The radical approach to the oligometastatic not small cell lung cancer patient: which? how? when? where?

In 1894, Halsted defined that a primary tumour spread first through lymphatics vessels to lymph nodes and then to distant organs. Hellman argued that cancer, even at the time of diagnosis, is a biologic variety from a local to systemic illness with several transitional states. Subsequently, in 1995, Hellman and Weichselbaum first suggested the oligometastatic theory, where the number of metastases should imitate the biologic behaviour of a tumour, determining the chance for potential therapeutic interventions (1). In the eighth edition of the TNM classification, intrathoracic metastatic disease recollects the M1a classification. Extrathoracic metastatic disease is nowadays classified in the case of a single metastasis as M1b (2). Even so, regarding lung cancer oligometastatic non-small cell lung cancer (OMTS) patients, the eighth edition of the TNM classification is not clear and does not allow the uniformity of the studies and the results. Therefore, OMTS is clinically assessed as lung cancer in an advanced stage, but it is dissimilar from advanced lung cancer in general. Nevertheless, controversies remain regarding the treatment approaches (3)