Treatment Options for Rectal Cancer

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

Seven types of standard treatment are used:

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

Surgery

Surgery (removing the cancer in an operation) is the most common treatment for all stages of rectal 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 into the rectum 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 rectum with anastomosis: If the cancer is larger, the doctor will perform a partial resection (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 rectum together). The doctor will also usually remove lymph nodes near the rectum and examine them under a microscope to see whether they contain cancer.

Resection of the rectum with colostomy: If the doctor is not able to sew the 2 ends of the rectum 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.

Pelvic exenteration: If the cancer has spread to other organs near the rectum, the lower colon, rectum, and bladder are removed. In women, the cervix, vagina, ovaries, and nearby lymph nodes may be removed. In men, the prostate may be removed. Artificial openings (stoma) are made for urine and stool to flow from the body to a collection bag.

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 may be combined with radiation to treat Stage II and Stage II rectal cancer
• Chemotherapy after surgery is called ‘adjuvant’ chemotherapy. Chemotherapy before surgery is called ‘neoadjuvant’ chemotherapy.
• Chemotherapy is used to treat Stage IV Rectal Cancers since these are often not removable surgically.
• Common chemotherapy drugs used for rectal 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 rectal 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.

Radiation therapy

• Radiation therapy is a cancer treatment that uses high-energy x-rays or other types of radiation to kill cancer cells or keep them from growing.
• External radiation therapy is used to treat rectal cancer.
• Radiation therapy is commonly given together with chemotherapy, either before or after surgery.
• Short-course preoperative radiation therapy is used in some types of rectal cancer. This treatment uses fewer and lower doses of radiation than standard treatment, followed by surgery several days after the last dose.

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 Rectal Cancer:

Treatment of stage I colon cancer usually includes the following:

• Local excision.
• Resection.
• Resection with radiation therapy and chemotherapy after surgery.

Treatment of Stage II/III Rectal Cancer:

• Surgery.
• Chemotherapy combined with radiation therapy, followed by surgery.
• Short-course radiation therapy followed by surgery and chemotherapy.
• Resection followed by chemotherapy combined with radiation therapy.
• Chemotherapy combined with radiation therapy, followed by active surveillance. Surgery may be done if the cancer recurs (comes back).
• A clinical trial of a new treatment.

Treatment of Stage IV and Recurrent Rectal Cancer:

• Surgery with or without chemotherapy or radiation therapy.
• Systemic chemotherapy with or without targeted therapy (angiogenesis inhibitor).
• Systemic chemotherapy with or without immunotherapy (immune checkpoint inhibitor therapy).
• Chemotherapy to control the growth of the tumor.
• Radiation therapy, chemotherapy, or a combination of both, as palliative therapy to relieve symptoms and improve the quality of life.
• Placement of a stent to help keep the rectum open if it is partly blocked by the tumor, as palliative therapy to relieve symptoms and improve the quality of life.
• Immunotherapy.
• Clinical trials of chemotherapy and/or targeted therapy.

Treatment of rectal cancer that has spread to other organs depends on where the cancer has spread.

• Treatment for areas of cancer that have spread to the liver includes the following:
• Surgery to remove the tumor. Chemotherapy may be given before surgery, to shrink the tumor.
• Cryosurgery or radiofrequency ablation.
• Chemoembolization and/or systemic chemotherapy.
• A clinical trial of chemoembolization combined with radiation therapy to the tumors in the liver.

Additional information can be found at: https://www.cancer.gov/types/colorectal/patient/rectal-treatment-pdq