Chemotherapy

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 chemotherapy data items.

Chemotherapy (also called chemo)is used to stop the growth of cancer cells, either by killing the cells or by stopping them from dividing. Chemotherapy can also be referred to as a systemic drug, opposed to radiation that typically targets a specific site/area/location. Chemotherapy may be given alone or with other types of treatment. The way the chemotherapy is given depends on the type and stage of the cancer being treated.

Chemotherapy, in conjunction with radiation (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)or Rectum NCCN Guidelines (PDF)

In addition, for some tumors, “regional chemotherapy” is done, which is placing drugs directly into the hepatic artery (main artery that supplies blood to the liver). This procedure is called chemoembolization. This type of therapy is used for cancer that has spread to the liver. This procedure blocks the hepatic artery and injects anticancer drugs between the blockage and the liver. The liver’s arteries then carry the drugs into the liver.

Chemoembolization is coded as chemotherapy.

See SEER*Rx Interactive Antineoplastic Drugs Database for more information on the specific Chemotherapy drugs for colorectal cancer. These can either be individual drugs, or part of a regimen.

Document chemotherapy details in NAACCR Item # 2640: Text-Chemo

Updated: June 24, 2025