Clinicopathological and prognostic relevance of uptake level using 18F-fluorodeoxyglucose positron emission tomography/computed tomography fusion imaging (18F-FDG PET/CT) in primary breast cancer.

Objective: Using integrated 18F-fluorodeoxyglucose positron emission tomography/computed tomography fusion imaging (18F-FDG PET/CT), the clinical significance of 18F-FDG uptake was evaluated in patients with primary breast cancer.

Methods: Clinicopathological correlation with the level of maximum standardized uptake values (SUV) 60 min obtained from preoperative 18F-FDG PET/CT were examined in 152 patients with primary breast cancer. The prognostic impact of the level of SUV was explored using simulated prognosis derived from computed program Adjuvant! in 136 (89%) patients with invasive ductal carcinoma (IDC).

Results: High SUV level was significantly correlated with tumor invasive size (< or = 2 cm) (P < 0.0001), higher score of nuclear grade (P < 0.0001), nuclear atypia (P < 0.0001) and mitosis counts (P < 0.0001), negative hormone receptor status (P = 0.001), high score of c-erbB-2 expression (P = 0.006), lymph node metastasis (P = 0.002), and IDC in comparison with invasive lobular carcinoma (P = 0.004). Multivariate analyses showed tumor invasive size, nuclear grade and estrogen receptor negativity were significantly correlated with SUV in primary breast cancer (P < 0.0001,< 0.0001, and < 0.012, respectively), and nuclear grade was significantly correlated with SUV in tumors of invasive size 2 cm or less (P < 0.0001). Tumors with high SUV (cutoff value 4.0) showed higher relapse and mortality rate compared to those with low SUV (P < 0.0001).

Conclusions: High uptake of 18F-FDG would be predictive of poor prognosis in patients with primary breast cancer, and aggressive features of cancer cells in patients with early breast cancer. 18F-FDG PET/CT could be a useful tool to pre-therapeutically predict biological characteristics and baseline risk of breast cancer.