Colorectal cancer – one of the most common types of cancer
Colorectal cancer (or CRC), also known as cancer of the large intestine, bowel cancer, rectal cancer or colon cancer, is a type of cancer that results from uncontrolled cell growth in the large intestine, colon or caecum.
The disease progression is often slow, happening over several years, and starts as a protruding growth of tissue, known as a polyp, which starts in the mucous membrane and then grows into the intestinal cavities. Polyps can be cancerous, i.e. capable of developing into a cancer unless removed. The cancer may eventually break through the wall of the intestine and spread to other organs. This is known as metastatic colorectal cancer (mCRC).
Colorectal cancer is the third most common type of cancer affecting both men and women. The global incidence (the number of new patients diagnosed every year) for this type of cancer is around 1,9 million patients per year.
Causes – partially enviromental and hereditary
As with most other types of cancer, there is no known single triggering factor for colorectal cancer. Hereditary factors and diet are thought to affect the risk level, while smoking and lifestyles resulting in obesity increase the risk.
The prognosis for patients with colorectal cancer has improved over the past decade, but the prognosis for survival is still worse than for breast or prostate cancer and is the second most common cause of cancer-related deaths. The prognosis for survival is, however, very good if it is diagnosed early. Health checks involving screening for blood in excrement allow colorectal cancer to be detected at an earlier stage, reducing the mortality rate. Late stage patients, when the cancer has spread to other organs (metastases) have a poorer prognosis and a substantially higher mortality rate. Only 10% of patients with mCRC are alive five years after diagnosis.