Whole-Skeleton SUV_mean Measured on ¹⁸F-NaF PET/CT Studies as a Prognostic Indicator in Patients with Breast Cancer Metastatic to Bone

Abstract

In this work, we assessed the association between the whole-skeleton SUV_mean measured on ¹⁸F-NaF PET/CT studies and overall survival (OS) in patients with breast cancer metastatic to bone. Methods: We retrospectively analyzed 176 patients with breast cancer and metastatic bone disease who underwent ¹⁸F-NaF PET/CT. The outcomes of the patients (dead or alive) were based on the last information available in their files. The SUV_mean and SUV_max were measured in a whole-skeleton volume of interest (wsVOI). The wsVOI was based on the CT component of the PET/CT study using Hounsfield unit thresholds. The wsVOI was then applied to the ¹⁸F-NaF PET image. Univariate analyses were performed to assess the association of SUVs with OS. We also analyzed the association between OS and patient age; presence of visceral metastatic disease; histologic subtype; presence of hormone receptors; human epidermal growth factor receptor 2 expression; and creatinine, cancer antigen (CA) 15-3, and alkaline phosphatase levels. The variables statistically significant in the univariate analyses were included in a multivariate Cox regression OS analysis. Results: In the univariate analyses, there were associations between OS and whole-skeleton SUV_mean and SUV_max, estrogen receptor status, and CA15-3 and alkaline phosphatase levels. In the multivariate analysis, all variables that were statistically significant in the univariate analyses were associated with OS, with the exception of CA15-3. Conclusion: In patients with breast cancer metastatic to bone, whole-skeleton SUV_mean is an independent predictor of OS.