Diagnostic performance of 18F‑FDG PET/CT vs. 18F‑NaF PET/CT in breast cancer with bone metastases: An indirect comparative meta‑analysis

Breast cancer remains the leading cause of cancer-related death in women, with 5-year survival rates of as high as 90% for patients with early-stage breast cancer without metastasis, falling to 10% once bone metastases (BM) occur. Currently, there is no cure for breast cancer with BM. However, appropriate treatment can extend survival and improve patients' quality of life. Therefore, it is important to accurately evaluate the presence of BM in patients with breast cancer. The present meta-analysis evaluated the diagnostic performance of ¹⁸F-FDG and ¹⁸F-NaF as PET/CT tracers for breast cancer-associated BM. The present study aimed to compare the diagnostic performance of fluorine-18 fluorodeoxyglucose (¹⁸F-FDG) positron emission tomography/computed tomographs (PET/CT) and ¹⁸F-sodium fluoride (¹⁸F-NaF) PET/CT in patients with breast cancer and BM. The PubMed and Embase databases were searched for English literature on the diagnostic performance of ¹⁸F-FDG PET/CT and ¹⁸F-NaF PET/CT for breast cancer BM, and two authors independently extracted data. All included studies presented data that could be used to construct a 2×2 contingency table. The methodological quality of the selected studies was assessed using QUADAS-2, and forest plots were generated based on the sensitivity and specificity of ¹⁸F-FDG PET/CT and ¹⁸F-NaF PET/CT in the diagnosis of BM associated with breast cancer. A total of 14 articles were identified, including eight on the analysis of ¹⁸F-FDG PET/CT, five on ¹⁸F-NaF PET/CT and one on both. The studies on ¹⁸F-FDG PET/CT and ¹⁸F-NaF PET/CT included 530 and 270 patients, respectively. The pooled sensitivities were 0.88 [95% confidence interval (95% CI), 0.76-0.94] for ¹⁸F-FDG PET/CT and 0.98 (95% CI, 0.92-1.00) for ¹⁸F-NaF PET/CT, and the pooled specificities were 0.99 (95% CI, 0.97-1.00) and 0.91 (95% CI: 0.76-0.97), respectively. The area under the summary receiver operating characteristic curve for both ¹⁸F-FDG PET/CT and ¹⁸F-NaF PET/CT was 0.99 (95% CI, 0.98-1.00). Lesion-based analysis using ¹⁸F-FDG PET/CT was performed for 909 lesions, with a sensitivity of 0.84 (95% CI, 0.67-1.00) and specificity of 1.00 (95% CI, 0.98-1.00). Compared with ¹⁸F-FDG PET/CT, ¹⁸F-NaF PET/CT showed higher sensitivity (98 vs. 88%) but lower specificity (91 vs. 99%), although the difference between methods was not statistically significant. In conclusion, the results of the present study indicated that ¹⁸F-NaF PET/CT and ¹⁸F-FDG PET/CT are both accurate methods for the detection of BM in patients with breast cancer, and have comparable diagnostic accuracy.