This section has been reviewed and approved by the Cancer.Net Editorial Board, 12/10
The treatment of colorectal cancer depends on the size and location of the tumor, whether the cancer has spread, and the person’s overall health. In many cases, a team of specialists—including a gastroenterologist (a doctor who specializes in the function and disorders of the gastrointestinal tract), surgeon, medical oncologist, and radiation oncologist—will work with the patient to determine the best treatment plan.
This section outlines treatments that are the standard of care (the best treatments available) for colorectal cancer. Patients are also encouraged to consider clinical trials as a treatment option when making treatment plan decisions. A clinical trial is a research study to test a new treatment to prove it is safe, effective, and possibly better than standard treatment. Your doctor can help you review all treatment options. For more information, see the Clinical Trials section.
Overview of colorectal cancer treatment
This section provides a brief overview of standard treatment of colon and rectal cancer by stage. Details about each treatment option follow this section.
The usual treatment of stage 0 cancer in situ is a simple polypectomy during a colonoscopy. There is no additional surgery unless the polyp is unable to be fully removed by polypectomy.
If the cancer is stage I, surgical removal of the tumor and lymph nodes is usually the only treatment necessary.
Patients with stage II colon cancer, which involves deeper penetration of the bowel lining without involving the regional lymph nodes, are advised to talk with their doctor about the need for further treatment after surgery, as some patients are treated with adjuvant chemotherapy. This is treatment after surgery with chemotherapy aimed at trying to destroy any remaining cancer cells. However, cure rates for surgery alone are quite good, and the benefits of additional treatment are still uncertain for people with this stage of colon cancer. Learn more about adjuvant therapy for stage II colorectal cancer.
A clinical trial is also an option after surgery. Additional drugs are being investigated in clinical trials.
If the cancer is stage III and has spread to nearby lymph nodes, the treatment usually involves surgical removal of the tumor followed by adjuvant chemotherapy. A clinical trial is also an option.
For patients with stage II or III rectal cancer, radiation therapy is usually offered in combination with chemotherapy, either before or after surgery.
At stage IV, it is usually not recommended that patients have surgery to remove the primary tumor in the colon, unless the tumor is causing physical problems, such as bleeding or blocking the intestines. Standard treatment includes chemotherapy along with a targeted treatment. If possible, surgery to remove metastases (areas where cancer has spread) may also be done. Generally, such surgery is possible if there are a limited number of spots to where the tumor has spread.
Descriptions of the most common treatment options for colorectal cancer are listed below.
The most common treatment for colorectal cancer is surgery to remove the tumor, called surgical resection. Part of the healthy colon or rectum and nearby lymph nodes will also be removed. While both general surgeons and specialists may perform colorectal surgery, many people consult specialists who have additional training and experience in colorectal surgery. A surgical oncologist is a doctor who specializes in treating cancer using surgery, and a colorectal surgeon has additional training beyond general surgery.
Some patients may be able to undergo laparoscopic colorectal cancer surgery. With this technique, several viewing scopes are passed into the abdomen while a patient is under anesthesia. The incisions are smaller and the recovery time is often shorter than with standard colon surgery. Laparoscopic surgery is as effective as conventional colon surgery in removing the cancer. Surgeons who perform laparoscopic surgery have been specially trained in that technique.
Less often, a person with rectal cancer may need to have a colostomy. This is a surgical opening, or stoma, through which the colon is connected to the abdominal surface to provide a pathway for waste to exit the body; such waste is collected in a pouch worn by the patient. Sometimes, the colostomy is only temporary to allow the rectum to heal, but it may be permanent. With modern surgical techniques and the use of radiation therapy and chemotherapy before surgery, most people treated for rectal cancer do not require a permanent colostomy.
Some patients may be candidates for surgery on the liver or lungs to remove tumors that have spread to those organs. An alternative is to use radiofrequency ablation (RFA; energy in the form of radiofrequency waves to heat the tumors). Not all liver or lung tumors can be treated with this approach. In some cases, RFA can be done through the skin. In other cases, RFA can be done during surgery. While this can allow preservation of liver and lung tissue that might be removed in a regular surgical resection, there is also a chance that some portions of the tumor will not be destroyed using this technique.
In general, the side effects of surgery include pain and tenderness in the area of the operation. The operation may also cause constipation or diarrhea, which usually goes away after a while. People who receive a colostomy may have irritation around the stoma. The doctor, nurse, or a specialist in colostomy management (called an enterostomal therapist) can teach the patient how to clean the area and prevent infection.
Many people require retraining of the bowel after surgery; this may require some time and assistance. People should talk with their doctor if they do not regain good control of bowel function.
Learn more about cancer surgery.
Radiation therapy is the use of high-energy x-rays to kill cancer cells and is commonly used for treating rectal cancer because this tumor tends to recur locally. A doctor who specializes in giving radiation therapy to treat cancer is called a radiation oncologist. A radiation therapy regimen (schedule) usually consists of a specific number of treatments given over a specific time.
External-beam radiation therapy uses a machine to deliver x-rays to the site of the body where the cancer is located. Radiation treatment is given five days a week for several weeks and may be given in the doctor’s office or at the hospital.
In some cases, specialized radiation therapy techniques, such as intraoperative radiation therapy (a high, single dose of radiation therapy given during surgery) or brachytherapy (placing radioactive “seeds” inside the body), may help eliminate small areas of tumor that could not be removed during surgery. In one type of brachytherapy with a product called SIR-Spheres, tiny amounts of yttrium-90 (a radioactive substance) are injected into the liver to treat colorectal cancer that has spread to the liver in cases when surgery is not an option. While limited information is available about how effective this approach is, some studies suggest that it may help slow the growth of cancer cells.
For rectal cancer, radiation therapy may be used before surgery (called neoadjuvant therapy) to shrink the tumor so that it is easier to remove or after surgery to destroy any remaining cancer cells, as both have shown value in treating this disease. One recent study found that pre-operative radiation therapy in combination with chemotherapy showed greater benefit compared with the same radiation therapy and chemotherapy given after surgery. The main benefits included a lower rate of the tumor coming back in the area where it started, fewer patients that needed permanent colostomies, and fewer problems with scarring of the bowel in the area where the radiation therapy was administered. Chemotherapy is often given at the same time as radiation therapy (called chemoradiation therapy) to increase the effectiveness of the radiation therapy. Chemoradiation therapy is often used in rectal cancer before surgery to avoid colostomy or reduce the chance that the cancer will recur.
Side effects from radiation therapy may include fatigue, mild skin reactions, upset stomach, and loose bowel movements. It may also cause bloody stools (bleeding through the rectum) or bowel obstruction. Most side effects go away soon after treatment is finished.
Sexual problems, as well as infertility (the inability to have a child) in both men and women, may occur after radiation therapy to the pelvis. Before treatment begins, talk with your doctor about the possible sexual and fertility-related side effects of your treatment and the available options for preserving fertility
Learn more about radiation therapy.
Chemotherapy is the use of drugs to kill cancer cells. Systemic chemotherapy is delivered through the bloodstream, targeting cancer cells throughout the body. Chemotherapy is usually given by a medical oncologist, a doctor who specializes in treating cancer with medication. Some people may receive chemotherapy in their doctor’s office or outpatient clinic; others may go to the hospital. A chemotherapy regimen (schedule) usually consists of a specific number of cycles given over a specific time. Chemotherapy for colorectal cancer is usually injected directly into a vein, although some chemotherapy can be given as a pill.
Chemotherapy may be given after surgery to eliminate any remaining cancer cells. In some situations, for rectal cancer, a doctor will give chemotherapy and radiation therapy before surgery to reduce the size of a rectal tumor and lower the chance of cancer returning.
Currently, seven drugs are approved for the treatment of colorectal cancer in the United States. Your doctor may recommend one or several of them at various times during treatment. These drugs are fluorouracil (5-FU, Adrucil), capecitabine (Xeloda), irinotecan (Camptosar), oxaliplatin (Eloxatin), bevacizumab (Avastin), cetuximab (Erbitux), and panitumumab (Vectibix). (These last three are described under “Targeted therapy” below.) Many new drugs are in the process of being tested and may provide additional future options for treatment. Some common treatments are:
- 5-FU with leucovorin, a vitamin that improves the effectiveness of 5-FU
- Capecitabine, an oral form of 5-FU
- 5-FU with leucovorin and oxaliplatin (FOLFOX)
- 5-FU with leucovorin and irinotecan (FOLFIRI)
- Irinotecan alone
- Capecitabine with either irinotecan or oxaliplatin
- Any of the above with either cetuximab or bevacizumab
The most common chemotherapy given for colorectal cancer may cause vomiting, nausea, diarrhea, or mouth sores. However, medications to prevent these side effects are available. Because of the way drugs are given, these side effects are less problematic than they have been in the past for most patients. In addition, patients may be unusually tired, and there is an increased risk of infection. Neuropathy (tingling or numbness in feet or hands) may also occur with some drugs. Hair loss is an uncommon side effect with the drugs used to treat colorectal cancer. Medications are available to ease most side effects, including nausea, neuropathy, and diarrhea. Most side effects usually go away once treatment is finished. If side effects are particularly difficult, the dose of drug may be lowered or a treatment session may be postponed. Patients should talk with their health care team to understand when to call their doctor about side effects. Read more about managing side effects.
Learn more about chemotherapy and preparing for treatment. The medications used to treat cancer are continually being evaluated. Talking with your doctor is often the best way to learn about the medications prescribed for you, their purpose, and their potential side effects or interactions with other medications. Learn more about your prescriptions by using searchable drug databases.
Targeted therapy is a treatment that targets specific genes, proteins, or the tissue environment that contributes to cancer growth and survival. These drugs are becoming more important in the treatment of colorectal cancer.
Anti-angiogenesis therapy. Some of the first targeted treatments focused on stopping angiogenesis, the process of making new blood vessels. Because a tumor needs the nutrients found in blood vessels to grow and spread, the goal of anti-angiogenesis therapies is to “starve” the tumor. One such therapy is a specialized drug made in a laboratory, bevacizumab, called a monoclonal antibody. When given with chemotherapy, bevacizumab improves survival for people with advanced colorectal cancer. In 2004, the U.S. Food and Drug Administration (FDA) approved bevacizumab along with chemotherapy for the first-line treatment of patients with advanced colorectal cancer. Recent studies have shown it also to be effective as second-line therapy along with chemotherapy.
Epidermal growth factor receptor (EGFR) inhibitors. Researchers have found that drugs that block EGFR may be effective in shrinking or stabilizing the growth of colorectal cancer. Cetuximab and panitumumab are monoclonal antibodies that block EGFR. Cetuximab is an antibody made from mouse cells that still has some of the mouse structure. Panitumumab is entirely made from human proteins and is less likely to cause an allergic reaction than cetuximab.
Recent studies show that cetuximab and panitumumab are not effective in patients with tumors that have specific mutations (changes) to a gene called KRAS. ASCO released a provisional clinical opinionrecommending that all patients with metastatic colorectal cancer who may receive anti-EFGR therapy, such as cetuximab and panitumumab, have their tumors tested for KRAS gene mutations. If a patient’s tumor has a mutated form of the KRAS gene, ASCO recommends against the use of anti-EFGR antibody therapy. Furthermore, the FDA now recommends that both cetuximab and panitumumab only be given to patients with tumors with non-mutated (sometimes called wild type) KRAS genes.
Research is underway to determine what role cetuximab and panitumumab might play in patients with metastatic colorectal cancer who’ve had surgery and who have not previously been given chemotherapy.
Learn more about targeted treatments.
In terms of side effects, targeted treatments can cause a rash to the face and upper body, which can be prevented or reduced with various treatments. Find out more about skin reactions to targeted therapies.
Advanced colorectal cancer (Stage IV; metastatic)
Colorectal cancer can spread to distant organs, such as the liver, lungs, peritoneum (the tissue lining the abdomen), or a woman’s ovaries. A combination of surgery, radiation therapy, and chemotherapy can be used to slow the spread of the disease and, in many cases, can temporarily shrink a cancerous tumor.
With metastatic colorectal cancer, it is particularly important to talk with doctors who are experienced in treating this disease. There can be different opinions about how to treat colorectal cancer, particularly in which combination of treatments to use. Patients are encouraged to seek a second opinion before starting treatment because they should be comfortable with the treatment plan they choose and should ask about clinical trials. Often surgeons, radiation oncologists, radiologists, and medical oncologists will work together to use various treatments over time. When these individuals work closely together they are referred to as a multidisciplinary team. Bringing the different skills of all of these doctors together can result in better care for the patient.
At this stage, surgery to remove the portion of the colon where the cancer started usually cannot cure the cancer, but it can help relieve blockage of the colon or other complications, if they occur. Surgery may also be used to remove parts of other organs that contain cancer (called resection) and can cure some people if a limited amount of cancer spreads to a single organ, such as the liver or lung.
In colon cancer, if spread is limited to the liver and if liver resection (surgery) is possible–either before or after chemotherapy–the patient has a chance of complete cure. Even in cases when cure is not possible, surgery may add months or even years to an individual’s life. Determining who can benefit from surgery in this setting is often a complicated process that involves collaboration between doctors of multiple specialties.
Chemotherapy and radiation therapy at this stage can rarely cure cancer, but they may help to relieve pain and other symptoms (called palliative care and prolong survival. Clinical trials that test new treatments may also be an option.
Recurrent colorectal cancer
Treatment of recurrent cancer depends on where the cancer is located and the person’s overall health. Generally, the treatment options for recurrent cancer are the same as those for metastatic cancer (see above) and include surgery, radiation therapy, and chemotherapy. Clinical trials of investigational treatments may also be an option.
Find out more about common terms used during cancer treatment.