18F-FDG dual-headed gamma camera PET in detection of axillary nodal disease in patients with large or locally advanced breast cancer: possible alternative staging of axilla.

Positron emission tomography (PET) has been used in staging the axilla. Gamma Camera PET (GCPET) is a cost effective alternative, but poorly studied. The aim of this study was to assess GCPET in demonstrating metastatic deposits in axillary nodes in patients with a high likelihood of nodal disease. Twenty-seven women with large (T2, T3 or T4) or advanced breast cancer (N1, N2 or M1) were recruited. All patients underwent axillary lymph node removal or biopsy (fine needle aspiration cytology (FNAC) or core cut) and whole body GCPET imaging. Images were reported anonymously and compared with the histological findings. Twenty-one patients proceeded to surgery and 10 had tumour-involved axillary nodes; GCPET was positive in 8 of these. The remaining 6 patients underwent core cut or FNAC of the axillary nodes, 2 of which contained a tumour. GCPET was positive in both cases. Thus, the diagnostic values were: sensitivity 83%, specificity 100%, positive predictive value 100%, negative predictive value 88% and accuracy 93%. In conclusion, GCPET is a reliable method and can be performed in a district general hospital and detecting disease in axillary nodes in certain patients, possibly obviating the need for surgery.