Conditions

Colorectal cancer begins in the colon or rectum, in the lower part of the body’s digestive system. During digestion, food moves through the stomach and the small intestine into the colon. The colon absorbs water and nutrients from the food and stores waste matter. Stool moves from the colon into the rectum before it leaves the body. Colon cancer is cancer of the large intestine (colon), the lower part of the digestive system. Rectal cancer is cancer of the last several inches of the colon. Together, they’re often referred to as colorectal cancers.

Most cases of colon cancer begin as small, noncancerous (benign) clumps of cells called adenomatous polyps. Over time, some of these polyps become colon cancers.
Polyps may be small and produce few, if any, symptoms. That’s why doctors recommend regular screening tests to help prevent colon cancer by identifying polyps before they become colon cancer. Colorectal cancer is the third most common type of cancer in men and women in the United States. The incidence of colorectal cancer has dropped with the use of colonoscopies and fecal occult blood tests, which check for blood in the stool.

In most cases, it’s not clear what causes colon cancer. It’s known that colon cancer occurs when healthy cells in the colon become altered. Consumption of red meat and alcohol, obesity and low fiber diet are the most important risk factors. Healthy cells grow and divide in an orderly way to keep the body functioning normally. But when a cell is damaged and becomes cancerous, cells continue to divide — even when new cells aren’t needed. These cancer cells can invade and destroy normal tissue nearby. And cancerous cells can travel to other parts of the body.

Colon cancer usually begins as clumps of precancerous cells (polyps) on the inside lining of the colon. Polyps can appear mushroom-shaped, or they can be flat or recessed into the wall of the colon. Removing polyps before they become cancerous can prevent colon cancer.

Inherited gene mutations that increase the risk of colon cancer can be passed through families, but these inherited genes are linked to only a small percentage of colon cancers. Inherited gene mutations don’t make cancer inevitable, but they may increase an individual’s risk of cancer significantly.

Symptoms
The early stages of colorectal cancer offer few, if any, symptoms. However, these signs and symptoms can include:

• Abdominal discomfort (frequent gas, bloating, fullness, cramps and pain)
• Blood in the stool
• Changes in bowel habits
• Fatigue
• Feeling that the bowel will not empty completely
• Pain with bowel movement
• Problems related to blood loss (anemia, weakness, shortness of breath, pounding heart, chest pain and intolerance to exercise)
• Unexplained weight loss

Many people with colon cancer experience no symptoms in the early stages of the disease. When symptoms appear, they’ll likely vary, depending on the cancer’s size and location in the large intestine.

Treatments

USC Norris is one of the global leaders in biomarker identification and drug treatment for colorectal cancer. The clinic’s comprehensive translation research program takes advantage of its pre-clinical models in colorectal cancer, allowing the fast translation of the latest findings from the bench into practice.

Our care is also unique in its deep understanding of cultural diversity and differences in efficacy and toxicity of drugs in different ethnic backgrounds. USC Norris patients receive a wide spectrum of straight-of-the-art treatments compassionately tailored to their individual situation and needs. In addition, the cancer center has successfully integrated predictive and prognostic molecular marker in its treatment practices and to have introduced new successful drugs into the clinic.

The clinic also provides a genetic counseling service, which identifies hereditary genetic cancer and delivers a profile of family members who may be potentially at risk of cancer through genetic tests.

The type of treatment the doctor recommends will depend largely on the stage of the cancer. The three primary treatment options are: surgery, chemotherapy and radiation therapy.

Surgery for early-stage colon cancer
The doctor may be able to remove the cancer completely during a colonoscopy if the detected cancer is small, localized in a polyp and in a very early stage. Larger polyps may be removed using endoscopic mucosal resection. If the pathologist determines that it’s likely that the cancer was completely removed, there may be no need for additional treatment.

Polyps that can’t be removed during a colonoscopy may be removed using laparoscopic surgery. During this procedure, the surgeon performs the operation through several small incisions in the abdominal wall, inserting instruments with attached cameras that display the patient’s colon on a video monitor. The surgeon may also take samples from lymph nodes in the area where the cancer is located.

Surgery for invasive colon cancer
If the colon cancer has grown into or through the colon, the surgeon may recommend a partial colectomy to remove the part of the colon that contains the cancer, along with a margin of normal tissue on either side of the cancer. Nearby lymph nodes are usually removed and tested for cancer.

The surgeon is often able to reconnect the healthy portions of the colon or rectum. But when that’s not possible, for instance if the cancer is at the outlet of the rectum, the patient may need to have a permanent or temporary colostomy. This involves creating an opening in the wall of the abdomen from a portion of the remaining bowel for the elimination of body waste into a special bag. Sometimes the colostomy is only temporary, allowing the colon or rectum time to heal after surgery. In some cases, the colostomy may be permanent.

Surgery for advanced cancer
If the cancer is very advanced or the patient’s overall health is very poor, the surgeon may recommend an operation to relieve blockage in the colon or other conditions in order to improve the symptoms. This surgery isn’t done to cure cancer, but instead to relieve signs and symptoms, such as bleeding and pain.

In specific cases where the cancer has spread only to the liver – and if the overall health is good – the doctor may recommend surgery to remove the cancerous lesion from the liver. Chemotherapy may be used before or after this type of surgery. This treatment may improve the prognosis.

For treatment of both benign and malignant colorectal disease, the team offers special surgical expertise, including:

Continent Ileostomy
These intestinal reservoirs allow patients to store intestinal waste and control its charge from the body after coloprotectomy, eliminating the need for an external appliance. These pouch procedures involve the creation of an internal pouch for storage and a valve for continence. The pouch is emptied through a catheter inserted into the pouch, allowing its contents to flow directly into the toilet.

Ileal pouch-anal anastomosis
In this procedure, surgeons create a pouch out of the terminal ileum and sew it to the anal muscles. Patients can then defecate through their anus in the usual way and maintain the ability to defer defecation until a socially convenient time.

Laparoscopically assisted surgery
Colorectal surgeons have expertise in performing laparoscopically assisted colectomy – an advanced procedure that allows surgeons to remove segments of the colon through minimally invasive surgical techniques. Preliminary studies indicate this procedure may reduce pain and the length of hospitalization.

Robotic Surgery
Robotic surgery is surgery that is performed using very small tools attached to a robotic arm. The surgeon controls the robotic arm with a computer. For patients, robotic surgery, when appropriate, provides a minimally invasive treatment choice that often leads to smaller incisions (less than one inch), less pain and less need for medication, minimal scarring and reduced bleeding. Other advantages for robotic surgery are a shorter hospital stay and faster recovery time for patients to return to normal daily routines – often shortening these times in half.

Novel Targeted Therapies Chemotherapy
Novel Targeted Therapies Chemotherapy uses medication to destroy cancer cells. Chemotherapy for colon cancer is usually given after surgery if the cancer has spread to the lymph nodes. In this way, chemotherapy may help reduce the risk of cancer recurrence. Chemotherapy can also be given to relieve symptoms of colon cancer that has spread to other areas of the body. Chemotherapy may be used before surgery to shrink the cancer before an operation. For patients with rectal cancer, chemotherapy is typically used along with radiation therapy.

Patients with advanced colon cancer may benefit from medications that target specific defects that allow cancer cells to grow. Examples of these medications include bevacizumab (Avastin®), cetuximab (Erbitux®), panitumumab (Vectibix®) and regorafenib (Stivarga®). Targeted drugs can be given along with chemotherapy or alone. Targeted drugs are typically reserved for people with advanced colon cancer. Some people benefit by targeted drugs, while others don’t. Researchers are trying to determine who is most likely to benefit from targeted drugs. Until then, doctors carefully weigh the limited benefit of targeted drugs against the risk of side effects and cost when deciding whether to use these treatments.

As a NCI-funded Cancer Center, we have a highly effective clinical trial program bringing the latest new drugs into the clinic for our patients with colorectal cancer. We are funded through NIH/NCI and our industry partner to develop cutting edge clinical trials bringing the most promising drugs into the clinic. USC was part of the development of the latest approved drug for this disease including TAS102 and regorafenib.

Genetic Fingerprinting and Advanced Research
As one of the country’s leading programs in cancer genetics and cancer treatment, our colorectal oncologists can create a genetic fingerprint of each patient’s particular cancer, which often results in reduced side effects from treatment. We provide personalized treatment and medicine at the genetic level – fighting colorectal cancer down to its DNA.

Our researchers have also traced the origins of colorectal cancer and, for the first time, discovered why tumor cells become “good” or “bad.” Finding these new clues one the behavior of colorectal cancer tumors can lead to improved cancer treatment and has the potential to stop the tumors before they start.

Radiation therapy
Radiation therapy uses powerful energy sources, such as X-rays, to kill cancer cells that might remain after surgery, to shrink large tumors before an operation so that they can be removed more easily, or to relieve symptoms of colon cancer and rectal cancer. Radiation therapy is rarely used in early-stage colon cancer, but is a routine part of treating rectal cancer, especially if the cancer has penetrated through the wall of the rectum or traveled to nearby lymph nodes. Radiation therapy, usually combined with chemotherapy, may be used after surgery to reduce the risk that the cancer may recur in the area where it began.

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