Surgery is the main treatment for cancer in the colon or rectum. Surgery often fully treats the cancer. But by the time the cancer is found, and surgery is done, some tumors may have grown through the wall of the colon or rectum and into nearby tissue. In some cases, cancer cells may have spread to other parts of the body. And sometimes tiny tumor cells that can’t be seen may be left behind during surgery. Your health care provider may suggest adjuvant therapy as a way to make sure that all cancer cells left behind are killed.
Adjuvant therapy is more cancer treatment that's done after surgery. It may help reduce the risk of cancer coming back in some people. It might include chemotherapy (chemo) after surgery. This can kill any cancer cells that are left. The chemo might be given along with radiation therapy. Radiation treatment uses high-energy X-rays to kill cancer cells and shrink tumors.
The stage of your cancer helps your health care team know if you are more likely to benefit from adjuvant therapy. It's most often used to treat stages II and III colon cancers and might be used in any stage of rectal cancer.
Stage II colon cancer
In this stage, cancer has usually grown through the colon wall. But it hasn’t spread to lymph nodes. Adjuvant therapy isn't commonly used but might be advised for people with a high-risk of the cancer coming back due to certain factors. These factors include:
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The tumor caused bowel blockage, hole (perforation), or leakage.
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The tumor had grown into nearby blood or lymph vessels.
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Cancer was found in or near the edge (margin) where the tissue was removed.
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Tumor tissue stuck to nearby organs and the surgeon can't be sure all the tumor was removed.
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Tumor cells look very abnormal under a microscope (high grade).
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Tumor cells that have gene changes that predict a worse prognosis.
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Fewer than 12 lymph nodes were removed and checked during surgery.
If you have 1 or more of these risk factors, you may be treated with 1 of the regimens noted below for stage III colon cancer.
Stage III colon cancer
Stage III colon cancer 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's often given for about 6 months. In some cases, only 3 months of treatment are recommended.
The most common adjuvant regimens are:
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FOLFOX. This includes the medicines folinic acid (leucovorin), fluorouracil (5-FU), and oxaliplatin. It's given every 2 weeks.
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CapeOx. This includes the medicines capecitabine (which is a pill) and oxaliplatin, given every 3 weeks.
Other choices are:
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Fluorouracil and leucovorin weekly.
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Capecitabine on its own.
FOLFOX and CapeOx may better lower the chance that the cancer will come back. But they also may have more side effects.
Rectal cancer
Rectal cancer is different from colon cancer. There is a greater chance that it will come back after surgery. The surgery is harder to do because it is done in a smaller space with the complicated rectal sphincter that is easily damaged. This means there's a greater chance that cancer cells may be left behind.
Chemo and radiation therapy plus surgery may increase the chance of longer survival. You may get chemo and radiation before surgery to shrink the tumor. This is called neoadjuvant therapy. Many health care providers now prefer to give radiation and chemotherapy before surgery, and more or adjuvant chemo afterward. These are standard treatments for both stage II and III rectal cancer. Often the same medicines are used as listed above for stage III colon 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. You may want to talk with your provider about being in a research study. This is often the only way to get new treatments that are thought to be better than those commonly used.
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