Usefulness of ¹⁸F-FDG uptake with clinicopathologic and immunohistochemical prognostic factors in breast cancer

Introduction: The aim of this study was to analyze the clinical significance of maxSUV with clinicopathologic and immunohistochemical prognostic factors in patients with primary breast cancer. Methods: Ninety-one women (48.5 ± 11.2 years of age) with breast cancer who underwent ¹⁸F-FDG PET (PET) before surgery were recruited. All of the breast cancers were invasive ductal carcinomas and ≥1 cm in size to exclude a partial volume effect. The maxSUV of breast cancers was compared with histopathologic and immunohistochemical findings. Additionally, the ability of PET to discriminate axillary nodal status (ANS) and correlation between ANS and tumor characteristics were evaluated. Results: A high maxSUV of breast cancer was significantly correlated with the following poor prognosis factors: tumor invasiveness >2 cm (2.9 vs. 5.4; p < 0.001); high score of nuclear (3.5 vs. 5.3; p = 0.008) or histologic grade (3.3 vs. 5.5; p < 0.001); MIB-1 ≥10% (3.0 vs. 4.9; p < 0.002); ER-negativity (4.8 vs. 3.8; p = 0.019); PR-negativity (5.0 vs. 3.6; p = 0.029); and triple negativity (ER-, PR-, and c-erbB-2-negative; 5.3 vs. 3.8; p < 0.016). MaxSUV was not affected by menopausal status, ANS, lymphovascular invasion, including CD34 and D2-40 (LVIs), p53, and c-erbB-2 status. Additionally, the sensitivity and specificity of PET for discriminating ANS were 51.1 and 97.8%, respectively. ANS was correlated with tumor invasiveness >2 cm (p = 0.046), LVIs (all of variables; p < 0.001), and triple negativity (p = 0.049). Conclusions: A high FDG uptake of breast tumor is correlated with several poor prognosis factors, such as tumor invasiveness >2 cm, higher tumor grade, higher MIB-1, hormonal receptor negativity, and triple negativity. However, PET has a limited value in discriminating axillary lymph nodes. Pre-operative PET is a useful modality to predict biologic poor prognosis factors which could affect adjunctive therapy of breast cancer.