Colorectal Cancer

Colorectal cancer begins when abnormal cells on the inner walls of the colon or rectum multiply uncontrollably, forming small growths called polyps. The colon, also known as the large intestine, is part of the digestive system. It’s roughly five feet long and sits at in the abdominal cavity, below the liver and stomach. The final 12 inches of the colon are called the rectum.

Colorectal cancer is very common and it affects both men and women. According to the American Cancer Society, over 130,000 Americans are diagnosed with colorectal cancer every year, and over 50,000 of them die from it. However, colorectal cancer is also highly treatable if caught early. There are over a million colorectal cancer survivors living in America today, and the survival rate for stage I or II is over 85 percent. Because of the impact early detection has on a colorectal cancer prognosis, it is vital for men and women to learn about colorectal cancer symptoms and the importance of regular screening.

Colorectal Cancer Symptoms

Being able to identify symptoms of colorectal cancer improves the chances the disease will be caught in its early stages. However, many of the symptoms are caused by colorectal cancer are also be caused by benign conditions, such as hemorrhoids and IBS. The primary difference is that colorectal cancer symptoms tend to arise very quickly and last longer than symptoms of benign conditions. The most common colorectal cancer signs are:

  • Diarrhea, constipation, and any other changes in bowel habits
  • A consistent feeling that the bowels are full
  • Thin or narrow stools
  • Bright red or very dark stools
  • Cramps and abdominal pain
  • Rectal bleeding
  • Sudden and unexplained weight loss
  • Persistent Fatigue
  • Unexplained anemia (low red-blood cell count)

If patients experience these symptoms for several weeks or if symptoms grow steadily worse, they should consult their doctor to see whether they need a colonoscopy or another form of cancer screening. Though people over 50 are most at risk, colorectal cancer can affect younger people as well, so everyone should be on the watch for these symptoms.

Colorectal Cancer Screening

Rates of colorectal cancer have declined steadily over the past 20 years, mostly due to improved screening techniques. These tests alert doctors when there are polyps in the colon and rectum, so they can be removed before they endanger the patient’s health. The three screening methods used to detect colorectal cancer are:


During a colonoscopy, a doctor examines the colon and rectum using a colonoscope – a thin, flexible tube with a light and camera attached to it. If the doctor discovers a polyp during the exam, specialized tools can be passed through the colonoscope to remove it or take a sample for biopsy. Doctors prescribe laxatives before the test, in order to empty the bowels and ensure the doctor has a clear view of the colon walls. For their own comfort, most patients are sedated during the procedure. Regular colonoscopies lower the risk of death from colorectal cancer by 60-70 percent.


Sigmoidscopies are similar to colonoscopies, except they only examine the rectum and the sigmoid colon (the last third of the large intestine). Doctors perform sigmoidscopies using a sigmoidoscope – a thin, flexible wand with a light and camera attached to it. If the doctor discovers a polyp during the exam, special tools can be inserted through the tube to remove it or collect a sample for biopsy. Regular sigmoidscopies also lower the risk of death from colorectal cancer by 60-70 percent.

Fecal Occult Blood Tests

Polyps have small, fragile blood vessels along their surface. As fecal matter passes through the colon, it often ruptures these vessels, creating bloody fecal matter. Polyps rarely release enough blood to be seen with the naked eye, so fecal occult blood tests use chemicals and antibodies to check for traces of hemme (a component of hemoglobin) in stool samples. Because certain types of food, such as red meat, also contain hemme, doctors require patients to restrict their diet for several days before the test is performed. Regular fecal occult blood tests lower the risk of death from colorectal cancer by 15-33 percent.

The United States Preventive Services Task Force recommends all men and women aged 50-70 years old to receive regular colorectal cancer screenings. However, patients do need to receive every type of screening in order to stay healthy. Patients may receive a fecal occult blood testing once a year, a sigmoidoscopy and fecal occult blood test every 3-5 years, or a colonoscopy every 10 years. Patients with a family history of colorectal cancer should start screening at a younger age and be tested more frequently. 

Colorectal Cancer Treatments

The most common treatment for colorectal cancer is a polypectomy, which is normally performed during a colonoscopy or a sigmoidscopy. The doctor passes a wire loop through the colonoscope and snips the polyp off at its base. Polypectomies are an effective way of treating early stage caners, but if the cancer has progressed further, a surgical resection may be required. During this operation, a surgeon removes the infected section of colon, along with a margin of healthy tissue. The surgeon may also remove a small number lymph nodes. If the cancer has spread to a majority of the colon, a full colectomy may be required. During this operation, all or a significant portion of the colon is removed and the patient is fitted with a colostomy bag.

Radiation therapy is normally as an adjunctive therapy for colorectal cancer, administered along with chemotherapy before or after surgery in order to shrink tumors or eliminate remaining cancer cells. However, if the cancer is confined to the rectum or affixed to the lining of the colon or the abdomen, it may be used directly, either to destroy tumors or relieve symptoms.

Chemotherapy is used to treat all types of colorectal cancers. Like radiation, it is given before surgery, to shrink tumors, or afterwards, to eliminate remaining cancer cells. It’s also used to treat advanced colorectal cancer, when it has spread beyond the bowels to other organs.

Colorectal Cancer Stages

Cancer stages describe how big the cancer has grown and how far it has spread. In order to determine a colorectal cancer stage, doctors examine the tumor to see whether it has grown into the intestinal wall, whether it has infected the lymphatic system, and whether it has metastasized and infected other organs. There are five stages of colorectal cancer, starting with stage 0.

Stage 0

Cancer cells are confined to the intestinal lining, called the mucosa. Doctors refer to this stage as cancer in stitu (in place or position).

Stage I

The cancer has spread beyond the mucosa into the second or third layers of the colon, but has not spread to any lymph nodes or into the surrounding tissue.

Stage II

The cancer has grown large enough to penetrate the wall of the colon and it may have spread into the lining of the abdomen or its surrounding structures. However, it has not infected any lymph nodes.

Stage III

The cancer has infected 1-4 lymph nodes and spread deep into the muscular layers of the intestines and into surrounding tissue. However, it is still confined to the bowels and abdomen.

Stage IV

The cancer has metastasized and spread to distant organs, such as the bones, liver, and lungs.

Colorectal cancer is a recurrent disease. Though it is possible to successfully treat it at every stage, there is always the possibility that it will return, which is why colorectal cancer survivors should always continue to receive regular screenings from their doctor.