LAUSR

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.