Abstract
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Objectives: Androgen receptor (AR) is an emerging diagnostic and therapeutic target in breast cancer, particularly in triple-negative breast cancer (TNBC). In this study, relation of AR status to various clinicopathologic features and metabolic phenotype shown on FDG PET was evaluated in TNBC.
Methods: Pathologically confirmed TNBC patients who underwent surgical resection in 2013-2015 were retrospectively enrolled. AR positivity was measured as percentage of positive cells on immunohistochemistry and > 0% was defined as AR-positive. Information on clinicopathologic features (age, tumor size, lymph node status, pathologic stage and histologic grade) were obtained from medical record review. Preoperative FDG PET was analyzed and maximum SUV (SUVmax) of primary tumor was measured. Relations of AR status to clinicopathologic and PET features were investigated.
Results: A total of 275 patients were enrolled (age 54.6 ± 11.6 y) and 88 (32.0%) were AR-positive. Age was significantly higher (57.7 ± 12.0 y vs. 53.1 ± 11.1 y, P = 0.002) and histologic grade was significantly lower (2.7 ± 0.5 vs. 2.9 ± 0.3, P < 0.001) in AR-positive, whereas other factors exhibited no difference. On FDG PET, SUVmax was significantly lower in AR-positive (9.3 ± 6.6 vs. 11.7 ± 7.4, P = 0.009), particularly in patients with small-sized (< 3 cm) tumors (6.8 ± 5.0 vs. 10.1 ± 6.6, P = 0.001). Additionally, AR positivity exhibited a linear correlation with SUVmax (r = -0.22, P < 0.001).
Conclusions: In TNBC, AR positivity is related to lower glucose metabolism, particularly in small-sized tumors, and higher age and lower histologic grade. Thus, AR positivity in TNBC can be regarded as a favorable prognostic marker as well as a potential therapeutic target. Further studies are warranted regarding prognostic effect of TNBC on real survival of patients.