Treatment Options for Colon Cancer

There are different types of treatment for patients with colon cancer.

Seven types of standard treatment are used:

• Surgery
• Chemotherapy
• Radiation therapy
• Targeted therapy
• Immunotherapy
• Radiofrequency ablation
• Cryosurgery
• New types of treatment are being tested in clinical trials.
• Treatment for colon cancer may cause side effects.

Surgery

Surgery (removing the cancer in an operation) is the most common treatment for all stages of colon cancer.

Local excision: If the cancer is found at a very early stage, the doctor may remove it without cutting through the abdominal wall. Instead, the doctor may put a tube with a cutting tool through the rectum into the colon and cut the cancer out. This is called a local excision. If the cancer is found in a polyp (a small bulging area of tissue), the operation is called a polypectomy.

Resection of the colon with anastomosis: If the cancer is larger, the doctor will perform a partial colectomy (removing the cancer and a small amount of healthy tissue around it). The doctor may then perform an anastomosis (sewing the healthy parts of the colon together). The doctor will also usually remove lymph nodes near the colon and examine them under a microscope to see whether they contain cancer.

Resection of the colon with colostomy: If the doctor is not able to sew the 2 ends of the colon back together, a stoma (an opening) is made on the outside of the body for waste to pass through. This procedure is called a colostomy. A bag is placed around the stoma to collect the waste.

Chemotherapy

• Chemotherapy is a cancer treatment that uses drugs to stop the growth of cancer cells, either by killing the cells or by stopping them from dividing. When chemotherapy is taken by mouth or injected into a vein or muscle, the drugs enter the bloodstream and can reach cancer cells throughout the body (systemic chemotherapy).
• Chemotherapy is offered for Stage III Colon Cancers after surgery. This is called ‘adjuvant’ chemotherapy.
• Chemotherapy is used to treat Stage IV Colon Cancers since these are often not removable surgically.
• Common chemotherapy drugs used for colon cancer include:
  • 5-FU (Fluorouracil Injection)
  • Irinotecan Hydrochloride
  • Oxaliplatin
  • Capecitabine (Xeloda)
  • Trifluridine and Tipiracil Hydrochloride
• These drugs are often administered in combinations that have names such as:
  • CAPOX
  • FOLFIRI
  • FOLFOX
  • FU-LV
  • XELIRI
  • XELOX

Targeted therapy

Targeted therapy is a type of treatment that uses drugs or other substances to identify and attack specific cancer cells. Targeted therapies usually cause less harm to normal cells than chemotherapy or radiation therapy do.

Types of targeted therapies used in the treatment of colon cancer include the following:

Monoclonal antibodies: Monoclonal antibodies are immune system proteins made in the laboratory to treat many diseases, including cancer. As a cancer treatment, these antibodies can attach to a specific target on cancer cells or other cells that may help cancer cells grow.

There are different types of monoclonal antibody therapy:

Vascular endothelial growth factor (VEGF) inhibitor therapy: Cancer cells make a substance called VEGF, which causes new blood vessels to form (angiogenesis) and helps the cancer grow. VEGF inhibitors block VEGF and stop new blood vessels from forming. This may kill cancer cells because they need new blood vessels to grow. Bevacizumab and ramucirumab are VEGF inhibitors and angiogenesis inhibitors.

Epidermal growth factor receptor (EGFR) inhibitor therapy: EGFRs are proteins found on the surface of certain cells, including cancer cells. Epidermal growth factor attaches to the EGFR on the surface of the cell and causes the cells to grow and divide. EGFR inhibitors block the receptor and stop the epidermal growth factor from attaching to the cancer cell.

Cetuximab and panitumumab are EGFR inhibitors.

Angiogenesis inhibitors: Angiogenesis inhibitors stop the growth of new blood vessels that tumors need to grow.

Ziv-aflibercept and Regorafenib fall into this category.

Immunotherapy

Immunotherapy is a treatment that uses the patient's immune system to fight cancer. Substances made by the body or made in a laboratory are used to boost, direct, or restore the body's natural defenses against cancer.

Immune checkpoint inhibitor therapy is a type of immunotherapy:

PD-1 and PD-L1 inhibitor therapy: PD-1 is a protein on the surface of T cells that helps keep the body’s immune responses in check. PD-L1 is a protein found on some types of cancer cells. When PD-1 attaches to PD-L1, it stops the T cell from killing the cancer cell. PD-1 and PD-L1 inhibitors keep PD-1 and PD-L1 proteins from attaching to each other. This allows the T cells to kill cancer cells.

Pembrolizumab is a type of PD-1 inhibitor.

Treatment of Stage 0 (Carcinoma in Situ):

Treatment of stage 0 (carcinoma in situ) may include the following types of surgery:

• Local excision or simple polypectomy.
• Resection and anastomosis. This is done when the tumor is too large to remove by local excision.

Treatment of Stage I Colon Cancer:

Treatment of stage I colon cancer usually includes the following:

• Resection and anastomosis.

Treatment of Stage II Colon Cancer::

Treatment of stage II colon cancer may include the following:

• Resection and anastomosis.
• ‘Adjuvant’ chemotherapy is not standard for most cases of colon cancer.

Treatment of Stage III Colon Cancer:

Treatment of stage III colon cancer may include the following:

• Resection and anastomosis which may be followed by chemotherapy.
• Clinical trials of new chemotherapy regimens after surgery.

Treatment of Stage IV and Recurrent Colon Cancer:

Treatment of stage IV and recurrent colon cancer may include the following:

• Local excision for tumors that have recurred.
• Resection with or without anastomosis.
• Surgery to remove parts of other organs, such as the liver, lungs, and ovaries, where the cancer may have recurred or spread. Treatment of cancer that has spread to the liver may also include the following:
  • Chemotherapy given before surgery to shrink the tumor, after surgery, or both before and after.
  • Radiofrequency ablation or cryosurgery, for patients who cannot have surgery.
  • Chemoembolization of the hepatic artery.
  • Radiation therapy or chemotherapy may be offered to some patients as palliative therapy to relieve symptoms and improve quality of life.
  • Chemotherapy and/or targeted therapy with a monoclonal antibody or an angiogenesis inhibitor.
  Immunotherapy.
  • Clinical trials of chemotherapy and/or targeted therapy.