MRI and FDG-PET/CT based assessment of axillary lymph node metastasis in early breast cancer: a meta-analysis

To evaluate the accuracy of magnetic resonance imaging (MRI) and combined 2-[¹⁸F]-fluoro-2-deoxy-d-glucose (FDG) positron-emission tomography/computed tomography (PET/CT) for N staging of breast cancer.

A search for relevant diagnostic studies published between January 2008 and October 2015 was conducted in the MEDLINE and EMBASE databases. The quality of the studies was assessed using Quality Assessment of Diagnostic Accuracy Studies (QUADAS) criteria. Sensitivity and specificity were analysed using the random-effect model and fixed effect model for MRI and PET/CT, respectively.

A total of 21 eligible studies were evaluated for the efficacy of MRI or PET/CT for diagnosing axillary lymph node status in breast cancer patients. The pooled specificities of MRI and PET/CT were similar at 0.93 (95% confidence interval [CI]: 0.92-0.94) and 0.93 (95% CI: 0.90-0.95), respectively; however, the pooled sensitivity of MRI was (0.82; 95% CI: 0.78-0.85) significantly greater than PET/CT (0.64; 95% CI: 0.59-0.69)]. Further analysis revealed that MRI had a significantly higher diagnostic odds ratio (DOR) value of 51.28 (95% CI: 22.44-117.17) compared to PET/CT at 18.84 (95% CI: 11.71-31.76).

The present meta-analysis suggests that MRI not only has the higher sensitivity for lymph node metastasis diagnosis compared to PET/CT, but also has high potential for being used as a non-invasive imaging diagnostic technique. Furthermore, the ultra-small super paramagnetic iron oxide (USPIO)-enhanced MRI showed high diagnostic accuracy for identifying axillary lymph node metastases in early-stage breast cancer patients.