Radiation therapy is not recommended for Stage II colon cancer, however in some cases radiation therapy is used for Stage II Rectal Cancer.
Adjuvant Chemoradiotherapy for Rectal Cancer
Both radiation (to control local disease) and chemotherapy (to help the radiation work better, and control distant disease) are used in the treatment of rectal cancer. Adjuvant chemotherapy combined with radiation therapy has been shown to improve outcomes (both local control and overall survival) in patients with transmural or node positive rectal cancers.
Chemoradiotherapy used to be given after surgery, but, more recently, the standard has changed to giving chemoradiotherapy preoperatively. The advantages of preoperative adjuvant chemotherapy and radiation therapy versus postoperative for rectal cancer include less local recurrence, increased sphincter preservation, less small intestinal radiation injury, and improved bowel function. Typically, preoperative therapy is reserved for those tumors with evidence of nodal or transmural disease.
Chemoradiotherapy is given for approximately six weeks, followed by a break of four to ten weeks before surgery. An additional four months of chemotherapy is given postoperatively.