Rectal cancer is generally approached from the abdomen with rectal excision and often restoration of continuity of the bowel with an anastomosis (join up) of the colon to the distal rectum.
The technology used to do this is with open or minimally invasive techniques such as laparoscopic or robotic surgery, most times the bowel is joined by staple guns. These guns usually cut a rim of bowel and staple the cut ends together. The staples are quite small but strong and inert being made of titanium.
Sometimes in low joins of the colon to the very low rectum, assistance is given to the join up by surgery done through the anus (transanal). New platforms and techniques have been developed whereby insufflation of CO2 in the anus and perirectal tissue can be used to assist in helping with the removal of the very low rectum.
In some cases small and very early stage rectal cancers are removed totally by transanal techniques. Also advanced and large rectal polyps can be removed this way. The commoner approach now is with the TAMIS surgery. This uses a platform of insufflation inside and outside the rectum. The TEMS surgery is the older version of this and this is still used in certain centres.
This approach can avoid abdominal surgery and speed recovery and reduce hospital stay.
These procedures are relatively new and highly specialised and often can only be performed in selected hospitals due to the highly technical nature of the equipment.