ORIGINAL ARTICLE Impact of FDG PET on the preoperative staging of newly diagnosed breast cancer Tevfik F. Çermik & Ayse Mavi & Sandip Basu & Abass Alavi Received: 10 May 2007 / Accepted: 14 August 2007 / Published online: 24 October 2007 # Springer-Verlag 2007 Abstract Purpose The main objective of this study was to determine the efficacy of 18 F-fluorodeoxyglucose positron emission tomography (FDG PET) to assess the impact of this technique in staging of patients with newly diagnosed breast cancer. Methods Two hundred and seventy-one consecutive patients (median age=51±11 years) with biopsy-proven primary breast cancer who were examined by FDG PET were enrolled in this prospective preoperative staging study. Whole-body FDG-PET images were acquired approximate- ly 60 min after the intravenous administration of FDG (5.2 MBq/kg). Visual assessment and the maximum standardized uptake value (SUVmax) of breast lesions for semiquantitative analysis were carried out. The PET results were compared with the histopathology results. Results For the tumor, node, metastases (TNM) staging, 240 patients (250 breasts) were considered eligible based on the criteria that were established for this analysis. Significant differences were noted in SUVmax of lesions according to the TNM staging (p <0.05). The average SUVmax of the primary tumor was calculated in patients with axillary involvement (n =58) and for the ones without axillary metastasis (n =79), and SUVmax were 4.1±3.5 and 2.8±2.3, respectively, with a significant difference between the two groups (p =0.03). PET imaging revealed patholog- ical FDG uptake in 54% (46/85) of patients with axillary lymph node metastases. The sensitivities of FDG PET for detecting axillary lymph node metastasis were found 41% in pN1, 67% in pN2, and 100% in pN3, and the specificity was 89% for pN0 stage. Detection of extra-axillary regional node or distant metastatic lesions revealed by PET scan in 22 of 24 patients resulted in a significant change in the TNM stage. Distant metastasis without axillary lymph node metastasis was noted in 21% (5/24) of patients. The results revealed that FDG PET upgraded TNM stage in 9.2% (22/ 240) of patients and 7.5% (18/240) of patients were diagnosed as having one or more distant metastases. Conclusion FDG PET was able to identify extra-axillary regional nodal and distant lesions in newly diagnosed patients with breast cancer; FDG PET may alter the staging and management of therapy in patients with newly diagnosed breast cancer. Keywords Breast cancer . FDG PET . Staging . Axillary lymph node involvement . Extra-axillary regional nodal metastasis . Distant metastasis Introduction Breast cancer is the most common malignancy that affects women and is also the second leading cause of cancer- related deaths [1]. Although it is curable when detected early, about one third of women with breast cancer eventually die of the disease [2]. It is accepted that axillary or regional lymph node involvement with metastatic tumor and the presence of distant metastasis are the two most important prognostic factors in patients with breast cancer. Therefore, accurate staging of breast cancer at the time of the initial diagnosis has a major impact on the choice of Eur J Nucl Med Mol Imaging (2008) 35:475–483 DOI 10.1007/s00259-007-0580-5 T. F. Çermik : S. Basu : A. Alavi (*) Department of Radiology, Division of Nuclear Medicine, Hospital of the University of Pennsylvania, 3400 Spruce Street, 110 Donner Bldg., Philadelphia, PA 19104, USA e-mail: alavi@rad.upenn.edu A. Mavi Department of Nuclear Medicine, Yeditepe University Hospital, Istanbul, Turkey