Colorectal cancer is the fourth most common cancer in the united states. More than 135,000 Americans are diagnosed with colorectal cancer each year.
Colorectal cancer is cancer that starts in the colon and/or the rectum. These cancers can also be named colon cancer or rectal cancer, depending on where they start. Colon cancer and rectal cancer are often grouped together because they have many features in common. Cancer starts when cells in the body start to grow out of control. Cells in nearly any part of the body can become cancerous and can spread to other areas of the body.
Colorectal cancer has many symptoms, but they might not show right away. If it does cause symptoms early they might be: a change in bowel habits, such as diarrhea, constipation, or narrowing of the stool, that lasts for more than a few days, a feeling that you need to have a bowel movement which is not relieved by voiding, rectal bleeding with bright red blood, and/or blood in the stool, which might make the stool look dark. Colorectal cancers can also bleed into the digestive tract. Sometimes the blood can be seen in the stool or make it look darker, but often the stool looks normal. Over time, the blood loss can build up and can lead to low red blood cell counts (anemia). Many of these symptoms can be caused by conditions other than colorectal cancer, such as infection, hemorrhoids, or irritable bowel syndrome. If the patient has any of these complications, it’s important to see their doctor right away so the cause can be found and treated, if needed.
Doctors use many tests to find or diagnose colorectal cancer. The doctors also do tests to see if the cancer has spread to another part of the body from where it started. If this happens, it is called metastasis. Metastasis is the development of secondary malignant growths at a distance from the primary site of cancer. Imaging tests can show if the cancer has spread to other parts of the body. Doctors may also do tests to learn which treatments would work best on the patient. The doctor might consider these factors when choosing a diagnostic test: the type of cancer suspected, the signs and symptoms the patient is having, the age and medical condition of the patient, the medical and family history, and the results of earlier tests that were done. In addition to a physical examination, the doctor might order a colonoscopy, biopsy, blood test, a MRI, and many other tests to diagnosis colorectal cancer. The most popular way to diagnosis blood in the patients’ stool is by a fecal occult blood screening. Blood can be detected in the feces by of a number of different methods, but all the published population-based screening trials used a guaiac-based test. Guaiac tests detect peroxidases associated with heme that enters the gastrointestinal tract as hemoglobin or myoglobin in food or as red cells from bleeding pathology. In the colon the heme loses its peroxidase activity by the action of the microflora so that guaiac tests are more likely to pick up distal than proximal sources of bleeding. A positive guaiac test is more likely to indicate colonic rather than gastric pathology. A colonoscopy allows the doctor to look inside the entire rectum and colon while a patient is sedated. Other tests can suggest that cancer is present, but only a biopsy can make a definite diagnosis of colorectal cancer.
The type of treatment the doctor recommends will depend on the stage of the patient’s cancer. Three primary treatment options are surgery, chemotherapy and radiation. If the patient’s colorectal cancer is very small, the doctor may recommend a minimally invasive approach to surgery. If the cancer is small, localized and completely contained within a polyp and in a very early stage, the doctor might be able to remove it completely during a colonoscopy. To remove larger polyps may require also taking a small amount of the lining of the colon or rectum in a procedure called an endoscopic mucosal resection. Endoscopic mucosal resection is a procedure to remove early-stage cancer and precancerous growths from the lining of the digestive tract. Polyps that can't be removed during a colonoscopy may be removed using laparoscopic surgery. In this procedure, the surgeon performs the operation through several small incisions in the patients’ abdominal wall, inserting instruments with attached cameras that display the colon on a video monitor. The surgeon may also take samples from lymph nodes in the area where the cancer is located. Chemotherapy uses drugs to destroy cancer cells in the patients’ body. Chemotherapy for colon cancer is usually given after surgery if the cancer has spread to lymph nodes. In this way, chemotherapy may help reduce the risk of cancer recurrence and death from cancer. Sometimes chemotherapy may be used before surgery as well, with the goal of shrinking the cancer before an operation. Chemotherapy before surgery is more common in rectal cancer than in colon cancer. Radiation therapy uses powerful energy sources, such as x-rays, to kill cancer cells, 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 either alone or combined with chemotherapy is one of the standard treatment options for the initial management of rectal cancer followed by surgery.
Every patient is different and responds differently to the treatment. However, with prompt and appropriate treatment, the outlook for a person with colorectal cancer is hopeful. The survival rate for people with colorectal cancer depends on the extent of the cancer at the time of diagnosis and the individual’s response to treatment. In addition, many new discoveries have the potential for improving the treatment of colorectal cancer, as well as the prognosis. Several factors determine how well a person will do after treatment for colorectal cancer. The stage of the cancer is one of the many factors. This is the most critical factor. The stage of your cancer when diagnosed helps determine the severity of the condition. Lower staged conditions (stages 0, i, ii) are characterized by cancers that have not spread to other organs in the body or lymph nodes. The survival rate goes down with higher staged cancers. The lymphatic system helps coordinate the immune system’s function to protect the body from foreign substances. The more lymph glands that were affected by the cancer, the more likely your cancer will recur. Chemotherapy may be needed in cases where lymph nodes are involved. Another factor is if the cancer has spread to other organs. If the colorectal cancer is advanced, it may spread to other organs, such as the liver or lungs. In this case, additional chemotherapy or radiation may be needed to help delay the further spread of the cancer. Many people who have colorectal cancer live normal lives, but others might not.