Positron emission tomography in breast cancer

Positron emission tomography (PET) is a relatively new approach that enables detection of malignant tumours by visualisation of their enhanced glucose metabolism. Performance of whole-body imaging is one of the favourable features of PET. The sensitivity and specificity in detecting breast cancer and in differentiating breast cancer from benign tumours have been reported to be 68 - 94% and 97 - 75%, respectively. In a recent study, performed in our institution, PET was twofold more sensitive in detecting multifocal lesions than the combination of ultrasonography and mammography, whereas the specificity was comparable. Currently, PET ist the most sensitive non-invasive imaging modality in detecting axillary (sensitivity 79%) and internal lymph node metastases. Furthermore, accuracy in detecting distant metastases is comparable to that of the combination of x-ray, ultrasonography of the liver and bone scintigraphy. Because of its unique capability to visualise tumour metabolism directly, PET seems to be optimal for therapy control. PET cannot replace histological examination of the primary tumour and of the axillary lymph nodes. Evaluation of the internal lymph nodes, therapy control and whole-body screening in patients with increased tumour marker serum levels are indications for efficient PET imaging in breast cancer.