the same interventions for AF. We need to improve the evidence base to understand if variation in utilization of rate and rhythm control management between men and women represents health inequities or appropriate clinical judgement.

The Association of New-Onset Atrial Fibrillation and Risk of Cancer: A Systematic Review and Meta-Analysis

Background

There are distinct results for the relationship between new-onset atrial fibrillation (NOAF) and subsequent incident cancer. To date, no systematic analysis has been conducted on this issue. This study aims to explore the relationship between NOAF and the risk of developing cancer through a meta-analysis with a large sample size.

Methods

Electronic databases, such as PubMed and EMBASE, were searched for published relevant studies on NOAF patients diagnosed with cancer after and during follow-ups, including reported records of baseline information and the statistical result of morbidity. Two investigators independently reviewed the articles and extracted the data using uniform standards and definitions. The meta-analysis was conducted using the Cochrane Program Review Manager.

Results

This meta-analysis consisted of five cohort studies and one case-control study, which comprised 533,514 participants. The pooled relative risk (RR) for incident cancer was 1.24 (95% CI: 1.10–1.39, P=0.0003). The temporal trend analysis demonstrated that an increased risk of cancer was observed during the initial 90 days (RR: 3.44, 95% CI: 2.29–5.57, P < 0.00001), but not after that. Lung cancer (RR: 1.51, 95% CI: 1.47–1.55, P < 0.00001) was associated with NOAF, but not colorectal cancer and breast cancer.

Conclusion

This meta-analysis provides evidence that NOAF is associated with increased risk of cancer. The risk of incident cancer particularly increases within 90 days after NOAF diagnosis, but not after that.

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

Background

Atrial Fibrillation (AFib) is the most common cardiac arrhythmia, occurring in ≈1% of the general population. 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.

Objectives

To evaluate the relationship between atrial fibrillation (AFib) and cancer.

Methods

We conducted an extensive database search on PubMed, Google Scholar, ScienceDirect, and SEER Database from their inception to September 2019 for any study that evaluated the association between AFib and cancer.

Results

In the first 3 months of AFib diagnosis, Ostenfeld et al. reported an absolute cancer risk of 2.5% with a standardized incidence ratio of 7.02 and 3.53 for metastatic and localized cancer, respectively. Likewise, Saliba et al. detected an increase in the odds of cancer diagnosis in first 90 days after AF diagnosis with OR of 1.85. Moreover, in another study new-onset breast and colorectal cancer was especially associated with AF in the first 90 days after diagnosis with HR of 3.4 but not thereafter (HR 1.0). Similarly, Conen et al. reported high relative risk of cancer with HR of 3.54 in the first 3 months after new-onset AFib. However, beyond the initial 90 day period, the risk of cancer in AFib is only slightly increased.

Conclusion

Based on our review, there appears to be an increase in risk of subsequent diagnosis of cancer in patients with AF, likely owing to the shared risk factors between the two conditions. While the results of this study raise interesting questions for future search, they are not currently strong enough to justify initiating cancer screening for an occult cancer in a patient with AF. Regardless, measures to target modification of these shared risk factors remains an important consideration.

Cardiovascular disease events within 5 years after a diagnosis of breast cancer

BACKGROUND

Concern for cardiovascular disease (particularly atrial fibrillation-AF) among women with breast cancer is becoming a major issue. We aimed at determining the incidence of cardiovascular disease events (AF, arterial and cardiac events, venous-thromboembolism-VTE) in patients diagnosed with breast cancer, and assessing potential risk factors.

METHODS

We reviewed medical records of all patients diagnosed with breast cancer from 2010 to 2011 in our cancer center. Baseline characteristics of patients and tumors were collected. The main outcome was the occurrence of cardiovascular disease events (AF, VTE, arterial and cardiac events) during the 5-years follow-up.

RESULTS

Among the 682 breast cancer patients, 22 (3.2%) patients had a history of atrial fibrillation. Thirty-four patients (5%) presented at least one cardiovascular disease event, leading to a cumulative incidence of 5.8% events at 5-years ([3.8-7.7] CI 95%), with most of them occurring in the first 2 years. AF cumulative incidence was 1.1% ([0.1-2.1] CI 95%). Factors associated with the occurrence of cardiovascular disease events (including AF) were an overexpression of HER-2 (HR 2.6 [1.21-5.56] p < 0.011), UICC-stage III tumors or more (HR 5.47 [2.78-10.76] p < 0.001) and pre-existing cardiovascular risk factors (HR 2.91 [1.36-6.23] p < 0.004).

CONCLUSION

The incidence of cardiovascular disease events was 5.8% ([3.8-7.7] CI 95%), with HER-2 over-expression, UICC-stage III tumors or more and pre-existing cardiovascular diseases being associated with them. These findings call for the development of preventive strategies in patients diagnosed with breast cancer.

Association of Early-Stage Breast Cancer and Subsequent Chemotherapy With Risk of Atrial Fibrillation

IMPORTANCE

Several types of cancer have been linked to a higher risk of developing atrial fibrillation (AF). Fewer data exist regarding early-stage breast cancer (EBC), for which cardio-oncology concerns are more pertinent.

OBJECTIVE

To investigate the association of EBC and subsequent chemotherapy with the risk of developing AF.

DESIGN, SETTING, AND PARTICIPANTS

This was a population-based, retrospective, matched cohort study conducted in Toronto, Ontario, Canada, of 68 113 women diagnosed with EBC between April 2007 and December 2016 who were matched 1:3 to a cancer-free control group based on birth year and receipt of breast imaging. Prevalence of AF before the index date (date of EBC diagnosis) was compared between the cohorts using the McNemar test. Cumulative incidence function curves were used to describe the AF incidence. To study preexisting AF, participants were matched before exclusion for prior AF. For the remaining analyses, we excluded women with prior AF before matching. An analysis was conducted beginning 1 year after the index date (ie, excluding AF diagnoses in year 1), which we stratified by chemotherapy exposure. Multivariable cause-specific regression was used to determine the hazard ratio (HR) associated with EBC relative to the controls and the association of chemotherapy with AF in patients with EBC.

EXPOSURES

Breast cancer and chemotherapy.

MAIN OUTCOMES AND MEASURES

Incidence of AF.

RESULTS

A total of 68 113 women with EBC and 204 330 cancer-free controls were included in the study; both groups had a mean (SD) age of 60 (13) years. Of the women with EBC, 44.3% were diagnosed as having stage I breast cancer; 38.7%, stage II; and 13.4%, stage III; cancer stage information was missing for 3.6% of the patients. No difference was observed in preexisting AF prevalence (5.3% in the EBC cohort vs 5.2% in controls; P = .21). At 10 years after the index date, the AF incidence was 7.4% (95% CI, 7.1%-7.7%) for women with EBC and 6.8% (95% CI, 6.7%-7.0%) for the controls (P < .001). The adjusted cause-specific HR was significantly elevated at year 1 (HR, 2.16; 95% CI, 1.94-2.41) and after year 5 (HR, 1.20; 95% CI, 1.11-1.30) but not during years 2 through 5. Analyses beginning 1 year after diagnosis showed attenuated differences that remained statistically significant: the cumulative incidence of AF at 9-year follow-up was 7.0% (95% CI, 6.7%-7.3%) for patients with EBC and 6.5% (95% CI, 6.3%-6.7%) for the cancer-free controls. The rate of AF was higher in women who received chemotherapy (adjusted HR, 1.23; 95% CI, 1.13-1.35) but was not associated with exposure to anthracyclines or trastuzumab.

CONCLUSIONS AND RELEVANCE

This study's findings suggest that patients with EBC may not have a higher prevalence of AF before cancer diagnosis. A higher rate of AF was observed in the first year and after 5 years following the EBC diagnosis. The rate of AF was higher in patients who received chemotherapy but appeared to not be associated with specific cardiotoxic agents. These findings suggest that the early and late periods of increased AF risk in EBC survivors warrant focused research to better understand the underlying causes and subsequent implications.

Association of Cancer and the Risk of Developing Atrial Fibrillation: A Systematic Review and Meta-Analysis

Aims

Previous studies have demonstrated epidemiological evidence for an association between cancer and the development of new-onset atrial fibrillation (AF). However, these results have been conflicting. This systematic review and meta-analysis was conducted to examine the relationship between cancer and the risk of developing atrial fibrillation.

Methods

PubMed and Web of Science were searched for publications examining the association between cancer and atrial fibrillation risk published until June 2017. Adjusted odds ratios (ORs) or hazard ratios (HRs) and 95% CI were extracted and pooled.

Results

A total of five studies involving 5,889,234 subjects were included in this meta-analysis. Solid cancer patients are at higher risk developing atrial fibrillation compared to noncancer patients (OR 1.47, 95% CI 1.31 to 1.66, p < 0.00001; I² = 67%, p=0.02). The risk of atrial fibrillation was highest within 90 days of cancer diagnosis (OR 7.62, 95% CI 3.08 to 18.88, p < 0.00001) and this risk diminished with time.

Conclusions

The risk of AF was highest within 90 days of cancer diagnosis. We should take into account the increased risk of atrial fibrillation development and, after this, study the embolic risk and potential indication of oral anticoagulation.

Atrial Fibrillation and Heart Failure in Women

Atrial fibrillation often occurs as a cause or consequence of heart failure. Clinical outcomes are worse when atrial fibrillation and heart failure coexist. There are important sex-related differences in the incidence, prevalence, pathophysiology, treatment, and outcomes of these patients. Women with heart failure are at greater risk of developing atrial fibrillation than men, and more women with atrial fibrillation develop heart failure. More women die of atrial fibrillation-related strokes. Despite significant morbidity and mortality, current treatments for women are inadequate. This review explores sex differences in atrial fibrillation and heart failure, emphasizing risk stratification and treatments to improve clinical outcomes.