COLORECTAL CANCER OVERVIEW

Colon and rectal cancer are cancers that involve the lowest part of the digestive system: the large intestine and the rectum (figure 1).

Tests that monitor or screen for colorectal cancer are important tools in finding colon and rectal cancer at an early stage. Screening tests are described separately. (See "Patient information: Colon cancer screening".)

This article has facts about the signs and symptoms, diagnosis, and treatment of early-stage colon and rectal cancer. More information about colon and rectal cancer is available by subscription. (See "Surgical management of primary colon cancer" and "Adjuvant therapy for resected colon cancer".)

COLORECTAL CANCER SYMPTOMS

The most common symptoms of colorectal cancer include:

• Stomach pain
• Change in bowel habits (constipation or diarrhea)
• Blood in the bowel movements
• Feeling weak or tired
• Low iron level (iron deficiency anemia)
• Black or dark-colored stools

COLORECTAL CANCER DIAGNOSIS

Your doctor or nurse may be concerned that you could have colon or rectal cancer if you have one or more of the above symptoms. In this case, a colonoscopy is often used to look inside the rectum and large intestine. Colonoscopy is described in a separate article. (See "Patient information: Colonoscopy".)

Staging — Once a colorectal cancer is diagnosed, the next step is to determine its stage. Staging is a system used to describe the aggressiveness and spread of a cancer. A colorectal cancer's stage is assigned based on:

• Whether there are signs of cancer spread on a physical exam, CT scan, or MRI of the abdomen and pelvis, chest X-ray, or other imaging tests.
• What the cancer looks like under the microscope (after surgery).

Colorectal cancer stages range from stage 0 (cancer has not invaded through the first inner layer of the intestine), to stage IV (the cancer has spread to distant organs, such as the liver). In general, lower-stage cancers are less aggressive and require less treatment than do higher-stage cancers. Stage I to III colorectal cancer are referred to as localized colorectal cancers, while stage IV is called advanced colorectal cancer.

COLON CANCER TREATMENT

The treatment of colon cancer usually involves surgery, and it may also involve chemotherapy and radiation therapy.

Surgery — The initial treatment of colon cancer usually involves surgery. During the surgery, the cancerous part of the colon and surrounding tissues are removed. The lymph nodes within this surrounding tissue are examined to determine if the cancer has spread beyond the colon.

In most people, the two ends of the colon can be reconnected immediately after the cancerous part has been removed. This means that you will continue to have bowel movements normally, through your rectum and anus.

In other cases, the colon cannot be reconnected during the initial surgery. This can happen if the surgeon feels there is a high risk of infection or if the tissues are inflamed and need time to heal. If this occurs, the surgeon will sew the colon to an opening in the skin on the abdomen. The opening is called a colostomy (figure 2). You will wear a bag over the colostomy to collect bowel movements.

The colostomy is usually temporary. The two ends of the colon can often be reconnected after a few months, sometimes after chemotherapy is completed. In other cases, you will need the colostomy permanently.

Life with a colostomy — Having a colostomy will change how your body looks, which can be hard to accept. However, with education and support, it is possible to lead an active life with a colostomy. A team effort, which includes the colorectal surgeon, oncologist, and an enterostomal therapy (ET) nurse, is valuable in learning about the surgery and also in the care and recovery required after the procedure. The United Ostomy Associations of America is also a good source of information and support (www.uoaa.org).

Chemotherapy — Chemotherapy is a treatment given to slow or stop the growth of cancer cells. Even after a cancer has been removed with surgery, cancer cells can remain in the body, increasing the risk of the cancer coming back (called a relapse or recurrence). In some people, chemotherapy can eliminate these cancer cells and increase the chance of cure. This type of chemotherapy is called "adjuvant," which means that it is given after curative surgery (where all the tumor was removed).

Chemotherapy is usually given in cycles. Most treatments involve a combination of several chemotherapy drugs. Most of the drugs are given into the vein (intravenous, IV), but sometimes a single drug will be recommended, which can be given in pill form. Regardless of the specific type of regimen, most adjuvant treatment regimens for colon cancer last about six months.

Your healthcare provider can describe which chemotherapy drugs will be needed, how long treatment will last, and what side effects are expected from your treatment.

Who needs chemotherapy? — Chemotherapy is recommended for most people with stage III colon cancer (spread to the lymph nodes) and some people with stage II colon cancer (invasion of the whole thickness of the bowel wall). Chemotherapy is not usually recommended for people with stage I colon cancer (cancer within the bowel wall, not all the way through).

Before you begin chemotherapy, it is important to discuss the potential risks and benefits of treatment with your doctor.

• In some cases, the benefits of chemotherapy (better chance of survival) clearly outweigh the possible risks (chemotherapy side effects like diarrhea, vomiting, hair loss, nerve damage, or more serious risks). Not everyone will have all of these side effects.
• In other cases, the small benefit of chemotherapy is not worth the risks.

A Web-based tool called Adjuvant! can help you and your healthcare provider estimate the risk of cancer recurrence and the potential benefits of chemotherapy.

RECTAL CANCER TREATMENT

The majority of rectal cancers are treated with a combination of surgery, radiation, and chemotherapy.

• Stage I rectal cancer — Surgery alone may cure the cancer.
• Stage II and III — Chemotherapy and radiation therapy are typically recommended along with surgery; most of the time, the chemotherapy and radiation are given before surgery (referred to as neoadjuvant chemoradiotherapy), with additional chemotherapy given after surgery.
• Stage IV — Predominantly treated with chemotherapy, with or without surgery. (See "Patient information: Colorectal cancer treatment; metastatic cancer".)

Neoadjuvant chemoradiotherapy — A combination of chemotherapy and radiation therapy may be recommended before surgery for patients with stage II or III rectal cancer; this is called neoadjuvant chemoradiotherapy. This treatment can shrink the tumor before it is removed, reduces the risk that the cancer will come back, and may reduce the chances that you will need a permanent colostomy. (See "Neoadjuvant chemoradiotherapy for rectal cancer".)

The two most common ways to take chemotherapy during radiation therapy are:

• A pump that fits into a pack you wear around your waist. The pump delivers the medicine (called 5-FU) into a port (an IV in your chest) continuously for about six weeks during radiation treatments.
• A daily dose of a pill. The pill is more convenient because you do not need a pump. Although 5-FU (5-Fluoracil) given by an IV pump is the "standard" treatment, capecitabine (the pill form) may be as effective as 5-FU given by pump. Studies are underway to confirm this. Discuss all the potential risks and benefits of capecitabine with your doctor.

Surgery — Surgery removes the cancerous part of the rectum and the associated lymph nodes. If the anus and rectum have to be removed, the surgeon will sew the remaining intestine to an opening in the skin on the abdomen. The opening is called a colostomy. You will wear a bag over the opening to collect bowel movements. (See 'Life with a colostomy' above.)

If the bowel can be reconnected after removing the tumor, the surgeon might sew a part of either the large intestine or small bowel to the skin (called a colostomy or ileostomy, respectively). This procedure might be temporary, and the opening will be closed after the tissues heal.

The type of surgery you have depends upon where your tumor is located and how far it has spread. Ask your surgeon to describe which surgery is right for you.

Treatment after surgery — Postoperative (adjuvant) chemotherapy is typically recommended after surgery. The type of treatment you have after surgery depends upon the stage of your cancer, as well as the treatment you had before surgery. (See "Adjuvant therapy for resected rectal cancer".)

• If your tumor is stage II or III, and you did not have chemoradiotherapy before surgery, you will probably have it after surgery. This is called adjuvant chemoradiotherapy, although it is very similar to neoadjuvant chemoradiotherapy (see 'Neoadjuvant chemoradiotherapy' above).
• If you had chemoradiotherapy before surgery, you will probably need four to six months of chemotherapy alone (without further radiation therapy) after surgery.

CLINICAL TRIALS

Progress in treating cancer requires that better treatments be identified through clinical trials, which are conducted all over the world. A clinical trial is a carefully controlled way to study the effectiveness of new treatments or new combinations of known therapies. Ask for more information about clinical trials, or read about clinical trials at:

• www.cancer.gov/clinical_trials/learning/
• http://clinicaltrials.gov/

FOLLOW-UP AFTER TREATMENT

After completing treatment for colorectal cancer, it is important to follow up with your healthcare team. You will need appointments on a regular basis for a few years to monitor for signs that the cancer has recurred. (See "Surveillance after colorectal cancer resection".)

Your follow-up schedule may differ slightly, but most people will have the following:

• A colonoscopy is recommended before or after surgery to monitor for polyps that were not seen previously. Colonoscopy is usually repeated one and four years after surgery, and every five years thereafter. If polyps or new cancers are found, this schedule may be adjusted.
• Visits with your healthcare provider are usually scheduled every three to six months for the first three years, every six months for two years, and then once per year. Most visits will include a discussion of how you are feeling and a physical examination. A blood test for a colon cancer tumor marker (CEA) may be done at each visit.
• A CT scan is usually recommended once per year for three years in people who have been treated for stage II or III colon cancer.
• For people who have had surgery (a low anterior resection) for rectal cancer but did not have radiation therapy, experts recommend a flexible proctosigmoidoscopy every six months for five years. (See "Patient information: Flexible sigmoidoscopy".)

COLON CANCER AND YOUR FAMILY

Having colon cancer means that your family is at an increased risk of developing colon cancer. If you have one parent, brother, sister, or child with colorectal cancer or adenomatous polyps at a young age (before the age of 60 years), or two relatives diagnosed at any age, you should begin screening for colon cancer earlier, typically at age 40, or 10 years younger than the earliest diagnosis in your family, whichever comes first. Colon cancer screening is discussed separately. (See "Patient information: Colon cancer screening".)

Certain genetic conditions increase the risk of colon cancer. The most common conditions include Lynch syndrome or hereditary nonpolyposis colon cancer (HNCC), familial adenomatous polyposis (FAP) and MYH-associated polyposis (MAP). If you have a strong family history of colon cancer (two or more close relatives), talk to your doctor about the need for genetic counseling and possible genetic testing.

Although the idea of genetic testing can be frightening, the results of genetic tests can help determine whether you and your family need further treatment, testing, or both.

WHERE TO GET MORE INFORMATION

Your healthcare provider is the best source of information for questions and concerns related to your medical problem.

This article will be updated as needed every four months on our Web site (www.uptodate.com/patients).

Related topics for patients, as well as selected articles written for healthcare professionals, are also available. Some of the most relevant are listed below.

Patient level information

Patient information: Colon cancer screening
Patient information: Colonoscopy
Patient information: Colorectal cancer treatment; metastatic cancer
Patient information: Flexible sigmoidoscopy

Professional level information

Adjuvant therapy for resected colon cancer
Adjuvant therapy for resected rectal cancer
Clinical manifestations, diagnosis, and staging of colorectal cancer
Colorectal cancer: Epidemiology, risk factors, and protective factors
Management of potentially resectable colorectal cancer liver metastases
Molecular genetics of colorectal cancer
Nonsurgical treatment strategies for colorectal cancer liver metastases
Surgical management and palliation in patients who present with stage IV colorectal cancer
Surgical management of primary colon cancer
Surveillance after colorectal cancer resection
Systemic chemotherapy for metastatic colorectal cancer: Completed clinical trials
Systemic chemotherapy for nonoperable metastatic colorectal cancer: Treatment recommendations
Therapy for metastatic colorectal cancer in elderly patients and those with a poor performance status
Neoadjuvant chemoradiotherapy for rectal cancer

The following organizations also provide reliable health information.

• National Cancer Institute

      1-800-4-CANCER
      (www.nci.nih.gov)

• American Society of Clinical Oncology

      (www.cancer.net/portal/site/patient)

• National Comprehensive Cancer Network

      (www.nccn.com)

• National Library of Medicine

      (www.nlm.nih.gov/medlineplus/healthtopics.html)

• "Colon Cancer Can Run in the Family," Berk, T, Macrae, F (Eds). Available at www.insight-group.org/links/CRCbook/.

Patient support — There are a number of online forums where patients can find information and support from other people with similar conditions.

• About.com Cancer Forum

      (http://cancer.about.com/forum)

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