Assessment of breast cancer and feasibility of subtyping of breast cancer using thoracoabdominal staging photon-counting detector computed tomography.

In this prospective study, we evaluated the performance of thoracoabdominal photon-counting detector computed tomography (PCD-CT) for breast cancer assessment with MRI as reference standard and iodine uptake as a potential marker for breast cancer subtyping. 75 women (mean age: 55.8 ± 13.9 years [SD]) with 79 newly diagnosed breast cancers and indication for staging CT received a prone-positioned contrast-enhanced thoracoabdominal PCD-CT and a breast MRI. Cancer visibility (median 1/1/1, IQR 0/1/1) and image quality (median 1/1/1, IQR 0/0/0) were rated excellent in PCD-CT on a 4-point Likert scale (1 = excellent, 4 = poor). Cancer size in PCD-CT correlated significantly with MRI (p < 0.001). Diagnostic accuracy was good for T-stage (pooled accuracy 0.814), focality (0.772), axillary (0.822) and internal mammary lymph nodes (0.981), moderate for ductal carcinoma in situ (0.591). A significantly lower maximum iodine uptake was revealed in cancer with ductal carcinoma in situ (p = 0.027), a significantly lower mean iodine uptake in triple negative cancers (p = 0.003). Thoracoabdominal PCD-CT demonstrated excellent cancer visibility with convincing results for assessing cancer size, T-stage, and lymph node status. Iodine uptake shows promising associations with triple negative breast cancer.