F-FDG PET/CT for Systemic Staging of Newly Diagnosed Breast Cancer in Men.

F-FDG PET/CT has demonstrated substantial value in systemic staging of newly diagnosed breast cancer in women. However, it is not known whether breast cancer in male patients benefits similarly. This study assesses F-FDG PET/CT systemic staging in patients with newly diagnosed male breast cancer and determines detection rates for unsuspected distant metastases stratified by pre-PET/CT stage. In this Institutional Review Board-approved retrospective study, our Health Care Information System was screened for stage I-III male patients with breast cancer who underwent F-FDG PET/CT before systemic or radiation therapy from 2004 to 2017. Initial stage was determined by mammography, ultrasound, or surgery. F-FDG PET/CT was evaluated to identify unsuspected extraaxillary regional nodal and distant metastases, and a post-PET/CT stage was determined. Rates of upstaging to stage IV were determined for each initial stage. During the 14-y period, 10,124 unique patients underwent F-FDG PET/CT for breast cancer at our institution. Of these, 106 patients were men, and 39 of these patients were imaged at initial staging and met the inclusion criteria. Median age was 62 y (range, 31-90 y), most had ductal carcinoma (95%), and most were estrogen receptor-positive (97%). In 7 of 39 patients (18%), F-FDG PET/CT identified previously unsuspected distant metastases, which increased patient stage to IV. This included 3 of 19 (16%) initial stage IIB patients and 4 of 12 (33%) initial stage III patients. F-FDG PET/CT also detected an unsuspected synchronous lymphoma in 1 patient. F-FDG PET/CT revealed previously unsuspected distant metastases in 16% of male patients with pre-PET/CT stage IIB breast cancer and 33% of those with stage III breast cancer. These rates are comparable to previously published upstaging rates in female patients. F-FDG PET/CT demonstrates value for systemic staging of male patients with breast cancer and should be considered for use in newly diagnosed patients, particularly those with stage IIB and III disease.