Surgery during cancer aims to remove the cancer from your body. If the cancer is only in one place, surgery can often cure it. In general, the earlier a cancer is found, the easier it is to remove.
As well as the tumour, your surgeon will remove some tissue around it, in case any cancer cells have spread there. The area around the tumour is called the margin. Your surgeon may also remove lymph nodes around the tumour area. This is because they may contain cancer cells if the cancer has started to spread.
The cells from the margin and/or lymph nodes will be examined after surgery to see if they have cancer cells in them. If they do, you may have other treatments, such as radiotherapy or chemotherapy.