The choice of treatment depends mainly on the tumor’s location in the colon or rectum and the stage of the disease. Treatment for colorectal cancer may involve surgery, chemotherapy, biological therapy, or radiation therapy. Some people have a combination of treatments. These treatments are described below.
Colon cancer sometimes is treated differently from rectal cancer. Treatments for colon and rectal cancer are described separately below.
Your doctor can describe your treatment choices and the expected results. You and your doctor can work together to develop a treatment plan that meets your needs.
Cancer treatment is either local therapy or systemic therapy:
- Local therapy: Surgery and radiation therapy are local therapies. They remove or destroy cancer in or near the colon or rectum. When colorectal cancer has spread to other parts of the body, local therapy may be used to control the disease in those specific areas.
- Systemic therapy: Chemotherapy and biological therapy are systemic therapies. The drugs enter the bloodstream and destroy or control cancer throughout the body.
Surgery for Colorectal Cancers
Colon Cancer Surgeries
Surgery is the most common treatment for colorectal cancer.
- Polypectomy: A small malignant polyp may be removed from your colon or upper rectum during a colonoscopy. Some small tumors in the lower rectum can be removed through your anus without a colonoscope. Sometimes, if the polyp is removed entirely during colonoscopy, no other treatment may be needed. However, a follow-up colonoscopy may be recommended to look for any other polyps.
- Local excision: If small cancers are seen on the lining of the colon during a colonoscopy, a local excision can be done to remove the cancer and a small amount of the surrounding healthy tissue.
- Colectomy: Surgery to remove all or part of the colon. These can be done with:
- Laparoscopic surgery
- Open surgery
Rectal Cancer Surgeries
Surgery is a common treatment for rectal cancer. The type of operation used to remove the rectal cancer depends on the stage (extent) of the cancer and its location within the rectum.
How close the tumor is to the anus can impact the type of surgery that will be performed. Common surgical procedures can include:
- Polypectomy, local transanal resection, or excision: These procedures are used to remove early-stage rectal cancers in the lower rectum. They are performed by instruments inserted through the rectum. The surgeon removes the cancer from the rectal wall and may remove some of the surrounding rectal tissue. This method allows the doctor to remove the polyps or cancer without cutting into the abdomen (belly).
- Transanal endoscopic surgery (TEM): This surgery is used to remove larger cancers that may be higher in the rectum and challenging to remove through local transanal resection. For this procedure, surgeons use a specially-designed magnifying scope inserted through the anus and into the rectum.
- Low anterior resection: This surgery, for some stage I, II, and III cancers in the upper rectum, removes the part of the rectum containing the tumor and then reattaches the colon to the remaining portion of the rectum so that a permanent colostomy is not needed. This surgery requires incisions to be made through the abdomen.
- Proctectomy: This surgery, for some stage I and many stage II and III cancers in the middle and lower rectum, removes the entire rectum. The rectum is removed so that a total mesorectal excision (TME) can be done to remove all of the lymph nodes near the rectum. The colon is then attached to the anus (called a colo-anal anastomosis) so that the patient will move their bowels in the usual way.
- Abdominoperineal resection (APR): This surgery, usually performed for stage II and stage III cancers in the lower to middle rectum, removes the rectum through abdominal incisions as well as the anus and sphincter muscles through incisions around the anus. An APR is often needed if the cancer is growing into the sphincter muscle (the muscle that keeps the anus closed and prevents stool leakage) or the nearby levator muscles that help control urine flow.
- Pelvic exenteration: This major operation may be recommended if the rectal cancer is growing into nearby organs. The surgeon will remove the rectum and any nearby organs that the cancer has reached, such as the bladder, prostate (in men), or uterus (in women).
Is a Colostomy Bag Required After Colon or Rectal Surgery?
When a section of your colon or rectum is removed, the surgeon can usually reconnect the healthy parts. However, sometimes reconnection is not possible right away. In this case, the surgeon creates a new path for waste to leave your body. The surgeon makes an opening (stoma) in the abdomen wall, connects the upper end of the intestine to the stoma, and closes the other end. The operation to create the stoma is called a colostomy. A flat bag fits over the stoma to collect waste, and a special adhesive holds it in place.
For many patients, the stoma is temporary. It is needed only until the colon or rectum heals from surgery. After healing takes place, the surgeon reconnects the parts of the intestine and closes the stoma. Some people, especially those with a tumor in the lower rectum, need a permanent stoma.
Radiation Therapy for Colon and Rectal Cancers
Radiation therapy (also called radiotherapy) uses high-energy rays to kill cancer cells. It affects cancer cells only in the treated area. Radiotherapy is often used for colorectal cancer patients because the disease tends to recur in the same place previously found. It may be given before surgery, after surgery, or both depending on whether the cancer spread and what was found during surgery.
Your cancer care team will include a radiation oncologist specializing in determining the right type and amount of radiation therapy that may be needed. This is based on the stage of cancer and location in the body.
Types of radiation therapy used for colorectal cancer include:
- External radiation: A machine (called a linear accelerator) delivers radiation that is carefully aimed at exactly where the radiation needs to be delivered in the colon or rectum. At WVCI, we can provide radiation therapy to our patients in our cancer centers. It’s often given five days a week for several weeks. Your cancer care team will decide the exact timing.
- Brachytherapy: Brachytherapy, also referred to as High Dose Radiation (HDR), is a type of internal radiation therapy. It is more commonly used to treat rectal cancer, where radiation therapy is delivered internally. The radiation oncologist places a small device that contains small radioactive seeds into the rectum and is positioned close to where the radiation needs to be delivered. Because it’s a high dose, the seeds are only inserted for a few minutes at a time before being removed. The patient can go home between treatments, which are about every two weeks for a total of about four treatments.
Chemotherapy (chemo) uses anti-cancer drugs to kill cancer cells. Chemo is used especially when colorectal cancer is found in other areas of the body. It may be used before surgery to shrink tumors. It can also be used after surgery to help kill any remaining cancer cells circulating in the body through the lymph system.
There have been significant advances in the chemotherapy options for colorectal cancer over the past 20 years. Several options are available. Your oncologist will select the treatment that you’re most likely to respond to based on genetic test results, pathology reports, and your overall health. You may also receive a combination of treatments, including chemotherapy and targeted therapies.
Immunotherapy for Colorectal Cancers
Immunotherapy, also referred to as biologic therapy, uses the body’s immune system to fight cancer. This treatment uses materials made either by the body or in a laboratory to simulate a natural substance.
Immune checkpoint inhibitors are relatively new cancer treatment. It is a drug that blocks proteins called checkpoints made by some types of immune system cells, such as T cells and certain cancer cells. These checkpoints keep the immune system from responding property and sometimes can keep T cells from killing cancer cells. Using the inhibitor blocks the proteins to reinforce the body’s ability to fight the cancer cells.
Targeted Therapy for Colorectal Cancer
This type of colorectal cancer treatment targets specific genes, proteins, or the tissue contributing to the cancer’s growth and blocks it while allowing healthy cells to continue growing with minimal impact.
Patients with colorectal cancer should be tested to find the most effective targeted therapy. The tests can identify the genes, proteins, and other factors in your tumor. Based on the results, one of the following types of targeted therapy may be included in your cancer treatment program.
- Anti-angiogenesis therapy: These unique cancer-fighting agents, called angiogenesis inhibitors, block the growth of blood vessels that support tumor growth rather than blocking the growth of tumor cells themselves. Some are monoclonal antibodies that specifically recognize and bind to VEGF (vascular endothelial growth factor), a substance made by cells that stimulate new blood vessel formation. In some cancers, angiogenesis inhibitors appear to be most effective when combined with additional therapies. Because angiogenesis inhibitors work by slowing or stopping tumor growth without killing cancer cells, they are given over a long period.
- Epidermal growth factor reception (EGFR) inhibitors: EGFR is a protein that helps cancer cells grow. Cancerous cells tend to have a lot of this protein on them. By slowing the growth of the protein, the colorectal cancer cells are slower to reproduce.
Clinical Trials Available in the Pacific Northwest for Colorectal Cancer
Willamette Valley Cancer Institute actively participates in clinical research to help identify better treatment options for cancer patients, including colorectal cancer patients. Your oncologist can talk to you about possible clinical trials that may be available through our clinics.