Several risk assessment tools have been developed to help clinicians predict stroke and thromboembolic risks in patients with atrial fibrillation (AF). “The CHA2DS2VASc score is a validated model that is often used to help identify individuals at risk for stroke, but this model may not accurately capture all risks for everyone,” says Rohit Moudgil, MD, PhD, FRCPC, FACC. “Recent studies have demonstrated a relationship between cancer and thrombosis, including venous thromboembolism and stroke. Despite this evidence, cancer is not currently part of the traditional CHA2DS2VASc score.”

Assessing the Impact of Adding Cancer to the CHA2DS2VASc

For a study published in IJC Heart & Vasculature, Dr. Moudgil and colleagues assessed whether cancer is an independent risk factor for thromboembolic stroke in patients with AF. “We also wanted to determine if adding cancer to the traditional CHA2DS2VASc score would make it a more complete model for predicting risks for stroke in patients with AF,” Dr. Moudgil says.

Using the SEER database, the authors identified patients who had lung, colon, breast, and prostate cancers and AF and had not received a prior diagnosis of stroke. These patients were compared with a control group within the dataset. All patients in the study had their CHA2DS2VASc score calculated. The primary endpoint was the rate of stroke per 100 person-years. More than 100,000 patients were included in the analysis, and baseline characteristics for each group were comparable across most medical comorbidities.

Cancer Raises Risks for Stroke & Atrial Fibrillation

“Results from the study showed the incidence of stroke was significantly higher in patients with cancer than in those without it, and this increased incidence was noted across all CHA2DS2VASc scores (Figure). For patients with cancer, the stroke incidence per 100 person-years was 2.962, compared to 2.377 for the non-cancer cohort. The overall mortality rate was also higher among patients with cancer than for those without it (68.0% vs 44.4%, respectively).

“Data from our study suggest that adding cancer to the CHA2DS2VASc model improved the predictability of assessing the probability of stroke-free survival,” says Dr. Moudgil. “Patients with AF who had lung, breast, colon, and prostate cancer were also at increased risk for developing thromboembolism due to AF.” This elevated risk was maintained across the spectrum of CHA2DS2VASc scores.

Since the CHA2DS2VASc acronym is simple and familiar, the investigators suggested adding another C to the acronym to account for cancer as a risk factor, proposing the CCHA2DS2VASc score, with the extra C standing for cancer. “Using our proposed CCHA2DS2VASc score, we may be able to further improve our ability to accurately assess patients and appropriately stratify them into specific risk categories,” Dr. Moudgil says. “We might also be able to offer anticoagulation to more at-risk populations.”

Current Analysis Is a Stepping Stone for More Research

Studies are needed to determine if there are differences in stroke incidence between various oncologic malignancies and to investigate the effects of cancer stage on thromboembolism risks. Dr. Moudgil says the current analysis should be viewed as a stepping stone for more research. “It will be important to explore the impact of all cancers—not just the ones included in our study—on risks for stroke and AF,” he says. “Future research also needs to establish which patients will benefit most from anticoagulation if the proposed CHA2- DS2VASc scoring system were to be implemented as a clinical tool.”

If emerging research continues to confirm that cancer is indeed a risk factor for stroke and AF, Dr. Moudgil says it should be added to the CHA2DS2VASc scoring system to ensure that patients with cancer are being treated equally. “Based on previous research, we know AF is common in cancer populations,” he says. “We now need to ensure these patients are accurately categorized by risk to ensure they receive proper treatment. Such efforts will strengthen our ability to provide equal care for everyone.”