Diagnostic Concordance Between Contrast-Enhanced CT and Bone Scintigraphy for Detecting Bone Metastases in Clinical...

Bone metastasis is a critical determinant of staging, prognosis, and treatment planning in patients with breast cancer. In patients with higher-risk localized disease (clinical T3 and/or N1), both contrast-enhanced computed tomography (CT) and bone scintigraphy are frequently used; however, the benefit of regular bone scintigraphy in an already-performed CT scan is debatable.

To evaluate the concordance between contrast-enhanced CT (CECT) and whole-body bone scintigraphy for detecting bone metastases during initial staging in patients with clinically T3 and/or N1 breast cancer, and to assess the incremental diagnostic value of bone scintigraphy in selected patients.

This retrospective observational study was carried out during a ten-year period (June 1, 2015, to May 31, 2025) at the Shaukat Khanum Memorial Cancer Hospital and Research Centre, Peshawar, Pakistan (SKMCH&RC). Women with newly diagnosed histopathologically confirmed clinical T3 and/or N1 breast cancer who underwent CECT (chest/abdomen/pelvis) and whole-body bone scintigraphy for initial staging were consecutively included. Patients who had prior treatment or recurrent disease, incomplete imaging documentation, metastases distant from the bone, or primary bone disease were excluded. The imaging results of the bone metastases were classified as positive or negative, and the concordance between the different modalities was evaluated by Cohen's kappa statistics and diagnostic accuracy measures.

CECT demonstrated high overall concordance with whole-body bone scintigraphy for detecting bone metastases during initial staging of clinically T3/N1 breast cancer. However, bone scintigraphy identified a limited number of additional CT-negative cases, suggesting a modest incremental diagnostic value in selected patients.