Rectal Cancer

The colon, or large bowel, has three sides: the ascending colon (right side), the transverse colon, and the descending colon (left side).

The left side of the colon has four sections: the descending colon, the sigmoid colon, the rectum, and the anus.

Staging Rectal Cancer

Special tests, taken before surgery, are very important to decide the stage of a rectal cancer. The tests may include CT scans, blood work, and transrectal ultrasounds.

Radiation Therapy and Chemotherapy

Oncologists usually recommend radiation therapy and chemotherapy treatments before surery for advanced rectal cancers. These treatments can reduce the size of the tumor. Surgery is scheduled after the treatments are completed.


A colectomy is the removal of a section of the colon. The type of coloectomy for rectal cancer depends on the exact area the cancer is located in the bowel. There are two options for surgery: a low anterior resection or an abdominal perineal resection.

Low Anterior Resection

If the cancer is located in the upper and mid-rectum, the part of the rectum with the cancer is removed along with surrounding lymph nodes.
The grey area shows the part of the bowel the surgeon will remove. The remaining bowel is then joined together. Joining the bowel is called an anastomosis

Abdominal Perineal Resection

If the rectal cancer is located very low in the rectum, close to the anus, it may require an abdominal perineal resection. The rectum and anus are removed during an abdominal perineal resection resulting in a the need for permanent colostomy (bag for stool collection).

The grey area shows the part of the bowel the surgeon will remove.

The end of the colostomy, called a stoma, now protrudes though the abdomen. A special bag is attached to the abdomen to collect the stool.

Cedars-Sinai has specialty nurses to help patients adjust to an ostomy. They are called enterostomal therapy or ET nurses. The ET nurse will talk to the patient before and after surgery.

At Cedars-Sinai, the majority of colon and rectal operations are performed using minimally invasive techniques (laparoscopy). The benefits of minimally invasive surgery include less pain after surgery, faster return of bowel function, quicker healing, less scarring and fewer days in the hospital to recover. Laparoscopy, however, may not be suitable for all patients. Ask your surgeon if you are an appropriate candidate for minimally invasive surgery.

After Surgery

After the surgeon removes the section of the colon, a pathologist evaluates the cancer under a microscope. If the pathologist sees evidence that cancer has spread to the lymph nodes, or if the cancer is a type that grows quickly, the oncologist will usually recommend further treatment with chemotherapy.

Follow-up Care

Bowel movements might be more frequent after a colectomy, but usually become more normal after one year. Your doctor can recommend a bowel care plan to help normalize bowel movements.

The most common time a cancer recurs is within the first two years following diagnosis and treatment. Follow-up care with the surgeon, gastroenterologist and oncologist is important. Periodic checkups may include a physical exam, blood tests, colonoscopy, CT scan or PET scan.