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Colorectal cancer

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Treatments for stage III rectal cancer

The following are treatment options for stage III rectal cancer. Your healthcare team will suggest treatments based on your needs and work with you to develop a treatment plan.

Radiation therapy

Radiation therapy is almost always offered for stage III rectal cancer. It may be given alone or as part of chemoradiation. External beam radiation therapy is the most common type of radiation used, but brachytherapy may be considered in some cases.

Radiation therapy alone may be given before surgery (called neoadjuvant radiation therapy) if the tumour is in the upper part of the rectum and it is not attached to surrounding tissues (called a non-fixed tumour). You may be given 5 treatments of radiation. This is called a short course of radiation.

If someone can’t have chemotherapy, radiation therapy alone may be used to treat a tumour in the lower part of the rectum, close to the fat tissue around the rectum (called mesorectum) or attached to surrounding tissues (called a fixed tumour). A long course of radiation therapy is used, which is given as 25–30 treatments.

Sometimes radiation therapy alone is given after surgery (called adjuvant radiation therapy).

Chemoradiation

Chemoradiation combines chemotherapy with radiation therapy. Chemotherapy is given during the same time period as radiation therapy. Some types of chemotherapy make radiation therapy more effective.

Chemoradiation may be given before surgery (called neoadjuvant chemoradiation) if the tumour is in the lower part of the rectum, if it is close to the fat tissue around the rectum (mesorectum) or if it is attached to surrounding tissues (called a fixed tumour). It is usually given as 25–30 treatments of radiation therapy (called a long course of radiation) and chemotherapy with 5-fluorouracil (Adrucil, 5-FU) or capecitabine (Xeloda) given for 5–6 weeks.

Chemoradiation may be given after surgery (called adjuvant chemoradiation). It is given as 25–30 treatments of radiation therapy and chemotherapy with 5-fluorouracil (Adrucil, 5-FU) or capecitabine (Xeloda). Chemoradiation is not given after surgery very often because neoadjuvant radiation therapy or chemoradiation has become standard.

Surgery

Surgery is the main treatment for stage III rectal cancer. A bowel resection is usually done to remove the tumour and a margin of healthy tissue on each side of the tumour. Depending on the location of the tumour, the surgeon may do a low anterior resection or abdominoperineal resection with total mesorectal excision. If the surgeon does a low anterior resection, the remaining 2 ends of the colon are joined together (called anastomosis).

Surgery is usually done 7–10 days after a short course of radiation therapy alone or 4–10 weeks after a long course of radiation therapy (either given alone or as part of chemoradiation).

Depending on the type of surgery done, the surgeon may need to do a temporary or permanent colostomy or ileostomy.

Chemotherapy

Chemotherapy may be given alone after surgery (called adjuvant chemotherapy). If neoadjuvant radiation therapy or chemoradiation was not used, adjuvant chemotherapy is usually given in addition to adjuvant chemoradiation.

Adjuvant chemotherapy is usually given for 4–6 months, but the length of chemotherapy depends on the amount of radiation or chemoradiation used before surgery.

The drugs used in adjuvant chemotherapy for stage III rectal cancer include:

  • FOLFOX – leucovorin (folinic acid), 5-fluorouracil (Adrucil, 5-FU) and oxaliplatin (Eloxatin)
  • capecitabine (Xeloda)
  • 5-fluorouracil (Adrucil, 5-FU) with leucovorin (folinic acid)
  • CAPOX (also called XELOX) – capecitabine (Xeloda) and oxaliplatin (Eloxatin)

FOLFOX and capecitabine (Xeloda) are used most often as adjuvant chemotherapy.

Clinical trials

You may be asked if you want to join a clinical trial for rectal cancer. Find out more about clinical trials.

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