Invasion and metastasis: a historical perspective.

The idea that neoplasms grow, becoming unresectable through dissemination, which is initially loco-regional, and systemic only in a later stage, is historically at the basis of the radical surgery - where, by 'radical', the old surgery meant the complete removal of the tumor and, in practice, aggressive surgery. Halsted's "radical mastectomy", as well as many principles of surgical anatomy of the first decades of the twentieth century, obey to an idea of tumor progression as a linear process taking place in continuity and contiguity, where the various anatomical layers and the peritumoral desmoplastic reaction are mistaken for a wall of defense against the neoplasm's dissemination, capable of containing and orienting it. However, the investigations of the processes of invasion and metastasis by Rudolf Virchow and Stephel Paget helped to reorient surgical approaches.