Colorectal cancer (also known as colon cancer, rectal cancer or bowel cancer) is the development of cancer in the colon or rectum (parts of the large intestine). It is due to the abnormal growth of cells that have the ability to invade or spread to other parts of the body. Colon cancer is cancer of the large intestine (colon), the lower part of your digestive system. Rectal cancer is cancer of the last several inches of the colon. Together, they're often referred to as colorectal cancers. Signs and symptoms may include blood in the stool, a change in bowel movements, weight loss, and feeling tired all the time.
With 655,000 deaths worldwide per year, it is the third most common form of cancer and the second leading cause of cancer-related death in the Western world, and the second leading cause of cancer-related deaths in the United States (after lung cancer). According to the American Cancer Society, almost 150,000 new cases of colorectal cancer were diagnosed and approximately 50,000 people died from the disease last year.
Risk factors for colorectal cancer include lifestyle, older age, and inherited genetic disorders that only occur in a small fraction of the population.
Other risk factors include diet, smoking, alcohol, lack of physical activity, family history of colon cancer and colon polyps, presence of colon polyps, race, exposure to radiation, and even other diseases such as diabetes, obesity.
A diet high in red, processed meat, while low in fiber increases the risk of colorectal cancer.
The risk of developing colorectal cancer also increases with age. Men and women aged 50 and older are at an increased risk for developing colorectal cancer, and should be screened at least every 5-10 years. Some people are at a higher risk and should be screened at an age younger than 50, including those with a personal or family history of inflammatory bowel disease, colorectal cancer or polyps.
An American Cancer Society study found that Women who smoked were more than 40% more likely to die from colorectal cancer than women who never had smoked. Male smokers had more than a 30% increase in risk of dying from the disease compared to men who never had smoked.
The comparison of colorectal cancer incidence in various countries strongly suggests that sedentarity, overeating (i.e., high caloric intake), and perhaps a diet high in meat (red or processed) could increase the risk of colorectal cancer. In contrast, a healthy body weight, physical fitness, and good nutrition decreases cancer risk in general. Accordingly, lifestyle changes could decrease the risk of colorectal cancer as much as 60-80%.
Colorectal cancer often has no symptoms until the disease has progressed beyond its earliest stages. The first symptoms of colon cancer are usually vague, like bleeding, weight loss, and fatigue (tiredness). Local (bowel) symptoms are rare until the tumor has grown to a large size. Generally, the nearer the tumor is to the anus, the more bowel symptoms there will be. Some potential signs and symptoms of colorectal cancer to watch for and ask your physician about include:
After colon cancer has been diagnosed, tests are done to find out if cancer cells have spread within the colon or to other parts of the body. The following stages are used for colon cancer:
Using the TNM system, the "T" plus a letter or number (0 to 4) is used to describe how deeply the primary tumour has grown into the bowel lining. Some stages are also divided into smaller groups that help describe the tumour in even more detail. TX: The primary tumour cannot be evaluated.
The 'N' in the TNM system stands for lymph nodes. The lymph nodes are tiny, bean-shaped organs located throughout the body. Lymph nodes help the body fight infections as part of the immune system. Lymph nodes near the colon and rectum are called regional lymph nodes. All others are distant lymph nodes that are found in other parts of the body. NX: The regional lymph nodes cannot be evaluated.
The 'M' in the TNM system describes cancer that has spread to other parts of the body, such as the liver or lungs. This is called distant metastasis.
The treatment depends on the staging of the cancer. When colorectal cancer is caught at early stages (with little spread) it can be curable. However when it is detected at later stages (when distant metastases are present) it is less likely to be curable.
Most colorectal cancers begin as a polyp, which is a tissue growth that starts in the lining of the colon or rectum. Identifying and removing a polyp early in its development may prevent it from becoming cancerous. Surgery remains the primary treatment while chemotherapy and/or radiotherapy may be recommended depending on the individual patient's staging and other medical factors.
Some cancers, if caught very early, can be treated with a colonoscopy and without the need for surgery.
Newer more advanced minimally invasive techniques, such as laparoscopic or endoscopic resections, allow more patients to undergo curative surgery without the need for lengthy hospital stays or a stoma ("bag").
With these techniques, pain is considerably less and patients are able to return to work and their daily activities in significantly less time than with standard operations.
Of cancers that affect both men and women, colorectal cancer is the second leading cause of cancer-related deaths in the United States and the third most common cancer in men and in women. In 2011;
*Incidence counts cover about 99% of the U.S. population; death counts cover about 100% of the U.S. population.
Left or Right Primary Tumor Location Predicts Colon Cancer Survival Rate - Patients with colorectal cancer whose primary tumor is situated on the left side of the colon survive significantly longer than patients whose cancer starts on the right side.