The primary treatment for colon and rectal cancer is surgery—but the surgery and outcome can vary depending on how severe the cancer is and where the cancer is located. Colon and rectal cancers can be very similar, which is why they’re often called “colorectal cancer,” but when it comes to surgery, the difference between them can matter.
Surgical Treatment of the Colon
“Colon cancer [that doesn’t affect the rectum] involves a portion of the colon that's free within the abdomen, the first five feet of the large intestine,” says Elliot Newman, MD, chief of surgical oncology at Lenox Hill Hospital, Northwell Health System. “It’s a very open area, so we're not worried about the confined space.”
The open area makes it easier to safely remove a margin of tissue (an extra border around the tumor to make sure all the cancer is removed), and it helps protect the cancer from affecting nearby organs.
Surgical Treatment of the Rectum
“Rectal cancer, which involves the last 6 or 8 inches of the large intestine, the area known as the rectum, is in a confined area in the pelvis,” says Dr. Newman. “The ability to get widely around the tumor can be challenging.”
One way doctors help deal with this is by using neoadjuvant (i.e., a therapy used prior to the main treatment) radiation therapy to shrink the tumor before surgery. A smaller tumor allows surgeons to get a better margin around the tumor, despite the confined space. Learn more about what radiation therapy for cancer is here.
Colostomy vs. No Colostomy
“Depending on where the tumor is located, most of the time, we can remove a piece of the colon or rectum and reconnect the patient so there's no need for permanent bags, or what is termed a colostomy,” says Dr. Newman.
This type of partial colectomy is sometimes called a segmental resection, since surgeons are literally removing one segment of the colon and then reconnecting them. This usually only removes about 1/4 to 1/3 of the large intestine.
“However, sometimes for cancers in the lowest portion of the rectum that are very close to the muscles that control our ability to go to the bathroom, commonly known as the sphincters, we may not have that option” of a segmental resection, says Dr. Newman.
In this case, surgeons may have to remove the rectum and the sphincter muscles. Because this affects their physical ability to have a bowel movement, they will receive a permanent colostomy—a bag that collects waste externally through an opening (a stoma) in the skin of the abdomen.
“People live quite well with a colostomy. We will send patients to special ostomy nurses who help them learn how to use and manage the colostomy,” says Dr. Newman. “They can lead a very normal and functional life, including physical activities.”