Adenocarcinoma of the Colon - Stages & Treatment

Adenocarcinoma is a type of cancer that starts in the cells that form glands making mucus to lubricate the inside of the colon and rectum. This is the most common type of colon and rectum cancer.

Colon cancer locations

As colon cancer grows and spreads beyond the inner lining of the colon (mucosa), it is called invasive (or infiltrating) adenocarcinoma. Cancers that are invasive are called true cancers because they can spread to other places in the body.

The stages of colon cancer are:

  • Stage I. The cancer has grown through the superficial lining (mucosa) of the colon or rectum but hasn’t spread beyond the colon wall or rectum.
  • Stage II. The cancer has grown into or through the wall of the colon or rectum but hasn’t spread to nearby lymph nodes.
  • Stage III. The cancer has invaded nearby lymph nodes but isn’t affecting other parts of your body yet
  • Stage IV. The cancer has spread to distant sites, such as other organs — for instance, to your liver or lung.

Treatment

The type of treatment your doctor recommends will depend largely on the stage of your cancer. The three primary treatment options are surgery, chemotherapy and radiation.

Surgery for early-stage colon cancer

If your colon cancer is very small, your doctor may recommend a minimally invasive approach to surgery, such as:

  • Removing polyps during a colonoscopy. If your cancer is small, localized and completely contained within a polyp and in a very early stage, your doctor may be able to remove it completely during a colonoscopy.
  • Endoscopic mucosal resection. Removing larger polyps may require also taking a small amount of the lining of the colon or rectum in a procedure called an endoscopic mucosal resection.
  • Minimally invasive surgery. Polyps that can’t be removed during a colonoscopy may be removed using laparoscopic surgery. In this procedure, your surgeon performs the operation through several small incisions in your abdominal wall, inserting instruments with attached cameras that display your colon on a video monitor. The surgeon may also take samples from lymph nodes in the area where the cancer is located.

Surgery for invasive colon cancer

If the cancer has grown into or through your colon, your surgeon may recommend:

  • Partial colectomy. During this procedure, the surgeon removes the part of your colon that contains the cancer, along with a margin of normal tissue on either side of the cancer. Your surgeon is often able to reconnect the healthy portions of your colon or rectum. This procedure can commonly be done by a minimally invasive approach (laparoscopy).
  • Surgery to create a way for waste to leave your body. When it’s not possible to reconnect the healthy portions of your colon or rectum, you may need an ostomy. This involves creating an opening in the wall of your abdomen from a portion of the remaining bowel for the elimination of stool into a bag that fits securely over the opening.
  • Sometimes the ostomy is only temporary, allowing your colon or rectum time to heal after surgery. In some cases, however, the colostomy may be permanent.
  • Lymph node removal. Nearby lymph nodes are usually also removed during colon cancer surgery and tested for cancer.

Surgery for advanced cancer

  • If your cancer is very advanced or your overall health very poor, your surgeon may recommend an operation to relieve a blockage of your colon or other conditions in order to improve your symptoms. This surgery isn’t done to cure cancer, but instead to relieve signs and symptoms, such as bleeding and pain.
  • In specific cases where the cancer has spread only to the liver but your overall health is otherwise good, your doctor may recommend surgery to remove the cancerous lesion from your liver. Chemotherapy may be used before or after this type of surgery. This approach provides a chance to be free of cancer over the long term.

Chemotherapy

Chemotherapy uses drugs to destroy cancer cells. Chemotherapy for colon cancer is usually given after surgery if the cancer has spread to lymph nodes. In this way, chemotherapy may help reduce the risk of cancer recurrence and death from cancer. Sometimes chemotherapy may be used before surgery as well, with the goal of shrinking the cancer before an operation. Chemotherapy before surgery is more common in rectal cancer than in colon cancer.

Chemotherapy can also be given to relieve symptoms of colon cancer that has spread to other areas of the body.

Radiation therapy

Radiation therapy uses powerful energy sources, such as X-rays, to kill cancer cells, to shrink large tumors before an operation so that they can be removed more easily, or to relieve symptoms of colon cancer and rectal cancer. Radiation therapy either alone or combined with chemotherapy is one of the standard treatment options for the initial management of rectal cancer followed by surgery.

Targeted drug therapy

Drugs that target specific malfunctions that allow cancer cells to grow are available to people with advanced colon cancer, including:

  • Bevacizumab (Avastin)
  • Cetuximab (Erbitux)
  • Panitumumab (Vectibix)
  • Ramucirumab (Cyramza)
  • Regorafenib (Stivarga)
  • Ziv-aflibercept (Zaltrap)

Targeted drugs can be given along with chemotherapy or alone. Targeted drugs are typically reserved for people with advanced colon cancer.

Some people are helped by targeted drugs, while others are not. Researchers have recently made progress in determining who is most likely to benefit from specific targeted drugs. Until more is known, doctors carefully weigh the possible benefit of targeted drugs against the risk of side effects and the cost when deciding whether to use these treatments.

Immunotherapy

Some patients with advanced colon cancer have a chance to benefit from immunotherapy with antibodies such as pembrolizumab (Keytruda) and nivolumab (Opdivo). Whether a colon cancer has the chance to respond to these immunotherapies can be determined by a specific test of the tumor tissue.

* The Content is not intended to be a substitute for professional medical advice, diagnosis, or treatment. Always seek the advice of your physician or other qualified health provider with any questions you may have regarding a medical condition.