Minimally invasive is a term pathologists use to describe cancer that has only spread a small distance into the non-cancerous surrounding tissue. For example, a type of cancer called squamous cell carcinoma in the mouth may be called minimally invasive if it has spread less than 0.5 cm into the surrounding non-cancerous tissue. Alternatively, squamous cell carcinoma in the skin may be called minimally invasive if it is more than 0.5 cm but still located within a layer of the skin called the dermis. The term ‘minimally invasive’ may be used to describe many different types of cancers. The actual distance that the tumour cells may spread into the normal tissue in order to be called minimally invasive varies between cancer types.