The B-S₂CALED Score's Utility in Predicting Stroke Risk in Breast Cancer Patients with Atrial Fibrillation

Area of Science:

• Oncology
• Cardiology
• Medical Informatics

Background:

• Breast cancer (BC) patients face elevated risks of atrial fibrillation (AF) and ischemic stroke (IS).
• Existing IS risk scores lack validation in cancer populations and do not incorporate cancer-specific factors.
• Current clinical guidelines lack tailored management strategies for IS risk in BC patients with AF.

Purpose of the Study:

• To develop and validate a novel risk prediction score for IS in BC patients diagnosed with AF.
• To create a tool that addresses the limitations of current scores in the cancer population.

Main Methods:

• Utilized data from UH Seidman Cancer Center (derivation/internal validation) and MCG Cancer Center (external validation).
• Included adult patients (≥18 years) with DCIS or stages I-IV BC who developed AF post-diagnosis.
• Employed LASSO Cox regression for variable selection, cubic splines for continuous predictors, and multivariable hazards to formulate the B-S2CALED score.
• Assessed discrimination using concordance index (C-index) and net reclassification improvement (NRI) against CHA2DS2-VASc.

Main Results:

• In internal validation (n=935), B-S2CALED achieved a C-index of 0.64 (vs. 0.54 for CHA2DS2-VASc) with an NRI of 0.188.
• In external validation (n=95), B-S2CALED showed a C-index of 0.77 (vs. 0.53 for CHA2DS2-VASc) with an NRI of 0.563.
• The B-S2CALED score demonstrated superior predictive performance for thromboembolic events in both cohorts.

Conclusions:

• The developed BC-specific B-S2CALED score significantly outperforms the CHA2DS2-VASc score in predicting IS risk among BC patients with AF.
• Further validation in larger patient cohorts is recommended prior to widespread clinical implementation.