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Colon and Rectal Cancers

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​​​​Colorectal cancer is the third most common cancer (excluding skin cancer) of both men and women in the U.S. 

The majority of colorectal cancers are cancers of the glandular cells that line the inside of the colon and rectum and are called adenocarcinomas. 

The treatments listed below are specific to adenocarcinomas. 

Treatment for the less common tumors of the colon or rectum including carcinoid tumors, stromal tumors and lymphomas differ from those listed below, but Marshfield Clinic provides a wide range of resources for patients with all forms of colorectal cancer.

Colon Cancer Treatments - Surgery

​Surgery is the main form of treatment for colon cancer.

  • Partial colectomy - This is the most common su​rgery for colon cancer, and involves the surgeon removing the cancer and a section of normal tissue on either side of the cancer as well as the nearby lymph nodes.
  • Colonoscopy - Very early colon cancers can be removed with this procedure which does not require the surgeon to go through the abdomen.
  • Laparoscope colectomy - In this procedure, surgeons remove a segment of the colon and nearby lymph nodes with a laparoscope, a long, lighted viewing tube through which the surgeon can operate with special surgical instruments.

Rectal Cancer Treatments - Surgery

  • Transanal resection - An option for Stage I rectal cancer, this surgery involves the surgeon going through the anus and cutting through all layers of the rectum to remove the cancer as well as surrounding normal tissue.
  • Low anterior (LA) resection or adbominoperineal (AP) resection - LA resection is used for cancers near the upper part of the rectum, close to where it connects to the sigmoid colon.
    After LA resection, the colon is attached to the lower rectum and feces are eliminated in the usual way. AP resection is used for cancer in the lower part of the rectum, close to its outer connection to the anus.
    During this procedure, the anus is also removed and a permanent colostomy is needed.

Radiation Therapy

Radiation therapy​ has a major role in treating rectal cancer. 

This treatment uses high-energy x-rays to kill cancer cells, and can be given either before surgery to shrink the tumor or after surgery to prevent the cancer from coming back.

  • External-Beam Radiation - Radiation therapy for rectal cancer is most often given by External Beam Radiation Therapy, which means that the radiation is delivered from a machine outside the body.
    This course of treatment is less precise, but allows a wider area of tissue around the tumor to be treated.

  • IMRT - Intensity Modulation Radiation Therapy (IMRT). This allows the radiation oncology team to:
    • Customize a patient's treatment to the size, shape and location of the tumor.
    • Minimize the amount of healthy tissue that is exposed to radiation.
    • Treat tumors previously considered untreatable
  • Tomotherapy - a form of IRMT radiation therapy that can be used for many tumors, including those that are hard to reach.
    Tomotherapy targets tumors using built-in CT scanning to confirm the shape and position of the tumor before each treatment.

Chemotherapy

Chemotherapy uses drugs to kill cancer cells. Chemotherapy drugs interfere with the growth of cancer cells, eventually causing the cells to die. Chemotherapy treatment is used to shrink the tumor, keep the tumor from spreading, and kill cancer cells that have spread to other areas of the body or relieve symptoms related to cancer.

Monoclonal antibodies

Monoclonal antibodies are laboratory-made drugs that find and attach to specific places (proteins) on the surface of cancer cells. When they attach, they stop the protein from doing its job, such as making cancer cells grow. Monoclonal antibodies can be used alone or in combination with other therapies.

Anti-angiogenesis

The formation of new blood vessels feeding tumors is called angiogenesis. Anti-angiogenesis drugs work by cutting off a tumor's blood supply so the tumor starves and is prevented from growing and/or spreading.​

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