What is surgery?

Many patients with colorectal cancer will have surgery at some point during their treatment. In surgery, tumors are physically removed from the body by a surgeon or surgical oncologist, a doctor who specializes in removing cancer. For non-metastatic cancer, treatment usually involves removing the primary tumor. For metastatic cancer, several factors determine whether the primary tumor will be removed.

The majority of this section will focus on surgeries in the colon and rectum.

How is surgery used to treat colorectal cancer?

Surgery can play different roles in treatment depending on the stage of your cancer.

Non-metastatic cancer

For patients with early-stage cancers, surgery can be curative on its own. Some patients also receive chemotherapy after surgery. 

Metastatic cancer

For patients with oligometastatic cancer — meaning cancer with some, but limited, cancer spread — surgery is used to remove a small number of metastases in patients with a good response to chemotherapy. Some stage IV patients have surgery first to address a blockage or something that needs to be addressed immediately. 

How will surgery fit into my treatment plan?

Your healthcare team has many different experts, including an oncologist and surgeon. Together, they will come up with a plan for treating your cancer, which can include surgery, radiation, chemotherapy or other medications.

Stage I and II colon cancer patients usually have surgery shortly after diagnosis. After surgery, patients may have chemotherapy. However, chemo is not usually recommended for stage I or II patients who are MSI-H or have a low risk of recurrence. Most stage III colon cancer patients will also have surgery first, while most stage II and II rectal cancer patients will have either chemo or chemoradiation first. Some stage II and III rectal cancer patients who have a complete response to chemo and radiation (tumor not seen based on many criteria) may not get surgery and instead follow a “watch and wait” approach.

For stage IV patients, chemo is usually the first and primary treatment. It is understandable that some patients want their tumors removed immediately, but research suggests that removing the primary tumor does not affect overall outcomes (meaning with and without removal of the primary tumor, the outcomes for stage IV patients with more extensive disease are similar).

Some stage IV patients who respond well to chemo may eventually qualify for surgery at some point during their treatment. These patients may have multiple surgeries to remove both their primary tumor and metastases.

For more information on sequencing chemotherapy and surgeries, read our chemo sequencing section. The NCCN Guidelines for Colon and Rectal Cancer are a great place to start as well.