18F-fluorodeoxyglucose uptake on PET/computed tomography in association with androgen receptor expression and other clinicopathologic factors in surgically resected triple-negative breast cancer.

OBJECTIVE To evaluate whether androgen receptor expression in triple-negative breast cancer (TNBC) is associated with F-fluorodeoxyglucose (FDG) uptake and to identify predictive factors of F-FDG uptake in TNBC. METHODS We retrospectively assessed data of 156 surgically resected primary TNBC in 156 consecutive patients who underwent F-FDG PET/computed tomography between July 2013 and May 2017. Clinicopathologic features, including androgen receptor expression, were categorized and the distribution of maximum standardized uptake value (SUVmax) was compared between the groups. We also evaluated the correlations between the predictive factors and SUVmax. RESULTS Median SUVmax was higher in the androgen receptor-negative group than in the androgen receptor-positive group (8.8 vs. 7.1, P = 0.026) with negative correlation between androgen receptor and SUVmax (P = 0.041, correlation coefficient (r) = -0.163). On multivariate regression analysis, tumor size (>20 mm), histological grade, Ki-67 (≥14%), and the presence of ductal carcinoma in situ (DCIS) were significantly associated with SUVmax (P < 0.001, P = 0.012, P = 0.017 and P = 0.021, respectively). Tumor size, histological grade and Ki-67 were positively correlated with SUVmax (P < 0.001, r = 0.450; P = 0.004, r = 0.228; P = 0.001, r = 0.269, respectively), while the presence of DCIS showed negative correlation with SUVmax (P < 0.001, r = -0.292). CONCLUSION Androgen receptor-positive TNBC showed lower F-FDG uptake than androgen receptor-negative triple-TNBC. Tumor size, histological grade, Ki-67 and the presence of DCIS significantly influenced F-FDG uptake in TNBC.