Atrial Fibrillation Risks Rise Soon After Cancer Diagnosis

A large prospective study based on the Atherosclerosis Risk in Communities (ARIC) cohort has found significant temporal association between cancer diagnosis and the atrial fibrillation (AF) risk, and vice versa. The results, published in Mayo Clinic Proceedings: Innovations, Quality & Outcomes, provide strong grounds for improving cardiac surveillance in cancer patients, particularly within the initial year of diagnosis.

This research involved 13,748 adults at baseline (mean age 54 years) who did not suffer AF or cancer in their history. The follow-up period was a minimum of 30 years, and the study lasted from 1987 to 2019; the cases of AF were identified by using ECGs and medical records, whereas state cancer registries, medical records, and death certificates identified cancer.

The researchers found that in 3,909 patients who developed cancer and later AF, the development of AF was extremely high within the first 3 months of the development of cancer (HR, 11.71; 95% CI, 9.52-14.41). The high risk also remained and was lower at 312 months (HR, 2.07) and greater than 12 months (HR, 1.46).

This tendency indicates that cancer and its treatment, eg, chemotherapy, radiation, or surgery, might be a risk factor because it can lead to the development of AF due to inflammatory and cardiotoxic effects. Another reason that may lead to earlier detection of AF is the greater medical surveillance after diagnosis of cancer.

In the reverse analysis, 1,973 individuals developed AF prior to a cancer diagnosis. The risk of cancer was greatest in the 3-month window after the onset of AF (HR, 2.24; 95% CI, 1.471.341) and dropped at 312 months (HR, 1.28) and more than 12 months (HR, 1.09). The trend in decline with time indicates a possible presence of detection bias and reverse causality.

In site-specific analysis, the risk of AF was much higher in patients with lung cancer (HR: 3.75) and postmenopausal breast cancer (HR, 1.66), but not in patients with prostate and colorectal cancers. On the contrary, AF was not significantly associated with long-term development of these cancers.

Significantly, the analysis adjusted the common cardiometabolic and lifestyle risk factors, which include smoking, obesity, diabetes, and hypertension. The results were similar across all sex and racial subgroups, and sensitivity analysis using multiple imputation confirmed the findings.

This study shows a complicated two-way correlation between cancer and AF and the necessity of collaborative care between cardiology and oncology. Clinicians should pay special attention to heart rhythm in patients with cancer, especially during the first few months of the diagnosis.