Left Hemicolectomy

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


The primary treatment for colon cancer is surgery. The part of the large bowel with cancer is removed, along with surrounding lymph nodes. Removal of the colon is called a colectomy. The remaining bowel is then joined together. Joining the bowel is called an anastomosis. When cancer is found in the descending colon, all or part of the left side is removed. The transverse colon is then reconnected to the remaining colon.

Left Hemicolectomy before surgery. The grey area shows the part of the bowel the surgeon will remove.

Left Hemicolectomy after surgery. The transverse colon now is attached to the remaining colon.

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. It is important to ask your surgeon if you are an appropriate candidate for minimally invasive 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