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Colorectal cancer

Cancer and oncological diseases Proctology

Colorectal cancer: symptoms, causes, treatment and prognosis

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What is colorectal cancer?

Colorectal cancer is a type of cancer that affects the digestive tract. Because early detection offers the best hope of curing this cancer, understanding its risk factors and symptoms can help save lives. People in high-risk groups should make appropriate lifestyle changes and get screened for colorectal cancer at recommended intervals.


Colorectal cancer is defined as a type of cancer that starts in either the colon or the rectum. It is also known as colon cancer or cancer of the large bowel.

Colorectal cancer–which is also called bowel cancer–occurs when abnormal cancerous cells begin to grow within the large intestine. In 2009, colorectal cancer accounted for nearly 50,000 deaths in the United States, based upon estimates provided by the National Cancer Institute (NCI). Speak with your doctor as soon as possible if you develop any signs and symptoms of colorectal cancer.

Symptoms of colorectal cancer

Nausea or Vomiting

If you have colorectal cancer, you can experience frequent episodes of nausea or vomiting as a result of this condition. Cancerous cell growth within the lining of the large intestine can cause you to experience stomach pain, cramping or bloating. Such symptoms are typically mild to moderate in severity and can be uncomfortable.

Diarrhea or Constipation

Colorectal cancer can cause noticeable changes in your bowel habits, explains the NCI. Patients with this condition can develop bouts of frequent, watery or loose stool production (diarrhea) or may find it abnormally difficult to have a bowel movement (constipation). Such symptoms can also be associated with abdominal pain, cramping or bloating.

Stool Changes

Irritation within the intestinal tract due to cancerous cell growth can cause blood to appear within the stool. If this occurs, your stools can appear very dark or bright red in color.

As cancerous cells build up along the colon, your intestinal tract can begin to narrow. As a result, your stools can appear abnormally thin if you have this condition.

Weight Loss

Intestinal irritation caused by colorectal cancer can interfere with the ability of your body to absorb nutrients and fluids from the food that you consume. Additional signs and symptoms of colorectal cancer, such as nausea, diarrhea or constipation, can cause you to experience a decrease in your normal appetite.

Diarrhea can also cause you to become malnourished or dehydrated. As a result of these symptoms, some patients with colorectal cancer can experience unintentional weight loss.


If your body is unable to obtain the needed nutrients from your daily dietary intake due to colorectal cancer, your cells will not receive the energy they need to function normally. When this occurs, your body cannot provide an adequate supply of energy to allow you to complete your normal activities.

This can cause patients with colorectal cancer to feel abnormally fatigued or lethargic on a daily basis. If you have this condition, symptoms of fatigue can prevent you from completing the responsibilities associated with your work, social or school activities.

Symptoms of Metastatic Colorectal Cancer

Colorectal cancer occurs when cells that line the large intestine and rectum develop genetic mutations. These mutations cause the cells to grow more normally than usual. Although colorectal cancer begins confined to one tumor, these cells may develop the ability to invade other areas of the body. These metastases can either move to other portions of the colon/rectum or can infiltrate other tissues.

General symptoms of a cancer in the colon

One of the hazards of colorectal cancer is its ability to spread. Colorectal cancer may spread to other portions of the colon and the rectum, or to other nearby organs. Many of the general (or constitutional) symptoms of metastatic colorectal cancer are shared by other forms of metastatic cancer.

They include pain, either in the abdomen, pelvis or around the rectum, depending on the cancer’s location. It may also cause extreme fatigue and weight loss that is coupled with a loss of appetite.

Finally, metastatic cancer may also cause increased urinary frequency.

Symptoms of Spread Throughout The Colon

Because the colon and rectum are connected, the easiest site of spread of colorectal cancer is to other parts of the colon or to the rectum. If the cancer spreads to the right portion of the colon (which is the first part and is closest to the small intestine, large amounts of blood may appear in the feces, which can cause fatigue and anemia. Spread to the left portion of the colon (the end portion) can cause obstruction of the bowel, leading to constipation alternating with diarrhea. Streaks of blood may also appear in the feces.

What is a colorectal cancer

Spread to the rectum will cause bleeding during defecation as well as a feeling of incomplete emptying of the bowels.

Symptoms of colorectal cancer Spread to Other Tissues

In some cases, colorectal cancer can spread outside of the colorectal system. The most common site for this is the liver. Liver metastases can cause yellowing of the skin and eyes (also known as jaundice). The liver may also become swollen (known as hepatomegaly), and fluid may accumulate in the abdomen.

In severe cases, the patient will also develop problems with blood clotting. In addition to liver spread, colorectal cancer can also spread throughout the lymphatic system to the lymph nodes. The most common site for lymph node involvement is the supraclavicular lymph node, which will cause the formation of small hard lumps just above the collar bone.

Signs & Symptoms of End Stage Metastatic Colorectal Cancer

Metastatic colorectal cancer is the cancer of the colon or the rectum, which has spread to other organs in the body. Fewer than 20 percent of patients diagnosed with metastatic colorectal cancer survive more than five years following the diagnosis of the disease, according to the book “Clinical Oncology.” The end stage of this cancer involves specific signs and symptoms.


Patients with metastatic colorectal cancer will experience pain in the organ(s) that the cancer has spread to. For instance, patients may experience severe, continuous and localized pain in the rib or the back due to the presence of metastatic colorectal cancer in the bone.

Patients also experience headache, dizziness, seizure and unsteadiness if the cancer has spread to the brain. If the lungs are involved, patients may experience shortness of breath.

Jaundice or abdominal pain might indicate the involvement of the liver, according to

Weight loss

Patients with metastatic colorectal cancer tend to experience unexplained weight loss. Patients also likely to experience lack of energy and constant fatigue.

Facts about colorectal cancer

Often Starts with Pre-Cancerous Growths

While the exact cause of colon cancer is not known, physicians from the Mayo Clinic report that precancerous growths can eventually turn into colorectal cancer. These growths can appear in the form of inflammatory polyps, adenomas or hyperplastic polyps. These clumps of cells grow on the wall of the large bowel.

Can be Impacted by Diet

The University of Maryland Medical Center reports that most people with colorectal cancer are over 50 years old. However, colorectal cancer can affect anyone of any age. People with an immediate family history of cancer are at an increased risk for developing the disease.

If someone has a history of polyps or has already had cancer of the colon, the risk for developing colorectal cancer in the future is increased. Cancer of the uterus, breast or ovaries is also a risk factor for colorectal cancer. Some risk factors for this disease can be reduced.

Since colorectal cancer has been linked to diets that are high in fat and low in fiber, the American Cancer Society recommends eating at least five servings of fruits and vegetables each day, choosing whole-grain foods instead of refined grains and limiting intake of processed red meats.

Fiber can be added to the diet by eating legumes, nuts, carrots, whole-grain breads, broccoli, apples, oranges and bananas.

Includes Specific Signs and Symptoms

Most of the signs and symptoms of colorectal cancer affect the digestive system. They include rectal bleeding, stomach pain, decreased appetite, diarrhea, constipation, narrowing of the stool and vomiting. General signs and symptoms such as jaundice, weakness and fatigue may also occur.

Can Be Treated

The American Cancer Society indicates that colorectal cancer may be treated with chemotherapy, monoclonal antibodies, radiation therapy or surgery. Two or more treatments may be used, depending on how advanced the cancer is. Surgery is often used in the early stages of colon cancer and involves removing the cancer and some normal tissue.

Symptoms of colorectal cancer

Very early colorectal cancers may be removed with a colonoscope, which helps patients avoid the risks and recovery period of abdominal surgery. If radiation therapy is used, it may be administered in the form of external-beam radiation or internal radiation. These therapies can cause fatigue, nausea, diarrhea and irritation of the rectum or bladder.

Chemotherapy involves the administration of oral or intravenous drugs used to kill cancer cells. This treatment causes unpleasant side effects such as nausea, vomiting, diarrhea, hair loss, loss of appetite, easy bleeding and bruising, and severe fatigue.

Prognosis Depends on Early Detection

The prognosis for colorectal cancer depends on how early the disease is detected. The Merck Manual Home Edition cites a 90 percent cure rate when the cancer is found only in the lining of the colon. When cancer has extended through the wall of the bowel, the cure rate drops to 70 percent.

The cure rate is only 30 to 50 percent if cancer has advanced to lymph nodes contained in the abdomen.

Detected Through Screening

Colorectal cancer prevention involves making lifestyle changes, avoiding substances linked to cancer development and getting regular colorectal cancer screenings. Since a diet that is low in fiber and high in fat and calories is associated with colorectal cancer, dietary changes should be made. The Centers for Disease Control recommends screening after the age of 50.

The fecal occult blood test, which checks for blood in the stool, should be done yearly. Flexible sigmoidoscopy should be done at five-year intervals.

Colonoscopy should be done every 10 years. People with an increased risk of developing colorectal cancer should be tested more frequently and should be screened at a younger age.

Colorectal cancer treatment

Colorectal cancer treatment options include surgery, radiation therapy, chemotherapy and biological therapy.

The colon is part of the digestive system. It’s responsible for absorbing nutrients from our diet. The first six feet of the large intestine are the large bowel or colon; the last six inches are called the rectum and anus. Colorectal cancer is a disease in which malignant cancer cells form in the tissue of the intestinal wall. The type of treatment that you may receive depends on the stage and severity of your cancer, as well as your overall health.

Surgical removal of colorectal cancer

There are several different types of surgical procedures that may be used for the treatment of colorectal cancer. Surgery (removing the cancer in an operation) is the most common treatment for all stages of colon cancer.

When you have colorectal cancer, your doctor may recommend surgical treatment to remove the cancerous cells from your body. There are several different types of surgical procedures utilized to treat this form of cancer. In the early stages of colorectal cancer, your surgeon may be able to remove the cancerous cells from the surface of the colon using a surgical instrument called a colonoscope. This allows your surgeon to access the cancerous tissue through your anus, rather than through surgical incisions within the abdomen.

With more advanced forms of colorectal cancer, your surgeon may recommend colon surgery (colectomy) – a procedure in which the portion of the colon that contains cancerous cells is removed through incisions in the abdomen.

If your rectum contains cancerous cells, your surgeon may have to remove your anus by performing a proctectomy, abdominal perineal resection or pelvic exenteration.

These types of surgical procedures are typically performed through incisions in the abdomen. A colostomy – an opening at the front of the stomach to allow waste from the colon to leave the body, is required if you undergo any surgical procedure that involves removal of the anus. Such procedures can cause a number of side effects, which should be discussed with your doctor before selecting this form of cancer treatment.

A local excision may be used if the cancer is small. A tube is inserted in the rectum and the cancer is removed. If the cancer is more advanced, a resection may be necessary. The affected area of the colon is removed, as well as the surrounding tissue. In some cases, the two areas of the colon may not be able to be reattached and a colostomy may be necessary. In some cases, a colostomy may be reversed at a later date.

Other surgical options include radio-frequency ablation and cryosurgery, in which high-frequency waves or freezing of the cancer cells is used.

Chemotherapy of colorectal cancer

Chemotherapeutic agents are medications used to kill cancer cells and stop them from dividing. They may be taken orally or intravenously. Chemo is sometimes used before surgery to try to shrink the cancer and make surgery easier, says the American Cancer Society. Some common chemotherapeutic agents used to treat colon cancer are 5-Fluorouracil (5-FU) and Avastin.

Chemotherapy–is a type of colorectal cancer treatment that utilizes oral or intravenous (IV) drugs to destroy cancer cells and to prevent them from replicating within the body.

Patients with colorectal cancer may receive chemotherapy treatment prior to surgery to help decrease the size of cancerous tumors within the colon. Doing so can make the surgical procedure easier for your surgeon to perform and can help ensure that all of the cancerous cells are removed. Side effects associated with chemo include hair loss, mouth sores, decreased appetite, fatigue or nausea and typically resolve once treatment has ended. If you have questions or concerns regarding chemo treatment, speak with your doctor for further guidance.


Radiation therapy uses high-beam radioactive waves to kill cancer cells. The radiation may come from outside the body (external radiation) or from radioactive materials put right in the tumor (brachytherapy or internal or implant radiation), the American Cancer Society says. Radiation may be helpful after surgery to kill any of the cancer cells that may have been left behind during surgery.

Radiation therapy is a type of colorectal cancer treatment that utilizes high-energy x-rays to destroy the abnormally replicating cancer cells. These high-energy rays can be applied to the cancer cells from the outside of the body (external radiation) or from within the cancerous tumor (implant radiation).

Patients with colorectal cancer may have radiation therapy following surgery to ensure that all of the cancer cells are killed. Side effects of radiation therapy, including skin irritation, nausea, diarrhea and fatigue, should be discussed in detail with your doctor before beginning this form of cancer treatment.

Colorectal cancer is a type of disease that develops when abnormal cancerous cells begin to grow within the lining of your colon (large intestine) and rectum.

Though the cause of this disease is unknown, certain risk factors, such as increased age, smoking or a high-fat diet, can make you more susceptible to developing colorectal cancer. If you have been diagnosed with this condition, speak with your doctor to discuss the colorectal cancer treatment options that are available to you.

Biological Therapy

If you have colorectal cancer that has spread to other parts of your body, your doctor may recommend the use of biological therapy to treat your cancer. Biological therapy involves the IV administration of monoclonal antibodies that specifically target and bind to cancerous colorectal cells.

These monoclonal antibodies can prevent cancerous cells from replicating, thereby inhibiting the spread of cancer throughout your body. Side effects of biological therapy can include skin rash, diarrhea, breathing problems, fever or skin rash and should be discussed with your doctor before you begin treatment.


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Julia Anderson
Doctor oncologist with 17 years of experience. Specializes on modern methods of preventive maintenance, treatment and rehabilitation, various diagnostics including mammography decoding, breast ultrasound.