Radiation Therapy

See the current version of the SEER Program Coding Manual under Reporting Guidelines, Section VII: First Course of Therapy, for complete coding instructions for the radiation data items.

Radiation therapy uses high-energy x-rays or other types of radiation to kill cancer cells or keep them from growing. Radiation for Colon and Rectum is usually done in conjunction with chemotherapy called chemoradiation.

Radiation, in conjunction with chemotherapy (chemoradiation) is frequently done in the preoperative setting (neoadjuvant therapy) for tumors that have extended through the muscularis propria into the subserosa, pericolic/perirectal tissues, serosa, visceral peritoneum and adjacent organs.

In addition, postoperative chemoradiation (or adjuvant therapy) may also be done. The main goal of adjuvant therapy is to eradicate residual disease, reducing local recurrence. Colon NCCN Guidelines (PDF)External Website Policy or Rectum NCCN Guidelines (PDF)External Website Policy

Document radiation details in NAACCR Item #’s

  • 2620: Text-Dx Proc-Radiation (Beam)
  • 2630: Text-Dx Proc-Radiation Other

See Additional Resources for Colorectal Cancer Treatment

Updated: June 24, 2025