AIM To investigate rates of distant metastases(DM) detected with [18]fluorodeoxyglucose-positron emissiontomography/computed tomography(~(18)FDG-PET/CT) in early stage invasive breast cancer.METHODS We searched the English language literature databases of PubM ed, EMBASE, ISI Web of Knowledge, Web of Science and Google Scholar, for publications on DM detected in patients who had ~(18)FDG-PET/CT scans as part of the staging for early stages of breast cancer(stage Ⅰ?and Ⅱ), prior to or immediately following surgery. Reports published between 2011 and 2017 were considered. The systematic review was conducted according to the PRISMA guidelines.RESULTS Among the 18 total studies included in the analysis, the risk of DM ranged from 0% to 8.3% and 0% to 12.9% for stage Ⅰ?and Ⅱ invasive breast cancer, respectively. Among the patients with clinical stage Ⅱ, the rate of occult metastases diagnosed by ~(18)FDG-PET/CT was 7.2%(range, 0%-19.6%) for stage ⅡA and 15.8%(range, 0%-40.8%) for stage ⅡB. In young patients(< 40-yearold), ~(18)FDG-PET/CT demonstrated a higher prevalence of DM at the time of diagnosis for those with aggressive histology(i.e., triple-negative receptors and poorly differentiated grade).CONCLUSION Young patients with poorly differentiated tumors and stage ⅡB triple-negative breast cancer may benefit from ~(18)FDG-PET/CT at initial staging to detect occult DM prior to surgery. AIM To investigate rates of distant metastases (DM) detected with [18] fluorodeoxyglucose-positron emission tomography / computed tomography (~ (18) FDG-PET / CT) in early stage invasive breast cancer.METHODS We searched the English language literature databases of PubM ed, EMBASE, ISI Web of Knowledge, Web of Science and Google Scholar, for publications on DM in in patients who had ~ (18) FDG-PET / CT scans as part of the staging for early stages of breast cancer (stage I? Reports of between 2011 and 2017 were considered. The systematic review was conducted according to the PRISMA guidelines. RESULTS Among the 18 total studies included in the analysis, the risk of DM ranged from 0% Among the patients with clinical stage II, the rate of occult metastases was diagnosed by ~ (18) FDG-PET / CT was 7.2% (range , 0% -19.6%) for stage IIA and 15.8% (range, 0% -40.8%) fo r stage IIB. In young patients (<40-yearold), ~ (18) FDG-PET / CT demonstrated a higher prevalence of DM at the time of diagnosis for those with aggressive histology (ie, triple-negative receptors and poorly differentiated grade ). CONCLUSION Young patients with poorly differentiated tumors and stage IIB triple-negative breast cancer may benefit from ~ (18) FDG-PET / CT at initial staging to detect occult DM prior to surgery.