[18F]FDG PET/CT versus Bone Scintigraphy for the Diagnosis of Bone Metastasis in Breast Cancer: A Systematic Review and Meta-Analysis.

Introduction: Breast cancer has become the most commonly diagnosed cancer in women worldwide, with advanced cases often leading to bone metastases that significantly affect prognosis and quality of life. This meta-analysis and systematic review aims to evaluate and compare the diagnostic performance of [18F]FDG PET/CT and bone scintigraphy for detecting bone metastases in breast cancer patients.

Methods: A systematic search was conducted across PubMed, Embase, Web of Science, and Scopus for studies published up to February 2025. Relevant articles were identified using a combination of subject-specific and free-text keywords, including "breast cancer," "positron emission tomography," "bone scintigraphy," and "bone metastasis." Studies assessing the diagnostic utility of [18F]FDG PET/CT and bone scintigraphy in detecting bone metastases were included. A bivariate random-effects model was used to calculate pooled estimates of sensitivity, specificity, and diagnostic accuracy with 95% confidence intervals (CIs). Potential sources of heterogeneity were explored using meta- regression analysis. The Quality Assessment of Diagnostic Accuracy Studies (QUADAS- 2) tool was applied to evaluate the methodological quality of the included studies.

Results: A total of 1407 publications were initially retrieved, and 13 studies involving 892 patients met the inclusion criteria. The pooled diagnostic performance for [18F]FDG PET/CT demonstrated a sensitivity of 0.91 (95% CI: 0.81-0.96) and a specificity of 0.98 (95% CI: 0.93-1.00), with an area under the curve (AUC) of 0.99 (95% CI: 0.97-0.99). In comparison, bone scintigraphy showed a sensitivity of 0.82 (95% CI: 0.72-0.89), specificity of 0.81 (95% CI: 0.73-0.87), and an AUC of 0.88 (95% CI: 0.85-0.91). Despite its higher diagnostic accuracy, PET/CT exhibited notable heterogeneity across studies, potentially influenced by differences in patient populations and imaging interpretation criteria.

Discussion: Our meta-analysis demonstrated the superior diagnostic performance of [18F]FDG PET/CT over bone scintigraphy, likely attributable to its enhanced sensitivity for osteolytic lesions and integrated anatomical-functional imaging. Nevertheless, considerable inter-study heterogeneity and incomplete clinical data reporting limit the generalizability and robustness, warranting further standardized prospective investigations.

Conclusion: The findings suggest that [18F]FDG PET/CT offers superior diagnostic accuracy compared to bone scintigraphy for detecting bone metastases in breast cancer patients. However, its clinical application requires further validation through large-scale, prospective studies. Additionally, considerations such as cost-effectiveness and accessibility must be addressed before widespread clinical adoption.