P2-09-11: Role of 18FDG-PET/CT in the Staging of Large Primary Operable Breast Cancer.

Abstract

Abstract Background: Prospective evaluation of the role of 18FDG-PET/CT in patients with large primary operable breast cancer. Material and Methods: During 56 months, consecutive patients with large (>2cm) breast cancer and clinical stage IIA/IIB/IIIA (based on clinical examination, mammography, breast MRI and ultrasonography) underwent 18FDG-PET/CT. The nuclear physician was blind to the results of any other procedure (bone scan, chest X-ray, liver ultrasound, or thoraco-abdominal CT scan). Results: Out of the 131 examined patients, 36 had clinical stage IIA (34 T2 N0, 2 T1 N1), 48 stage IIB (20 T3 N0, 28 T2 N1), and 47 stage IIIA (29 T3 N1, 9 T2 N2, 9 T3 N2). 18FDG-PET/CT modified staging for 5.6% of stage IIA patients, for 14.6% of stage IIB patients, and for 27.6% of stage IIIA patients. However, within stage IIIA, the yield was specifically high among the 18 patients with N2 disease (56% stage modification). When considering stage IIB and primary operable IIIA (T3 N1) together, the yield of 18FDG-PET/CT was 13% (10/77); extra-axillary regional lymph nodes were detected in 5 and distant metastases in 7 patients. In this series, 18FDG-PET/CT outperformed bone scan with only 1 misclassification versus 8 for bone scan (p=0.036). Discussion: 18FDG-PET/CT provided useful information in 13% of patients with T3 N0 / T2 N1 / T3 N1 disease. The yield was more modest in patients with T2 N0 disease. The very high yield in the case of lymph nodes classified N2 demonstrates that stage IIIA comprises two quite distinct groups of patients. Citation Information: Cancer Res 2011;71(24 Suppl):Abstract nr P2-09-11.