Introduction: neoadjuvant and adjuvant therapy for rectal cancer

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Clinical practice guidelines for the prevention, early detection and management of colorectal cancer > Introduction: neoadjuvant and adjuvant therapy for rectal cancer

The aim of neoadjuvant and adjuvant therapy for rectal cancer is to reduce the risk of local and distant recurrence (metastatic disease). Locally recurrent rectal cancer is often incurable and is associated with high morbidity and deterioration in quality of life. Distant recurrenceWhen the cancer has spread (metastasised) to organs or tissues far from the place of the original cancer., if unresectable, is virtually always fatal.

Adjuvant therapyA treatment given with or shortly after another treatment to make it more effective. This usually refers to surgery followed by chemotherapy or radiotherapy. is any treatment that is given in addition to a standard curative cancer treatment such as surgery. By convention, the term ‘adjuvant’ is reserved for postoperative treatment, while ‘neoadjuvant’ refers to treatment given prior to the definitive treatment.

Radiation treatment

Radiation treatment uses ionising radiation to kill cancer cells. Only tissues within the treatment portals are affected. Radiation treatment prevents or reduces the incidence of recurrent rectal cancer within the pelvis.[1]

The value of radiation treatment (preferably given preoperatively) in the management of rectal cancer is well established. Several meta-analyses that included multiple trials have demonstrated a significant improvement in local disease control.[2]

Chemotherapy

Chemotherapy is cytotoxic drug treatment. Systemic chemotherapyAnti-cancer drugs that are injected into a vein or given by mouth. These drugs travel through the bloodstream to all parts of the body. affects the entire body, and is given with the intent of killing circulating cancer cells that may lodge and grow in distant organs such as the liver and lungs.[3]

The addition of fluoropyrimidine-based chemotherapy to radiation treatment in the treatment of rectal cancer is primarily for its effect as a radiosensitiser, enhancing the effect of radiation. Adjuvant chemotherapy cycles are given with the aim of eradicating systemic micro-metastatic disease.


References

  1. Barton, M. Oncology for Medical Students: Principles of radiotherapy. [homepage on the internet] Cancer Council Australia 2014; 2017 Nov 17 [cited 2016 Dec 28]. Available from: http://wiki.cancer.org.au/oncologyformedicalstudents_mw/index.php?oldid=1680.
  2. ColorectalReferring to the large bowel, comprising the colon and rectum. Cancer Collaborative Group.. Adjuvant radiotherapy for rectal cancer: a systematic overview of 8,507 patients from 22 randomised trials. Lancet 2001 Oct 20;358(9290):1291-304 Abstract available at http://www.ncbi.nlm.nih.gov/pubmed/11684209.
  3. George, M; Schwarz, M; McKinnon, R. Clinical Oncology for Medical Students: Principles of medical therapy. [homepage on the internet] Cancer Council Australia 2014; 2017 Nov 17 [cited 2016 Dec 26]. Available from: http://wiki.cancer.org.au/oncologyformedicalstudents_mw/index.php?oldid=1683.