Clinical value of delayed 18F-FDG PET/CT for predicting nipple-areolar complex involvement in breast cancer: A comparison with clinical symptoms and breast MRI

Objective: We aimed to evaluate the predictive value of delayed 18F-FDG PET/CT for identifying malignancies involved in the nipple-areolar complex (NAC) in comparison with clinical symptoms and breast MRI. Methods: We enrolled 90 patients who underwent preoperative delayed 18F-FDG PET/CT and MRI between October 2015 and May 2017. We calculated the NAC-Standardized uptake value ratio (SUVR) using the following formula: maximum SUV (SUVmax) of the NAC in the malignant breast /SUVmax of the NAC in the contralateral normal breast on early (NAC-SUVRearly) and delayed (NAC-SUVRdelay) phase images. MRI was used to measure the distance between the tumor and NAC and to analyze NAC enhancement patterns. Univariate and multivariate analyses were performed to identify significant predictive factors for NAC involvement. Results: Seventeen patients were confirmed to have pathologic NAC involvement. NAC symptoms (p = 0.009), tumor multiplicity (p = 0.006), NAC-SUVRdelay (> 1.23, p = 0.007), and MRI-based tumor-to-NAC distance (≤ 22.0 mm, p = 0.003) were independent predictive factors for NAC involvement. Ten of 76 patients with no clinical NAC symptoms had NAC malignancy. Tumor multiplicity (p = 0.009), tumor-to-NAC distance (≤ 20.0 mm, p = 0.014)), and NAC-SUVRdelay (> 1.23, p = 0.018) had independent predictive value for NAC involvement. Conclusions: Delayed 18F-FDG PET/CT is a useful modality for predicting NAC involvement in breast cancer patients whether or not NAC symptoms are present.