Prognostic factors in pulmonary metastasectomy: spotlight on molecular and radiological markers

Pulmonary metastasectomy is nowadays a common practice in thoracic surgery. Clinical prognostic markers for poor outcome after pulmonary metastasectomy have been proposed in the late 1970's of the last century. Despite new insights in molecular mechanisms and advances in imaging techniques, neither molecular markers nor radiological features of metastases are used as prognosticators in routine clinical practice. Biomarkers associated with aggressive tumour behaviour came into the focus of clinical research and are the basis of personalized medicine. In addition, non-invasive imaging modalities like positron emission tomography and high-resolution computed tomography can provide further information on tumour aggressiveness. Regardless of a myriad of studies assessing prognostic markers in primary tumours, little is known about these markers in metastatic lesions. Furthermore, it has been emphasized that tumour biology of the primary might not reflect the behaviour of the corresponding metastasis. Therefore, information on the biology of metastases is necessary to treat patients adequately. This work reviews potential prognostic biomarkers in patients with pulmonary metastases, grouped in soluble tumour markers, tumour suppressor genes/proto-oncogenes and proteins involved in cell adhesion, tumour growth, cell metabolism and tumour angiogenesis.