Ablative Therapy for Oligometastatic Non-Small Cell Lung Cancer

The oligometastatic state represents a distinct entity among those with metastatic disease and consists of patients with metastases limited in number and location, representing an intermediate state between locally confined and widely metastatic cancer. Although similar, "oligorecurrence" (limited number of metachronous metastases under conditions of a controlled primary lesion) and "oligoprogressive" (disease progression at a limited number of sites with disease controlled at other disease sites) states are distinct entities. In non-small cell lung cancer (NSCLC), the oligometastatic state is relatively common, with 20% to 50% of patients having oligometastatic disease at diagnosis. This subgroup of patients when receiving ablative therapy, such as surgery or stereotactic body radiation radiotherapy, can obtain markedly long progression-free and overall survival. The role of radical treatment for intracranial oligometastases is well established. Fewer data exist regarding radical treatment of extracranial metastases in lung cancer; however, retrospective series using surgery or stereotactic body radiotherapy for extracranial oligometastatic disease in NSCLC have shown excellent local control, with a suggestion of improvement in progression-free survival. In the present report, we have reviewed the data on the treatment of brain metastases in oligometastatic NSCLC and the results of ablative treatment of extracranial sites. Recently, the first randomized trial comparing ablative treatment versus control in oligometastatic disease was reported, and those data are reviewed in the context of smaller series. Finally, areas of controversy are discussed and a therapeutic approach for patients with oligometastatic disease is proposed.