The use of FDG-PET in assessing axillary lymph node status in breast cancer: a systematic review and meta-analysis of the literature.

Axillary lymph node status is the most powerful prognostic indicator in patients with breast cancer. FDG-PET has been suggested as a non-invasive method of staging the axilla. The aim of this study was to review and aggregate all studies that measured the performance of FDG-PET in patients with breast cancer, using surgically obtained axillary histology as a reference, in a meta-analysis. A systematic review of the literature was performed and data extracted from all eligible studies. These were then analysed using meta-analysis software and summary receiver operating characteristic (SROC) curves were plotted for the aggregate data. The data was then tested to determine which parameters impacted on the sensitivity and specificity of the studies. Sensitivities ranging from 20 to 100% and specificities ranging from 65 to 100% have been reported. An aggregated ROC analysis found an area under the curve of 0.95 (95% CI 0.91-0.97) and a Q* value of 0.89 (95% CI 0.85-0.92) in a total of 25 studies involving 2,460 patients. The AUC and Q* values indicated little difference between the compared study characteristics. The performance of the technique currently remains below, which is required to replace assessment of axillary node status by surgical biopsy and histological assessment. However, sensitivity and specificity are high and FDG-PET may have a role to play under particular circumstances. Moreover, the additional benefit of an assessment of distal metastatic spread provided by FDG-PET requires further investigation.