Colorectal Cancer: Adjuvant Therapy After Surgery

Surgery is the main treatment for cancer in the colon or rectum. Surgery often fully treats the cancer. But by the time surgery is done, some tumors may have grown through the wall of the colon or rectum and into nearby tissue. Or cancer cells may have spread to other parts of the body. Or tiny tumor cells that can’t be seen may be left behind during surgery. Because of these problems, your doctor may advise adjuvant therapy. This is additional treatment that may reduce the risk of cancer returning in some people. Adjuvant therapy may include chemotherapy (chemo) after surgery. This can kill any cancer cells that are left. The chemo may also be given with radiation. Radiation treatment uses high-energy X-rays to kill cancer cells and shrink tumors.

Your stage of cancer helps your healthcare team know if you are more likely to benefit from adjuvant therapy.

Stage III colon cancer

Stage III colon cancer is cancer that has spread to nearby lymph nodes. It has not spread to other parts of the body. Adjuvant chemo after surgery is standard treatment for this stage of colon cancer. It is often given for about 6 months.

The most common adjuvant regimens are:

• FOLFOX. This includes the medicines folinic acid (leucovorin calcium), fluorouracil, and oxaliplatin.

• CapeOx.This includes the medicines capecitabine and oxaliplatin.

Other options are:

• Fluorouracil and leucovorin

• Oral capecitabine on its own

FOLFOX and CapeOx may better lower the chance the cancer will come back. But they also tend to have more side effects.

Stage II colon cancer

In this stage, cancer has often grown through the colon wall. But it hasn’t yet spread to the lymph nodes. Studies have not yet shown a large benefit of adjuvant therapy for people with stage II colon cancer. So it is not often advised for this stage. But it may be advised for some people with a high-risk factor. This is something that shows that the cancer may be more likely to come back. These factors include:

• Bowel blockage or leakage

• Tumor that grows into nearby tissue

• Tumor tissue that sticks (adheres) to nearby organs

• Tumor cells that look very abnormal under a microscope (high grade)

• Tumor cells that have gene changes that predict a worse prognosis

• Fewer than 12 lymph nodes were removed and checked during surgery

• The surgeon is not sure all the tumor was removed

If you have one or more of these risk factors, you may have therapy with 1 of the regimens noted above for stage III colon cancer.

Rectal cancer

Rectal cancer is different than colon cancer. There is a greater chance that rectal cancer will come back. The surgery is more difficult. This is because it is done in a smaller space. So there is a greater chance that tiny areas of cancer cells may be left behind.

Chemo and radiation therapy plus surgery may increase the chance of longer survival. You may have chemo and radiation before surgery to shrink the tumor. This is known as neoadjuvant therapy. Many doctors now prefer to give radiation and chemotherapy before surgery, and more chemo afterward. These are standard therapies for both stage II and III rectal cancer.

Research for other adjuvant treatment

Researchers continue to study new medicine combinations. They also study the best doses, methods, and schedules. New targeted medicines are also being studied to be used with chemo. So far these have not worked better than chemo alone.  In some cases, you may be able to take part in a research study. Talk with your healthcare provider.