Radical surgery, also called radical dissection, is a surgery that is more extensive than "conservative" surgery in somewhat manner.
When it comes to surgical oncology, radical surgery is surgery involve removing both a tumor and any metastases for diagnostic motive or treatment purposes. It implies that it consists removal of a tumor or mass and ancillary lymph nodes that may drain the mass, as in radical mastectomy.

Whilst in histopathology, radicality of tumor excisions is defined as the absence of tumor cells in a certain resection margin, with the specific margin width varying by tumor type and local guidelines.